1 /*
2  * Copyright © 2014 Red Hat
3  *
4  * Permission to use, copy, modify, distribute, and sell this software and its
5  * documentation for any purpose is hereby granted without fee, provided that
6  * the above copyright notice appear in all copies and that both that copyright
7  * notice and this permission notice appear in supporting documentation, and
8  * that the name of the copyright holders not be used in advertising or
9  * publicity pertaining to distribution of the software without specific,
10  * written prior permission.  The copyright holders make no representations
11  * about the suitability of this software for any purpose.  It is provided "as
12  * is" without express or implied warranty.
13  *
14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20  * OF THIS SOFTWARE.
21  */
22 
23 #include <linux/bitfield.h>
24 #include <linux/delay.h>
25 #include <linux/errno.h>
26 #include <linux/i2c.h>
27 #include <linux/init.h>
28 #include <linux/kernel.h>
29 #include <linux/random.h>
30 #include <linux/sched.h>
31 #include <linux/seq_file.h>
32 #include <linux/iopoll.h>
33 
34 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
35 #include <linux/stacktrace.h>
36 #include <linux/sort.h>
37 #include <linux/timekeeping.h>
38 #include <linux/math64.h>
39 #endif
40 
41 #include <drm/display/drm_dp_mst_helper.h>
42 #include <drm/drm_atomic.h>
43 #include <drm/drm_atomic_helper.h>
44 #include <drm/drm_drv.h>
45 #include <drm/drm_print.h>
46 #include <drm/drm_probe_helper.h>
47 
48 #include "drm_dp_helper_internal.h"
49 #include "drm_dp_mst_topology_internal.h"
50 
51 /**
52  * DOC: dp mst helper
53  *
54  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
55  * protocol. The helpers contain a topology manager and bandwidth manager.
56  * The helpers encapsulate the sending and received of sideband msgs.
57  */
58 struct drm_dp_pending_up_req {
59 	struct drm_dp_sideband_msg_hdr hdr;
60 	struct drm_dp_sideband_msg_req_body msg;
61 	struct list_head next;
62 };
63 
64 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
65 				  char *buf);
66 
67 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
68 
69 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
70 				     int id,
71 				     struct drm_dp_payload *payload);
72 
73 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
74 				 struct drm_dp_mst_port *port,
75 				 int offset, int size, u8 *bytes);
76 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
77 				  struct drm_dp_mst_port *port,
78 				  int offset, int size, u8 *bytes);
79 
80 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
81 				    struct drm_dp_mst_branch *mstb);
82 
83 static void
84 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
85 				   struct drm_dp_mst_branch *mstb);
86 
87 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
88 					   struct drm_dp_mst_branch *mstb,
89 					   struct drm_dp_mst_port *port);
90 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
91 				 u8 *guid);
92 
93 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
94 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
95 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
96 
97 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
98 						 struct drm_dp_mst_branch *branch);
99 
100 #define DBG_PREFIX "[dp_mst]"
101 
102 #define DP_STR(x) [DP_ ## x] = #x
103 
drm_dp_mst_req_type_str(u8 req_type)104 static const char *drm_dp_mst_req_type_str(u8 req_type)
105 {
106 	static const char * const req_type_str[] = {
107 		DP_STR(GET_MSG_TRANSACTION_VERSION),
108 		DP_STR(LINK_ADDRESS),
109 		DP_STR(CONNECTION_STATUS_NOTIFY),
110 		DP_STR(ENUM_PATH_RESOURCES),
111 		DP_STR(ALLOCATE_PAYLOAD),
112 		DP_STR(QUERY_PAYLOAD),
113 		DP_STR(RESOURCE_STATUS_NOTIFY),
114 		DP_STR(CLEAR_PAYLOAD_ID_TABLE),
115 		DP_STR(REMOTE_DPCD_READ),
116 		DP_STR(REMOTE_DPCD_WRITE),
117 		DP_STR(REMOTE_I2C_READ),
118 		DP_STR(REMOTE_I2C_WRITE),
119 		DP_STR(POWER_UP_PHY),
120 		DP_STR(POWER_DOWN_PHY),
121 		DP_STR(SINK_EVENT_NOTIFY),
122 		DP_STR(QUERY_STREAM_ENC_STATUS),
123 	};
124 
125 	if (req_type >= ARRAY_SIZE(req_type_str) ||
126 	    !req_type_str[req_type])
127 		return "unknown";
128 
129 	return req_type_str[req_type];
130 }
131 
132 #undef DP_STR
133 #define DP_STR(x) [DP_NAK_ ## x] = #x
134 
drm_dp_mst_nak_reason_str(u8 nak_reason)135 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
136 {
137 	static const char * const nak_reason_str[] = {
138 		DP_STR(WRITE_FAILURE),
139 		DP_STR(INVALID_READ),
140 		DP_STR(CRC_FAILURE),
141 		DP_STR(BAD_PARAM),
142 		DP_STR(DEFER),
143 		DP_STR(LINK_FAILURE),
144 		DP_STR(NO_RESOURCES),
145 		DP_STR(DPCD_FAIL),
146 		DP_STR(I2C_NAK),
147 		DP_STR(ALLOCATE_FAIL),
148 	};
149 
150 	if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
151 	    !nak_reason_str[nak_reason])
152 		return "unknown";
153 
154 	return nak_reason_str[nak_reason];
155 }
156 
157 #undef DP_STR
158 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
159 
drm_dp_mst_sideband_tx_state_str(int state)160 static const char *drm_dp_mst_sideband_tx_state_str(int state)
161 {
162 	static const char * const sideband_reason_str[] = {
163 		DP_STR(QUEUED),
164 		DP_STR(START_SEND),
165 		DP_STR(SENT),
166 		DP_STR(RX),
167 		DP_STR(TIMEOUT),
168 	};
169 
170 	if (state >= ARRAY_SIZE(sideband_reason_str) ||
171 	    !sideband_reason_str[state])
172 		return "unknown";
173 
174 	return sideband_reason_str[state];
175 }
176 
177 static int
drm_dp_mst_rad_to_str(const u8 rad[8],u8 lct,char * out,size_t len)178 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
179 {
180 	int i;
181 	u8 unpacked_rad[16];
182 
183 	for (i = 0; i < lct; i++) {
184 		if (i % 2)
185 			unpacked_rad[i] = rad[i / 2] >> 4;
186 		else
187 			unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
188 	}
189 
190 	/* TODO: Eventually add something to printk so we can format the rad
191 	 * like this: 1.2.3
192 	 */
193 	return snprintf(out, len, "%*phC", lct, unpacked_rad);
194 }
195 
196 /* sideband msg handling */
drm_dp_msg_header_crc4(const uint8_t * data,size_t num_nibbles)197 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
198 {
199 	u8 bitmask = 0x80;
200 	u8 bitshift = 7;
201 	u8 array_index = 0;
202 	int number_of_bits = num_nibbles * 4;
203 	u8 remainder = 0;
204 
205 	while (number_of_bits != 0) {
206 		number_of_bits--;
207 		remainder <<= 1;
208 		remainder |= (data[array_index] & bitmask) >> bitshift;
209 		bitmask >>= 1;
210 		bitshift--;
211 		if (bitmask == 0) {
212 			bitmask = 0x80;
213 			bitshift = 7;
214 			array_index++;
215 		}
216 		if ((remainder & 0x10) == 0x10)
217 			remainder ^= 0x13;
218 	}
219 
220 	number_of_bits = 4;
221 	while (number_of_bits != 0) {
222 		number_of_bits--;
223 		remainder <<= 1;
224 		if ((remainder & 0x10) != 0)
225 			remainder ^= 0x13;
226 	}
227 
228 	return remainder;
229 }
230 
drm_dp_msg_data_crc4(const uint8_t * data,u8 number_of_bytes)231 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
232 {
233 	u8 bitmask = 0x80;
234 	u8 bitshift = 7;
235 	u8 array_index = 0;
236 	int number_of_bits = number_of_bytes * 8;
237 	u16 remainder = 0;
238 
239 	while (number_of_bits != 0) {
240 		number_of_bits--;
241 		remainder <<= 1;
242 		remainder |= (data[array_index] & bitmask) >> bitshift;
243 		bitmask >>= 1;
244 		bitshift--;
245 		if (bitmask == 0) {
246 			bitmask = 0x80;
247 			bitshift = 7;
248 			array_index++;
249 		}
250 		if ((remainder & 0x100) == 0x100)
251 			remainder ^= 0xd5;
252 	}
253 
254 	number_of_bits = 8;
255 	while (number_of_bits != 0) {
256 		number_of_bits--;
257 		remainder <<= 1;
258 		if ((remainder & 0x100) != 0)
259 			remainder ^= 0xd5;
260 	}
261 
262 	return remainder & 0xff;
263 }
drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr * hdr)264 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
265 {
266 	u8 size = 3;
267 
268 	size += (hdr->lct / 2);
269 	return size;
270 }
271 
drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr * hdr,u8 * buf,int * len)272 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
273 					   u8 *buf, int *len)
274 {
275 	int idx = 0;
276 	int i;
277 	u8 crc4;
278 
279 	buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
280 	for (i = 0; i < (hdr->lct / 2); i++)
281 		buf[idx++] = hdr->rad[i];
282 	buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
283 		(hdr->msg_len & 0x3f);
284 	buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
285 
286 	crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
287 	buf[idx - 1] |= (crc4 & 0xf);
288 
289 	*len = idx;
290 }
291 
drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_hdr * hdr,u8 * buf,int buflen,u8 * hdrlen)292 static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
293 					   struct drm_dp_sideband_msg_hdr *hdr,
294 					   u8 *buf, int buflen, u8 *hdrlen)
295 {
296 	u8 crc4;
297 	u8 len;
298 	int i;
299 	u8 idx;
300 
301 	if (buf[0] == 0)
302 		return false;
303 	len = 3;
304 	len += ((buf[0] & 0xf0) >> 4) / 2;
305 	if (len > buflen)
306 		return false;
307 	crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
308 
309 	if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
310 		drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
311 		return false;
312 	}
313 
314 	hdr->lct = (buf[0] & 0xf0) >> 4;
315 	hdr->lcr = (buf[0] & 0xf);
316 	idx = 1;
317 	for (i = 0; i < (hdr->lct / 2); i++)
318 		hdr->rad[i] = buf[idx++];
319 	hdr->broadcast = (buf[idx] >> 7) & 0x1;
320 	hdr->path_msg = (buf[idx] >> 6) & 0x1;
321 	hdr->msg_len = buf[idx] & 0x3f;
322 	idx++;
323 	hdr->somt = (buf[idx] >> 7) & 0x1;
324 	hdr->eomt = (buf[idx] >> 6) & 0x1;
325 	hdr->seqno = (buf[idx] >> 4) & 0x1;
326 	idx++;
327 	*hdrlen = idx;
328 	return true;
329 }
330 
331 void
drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body * req,struct drm_dp_sideband_msg_tx * raw)332 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
333 			   struct drm_dp_sideband_msg_tx *raw)
334 {
335 	int idx = 0;
336 	int i;
337 	u8 *buf = raw->msg;
338 
339 	buf[idx++] = req->req_type & 0x7f;
340 
341 	switch (req->req_type) {
342 	case DP_ENUM_PATH_RESOURCES:
343 	case DP_POWER_DOWN_PHY:
344 	case DP_POWER_UP_PHY:
345 		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
346 		idx++;
347 		break;
348 	case DP_ALLOCATE_PAYLOAD:
349 		buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
350 			(req->u.allocate_payload.number_sdp_streams & 0xf);
351 		idx++;
352 		buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
353 		idx++;
354 		buf[idx] = (req->u.allocate_payload.pbn >> 8);
355 		idx++;
356 		buf[idx] = (req->u.allocate_payload.pbn & 0xff);
357 		idx++;
358 		for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
359 			buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
360 				(req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
361 			idx++;
362 		}
363 		if (req->u.allocate_payload.number_sdp_streams & 1) {
364 			i = req->u.allocate_payload.number_sdp_streams - 1;
365 			buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
366 			idx++;
367 		}
368 		break;
369 	case DP_QUERY_PAYLOAD:
370 		buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
371 		idx++;
372 		buf[idx] = (req->u.query_payload.vcpi & 0x7f);
373 		idx++;
374 		break;
375 	case DP_REMOTE_DPCD_READ:
376 		buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
377 		buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
378 		idx++;
379 		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
380 		idx++;
381 		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
382 		idx++;
383 		buf[idx] = (req->u.dpcd_read.num_bytes);
384 		idx++;
385 		break;
386 
387 	case DP_REMOTE_DPCD_WRITE:
388 		buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
389 		buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
390 		idx++;
391 		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
392 		idx++;
393 		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
394 		idx++;
395 		buf[idx] = (req->u.dpcd_write.num_bytes);
396 		idx++;
397 		memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
398 		idx += req->u.dpcd_write.num_bytes;
399 		break;
400 	case DP_REMOTE_I2C_READ:
401 		buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
402 		buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
403 		idx++;
404 		for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
405 			buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
406 			idx++;
407 			buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
408 			idx++;
409 			memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
410 			idx += req->u.i2c_read.transactions[i].num_bytes;
411 
412 			buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
413 			buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
414 			idx++;
415 		}
416 		buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
417 		idx++;
418 		buf[idx] = (req->u.i2c_read.num_bytes_read);
419 		idx++;
420 		break;
421 
422 	case DP_REMOTE_I2C_WRITE:
423 		buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
424 		idx++;
425 		buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
426 		idx++;
427 		buf[idx] = (req->u.i2c_write.num_bytes);
428 		idx++;
429 		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
430 		idx += req->u.i2c_write.num_bytes;
431 		break;
432 	case DP_QUERY_STREAM_ENC_STATUS: {
433 		const struct drm_dp_query_stream_enc_status *msg;
434 
435 		msg = &req->u.enc_status;
436 		buf[idx] = msg->stream_id;
437 		idx++;
438 		memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
439 		idx += sizeof(msg->client_id);
440 		buf[idx] = 0;
441 		buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
442 		buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
443 		buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
444 		buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
445 		idx++;
446 		}
447 		break;
448 	}
449 	raw->cur_len = idx;
450 }
451 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
452 
453 /* Decode a sideband request we've encoded, mainly used for debugging */
454 int
drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx * raw,struct drm_dp_sideband_msg_req_body * req)455 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
456 			   struct drm_dp_sideband_msg_req_body *req)
457 {
458 	const u8 *buf = raw->msg;
459 	int i, idx = 0;
460 
461 	req->req_type = buf[idx++] & 0x7f;
462 	switch (req->req_type) {
463 	case DP_ENUM_PATH_RESOURCES:
464 	case DP_POWER_DOWN_PHY:
465 	case DP_POWER_UP_PHY:
466 		req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
467 		break;
468 	case DP_ALLOCATE_PAYLOAD:
469 		{
470 			struct drm_dp_allocate_payload *a =
471 				&req->u.allocate_payload;
472 
473 			a->number_sdp_streams = buf[idx] & 0xf;
474 			a->port_number = (buf[idx] >> 4) & 0xf;
475 
476 			WARN_ON(buf[++idx] & 0x80);
477 			a->vcpi = buf[idx] & 0x7f;
478 
479 			a->pbn = buf[++idx] << 8;
480 			a->pbn |= buf[++idx];
481 
482 			idx++;
483 			for (i = 0; i < a->number_sdp_streams; i++) {
484 				a->sdp_stream_sink[i] =
485 					(buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
486 			}
487 		}
488 		break;
489 	case DP_QUERY_PAYLOAD:
490 		req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
491 		WARN_ON(buf[++idx] & 0x80);
492 		req->u.query_payload.vcpi = buf[idx] & 0x7f;
493 		break;
494 	case DP_REMOTE_DPCD_READ:
495 		{
496 			struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
497 
498 			r->port_number = (buf[idx] >> 4) & 0xf;
499 
500 			r->dpcd_address = (buf[idx] << 16) & 0xf0000;
501 			r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
502 			r->dpcd_address |= buf[++idx] & 0xff;
503 
504 			r->num_bytes = buf[++idx];
505 		}
506 		break;
507 	case DP_REMOTE_DPCD_WRITE:
508 		{
509 			struct drm_dp_remote_dpcd_write *w =
510 				&req->u.dpcd_write;
511 
512 			w->port_number = (buf[idx] >> 4) & 0xf;
513 
514 			w->dpcd_address = (buf[idx] << 16) & 0xf0000;
515 			w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
516 			w->dpcd_address |= buf[++idx] & 0xff;
517 
518 			w->num_bytes = buf[++idx];
519 
520 			w->bytes = kmemdup(&buf[++idx], w->num_bytes,
521 					   GFP_KERNEL);
522 			if (!w->bytes)
523 				return -ENOMEM;
524 		}
525 		break;
526 	case DP_REMOTE_I2C_READ:
527 		{
528 			struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
529 			struct drm_dp_remote_i2c_read_tx *tx;
530 			bool failed = false;
531 
532 			r->num_transactions = buf[idx] & 0x3;
533 			r->port_number = (buf[idx] >> 4) & 0xf;
534 			for (i = 0; i < r->num_transactions; i++) {
535 				tx = &r->transactions[i];
536 
537 				tx->i2c_dev_id = buf[++idx] & 0x7f;
538 				tx->num_bytes = buf[++idx];
539 				tx->bytes = kmemdup(&buf[++idx],
540 						    tx->num_bytes,
541 						    GFP_KERNEL);
542 				if (!tx->bytes) {
543 					failed = true;
544 					break;
545 				}
546 				idx += tx->num_bytes;
547 				tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
548 				tx->i2c_transaction_delay = buf[idx] & 0xf;
549 			}
550 
551 			if (failed) {
552 				for (i = 0; i < r->num_transactions; i++) {
553 					tx = &r->transactions[i];
554 					kfree(tx->bytes);
555 				}
556 				return -ENOMEM;
557 			}
558 
559 			r->read_i2c_device_id = buf[++idx] & 0x7f;
560 			r->num_bytes_read = buf[++idx];
561 		}
562 		break;
563 	case DP_REMOTE_I2C_WRITE:
564 		{
565 			struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
566 
567 			w->port_number = (buf[idx] >> 4) & 0xf;
568 			w->write_i2c_device_id = buf[++idx] & 0x7f;
569 			w->num_bytes = buf[++idx];
570 			w->bytes = kmemdup(&buf[++idx], w->num_bytes,
571 					   GFP_KERNEL);
572 			if (!w->bytes)
573 				return -ENOMEM;
574 		}
575 		break;
576 	case DP_QUERY_STREAM_ENC_STATUS:
577 		req->u.enc_status.stream_id = buf[idx++];
578 		for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
579 			req->u.enc_status.client_id[i] = buf[idx++];
580 
581 		req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
582 							   buf[idx]);
583 		req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
584 								 buf[idx]);
585 		req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
586 							      buf[idx]);
587 		req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
588 								    buf[idx]);
589 		break;
590 	}
591 
592 	return 0;
593 }
594 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
595 
596 void
drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body * req,int indent,struct drm_printer * printer)597 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
598 				  int indent, struct drm_printer *printer)
599 {
600 	int i;
601 
602 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
603 	if (req->req_type == DP_LINK_ADDRESS) {
604 		/* No contents to print */
605 		P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
606 		return;
607 	}
608 
609 	P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
610 	indent++;
611 
612 	switch (req->req_type) {
613 	case DP_ENUM_PATH_RESOURCES:
614 	case DP_POWER_DOWN_PHY:
615 	case DP_POWER_UP_PHY:
616 		P("port=%d\n", req->u.port_num.port_number);
617 		break;
618 	case DP_ALLOCATE_PAYLOAD:
619 		P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
620 		  req->u.allocate_payload.port_number,
621 		  req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
622 		  req->u.allocate_payload.number_sdp_streams,
623 		  req->u.allocate_payload.number_sdp_streams,
624 		  req->u.allocate_payload.sdp_stream_sink);
625 		break;
626 	case DP_QUERY_PAYLOAD:
627 		P("port=%d vcpi=%d\n",
628 		  req->u.query_payload.port_number,
629 		  req->u.query_payload.vcpi);
630 		break;
631 	case DP_REMOTE_DPCD_READ:
632 		P("port=%d dpcd_addr=%05x len=%d\n",
633 		  req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
634 		  req->u.dpcd_read.num_bytes);
635 		break;
636 	case DP_REMOTE_DPCD_WRITE:
637 		P("port=%d addr=%05x len=%d: %*ph\n",
638 		  req->u.dpcd_write.port_number,
639 		  req->u.dpcd_write.dpcd_address,
640 		  req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
641 		  req->u.dpcd_write.bytes);
642 		break;
643 	case DP_REMOTE_I2C_READ:
644 		P("port=%d num_tx=%d id=%d size=%d:\n",
645 		  req->u.i2c_read.port_number,
646 		  req->u.i2c_read.num_transactions,
647 		  req->u.i2c_read.read_i2c_device_id,
648 		  req->u.i2c_read.num_bytes_read);
649 
650 		indent++;
651 		for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
652 			const struct drm_dp_remote_i2c_read_tx *rtx =
653 				&req->u.i2c_read.transactions[i];
654 
655 			P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
656 			  i, rtx->i2c_dev_id, rtx->num_bytes,
657 			  rtx->no_stop_bit, rtx->i2c_transaction_delay,
658 			  rtx->num_bytes, rtx->bytes);
659 		}
660 		break;
661 	case DP_REMOTE_I2C_WRITE:
662 		P("port=%d id=%d size=%d: %*ph\n",
663 		  req->u.i2c_write.port_number,
664 		  req->u.i2c_write.write_i2c_device_id,
665 		  req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
666 		  req->u.i2c_write.bytes);
667 		break;
668 	case DP_QUERY_STREAM_ENC_STATUS:
669 		P("stream_id=%u client_id=%*ph stream_event=%x "
670 		  "valid_event=%d stream_behavior=%x valid_behavior=%d",
671 		  req->u.enc_status.stream_id,
672 		  (int)ARRAY_SIZE(req->u.enc_status.client_id),
673 		  req->u.enc_status.client_id, req->u.enc_status.stream_event,
674 		  req->u.enc_status.valid_stream_event,
675 		  req->u.enc_status.stream_behavior,
676 		  req->u.enc_status.valid_stream_behavior);
677 		break;
678 	default:
679 		P("???\n");
680 		break;
681 	}
682 #undef P
683 }
684 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
685 
686 static inline void
drm_dp_mst_dump_sideband_msg_tx(struct drm_printer * p,const struct drm_dp_sideband_msg_tx * txmsg)687 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
688 				const struct drm_dp_sideband_msg_tx *txmsg)
689 {
690 	struct drm_dp_sideband_msg_req_body req;
691 	char buf[64];
692 	int ret;
693 	int i;
694 
695 	drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
696 			      sizeof(buf));
697 	drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
698 		   txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
699 		   drm_dp_mst_sideband_tx_state_str(txmsg->state),
700 		   txmsg->path_msg, buf);
701 
702 	ret = drm_dp_decode_sideband_req(txmsg, &req);
703 	if (ret) {
704 		drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
705 		return;
706 	}
707 	drm_dp_dump_sideband_msg_req_body(&req, 1, p);
708 
709 	switch (req.req_type) {
710 	case DP_REMOTE_DPCD_WRITE:
711 		kfree(req.u.dpcd_write.bytes);
712 		break;
713 	case DP_REMOTE_I2C_READ:
714 		for (i = 0; i < req.u.i2c_read.num_transactions; i++)
715 			kfree(req.u.i2c_read.transactions[i].bytes);
716 		break;
717 	case DP_REMOTE_I2C_WRITE:
718 		kfree(req.u.i2c_write.bytes);
719 		break;
720 	}
721 }
722 
drm_dp_crc_sideband_chunk_req(u8 * msg,u8 len)723 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
724 {
725 	u8 crc4;
726 
727 	crc4 = drm_dp_msg_data_crc4(msg, len);
728 	msg[len] = crc4;
729 }
730 
drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body * rep,struct drm_dp_sideband_msg_tx * raw)731 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
732 					 struct drm_dp_sideband_msg_tx *raw)
733 {
734 	int idx = 0;
735 	u8 *buf = raw->msg;
736 
737 	buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
738 
739 	raw->cur_len = idx;
740 }
741 
drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx * msg,struct drm_dp_sideband_msg_hdr * hdr,u8 hdrlen)742 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
743 					  struct drm_dp_sideband_msg_hdr *hdr,
744 					  u8 hdrlen)
745 {
746 	/*
747 	 * ignore out-of-order messages or messages that are part of a
748 	 * failed transaction
749 	 */
750 	if (!hdr->somt && !msg->have_somt)
751 		return false;
752 
753 	/* get length contained in this portion */
754 	msg->curchunk_idx = 0;
755 	msg->curchunk_len = hdr->msg_len;
756 	msg->curchunk_hdrlen = hdrlen;
757 
758 	/* we have already gotten an somt - don't bother parsing */
759 	if (hdr->somt && msg->have_somt)
760 		return false;
761 
762 	if (hdr->somt) {
763 		memcpy(&msg->initial_hdr, hdr,
764 		       sizeof(struct drm_dp_sideband_msg_hdr));
765 		msg->have_somt = true;
766 	}
767 	if (hdr->eomt)
768 		msg->have_eomt = true;
769 
770 	return true;
771 }
772 
773 /* this adds a chunk of msg to the builder to get the final msg */
drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx * msg,u8 * replybuf,u8 replybuflen)774 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
775 					   u8 *replybuf, u8 replybuflen)
776 {
777 	u8 crc4;
778 
779 	memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
780 	msg->curchunk_idx += replybuflen;
781 
782 	if (msg->curchunk_idx >= msg->curchunk_len) {
783 		/* do CRC */
784 		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
785 		if (crc4 != msg->chunk[msg->curchunk_len - 1])
786 			print_hex_dump(KERN_DEBUG, "wrong crc",
787 				       DUMP_PREFIX_NONE, 16, 1,
788 				       msg->chunk,  msg->curchunk_len, false);
789 		/* copy chunk into bigger msg */
790 		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
791 		msg->curlen += msg->curchunk_len - 1;
792 	}
793 	return true;
794 }
795 
drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)796 static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
797 					       struct drm_dp_sideband_msg_rx *raw,
798 					       struct drm_dp_sideband_msg_reply_body *repmsg)
799 {
800 	int idx = 1;
801 	int i;
802 
803 	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
804 	idx += 16;
805 	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
806 	idx++;
807 	if (idx > raw->curlen)
808 		goto fail_len;
809 	for (i = 0; i < repmsg->u.link_addr.nports; i++) {
810 		if (raw->msg[idx] & 0x80)
811 			repmsg->u.link_addr.ports[i].input_port = 1;
812 
813 		repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
814 		repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
815 
816 		idx++;
817 		if (idx > raw->curlen)
818 			goto fail_len;
819 		repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
820 		repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
821 		if (repmsg->u.link_addr.ports[i].input_port == 0)
822 			repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
823 		idx++;
824 		if (idx > raw->curlen)
825 			goto fail_len;
826 		if (repmsg->u.link_addr.ports[i].input_port == 0) {
827 			repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
828 			idx++;
829 			if (idx > raw->curlen)
830 				goto fail_len;
831 			memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
832 			idx += 16;
833 			if (idx > raw->curlen)
834 				goto fail_len;
835 			repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
836 			repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
837 			idx++;
838 
839 		}
840 		if (idx > raw->curlen)
841 			goto fail_len;
842 	}
843 
844 	return true;
845 fail_len:
846 	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
847 	return false;
848 }
849 
drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)850 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
851 						   struct drm_dp_sideband_msg_reply_body *repmsg)
852 {
853 	int idx = 1;
854 
855 	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
856 	idx++;
857 	if (idx > raw->curlen)
858 		goto fail_len;
859 	repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
860 	idx++;
861 	if (idx > raw->curlen)
862 		goto fail_len;
863 
864 	memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
865 	return true;
866 fail_len:
867 	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
868 	return false;
869 }
870 
drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)871 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
872 						      struct drm_dp_sideband_msg_reply_body *repmsg)
873 {
874 	int idx = 1;
875 
876 	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
877 	idx++;
878 	if (idx > raw->curlen)
879 		goto fail_len;
880 	return true;
881 fail_len:
882 	DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
883 	return false;
884 }
885 
drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)886 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
887 						      struct drm_dp_sideband_msg_reply_body *repmsg)
888 {
889 	int idx = 1;
890 
891 	repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
892 	idx++;
893 	if (idx > raw->curlen)
894 		goto fail_len;
895 	repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
896 	idx++;
897 	/* TODO check */
898 	memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
899 	return true;
900 fail_len:
901 	DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
902 	return false;
903 }
904 
drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)905 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
906 							  struct drm_dp_sideband_msg_reply_body *repmsg)
907 {
908 	int idx = 1;
909 
910 	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
911 	repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
912 	idx++;
913 	if (idx > raw->curlen)
914 		goto fail_len;
915 	repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
916 	idx += 2;
917 	if (idx > raw->curlen)
918 		goto fail_len;
919 	repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
920 	idx += 2;
921 	if (idx > raw->curlen)
922 		goto fail_len;
923 	return true;
924 fail_len:
925 	DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
926 	return false;
927 }
928 
drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)929 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
930 							  struct drm_dp_sideband_msg_reply_body *repmsg)
931 {
932 	int idx = 1;
933 
934 	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
935 	idx++;
936 	if (idx > raw->curlen)
937 		goto fail_len;
938 	repmsg->u.allocate_payload.vcpi = raw->msg[idx];
939 	idx++;
940 	if (idx > raw->curlen)
941 		goto fail_len;
942 	repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
943 	idx += 2;
944 	if (idx > raw->curlen)
945 		goto fail_len;
946 	return true;
947 fail_len:
948 	DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
949 	return false;
950 }
951 
drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)952 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
953 						    struct drm_dp_sideband_msg_reply_body *repmsg)
954 {
955 	int idx = 1;
956 
957 	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
958 	idx++;
959 	if (idx > raw->curlen)
960 		goto fail_len;
961 	repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
962 	idx += 2;
963 	if (idx > raw->curlen)
964 		goto fail_len;
965 	return true;
966 fail_len:
967 	DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
968 	return false;
969 }
970 
drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)971 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
972 						       struct drm_dp_sideband_msg_reply_body *repmsg)
973 {
974 	int idx = 1;
975 
976 	repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
977 	idx++;
978 	if (idx > raw->curlen) {
979 		DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
980 			      idx, raw->curlen);
981 		return false;
982 	}
983 	return true;
984 }
985 
986 static bool
drm_dp_sideband_parse_query_stream_enc_status(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)987 drm_dp_sideband_parse_query_stream_enc_status(
988 				struct drm_dp_sideband_msg_rx *raw,
989 				struct drm_dp_sideband_msg_reply_body *repmsg)
990 {
991 	struct drm_dp_query_stream_enc_status_ack_reply *reply;
992 
993 	reply = &repmsg->u.enc_status;
994 
995 	reply->stream_id = raw->msg[3];
996 
997 	reply->reply_signed = raw->msg[2] & BIT(0);
998 
999 	/*
1000 	 * NOTE: It's my impression from reading the spec that the below parsing
1001 	 * is correct. However I noticed while testing with an HDCP 1.4 display
1002 	 * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1003 	 * would expect both bits to be set. So keep the parsing following the
1004 	 * spec, but beware reality might not match the spec (at least for some
1005 	 * configurations).
1006 	 */
1007 	reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1008 	reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1009 
1010 	reply->query_capable_device_present = raw->msg[2] & BIT(5);
1011 	reply->legacy_device_present = raw->msg[2] & BIT(6);
1012 	reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1013 
1014 	reply->auth_completed = !!(raw->msg[1] & BIT(3));
1015 	reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1016 	reply->repeater_present = !!(raw->msg[1] & BIT(5));
1017 	reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1018 
1019 	return true;
1020 }
1021 
drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * msg)1022 static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1023 					struct drm_dp_sideband_msg_rx *raw,
1024 					struct drm_dp_sideband_msg_reply_body *msg)
1025 {
1026 	memset(msg, 0, sizeof(*msg));
1027 	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1028 	msg->req_type = (raw->msg[0] & 0x7f);
1029 
1030 	if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1031 		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1032 		msg->u.nak.reason = raw->msg[17];
1033 		msg->u.nak.nak_data = raw->msg[18];
1034 		return false;
1035 	}
1036 
1037 	switch (msg->req_type) {
1038 	case DP_LINK_ADDRESS:
1039 		return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1040 	case DP_QUERY_PAYLOAD:
1041 		return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1042 	case DP_REMOTE_DPCD_READ:
1043 		return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1044 	case DP_REMOTE_DPCD_WRITE:
1045 		return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1046 	case DP_REMOTE_I2C_READ:
1047 		return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1048 	case DP_REMOTE_I2C_WRITE:
1049 		return true; /* since there's nothing to parse */
1050 	case DP_ENUM_PATH_RESOURCES:
1051 		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1052 	case DP_ALLOCATE_PAYLOAD:
1053 		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1054 	case DP_POWER_DOWN_PHY:
1055 	case DP_POWER_UP_PHY:
1056 		return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1057 	case DP_CLEAR_PAYLOAD_ID_TABLE:
1058 		return true; /* since there's nothing to parse */
1059 	case DP_QUERY_STREAM_ENC_STATUS:
1060 		return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1061 	default:
1062 		drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1063 			msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1064 		return false;
1065 	}
1066 }
1067 
1068 static bool
drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1069 drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1070 					       struct drm_dp_sideband_msg_rx *raw,
1071 					       struct drm_dp_sideband_msg_req_body *msg)
1072 {
1073 	int idx = 1;
1074 
1075 	msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1076 	idx++;
1077 	if (idx > raw->curlen)
1078 		goto fail_len;
1079 
1080 	memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1081 	idx += 16;
1082 	if (idx > raw->curlen)
1083 		goto fail_len;
1084 
1085 	msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1086 	msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1087 	msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1088 	msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1089 	msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1090 	idx++;
1091 	return true;
1092 fail_len:
1093 	drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1094 		    idx, raw->curlen);
1095 	return false;
1096 }
1097 
drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1098 static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1099 							 struct drm_dp_sideband_msg_rx *raw,
1100 							 struct drm_dp_sideband_msg_req_body *msg)
1101 {
1102 	int idx = 1;
1103 
1104 	msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1105 	idx++;
1106 	if (idx > raw->curlen)
1107 		goto fail_len;
1108 
1109 	memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1110 	idx += 16;
1111 	if (idx > raw->curlen)
1112 		goto fail_len;
1113 
1114 	msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1115 	idx++;
1116 	return true;
1117 fail_len:
1118 	drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1119 	return false;
1120 }
1121 
drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1122 static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1123 				      struct drm_dp_sideband_msg_rx *raw,
1124 				      struct drm_dp_sideband_msg_req_body *msg)
1125 {
1126 	memset(msg, 0, sizeof(*msg));
1127 	msg->req_type = (raw->msg[0] & 0x7f);
1128 
1129 	switch (msg->req_type) {
1130 	case DP_CONNECTION_STATUS_NOTIFY:
1131 		return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1132 	case DP_RESOURCE_STATUS_NOTIFY:
1133 		return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1134 	default:
1135 		drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1136 			msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1137 		return false;
1138 	}
1139 }
1140 
build_dpcd_write(struct drm_dp_sideband_msg_tx * msg,u8 port_num,u32 offset,u8 num_bytes,u8 * bytes)1141 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1142 			     u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1143 {
1144 	struct drm_dp_sideband_msg_req_body req;
1145 
1146 	req.req_type = DP_REMOTE_DPCD_WRITE;
1147 	req.u.dpcd_write.port_number = port_num;
1148 	req.u.dpcd_write.dpcd_address = offset;
1149 	req.u.dpcd_write.num_bytes = num_bytes;
1150 	req.u.dpcd_write.bytes = bytes;
1151 	drm_dp_encode_sideband_req(&req, msg);
1152 }
1153 
build_link_address(struct drm_dp_sideband_msg_tx * msg)1154 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1155 {
1156 	struct drm_dp_sideband_msg_req_body req;
1157 
1158 	req.req_type = DP_LINK_ADDRESS;
1159 	drm_dp_encode_sideband_req(&req, msg);
1160 }
1161 
build_clear_payload_id_table(struct drm_dp_sideband_msg_tx * msg)1162 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1163 {
1164 	struct drm_dp_sideband_msg_req_body req;
1165 
1166 	req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1167 	drm_dp_encode_sideband_req(&req, msg);
1168 	msg->path_msg = true;
1169 }
1170 
build_enum_path_resources(struct drm_dp_sideband_msg_tx * msg,int port_num)1171 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1172 				     int port_num)
1173 {
1174 	struct drm_dp_sideband_msg_req_body req;
1175 
1176 	req.req_type = DP_ENUM_PATH_RESOURCES;
1177 	req.u.port_num.port_number = port_num;
1178 	drm_dp_encode_sideband_req(&req, msg);
1179 	msg->path_msg = true;
1180 	return 0;
1181 }
1182 
build_allocate_payload(struct drm_dp_sideband_msg_tx * msg,int port_num,u8 vcpi,uint16_t pbn,u8 number_sdp_streams,u8 * sdp_stream_sink)1183 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1184 				   int port_num,
1185 				   u8 vcpi, uint16_t pbn,
1186 				   u8 number_sdp_streams,
1187 				   u8 *sdp_stream_sink)
1188 {
1189 	struct drm_dp_sideband_msg_req_body req;
1190 
1191 	memset(&req, 0, sizeof(req));
1192 	req.req_type = DP_ALLOCATE_PAYLOAD;
1193 	req.u.allocate_payload.port_number = port_num;
1194 	req.u.allocate_payload.vcpi = vcpi;
1195 	req.u.allocate_payload.pbn = pbn;
1196 	req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1197 	memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1198 		   number_sdp_streams);
1199 	drm_dp_encode_sideband_req(&req, msg);
1200 	msg->path_msg = true;
1201 }
1202 
build_power_updown_phy(struct drm_dp_sideband_msg_tx * msg,int port_num,bool power_up)1203 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1204 				   int port_num, bool power_up)
1205 {
1206 	struct drm_dp_sideband_msg_req_body req;
1207 
1208 	if (power_up)
1209 		req.req_type = DP_POWER_UP_PHY;
1210 	else
1211 		req.req_type = DP_POWER_DOWN_PHY;
1212 
1213 	req.u.port_num.port_number = port_num;
1214 	drm_dp_encode_sideband_req(&req, msg);
1215 	msg->path_msg = true;
1216 }
1217 
1218 static int
build_query_stream_enc_status(struct drm_dp_sideband_msg_tx * msg,u8 stream_id,u8 * q_id)1219 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1220 			      u8 *q_id)
1221 {
1222 	struct drm_dp_sideband_msg_req_body req;
1223 
1224 	req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1225 	req.u.enc_status.stream_id = stream_id;
1226 	memcpy(req.u.enc_status.client_id, q_id,
1227 	       sizeof(req.u.enc_status.client_id));
1228 	req.u.enc_status.stream_event = 0;
1229 	req.u.enc_status.valid_stream_event = false;
1230 	req.u.enc_status.stream_behavior = 0;
1231 	req.u.enc_status.valid_stream_behavior = false;
1232 
1233 	drm_dp_encode_sideband_req(&req, msg);
1234 	return 0;
1235 }
1236 
drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_vcpi * vcpi)1237 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1238 					struct drm_dp_vcpi *vcpi)
1239 {
1240 	int ret, vcpi_ret;
1241 
1242 	mutex_lock(&mgr->payload_lock);
1243 	ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
1244 	if (ret > mgr->max_payloads) {
1245 		ret = -EINVAL;
1246 		drm_dbg_kms(mgr->dev, "out of payload ids %d\n", ret);
1247 		goto out_unlock;
1248 	}
1249 
1250 	vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
1251 	if (vcpi_ret > mgr->max_payloads) {
1252 		ret = -EINVAL;
1253 		drm_dbg_kms(mgr->dev, "out of vcpi ids %d\n", ret);
1254 		goto out_unlock;
1255 	}
1256 
1257 	set_bit(ret, &mgr->payload_mask);
1258 	set_bit(vcpi_ret, &mgr->vcpi_mask);
1259 	vcpi->vcpi = vcpi_ret + 1;
1260 	mgr->proposed_vcpis[ret - 1] = vcpi;
1261 out_unlock:
1262 	mutex_unlock(&mgr->payload_lock);
1263 	return ret;
1264 }
1265 
drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr * mgr,int vcpi)1266 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1267 				      int vcpi)
1268 {
1269 	int i;
1270 
1271 	if (vcpi == 0)
1272 		return;
1273 
1274 	mutex_lock(&mgr->payload_lock);
1275 	drm_dbg_kms(mgr->dev, "putting payload %d\n", vcpi);
1276 	clear_bit(vcpi - 1, &mgr->vcpi_mask);
1277 
1278 	for (i = 0; i < mgr->max_payloads; i++) {
1279 		if (mgr->proposed_vcpis[i] &&
1280 		    mgr->proposed_vcpis[i]->vcpi == vcpi) {
1281 			mgr->proposed_vcpis[i] = NULL;
1282 			clear_bit(i + 1, &mgr->payload_mask);
1283 		}
1284 	}
1285 	mutex_unlock(&mgr->payload_lock);
1286 }
1287 
check_txmsg_state(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg)1288 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1289 			      struct drm_dp_sideband_msg_tx *txmsg)
1290 {
1291 	unsigned int state;
1292 
1293 	/*
1294 	 * All updates to txmsg->state are protected by mgr->qlock, and the two
1295 	 * cases we check here are terminal states. For those the barriers
1296 	 * provided by the wake_up/wait_event pair are enough.
1297 	 */
1298 	state = READ_ONCE(txmsg->state);
1299 	return (state == DRM_DP_SIDEBAND_TX_RX ||
1300 		state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1301 }
1302 
drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch * mstb,struct drm_dp_sideband_msg_tx * txmsg)1303 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1304 				    struct drm_dp_sideband_msg_tx *txmsg)
1305 {
1306 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1307 	unsigned long wait_timeout = msecs_to_jiffies(4000);
1308 	unsigned long wait_expires = jiffies + wait_timeout;
1309 	int ret;
1310 
1311 	for (;;) {
1312 		/*
1313 		 * If the driver provides a way for this, change to
1314 		 * poll-waiting for the MST reply interrupt if we didn't receive
1315 		 * it for 50 msec. This would cater for cases where the HPD
1316 		 * pulse signal got lost somewhere, even though the sink raised
1317 		 * the corresponding MST interrupt correctly. One example is the
1318 		 * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1319 		 * filters out short pulses with a duration less than ~540 usec.
1320 		 *
1321 		 * The poll period is 50 msec to avoid missing an interrupt
1322 		 * after the sink has cleared it (after a 110msec timeout
1323 		 * since it raised the interrupt).
1324 		 */
1325 		ret = wait_event_timeout(mgr->tx_waitq,
1326 					 check_txmsg_state(mgr, txmsg),
1327 					 mgr->cbs->poll_hpd_irq ?
1328 						msecs_to_jiffies(50) :
1329 						wait_timeout);
1330 
1331 		if (ret || !mgr->cbs->poll_hpd_irq ||
1332 		    time_after(jiffies, wait_expires))
1333 			break;
1334 
1335 		mgr->cbs->poll_hpd_irq(mgr);
1336 	}
1337 
1338 	mutex_lock(&mgr->qlock);
1339 	if (ret > 0) {
1340 		if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1341 			ret = -EIO;
1342 			goto out;
1343 		}
1344 	} else {
1345 		drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1346 			    txmsg, txmsg->state, txmsg->seqno);
1347 
1348 		/* dump some state */
1349 		ret = -EIO;
1350 
1351 		/* remove from q */
1352 		if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1353 		    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1354 		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1355 			list_del(&txmsg->next);
1356 	}
1357 out:
1358 	if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1359 		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1360 
1361 		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1362 	}
1363 	mutex_unlock(&mgr->qlock);
1364 
1365 	drm_dp_mst_kick_tx(mgr);
1366 	return ret;
1367 }
1368 
drm_dp_add_mst_branch_device(u8 lct,u8 * rad)1369 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1370 {
1371 	struct drm_dp_mst_branch *mstb;
1372 
1373 	mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1374 	if (!mstb)
1375 		return NULL;
1376 
1377 	mstb->lct = lct;
1378 	if (lct > 1)
1379 		memcpy(mstb->rad, rad, lct / 2);
1380 	INIT_LIST_HEAD(&mstb->ports);
1381 	kref_init(&mstb->topology_kref);
1382 	kref_init(&mstb->malloc_kref);
1383 	return mstb;
1384 }
1385 
drm_dp_free_mst_branch_device(struct kref * kref)1386 static void drm_dp_free_mst_branch_device(struct kref *kref)
1387 {
1388 	struct drm_dp_mst_branch *mstb =
1389 		container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1390 
1391 	if (mstb->port_parent)
1392 		drm_dp_mst_put_port_malloc(mstb->port_parent);
1393 
1394 	kfree(mstb);
1395 }
1396 
1397 /**
1398  * DOC: Branch device and port refcounting
1399  *
1400  * Topology refcount overview
1401  * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1402  *
1403  * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1404  * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1405  * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1406  *
1407  * Topology refcounts are not exposed to drivers, and are handled internally
1408  * by the DP MST helpers. The helpers use them in order to prevent the
1409  * in-memory topology state from being changed in the middle of critical
1410  * operations like changing the internal state of payload allocations. This
1411  * means each branch and port will be considered to be connected to the rest
1412  * of the topology until its topology refcount reaches zero. Additionally,
1413  * for ports this means that their associated &struct drm_connector will stay
1414  * registered with userspace until the port's refcount reaches 0.
1415  *
1416  * Malloc refcount overview
1417  * ~~~~~~~~~~~~~~~~~~~~~~~~
1418  *
1419  * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1420  * drm_dp_mst_branch allocated even after all of its topology references have
1421  * been dropped, so that the driver or MST helpers can safely access each
1422  * branch's last known state before it was disconnected from the topology.
1423  * When the malloc refcount of a port or branch reaches 0, the memory
1424  * allocation containing the &struct drm_dp_mst_branch or &struct
1425  * drm_dp_mst_port respectively will be freed.
1426  *
1427  * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1428  * to drivers. As of writing this documentation, there are no drivers that
1429  * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1430  * helpers. Exposing this API to drivers in a race-free manner would take more
1431  * tweaking of the refcounting scheme, however patches are welcome provided
1432  * there is a legitimate driver usecase for this.
1433  *
1434  * Refcount relationships in a topology
1435  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1436  *
1437  * Let's take a look at why the relationship between topology and malloc
1438  * refcounts is designed the way it is.
1439  *
1440  * .. kernel-figure:: dp-mst/topology-figure-1.dot
1441  *
1442  *    An example of topology and malloc refs in a DP MST topology with two
1443  *    active payloads. Topology refcount increments are indicated by solid
1444  *    lines, and malloc refcount increments are indicated by dashed lines.
1445  *    Each starts from the branch which incremented the refcount, and ends at
1446  *    the branch to which the refcount belongs to, i.e. the arrow points the
1447  *    same way as the C pointers used to reference a structure.
1448  *
1449  * As you can see in the above figure, every branch increments the topology
1450  * refcount of its children, and increments the malloc refcount of its
1451  * parent. Additionally, every payload increments the malloc refcount of its
1452  * assigned port by 1.
1453  *
1454  * So, what would happen if MSTB #3 from the above figure was unplugged from
1455  * the system, but the driver hadn't yet removed payload #2 from port #3? The
1456  * topology would start to look like the figure below.
1457  *
1458  * .. kernel-figure:: dp-mst/topology-figure-2.dot
1459  *
1460  *    Ports and branch devices which have been released from memory are
1461  *    colored grey, and references which have been removed are colored red.
1462  *
1463  * Whenever a port or branch device's topology refcount reaches zero, it will
1464  * decrement the topology refcounts of all its children, the malloc refcount
1465  * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1466  * #4, this means they both have been disconnected from the topology and freed
1467  * from memory. But, because payload #2 is still holding a reference to port
1468  * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1469  * is still accessible from memory. This also means port #3 has not yet
1470  * decremented the malloc refcount of MSTB #3, so its &struct
1471  * drm_dp_mst_branch will also stay allocated in memory until port #3's
1472  * malloc refcount reaches 0.
1473  *
1474  * This relationship is necessary because in order to release payload #2, we
1475  * need to be able to figure out the last relative of port #3 that's still
1476  * connected to the topology. In this case, we would travel up the topology as
1477  * shown below.
1478  *
1479  * .. kernel-figure:: dp-mst/topology-figure-3.dot
1480  *
1481  * And finally, remove payload #2 by communicating with port #2 through
1482  * sideband transactions.
1483  */
1484 
1485 /**
1486  * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1487  * device
1488  * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1489  *
1490  * Increments &drm_dp_mst_branch.malloc_kref. When
1491  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1492  * will be released and @mstb may no longer be used.
1493  *
1494  * See also: drm_dp_mst_put_mstb_malloc()
1495  */
1496 static void
drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch * mstb)1497 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1498 {
1499 	kref_get(&mstb->malloc_kref);
1500 	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1501 }
1502 
1503 /**
1504  * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1505  * device
1506  * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1507  *
1508  * Decrements &drm_dp_mst_branch.malloc_kref. When
1509  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1510  * will be released and @mstb may no longer be used.
1511  *
1512  * See also: drm_dp_mst_get_mstb_malloc()
1513  */
1514 static void
drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch * mstb)1515 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1516 {
1517 	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1518 	kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1519 }
1520 
drm_dp_free_mst_port(struct kref * kref)1521 static void drm_dp_free_mst_port(struct kref *kref)
1522 {
1523 	struct drm_dp_mst_port *port =
1524 		container_of(kref, struct drm_dp_mst_port, malloc_kref);
1525 
1526 	drm_dp_mst_put_mstb_malloc(port->parent);
1527 	kfree(port);
1528 }
1529 
1530 /**
1531  * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1532  * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1533  *
1534  * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1535  * reaches 0, the memory allocation for @port will be released and @port may
1536  * no longer be used.
1537  *
1538  * Because @port could potentially be freed at any time by the DP MST helpers
1539  * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1540  * function, drivers that which to make use of &struct drm_dp_mst_port should
1541  * ensure that they grab at least one main malloc reference to their MST ports
1542  * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1543  * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1544  *
1545  * See also: drm_dp_mst_put_port_malloc()
1546  */
1547 void
drm_dp_mst_get_port_malloc(struct drm_dp_mst_port * port)1548 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1549 {
1550 	kref_get(&port->malloc_kref);
1551 	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1552 }
1553 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1554 
1555 /**
1556  * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1557  * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1558  *
1559  * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1560  * reaches 0, the memory allocation for @port will be released and @port may
1561  * no longer be used.
1562  *
1563  * See also: drm_dp_mst_get_port_malloc()
1564  */
1565 void
drm_dp_mst_put_port_malloc(struct drm_dp_mst_port * port)1566 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1567 {
1568 	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1569 	kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1570 }
1571 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1572 
1573 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1574 
1575 #define STACK_DEPTH 8
1576 
1577 static noinline void
__topology_ref_save(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_ref_history * history,enum drm_dp_mst_topology_ref_type type)1578 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1579 		    struct drm_dp_mst_topology_ref_history *history,
1580 		    enum drm_dp_mst_topology_ref_type type)
1581 {
1582 	struct drm_dp_mst_topology_ref_entry *entry = NULL;
1583 	depot_stack_handle_t backtrace;
1584 	ulong stack_entries[STACK_DEPTH];
1585 	uint n;
1586 	int i;
1587 
1588 	n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1589 	backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1590 	if (!backtrace)
1591 		return;
1592 
1593 	/* Try to find an existing entry for this backtrace */
1594 	for (i = 0; i < history->len; i++) {
1595 		if (history->entries[i].backtrace == backtrace) {
1596 			entry = &history->entries[i];
1597 			break;
1598 		}
1599 	}
1600 
1601 	/* Otherwise add one */
1602 	if (!entry) {
1603 		struct drm_dp_mst_topology_ref_entry *new;
1604 		int new_len = history->len + 1;
1605 
1606 		new = krealloc(history->entries, sizeof(*new) * new_len,
1607 			       GFP_KERNEL);
1608 		if (!new)
1609 			return;
1610 
1611 		entry = &new[history->len];
1612 		history->len = new_len;
1613 		history->entries = new;
1614 
1615 		entry->backtrace = backtrace;
1616 		entry->type = type;
1617 		entry->count = 0;
1618 	}
1619 	entry->count++;
1620 	entry->ts_nsec = ktime_get_ns();
1621 }
1622 
1623 static int
topology_ref_history_cmp(const void * a,const void * b)1624 topology_ref_history_cmp(const void *a, const void *b)
1625 {
1626 	const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1627 
1628 	if (entry_a->ts_nsec > entry_b->ts_nsec)
1629 		return 1;
1630 	else if (entry_a->ts_nsec < entry_b->ts_nsec)
1631 		return -1;
1632 	else
1633 		return 0;
1634 }
1635 
1636 static inline const char *
topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)1637 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1638 {
1639 	if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1640 		return "get";
1641 	else
1642 		return "put";
1643 }
1644 
1645 static void
__dump_topology_ref_history(struct drm_dp_mst_topology_ref_history * history,void * ptr,const char * type_str)1646 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1647 			    void *ptr, const char *type_str)
1648 {
1649 	struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1650 	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1651 	int i;
1652 
1653 	if (!buf)
1654 		return;
1655 
1656 	if (!history->len)
1657 		goto out;
1658 
1659 	/* First, sort the list so that it goes from oldest to newest
1660 	 * reference entry
1661 	 */
1662 	sort(history->entries, history->len, sizeof(*history->entries),
1663 	     topology_ref_history_cmp, NULL);
1664 
1665 	drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1666 		   type_str, ptr);
1667 
1668 	for (i = 0; i < history->len; i++) {
1669 		const struct drm_dp_mst_topology_ref_entry *entry =
1670 			&history->entries[i];
1671 		u64 ts_nsec = entry->ts_nsec;
1672 		u32 rem_nsec = do_div(ts_nsec, 1000000000);
1673 
1674 		stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
1675 
1676 		drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1677 			   entry->count,
1678 			   topology_ref_type_to_str(entry->type),
1679 			   ts_nsec, rem_nsec / 1000, buf);
1680 	}
1681 
1682 	/* Now free the history, since this is the only time we expose it */
1683 	kfree(history->entries);
1684 out:
1685 	kfree(buf);
1686 }
1687 
1688 static __always_inline void
drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch * mstb)1689 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1690 {
1691 	__dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1692 				    "MSTB");
1693 }
1694 
1695 static __always_inline void
drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port * port)1696 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1697 {
1698 	__dump_topology_ref_history(&port->topology_ref_history, port,
1699 				    "Port");
1700 }
1701 
1702 static __always_inline void
save_mstb_topology_ref(struct drm_dp_mst_branch * mstb,enum drm_dp_mst_topology_ref_type type)1703 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1704 		       enum drm_dp_mst_topology_ref_type type)
1705 {
1706 	__topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1707 }
1708 
1709 static __always_inline void
save_port_topology_ref(struct drm_dp_mst_port * port,enum drm_dp_mst_topology_ref_type type)1710 save_port_topology_ref(struct drm_dp_mst_port *port,
1711 		       enum drm_dp_mst_topology_ref_type type)
1712 {
1713 	__topology_ref_save(port->mgr, &port->topology_ref_history, type);
1714 }
1715 
1716 static inline void
topology_ref_history_lock(struct drm_dp_mst_topology_mgr * mgr)1717 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1718 {
1719 	mutex_lock(&mgr->topology_ref_history_lock);
1720 }
1721 
1722 static inline void
topology_ref_history_unlock(struct drm_dp_mst_topology_mgr * mgr)1723 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1724 {
1725 	mutex_unlock(&mgr->topology_ref_history_lock);
1726 }
1727 #else
1728 static inline void
topology_ref_history_lock(struct drm_dp_mst_topology_mgr * mgr)1729 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1730 static inline void
topology_ref_history_unlock(struct drm_dp_mst_topology_mgr * mgr)1731 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1732 static inline void
drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch * mstb)1733 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1734 static inline void
drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port * port)1735 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1736 #define save_mstb_topology_ref(mstb, type)
1737 #define save_port_topology_ref(port, type)
1738 #endif
1739 
drm_dp_destroy_mst_branch_device(struct kref * kref)1740 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1741 {
1742 	struct drm_dp_mst_branch *mstb =
1743 		container_of(kref, struct drm_dp_mst_branch, topology_kref);
1744 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1745 
1746 	drm_dp_mst_dump_mstb_topology_history(mstb);
1747 
1748 	INIT_LIST_HEAD(&mstb->destroy_next);
1749 
1750 	/*
1751 	 * This can get called under mgr->mutex, so we need to perform the
1752 	 * actual destruction of the mstb in another worker
1753 	 */
1754 	mutex_lock(&mgr->delayed_destroy_lock);
1755 	list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1756 	mutex_unlock(&mgr->delayed_destroy_lock);
1757 	queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1758 }
1759 
1760 /**
1761  * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1762  * branch device unless it's zero
1763  * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1764  *
1765  * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1766  * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1767  * reached 0). Holding a topology reference implies that a malloc reference
1768  * will be held to @mstb as long as the user holds the topology reference.
1769  *
1770  * Care should be taken to ensure that the user has at least one malloc
1771  * reference to @mstb. If you already have a topology reference to @mstb, you
1772  * should use drm_dp_mst_topology_get_mstb() instead.
1773  *
1774  * See also:
1775  * drm_dp_mst_topology_get_mstb()
1776  * drm_dp_mst_topology_put_mstb()
1777  *
1778  * Returns:
1779  * * 1: A topology reference was grabbed successfully
1780  * * 0: @port is no longer in the topology, no reference was grabbed
1781  */
1782 static int __must_check
drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch * mstb)1783 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1784 {
1785 	int ret;
1786 
1787 	topology_ref_history_lock(mstb->mgr);
1788 	ret = kref_get_unless_zero(&mstb->topology_kref);
1789 	if (ret) {
1790 		drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1791 		save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1792 	}
1793 
1794 	topology_ref_history_unlock(mstb->mgr);
1795 
1796 	return ret;
1797 }
1798 
1799 /**
1800  * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1801  * branch device
1802  * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1803  *
1804  * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1805  * not it's already reached 0. This is only valid to use in scenarios where
1806  * you are already guaranteed to have at least one active topology reference
1807  * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1808  *
1809  * See also:
1810  * drm_dp_mst_topology_try_get_mstb()
1811  * drm_dp_mst_topology_put_mstb()
1812  */
drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch * mstb)1813 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1814 {
1815 	topology_ref_history_lock(mstb->mgr);
1816 
1817 	save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1818 	WARN_ON(kref_read(&mstb->topology_kref) == 0);
1819 	kref_get(&mstb->topology_kref);
1820 	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1821 
1822 	topology_ref_history_unlock(mstb->mgr);
1823 }
1824 
1825 /**
1826  * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1827  * device
1828  * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1829  *
1830  * Releases a topology reference from @mstb by decrementing
1831  * &drm_dp_mst_branch.topology_kref.
1832  *
1833  * See also:
1834  * drm_dp_mst_topology_try_get_mstb()
1835  * drm_dp_mst_topology_get_mstb()
1836  */
1837 static void
drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch * mstb)1838 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1839 {
1840 	topology_ref_history_lock(mstb->mgr);
1841 
1842 	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1843 	save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1844 
1845 	topology_ref_history_unlock(mstb->mgr);
1846 	kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1847 }
1848 
drm_dp_destroy_port(struct kref * kref)1849 static void drm_dp_destroy_port(struct kref *kref)
1850 {
1851 	struct drm_dp_mst_port *port =
1852 		container_of(kref, struct drm_dp_mst_port, topology_kref);
1853 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1854 
1855 	drm_dp_mst_dump_port_topology_history(port);
1856 
1857 	/* There's nothing that needs locking to destroy an input port yet */
1858 	if (port->input) {
1859 		drm_dp_mst_put_port_malloc(port);
1860 		return;
1861 	}
1862 
1863 	kfree(port->cached_edid);
1864 
1865 	/*
1866 	 * we can't destroy the connector here, as we might be holding the
1867 	 * mode_config.mutex from an EDID retrieval
1868 	 */
1869 	mutex_lock(&mgr->delayed_destroy_lock);
1870 	list_add(&port->next, &mgr->destroy_port_list);
1871 	mutex_unlock(&mgr->delayed_destroy_lock);
1872 	queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1873 }
1874 
1875 /**
1876  * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1877  * port unless it's zero
1878  * @port: &struct drm_dp_mst_port to increment the topology refcount of
1879  *
1880  * Attempts to grab a topology reference to @port, if it hasn't yet been
1881  * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1882  * 0). Holding a topology reference implies that a malloc reference will be
1883  * held to @port as long as the user holds the topology reference.
1884  *
1885  * Care should be taken to ensure that the user has at least one malloc
1886  * reference to @port. If you already have a topology reference to @port, you
1887  * should use drm_dp_mst_topology_get_port() instead.
1888  *
1889  * See also:
1890  * drm_dp_mst_topology_get_port()
1891  * drm_dp_mst_topology_put_port()
1892  *
1893  * Returns:
1894  * * 1: A topology reference was grabbed successfully
1895  * * 0: @port is no longer in the topology, no reference was grabbed
1896  */
1897 static int __must_check
drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port * port)1898 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1899 {
1900 	int ret;
1901 
1902 	topology_ref_history_lock(port->mgr);
1903 	ret = kref_get_unless_zero(&port->topology_kref);
1904 	if (ret) {
1905 		drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1906 		save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1907 	}
1908 
1909 	topology_ref_history_unlock(port->mgr);
1910 	return ret;
1911 }
1912 
1913 /**
1914  * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1915  * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1916  *
1917  * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1918  * not it's already reached 0. This is only valid to use in scenarios where
1919  * you are already guaranteed to have at least one active topology reference
1920  * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1921  *
1922  * See also:
1923  * drm_dp_mst_topology_try_get_port()
1924  * drm_dp_mst_topology_put_port()
1925  */
drm_dp_mst_topology_get_port(struct drm_dp_mst_port * port)1926 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1927 {
1928 	topology_ref_history_lock(port->mgr);
1929 
1930 	WARN_ON(kref_read(&port->topology_kref) == 0);
1931 	kref_get(&port->topology_kref);
1932 	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1933 	save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1934 
1935 	topology_ref_history_unlock(port->mgr);
1936 }
1937 
1938 /**
1939  * drm_dp_mst_topology_put_port() - release a topology reference to a port
1940  * @port: The &struct drm_dp_mst_port to release the topology reference from
1941  *
1942  * Releases a topology reference from @port by decrementing
1943  * &drm_dp_mst_port.topology_kref.
1944  *
1945  * See also:
1946  * drm_dp_mst_topology_try_get_port()
1947  * drm_dp_mst_topology_get_port()
1948  */
drm_dp_mst_topology_put_port(struct drm_dp_mst_port * port)1949 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1950 {
1951 	topology_ref_history_lock(port->mgr);
1952 
1953 	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1954 	save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1955 
1956 	topology_ref_history_unlock(port->mgr);
1957 	kref_put(&port->topology_kref, drm_dp_destroy_port);
1958 }
1959 
1960 static struct drm_dp_mst_branch *
drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_branch * to_find)1961 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1962 					      struct drm_dp_mst_branch *to_find)
1963 {
1964 	struct drm_dp_mst_port *port;
1965 	struct drm_dp_mst_branch *rmstb;
1966 
1967 	if (to_find == mstb)
1968 		return mstb;
1969 
1970 	list_for_each_entry(port, &mstb->ports, next) {
1971 		if (port->mstb) {
1972 			rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1973 			    port->mstb, to_find);
1974 			if (rmstb)
1975 				return rmstb;
1976 		}
1977 	}
1978 	return NULL;
1979 }
1980 
1981 static struct drm_dp_mst_branch *
drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)1982 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1983 				       struct drm_dp_mst_branch *mstb)
1984 {
1985 	struct drm_dp_mst_branch *rmstb = NULL;
1986 
1987 	mutex_lock(&mgr->lock);
1988 	if (mgr->mst_primary) {
1989 		rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1990 		    mgr->mst_primary, mstb);
1991 
1992 		if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1993 			rmstb = NULL;
1994 	}
1995 	mutex_unlock(&mgr->lock);
1996 	return rmstb;
1997 }
1998 
1999 static struct drm_dp_mst_port *
drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * to_find)2000 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
2001 					      struct drm_dp_mst_port *to_find)
2002 {
2003 	struct drm_dp_mst_port *port, *mport;
2004 
2005 	list_for_each_entry(port, &mstb->ports, next) {
2006 		if (port == to_find)
2007 			return port;
2008 
2009 		if (port->mstb) {
2010 			mport = drm_dp_mst_topology_get_port_validated_locked(
2011 			    port->mstb, to_find);
2012 			if (mport)
2013 				return mport;
2014 		}
2015 	}
2016 	return NULL;
2017 }
2018 
2019 static struct drm_dp_mst_port *
drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)2020 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
2021 				       struct drm_dp_mst_port *port)
2022 {
2023 	struct drm_dp_mst_port *rport = NULL;
2024 
2025 	mutex_lock(&mgr->lock);
2026 	if (mgr->mst_primary) {
2027 		rport = drm_dp_mst_topology_get_port_validated_locked(
2028 		    mgr->mst_primary, port);
2029 
2030 		if (rport && !drm_dp_mst_topology_try_get_port(rport))
2031 			rport = NULL;
2032 	}
2033 	mutex_unlock(&mgr->lock);
2034 	return rport;
2035 }
2036 
drm_dp_get_port(struct drm_dp_mst_branch * mstb,u8 port_num)2037 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2038 {
2039 	struct drm_dp_mst_port *port;
2040 	int ret;
2041 
2042 	list_for_each_entry(port, &mstb->ports, next) {
2043 		if (port->port_num == port_num) {
2044 			ret = drm_dp_mst_topology_try_get_port(port);
2045 			return ret ? port : NULL;
2046 		}
2047 	}
2048 
2049 	return NULL;
2050 }
2051 
2052 /*
2053  * calculate a new RAD for this MST branch device
2054  * if parent has an LCT of 2 then it has 1 nibble of RAD,
2055  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2056  */
drm_dp_calculate_rad(struct drm_dp_mst_port * port,u8 * rad)2057 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2058 				 u8 *rad)
2059 {
2060 	int parent_lct = port->parent->lct;
2061 	int shift = 4;
2062 	int idx = (parent_lct - 1) / 2;
2063 
2064 	if (parent_lct > 1) {
2065 		memcpy(rad, port->parent->rad, idx + 1);
2066 		shift = (parent_lct % 2) ? 4 : 0;
2067 	} else
2068 		rad[0] = 0;
2069 
2070 	rad[idx] |= port->port_num << shift;
2071 	return parent_lct + 1;
2072 }
2073 
drm_dp_mst_is_end_device(u8 pdt,bool mcs)2074 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2075 {
2076 	switch (pdt) {
2077 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2078 	case DP_PEER_DEVICE_SST_SINK:
2079 		return true;
2080 	case DP_PEER_DEVICE_MST_BRANCHING:
2081 		/* For sst branch device */
2082 		if (!mcs)
2083 			return true;
2084 
2085 		return false;
2086 	}
2087 	return true;
2088 }
2089 
2090 static int
drm_dp_port_set_pdt(struct drm_dp_mst_port * port,u8 new_pdt,bool new_mcs)2091 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2092 		    bool new_mcs)
2093 {
2094 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2095 	struct drm_dp_mst_branch *mstb;
2096 	u8 rad[8], lct;
2097 	int ret = 0;
2098 
2099 	if (port->pdt == new_pdt && port->mcs == new_mcs)
2100 		return 0;
2101 
2102 	/* Teardown the old pdt, if there is one */
2103 	if (port->pdt != DP_PEER_DEVICE_NONE) {
2104 		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2105 			/*
2106 			 * If the new PDT would also have an i2c bus,
2107 			 * don't bother with reregistering it
2108 			 */
2109 			if (new_pdt != DP_PEER_DEVICE_NONE &&
2110 			    drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2111 				port->pdt = new_pdt;
2112 				port->mcs = new_mcs;
2113 				return 0;
2114 			}
2115 
2116 			/* remove i2c over sideband */
2117 			drm_dp_mst_unregister_i2c_bus(port);
2118 		} else {
2119 			mutex_lock(&mgr->lock);
2120 			drm_dp_mst_topology_put_mstb(port->mstb);
2121 			port->mstb = NULL;
2122 			mutex_unlock(&mgr->lock);
2123 		}
2124 	}
2125 
2126 	port->pdt = new_pdt;
2127 	port->mcs = new_mcs;
2128 
2129 	if (port->pdt != DP_PEER_DEVICE_NONE) {
2130 		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2131 			/* add i2c over sideband */
2132 			ret = drm_dp_mst_register_i2c_bus(port);
2133 		} else {
2134 			lct = drm_dp_calculate_rad(port, rad);
2135 			mstb = drm_dp_add_mst_branch_device(lct, rad);
2136 			if (!mstb) {
2137 				ret = -ENOMEM;
2138 				drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2139 				goto out;
2140 			}
2141 
2142 			mutex_lock(&mgr->lock);
2143 			port->mstb = mstb;
2144 			mstb->mgr = port->mgr;
2145 			mstb->port_parent = port;
2146 
2147 			/*
2148 			 * Make sure this port's memory allocation stays
2149 			 * around until its child MSTB releases it
2150 			 */
2151 			drm_dp_mst_get_port_malloc(port);
2152 			mutex_unlock(&mgr->lock);
2153 
2154 			/* And make sure we send a link address for this */
2155 			ret = 1;
2156 		}
2157 	}
2158 
2159 out:
2160 	if (ret < 0)
2161 		port->pdt = DP_PEER_DEVICE_NONE;
2162 	return ret;
2163 }
2164 
2165 /**
2166  * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2167  * @aux: Fake sideband AUX CH
2168  * @offset: address of the (first) register to read
2169  * @buffer: buffer to store the register values
2170  * @size: number of bytes in @buffer
2171  *
2172  * Performs the same functionality for remote devices via
2173  * sideband messaging as drm_dp_dpcd_read() does for local
2174  * devices via actual AUX CH.
2175  *
2176  * Return: Number of bytes read, or negative error code on failure.
2177  */
drm_dp_mst_dpcd_read(struct drm_dp_aux * aux,unsigned int offset,void * buffer,size_t size)2178 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2179 			     unsigned int offset, void *buffer, size_t size)
2180 {
2181 	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2182 						    aux);
2183 
2184 	return drm_dp_send_dpcd_read(port->mgr, port,
2185 				     offset, size, buffer);
2186 }
2187 
2188 /**
2189  * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2190  * @aux: Fake sideband AUX CH
2191  * @offset: address of the (first) register to write
2192  * @buffer: buffer containing the values to write
2193  * @size: number of bytes in @buffer
2194  *
2195  * Performs the same functionality for remote devices via
2196  * sideband messaging as drm_dp_dpcd_write() does for local
2197  * devices via actual AUX CH.
2198  *
2199  * Return: number of bytes written on success, negative error code on failure.
2200  */
drm_dp_mst_dpcd_write(struct drm_dp_aux * aux,unsigned int offset,void * buffer,size_t size)2201 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2202 			      unsigned int offset, void *buffer, size_t size)
2203 {
2204 	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2205 						    aux);
2206 
2207 	return drm_dp_send_dpcd_write(port->mgr, port,
2208 				      offset, size, buffer);
2209 }
2210 
drm_dp_check_mstb_guid(struct drm_dp_mst_branch * mstb,u8 * guid)2211 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2212 {
2213 	int ret = 0;
2214 
2215 	memcpy(mstb->guid, guid, 16);
2216 
2217 	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2218 		if (mstb->port_parent) {
2219 			ret = drm_dp_send_dpcd_write(mstb->mgr,
2220 						     mstb->port_parent,
2221 						     DP_GUID, 16, mstb->guid);
2222 		} else {
2223 			ret = drm_dp_dpcd_write(mstb->mgr->aux,
2224 						DP_GUID, mstb->guid, 16);
2225 		}
2226 	}
2227 
2228 	if (ret < 16 && ret > 0)
2229 		return -EPROTO;
2230 
2231 	return ret == 16 ? 0 : ret;
2232 }
2233 
build_mst_prop_path(const struct drm_dp_mst_branch * mstb,int pnum,char * proppath,size_t proppath_size)2234 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2235 				int pnum,
2236 				char *proppath,
2237 				size_t proppath_size)
2238 {
2239 	int i;
2240 	char temp[8];
2241 
2242 	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2243 	for (i = 0; i < (mstb->lct - 1); i++) {
2244 		int shift = (i % 2) ? 0 : 4;
2245 		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2246 
2247 		snprintf(temp, sizeof(temp), "-%d", port_num);
2248 		strlcat(proppath, temp, proppath_size);
2249 	}
2250 	snprintf(temp, sizeof(temp), "-%d", pnum);
2251 	strlcat(proppath, temp, proppath_size);
2252 }
2253 
2254 /**
2255  * drm_dp_mst_connector_late_register() - Late MST connector registration
2256  * @connector: The MST connector
2257  * @port: The MST port for this connector
2258  *
2259  * Helper to register the remote aux device for this MST port. Drivers should
2260  * call this from their mst connector's late_register hook to enable MST aux
2261  * devices.
2262  *
2263  * Return: 0 on success, negative error code on failure.
2264  */
drm_dp_mst_connector_late_register(struct drm_connector * connector,struct drm_dp_mst_port * port)2265 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2266 				       struct drm_dp_mst_port *port)
2267 {
2268 	drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2269 		    port->aux.name, connector->kdev->kobj.name);
2270 
2271 	port->aux.dev = connector->kdev;
2272 	return drm_dp_aux_register_devnode(&port->aux);
2273 }
2274 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2275 
2276 /**
2277  * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2278  * @connector: The MST connector
2279  * @port: The MST port for this connector
2280  *
2281  * Helper to unregister the remote aux device for this MST port, registered by
2282  * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2283  * connector's early_unregister hook.
2284  */
drm_dp_mst_connector_early_unregister(struct drm_connector * connector,struct drm_dp_mst_port * port)2285 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2286 					   struct drm_dp_mst_port *port)
2287 {
2288 	drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2289 		    port->aux.name, connector->kdev->kobj.name);
2290 	drm_dp_aux_unregister_devnode(&port->aux);
2291 }
2292 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2293 
2294 static void
drm_dp_mst_port_add_connector(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port)2295 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2296 			      struct drm_dp_mst_port *port)
2297 {
2298 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2299 	char proppath[255];
2300 	int ret;
2301 
2302 	build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2303 	port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2304 	if (!port->connector) {
2305 		ret = -ENOMEM;
2306 		goto error;
2307 	}
2308 
2309 	if (port->pdt != DP_PEER_DEVICE_NONE &&
2310 	    drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2311 	    port->port_num >= DP_MST_LOGICAL_PORT_0)
2312 		port->cached_edid = drm_get_edid(port->connector,
2313 						 &port->aux.ddc);
2314 
2315 	drm_connector_register(port->connector);
2316 	return;
2317 
2318 error:
2319 	drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2320 }
2321 
2322 /*
2323  * Drop a topology reference, and unlink the port from the in-memory topology
2324  * layout
2325  */
2326 static void
drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)2327 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2328 				struct drm_dp_mst_port *port)
2329 {
2330 	mutex_lock(&mgr->lock);
2331 	port->parent->num_ports--;
2332 	list_del(&port->next);
2333 	mutex_unlock(&mgr->lock);
2334 	drm_dp_mst_topology_put_port(port);
2335 }
2336 
2337 static struct drm_dp_mst_port *
drm_dp_mst_add_port(struct drm_device * dev,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,u8 port_number)2338 drm_dp_mst_add_port(struct drm_device *dev,
2339 		    struct drm_dp_mst_topology_mgr *mgr,
2340 		    struct drm_dp_mst_branch *mstb, u8 port_number)
2341 {
2342 	struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2343 
2344 	if (!port)
2345 		return NULL;
2346 
2347 	kref_init(&port->topology_kref);
2348 	kref_init(&port->malloc_kref);
2349 	port->parent = mstb;
2350 	port->port_num = port_number;
2351 	port->mgr = mgr;
2352 	port->aux.name = "DPMST";
2353 	port->aux.dev = dev->dev;
2354 	port->aux.is_remote = true;
2355 
2356 	/* initialize the MST downstream port's AUX crc work queue */
2357 	port->aux.drm_dev = dev;
2358 	drm_dp_remote_aux_init(&port->aux);
2359 
2360 	/*
2361 	 * Make sure the memory allocation for our parent branch stays
2362 	 * around until our own memory allocation is released
2363 	 */
2364 	drm_dp_mst_get_mstb_malloc(mstb);
2365 
2366 	return port;
2367 }
2368 
2369 static int
drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch * mstb,struct drm_device * dev,struct drm_dp_link_addr_reply_port * port_msg)2370 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2371 				    struct drm_device *dev,
2372 				    struct drm_dp_link_addr_reply_port *port_msg)
2373 {
2374 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2375 	struct drm_dp_mst_port *port;
2376 	int old_ddps = 0, ret;
2377 	u8 new_pdt = DP_PEER_DEVICE_NONE;
2378 	bool new_mcs = 0;
2379 	bool created = false, send_link_addr = false, changed = false;
2380 
2381 	port = drm_dp_get_port(mstb, port_msg->port_number);
2382 	if (!port) {
2383 		port = drm_dp_mst_add_port(dev, mgr, mstb,
2384 					   port_msg->port_number);
2385 		if (!port)
2386 			return -ENOMEM;
2387 		created = true;
2388 		changed = true;
2389 	} else if (!port->input && port_msg->input_port && port->connector) {
2390 		/* Since port->connector can't be changed here, we create a
2391 		 * new port if input_port changes from 0 to 1
2392 		 */
2393 		drm_dp_mst_topology_unlink_port(mgr, port);
2394 		drm_dp_mst_topology_put_port(port);
2395 		port = drm_dp_mst_add_port(dev, mgr, mstb,
2396 					   port_msg->port_number);
2397 		if (!port)
2398 			return -ENOMEM;
2399 		changed = true;
2400 		created = true;
2401 	} else if (port->input && !port_msg->input_port) {
2402 		changed = true;
2403 	} else if (port->connector) {
2404 		/* We're updating a port that's exposed to userspace, so do it
2405 		 * under lock
2406 		 */
2407 		drm_modeset_lock(&mgr->base.lock, NULL);
2408 
2409 		old_ddps = port->ddps;
2410 		changed = port->ddps != port_msg->ddps ||
2411 			(port->ddps &&
2412 			 (port->ldps != port_msg->legacy_device_plug_status ||
2413 			  port->dpcd_rev != port_msg->dpcd_revision ||
2414 			  port->mcs != port_msg->mcs ||
2415 			  port->pdt != port_msg->peer_device_type ||
2416 			  port->num_sdp_stream_sinks !=
2417 			  port_msg->num_sdp_stream_sinks));
2418 	}
2419 
2420 	port->input = port_msg->input_port;
2421 	if (!port->input)
2422 		new_pdt = port_msg->peer_device_type;
2423 	new_mcs = port_msg->mcs;
2424 	port->ddps = port_msg->ddps;
2425 	port->ldps = port_msg->legacy_device_plug_status;
2426 	port->dpcd_rev = port_msg->dpcd_revision;
2427 	port->num_sdp_streams = port_msg->num_sdp_streams;
2428 	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2429 
2430 	/* manage mstb port lists with mgr lock - take a reference
2431 	   for this list */
2432 	if (created) {
2433 		mutex_lock(&mgr->lock);
2434 		drm_dp_mst_topology_get_port(port);
2435 		list_add(&port->next, &mstb->ports);
2436 		mstb->num_ports++;
2437 		mutex_unlock(&mgr->lock);
2438 	}
2439 
2440 	/*
2441 	 * Reprobe PBN caps on both hotplug, and when re-probing the link
2442 	 * for our parent mstb
2443 	 */
2444 	if (old_ddps != port->ddps || !created) {
2445 		if (port->ddps && !port->input) {
2446 			ret = drm_dp_send_enum_path_resources(mgr, mstb,
2447 							      port);
2448 			if (ret == 1)
2449 				changed = true;
2450 		} else {
2451 			port->full_pbn = 0;
2452 		}
2453 	}
2454 
2455 	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2456 	if (ret == 1) {
2457 		send_link_addr = true;
2458 	} else if (ret < 0) {
2459 		drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2460 		goto fail;
2461 	}
2462 
2463 	/*
2464 	 * If this port wasn't just created, then we're reprobing because
2465 	 * we're coming out of suspend. In this case, always resend the link
2466 	 * address if there's an MSTB on this port
2467 	 */
2468 	if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2469 	    port->mcs)
2470 		send_link_addr = true;
2471 
2472 	if (port->connector)
2473 		drm_modeset_unlock(&mgr->base.lock);
2474 	else if (!port->input)
2475 		drm_dp_mst_port_add_connector(mstb, port);
2476 
2477 	if (send_link_addr && port->mstb) {
2478 		ret = drm_dp_send_link_address(mgr, port->mstb);
2479 		if (ret == 1) /* MSTB below us changed */
2480 			changed = true;
2481 		else if (ret < 0)
2482 			goto fail_put;
2483 	}
2484 
2485 	/* put reference to this port */
2486 	drm_dp_mst_topology_put_port(port);
2487 	return changed;
2488 
2489 fail:
2490 	drm_dp_mst_topology_unlink_port(mgr, port);
2491 	if (port->connector)
2492 		drm_modeset_unlock(&mgr->base.lock);
2493 fail_put:
2494 	drm_dp_mst_topology_put_port(port);
2495 	return ret;
2496 }
2497 
2498 static void
drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch * mstb,struct drm_dp_connection_status_notify * conn_stat)2499 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2500 			    struct drm_dp_connection_status_notify *conn_stat)
2501 {
2502 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2503 	struct drm_dp_mst_port *port;
2504 	int old_ddps, ret;
2505 	u8 new_pdt;
2506 	bool new_mcs;
2507 	bool dowork = false, create_connector = false;
2508 
2509 	port = drm_dp_get_port(mstb, conn_stat->port_number);
2510 	if (!port)
2511 		return;
2512 
2513 	if (port->connector) {
2514 		if (!port->input && conn_stat->input_port) {
2515 			/*
2516 			 * We can't remove a connector from an already exposed
2517 			 * port, so just throw the port out and make sure we
2518 			 * reprobe the link address of it's parent MSTB
2519 			 */
2520 			drm_dp_mst_topology_unlink_port(mgr, port);
2521 			mstb->link_address_sent = false;
2522 			dowork = true;
2523 			goto out;
2524 		}
2525 
2526 		/* Locking is only needed if the port's exposed to userspace */
2527 		drm_modeset_lock(&mgr->base.lock, NULL);
2528 	} else if (port->input && !conn_stat->input_port) {
2529 		create_connector = true;
2530 		/* Reprobe link address so we get num_sdp_streams */
2531 		mstb->link_address_sent = false;
2532 		dowork = true;
2533 	}
2534 
2535 	old_ddps = port->ddps;
2536 	port->input = conn_stat->input_port;
2537 	port->ldps = conn_stat->legacy_device_plug_status;
2538 	port->ddps = conn_stat->displayport_device_plug_status;
2539 
2540 	if (old_ddps != port->ddps) {
2541 		if (port->ddps && !port->input)
2542 			drm_dp_send_enum_path_resources(mgr, mstb, port);
2543 		else
2544 			port->full_pbn = 0;
2545 	}
2546 
2547 	new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2548 	new_mcs = conn_stat->message_capability_status;
2549 	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2550 	if (ret == 1) {
2551 		dowork = true;
2552 	} else if (ret < 0) {
2553 		drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2554 		dowork = false;
2555 	}
2556 
2557 	if (port->connector)
2558 		drm_modeset_unlock(&mgr->base.lock);
2559 	else if (create_connector)
2560 		drm_dp_mst_port_add_connector(mstb, port);
2561 
2562 out:
2563 	drm_dp_mst_topology_put_port(port);
2564 	if (dowork)
2565 		queue_work(system_long_wq, &mstb->mgr->work);
2566 }
2567 
drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr * mgr,u8 lct,u8 * rad)2568 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2569 							       u8 lct, u8 *rad)
2570 {
2571 	struct drm_dp_mst_branch *mstb;
2572 	struct drm_dp_mst_port *port;
2573 	int i, ret;
2574 	/* find the port by iterating down */
2575 
2576 	mutex_lock(&mgr->lock);
2577 	mstb = mgr->mst_primary;
2578 
2579 	if (!mstb)
2580 		goto out;
2581 
2582 	for (i = 0; i < lct - 1; i++) {
2583 		int shift = (i % 2) ? 0 : 4;
2584 		int port_num = (rad[i / 2] >> shift) & 0xf;
2585 
2586 		list_for_each_entry(port, &mstb->ports, next) {
2587 			if (port->port_num == port_num) {
2588 				mstb = port->mstb;
2589 				if (!mstb) {
2590 					drm_err(mgr->dev,
2591 						"failed to lookup MSTB with lct %d, rad %02x\n",
2592 						lct, rad[0]);
2593 					goto out;
2594 				}
2595 
2596 				break;
2597 			}
2598 		}
2599 	}
2600 	ret = drm_dp_mst_topology_try_get_mstb(mstb);
2601 	if (!ret)
2602 		mstb = NULL;
2603 out:
2604 	mutex_unlock(&mgr->lock);
2605 	return mstb;
2606 }
2607 
get_mst_branch_device_by_guid_helper(struct drm_dp_mst_branch * mstb,const uint8_t * guid)2608 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2609 	struct drm_dp_mst_branch *mstb,
2610 	const uint8_t *guid)
2611 {
2612 	struct drm_dp_mst_branch *found_mstb;
2613 	struct drm_dp_mst_port *port;
2614 
2615 	if (memcmp(mstb->guid, guid, 16) == 0)
2616 		return mstb;
2617 
2618 
2619 	list_for_each_entry(port, &mstb->ports, next) {
2620 		if (!port->mstb)
2621 			continue;
2622 
2623 		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2624 
2625 		if (found_mstb)
2626 			return found_mstb;
2627 	}
2628 
2629 	return NULL;
2630 }
2631 
2632 static struct drm_dp_mst_branch *
drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr * mgr,const uint8_t * guid)2633 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2634 				     const uint8_t *guid)
2635 {
2636 	struct drm_dp_mst_branch *mstb;
2637 	int ret;
2638 
2639 	/* find the port by iterating down */
2640 	mutex_lock(&mgr->lock);
2641 
2642 	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2643 	if (mstb) {
2644 		ret = drm_dp_mst_topology_try_get_mstb(mstb);
2645 		if (!ret)
2646 			mstb = NULL;
2647 	}
2648 
2649 	mutex_unlock(&mgr->lock);
2650 	return mstb;
2651 }
2652 
drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)2653 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2654 					       struct drm_dp_mst_branch *mstb)
2655 {
2656 	struct drm_dp_mst_port *port;
2657 	int ret;
2658 	bool changed = false;
2659 
2660 	if (!mstb->link_address_sent) {
2661 		ret = drm_dp_send_link_address(mgr, mstb);
2662 		if (ret == 1)
2663 			changed = true;
2664 		else if (ret < 0)
2665 			return ret;
2666 	}
2667 
2668 	list_for_each_entry(port, &mstb->ports, next) {
2669 		struct drm_dp_mst_branch *mstb_child = NULL;
2670 
2671 		if (port->input || !port->ddps)
2672 			continue;
2673 
2674 		if (port->mstb)
2675 			mstb_child = drm_dp_mst_topology_get_mstb_validated(
2676 			    mgr, port->mstb);
2677 
2678 		if (mstb_child) {
2679 			ret = drm_dp_check_and_send_link_address(mgr,
2680 								 mstb_child);
2681 			drm_dp_mst_topology_put_mstb(mstb_child);
2682 			if (ret == 1)
2683 				changed = true;
2684 			else if (ret < 0)
2685 				return ret;
2686 		}
2687 	}
2688 
2689 	return changed;
2690 }
2691 
drm_dp_mst_link_probe_work(struct work_struct * work)2692 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2693 {
2694 	struct drm_dp_mst_topology_mgr *mgr =
2695 		container_of(work, struct drm_dp_mst_topology_mgr, work);
2696 	struct drm_device *dev = mgr->dev;
2697 	struct drm_dp_mst_branch *mstb;
2698 	int ret;
2699 	bool clear_payload_id_table;
2700 
2701 	mutex_lock(&mgr->probe_lock);
2702 
2703 	mutex_lock(&mgr->lock);
2704 	clear_payload_id_table = !mgr->payload_id_table_cleared;
2705 	mgr->payload_id_table_cleared = true;
2706 
2707 	mstb = mgr->mst_primary;
2708 	if (mstb) {
2709 		ret = drm_dp_mst_topology_try_get_mstb(mstb);
2710 		if (!ret)
2711 			mstb = NULL;
2712 	}
2713 	mutex_unlock(&mgr->lock);
2714 	if (!mstb) {
2715 		mutex_unlock(&mgr->probe_lock);
2716 		return;
2717 	}
2718 
2719 	/*
2720 	 * Certain branch devices seem to incorrectly report an available_pbn
2721 	 * of 0 on downstream sinks, even after clearing the
2722 	 * DP_PAYLOAD_ALLOCATE_* registers in
2723 	 * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2724 	 * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2725 	 * things work again.
2726 	 */
2727 	if (clear_payload_id_table) {
2728 		drm_dbg_kms(dev, "Clearing payload ID table\n");
2729 		drm_dp_send_clear_payload_id_table(mgr, mstb);
2730 	}
2731 
2732 	ret = drm_dp_check_and_send_link_address(mgr, mstb);
2733 	drm_dp_mst_topology_put_mstb(mstb);
2734 
2735 	mutex_unlock(&mgr->probe_lock);
2736 	if (ret > 0)
2737 		drm_kms_helper_hotplug_event(dev);
2738 }
2739 
drm_dp_validate_guid(struct drm_dp_mst_topology_mgr * mgr,u8 * guid)2740 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2741 				 u8 *guid)
2742 {
2743 	u64 salt;
2744 
2745 	if (memchr_inv(guid, 0, 16))
2746 		return true;
2747 
2748 	salt = get_jiffies_64();
2749 
2750 	memcpy(&guid[0], &salt, sizeof(u64));
2751 	memcpy(&guid[8], &salt, sizeof(u64));
2752 
2753 	return false;
2754 }
2755 
build_dpcd_read(struct drm_dp_sideband_msg_tx * msg,u8 port_num,u32 offset,u8 num_bytes)2756 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2757 			    u8 port_num, u32 offset, u8 num_bytes)
2758 {
2759 	struct drm_dp_sideband_msg_req_body req;
2760 
2761 	req.req_type = DP_REMOTE_DPCD_READ;
2762 	req.u.dpcd_read.port_number = port_num;
2763 	req.u.dpcd_read.dpcd_address = offset;
2764 	req.u.dpcd_read.num_bytes = num_bytes;
2765 	drm_dp_encode_sideband_req(&req, msg);
2766 }
2767 
drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr * mgr,bool up,u8 * msg,int len)2768 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2769 				    bool up, u8 *msg, int len)
2770 {
2771 	int ret;
2772 	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2773 	int tosend, total, offset;
2774 	int retries = 0;
2775 
2776 retry:
2777 	total = len;
2778 	offset = 0;
2779 	do {
2780 		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2781 
2782 		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2783 					&msg[offset],
2784 					tosend);
2785 		if (ret != tosend) {
2786 			if (ret == -EIO && retries < 5) {
2787 				retries++;
2788 				goto retry;
2789 			}
2790 			drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2791 
2792 			return -EIO;
2793 		}
2794 		offset += tosend;
2795 		total -= tosend;
2796 	} while (total > 0);
2797 	return 0;
2798 }
2799 
set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr * hdr,struct drm_dp_sideband_msg_tx * txmsg)2800 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2801 				  struct drm_dp_sideband_msg_tx *txmsg)
2802 {
2803 	struct drm_dp_mst_branch *mstb = txmsg->dst;
2804 	u8 req_type;
2805 
2806 	req_type = txmsg->msg[0] & 0x7f;
2807 	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2808 		req_type == DP_RESOURCE_STATUS_NOTIFY ||
2809 		req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2810 		hdr->broadcast = 1;
2811 	else
2812 		hdr->broadcast = 0;
2813 	hdr->path_msg = txmsg->path_msg;
2814 	if (hdr->broadcast) {
2815 		hdr->lct = 1;
2816 		hdr->lcr = 6;
2817 	} else {
2818 		hdr->lct = mstb->lct;
2819 		hdr->lcr = mstb->lct - 1;
2820 	}
2821 
2822 	memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2823 
2824 	return 0;
2825 }
2826 /*
2827  * process a single block of the next message in the sideband queue
2828  */
process_single_tx_qlock(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg,bool up)2829 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2830 				   struct drm_dp_sideband_msg_tx *txmsg,
2831 				   bool up)
2832 {
2833 	u8 chunk[48];
2834 	struct drm_dp_sideband_msg_hdr hdr;
2835 	int len, space, idx, tosend;
2836 	int ret;
2837 
2838 	if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2839 		return 0;
2840 
2841 	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2842 
2843 	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2844 		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2845 
2846 	/* make hdr from dst mst */
2847 	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2848 	if (ret < 0)
2849 		return ret;
2850 
2851 	/* amount left to send in this message */
2852 	len = txmsg->cur_len - txmsg->cur_offset;
2853 
2854 	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2855 	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2856 
2857 	tosend = min(len, space);
2858 	if (len == txmsg->cur_len)
2859 		hdr.somt = 1;
2860 	if (space >= len)
2861 		hdr.eomt = 1;
2862 
2863 
2864 	hdr.msg_len = tosend + 1;
2865 	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2866 	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2867 	/* add crc at end */
2868 	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2869 	idx += tosend + 1;
2870 
2871 	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2872 	if (ret) {
2873 		if (drm_debug_enabled(DRM_UT_DP)) {
2874 			struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2875 
2876 			drm_printf(&p, "sideband msg failed to send\n");
2877 			drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2878 		}
2879 		return ret;
2880 	}
2881 
2882 	txmsg->cur_offset += tosend;
2883 	if (txmsg->cur_offset == txmsg->cur_len) {
2884 		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2885 		return 1;
2886 	}
2887 	return 0;
2888 }
2889 
process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr * mgr)2890 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2891 {
2892 	struct drm_dp_sideband_msg_tx *txmsg;
2893 	int ret;
2894 
2895 	WARN_ON(!mutex_is_locked(&mgr->qlock));
2896 
2897 	/* construct a chunk from the first msg in the tx_msg queue */
2898 	if (list_empty(&mgr->tx_msg_downq))
2899 		return;
2900 
2901 	txmsg = list_first_entry(&mgr->tx_msg_downq,
2902 				 struct drm_dp_sideband_msg_tx, next);
2903 	ret = process_single_tx_qlock(mgr, txmsg, false);
2904 	if (ret < 0) {
2905 		drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2906 		list_del(&txmsg->next);
2907 		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2908 		wake_up_all(&mgr->tx_waitq);
2909 	}
2910 }
2911 
drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg)2912 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2913 				 struct drm_dp_sideband_msg_tx *txmsg)
2914 {
2915 	mutex_lock(&mgr->qlock);
2916 	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2917 
2918 	if (drm_debug_enabled(DRM_UT_DP)) {
2919 		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2920 
2921 		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2922 	}
2923 
2924 	if (list_is_singular(&mgr->tx_msg_downq))
2925 		process_single_down_tx_qlock(mgr);
2926 	mutex_unlock(&mgr->qlock);
2927 }
2928 
2929 static void
drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_link_address_ack_reply * reply)2930 drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2931 			 struct drm_dp_link_address_ack_reply *reply)
2932 {
2933 	struct drm_dp_link_addr_reply_port *port_reply;
2934 	int i;
2935 
2936 	for (i = 0; i < reply->nports; i++) {
2937 		port_reply = &reply->ports[i];
2938 		drm_dbg_kms(mgr->dev,
2939 			    "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2940 			    i,
2941 			    port_reply->input_port,
2942 			    port_reply->peer_device_type,
2943 			    port_reply->port_number,
2944 			    port_reply->dpcd_revision,
2945 			    port_reply->mcs,
2946 			    port_reply->ddps,
2947 			    port_reply->legacy_device_plug_status,
2948 			    port_reply->num_sdp_streams,
2949 			    port_reply->num_sdp_stream_sinks);
2950 	}
2951 }
2952 
drm_dp_send_link_address(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)2953 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2954 				     struct drm_dp_mst_branch *mstb)
2955 {
2956 	struct drm_dp_sideband_msg_tx *txmsg;
2957 	struct drm_dp_link_address_ack_reply *reply;
2958 	struct drm_dp_mst_port *port, *tmp;
2959 	int i, ret, port_mask = 0;
2960 	bool changed = false;
2961 
2962 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2963 	if (!txmsg)
2964 		return -ENOMEM;
2965 
2966 	txmsg->dst = mstb;
2967 	build_link_address(txmsg);
2968 
2969 	mstb->link_address_sent = true;
2970 	drm_dp_queue_down_tx(mgr, txmsg);
2971 
2972 	/* FIXME: Actually do some real error handling here */
2973 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2974 	if (ret <= 0) {
2975 		drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2976 		goto out;
2977 	}
2978 	if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2979 		drm_err(mgr->dev, "link address NAK received\n");
2980 		ret = -EIO;
2981 		goto out;
2982 	}
2983 
2984 	reply = &txmsg->reply.u.link_addr;
2985 	drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2986 	drm_dp_dump_link_address(mgr, reply);
2987 
2988 	ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2989 	if (ret) {
2990 		char buf[64];
2991 
2992 		drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2993 		drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2994 		goto out;
2995 	}
2996 
2997 	for (i = 0; i < reply->nports; i++) {
2998 		port_mask |= BIT(reply->ports[i].port_number);
2999 		ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
3000 							  &reply->ports[i]);
3001 		if (ret == 1)
3002 			changed = true;
3003 		else if (ret < 0)
3004 			goto out;
3005 	}
3006 
3007 	/* Prune any ports that are currently a part of mstb in our in-memory
3008 	 * topology, but were not seen in this link address. Usually this
3009 	 * means that they were removed while the topology was out of sync,
3010 	 * e.g. during suspend/resume
3011 	 */
3012 	mutex_lock(&mgr->lock);
3013 	list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
3014 		if (port_mask & BIT(port->port_num))
3015 			continue;
3016 
3017 		drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
3018 			    port->port_num);
3019 		list_del(&port->next);
3020 		drm_dp_mst_topology_put_port(port);
3021 		changed = true;
3022 	}
3023 	mutex_unlock(&mgr->lock);
3024 
3025 out:
3026 	if (ret <= 0)
3027 		mstb->link_address_sent = false;
3028 	kfree(txmsg);
3029 	return ret < 0 ? ret : changed;
3030 }
3031 
3032 static void
drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)3033 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
3034 				   struct drm_dp_mst_branch *mstb)
3035 {
3036 	struct drm_dp_sideband_msg_tx *txmsg;
3037 	int ret;
3038 
3039 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3040 	if (!txmsg)
3041 		return;
3042 
3043 	txmsg->dst = mstb;
3044 	build_clear_payload_id_table(txmsg);
3045 
3046 	drm_dp_queue_down_tx(mgr, txmsg);
3047 
3048 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3049 	if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3050 		drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3051 
3052 	kfree(txmsg);
3053 }
3054 
3055 static int
drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port)3056 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3057 				struct drm_dp_mst_branch *mstb,
3058 				struct drm_dp_mst_port *port)
3059 {
3060 	struct drm_dp_enum_path_resources_ack_reply *path_res;
3061 	struct drm_dp_sideband_msg_tx *txmsg;
3062 	int ret;
3063 
3064 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3065 	if (!txmsg)
3066 		return -ENOMEM;
3067 
3068 	txmsg->dst = mstb;
3069 	build_enum_path_resources(txmsg, port->port_num);
3070 
3071 	drm_dp_queue_down_tx(mgr, txmsg);
3072 
3073 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3074 	if (ret > 0) {
3075 		ret = 0;
3076 		path_res = &txmsg->reply.u.path_resources;
3077 
3078 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3079 			drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3080 		} else {
3081 			if (port->port_num != path_res->port_number)
3082 				DRM_ERROR("got incorrect port in response\n");
3083 
3084 			drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3085 				    path_res->port_number,
3086 				    path_res->full_payload_bw_number,
3087 				    path_res->avail_payload_bw_number);
3088 
3089 			/*
3090 			 * If something changed, make sure we send a
3091 			 * hotplug
3092 			 */
3093 			if (port->full_pbn != path_res->full_payload_bw_number ||
3094 			    port->fec_capable != path_res->fec_capable)
3095 				ret = 1;
3096 
3097 			port->full_pbn = path_res->full_payload_bw_number;
3098 			port->fec_capable = path_res->fec_capable;
3099 		}
3100 	}
3101 
3102 	kfree(txmsg);
3103 	return ret;
3104 }
3105 
drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch * mstb)3106 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3107 {
3108 	if (!mstb->port_parent)
3109 		return NULL;
3110 
3111 	if (mstb->port_parent->mstb != mstb)
3112 		return mstb->port_parent;
3113 
3114 	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3115 }
3116 
3117 /*
3118  * Searches upwards in the topology starting from mstb to try to find the
3119  * closest available parent of mstb that's still connected to the rest of the
3120  * topology. This can be used in order to perform operations like releasing
3121  * payloads, where the branch device which owned the payload may no longer be
3122  * around and thus would require that the payload on the last living relative
3123  * be freed instead.
3124  */
3125 static struct drm_dp_mst_branch *
drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,int * port_num)3126 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3127 					struct drm_dp_mst_branch *mstb,
3128 					int *port_num)
3129 {
3130 	struct drm_dp_mst_branch *rmstb = NULL;
3131 	struct drm_dp_mst_port *found_port;
3132 
3133 	mutex_lock(&mgr->lock);
3134 	if (!mgr->mst_primary)
3135 		goto out;
3136 
3137 	do {
3138 		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3139 		if (!found_port)
3140 			break;
3141 
3142 		if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3143 			rmstb = found_port->parent;
3144 			*port_num = found_port->port_num;
3145 		} else {
3146 			/* Search again, starting from this parent */
3147 			mstb = found_port->parent;
3148 		}
3149 	} while (!rmstb);
3150 out:
3151 	mutex_unlock(&mgr->lock);
3152 	return rmstb;
3153 }
3154 
drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int id,int pbn)3155 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3156 				   struct drm_dp_mst_port *port,
3157 				   int id,
3158 				   int pbn)
3159 {
3160 	struct drm_dp_sideband_msg_tx *txmsg;
3161 	struct drm_dp_mst_branch *mstb;
3162 	int ret, port_num;
3163 	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3164 	int i;
3165 
3166 	port_num = port->port_num;
3167 	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3168 	if (!mstb) {
3169 		mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3170 							       port->parent,
3171 							       &port_num);
3172 
3173 		if (!mstb)
3174 			return -EINVAL;
3175 	}
3176 
3177 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3178 	if (!txmsg) {
3179 		ret = -ENOMEM;
3180 		goto fail_put;
3181 	}
3182 
3183 	for (i = 0; i < port->num_sdp_streams; i++)
3184 		sinks[i] = i;
3185 
3186 	txmsg->dst = mstb;
3187 	build_allocate_payload(txmsg, port_num,
3188 			       id,
3189 			       pbn, port->num_sdp_streams, sinks);
3190 
3191 	drm_dp_queue_down_tx(mgr, txmsg);
3192 
3193 	/*
3194 	 * FIXME: there is a small chance that between getting the last
3195 	 * connected mstb and sending the payload message, the last connected
3196 	 * mstb could also be removed from the topology. In the future, this
3197 	 * needs to be fixed by restarting the
3198 	 * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3199 	 * timeout if the topology is still connected to the system.
3200 	 */
3201 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3202 	if (ret > 0) {
3203 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3204 			ret = -EINVAL;
3205 		else
3206 			ret = 0;
3207 	}
3208 	kfree(txmsg);
3209 fail_put:
3210 	drm_dp_mst_topology_put_mstb(mstb);
3211 	return ret;
3212 }
3213 
drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,bool power_up)3214 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3215 				 struct drm_dp_mst_port *port, bool power_up)
3216 {
3217 	struct drm_dp_sideband_msg_tx *txmsg;
3218 	int ret;
3219 
3220 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3221 	if (!port)
3222 		return -EINVAL;
3223 
3224 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3225 	if (!txmsg) {
3226 		drm_dp_mst_topology_put_port(port);
3227 		return -ENOMEM;
3228 	}
3229 
3230 	txmsg->dst = port->parent;
3231 	build_power_updown_phy(txmsg, port->port_num, power_up);
3232 	drm_dp_queue_down_tx(mgr, txmsg);
3233 
3234 	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3235 	if (ret > 0) {
3236 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3237 			ret = -EINVAL;
3238 		else
3239 			ret = 0;
3240 	}
3241 	kfree(txmsg);
3242 	drm_dp_mst_topology_put_port(port);
3243 
3244 	return ret;
3245 }
3246 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3247 
drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,struct drm_dp_query_stream_enc_status_ack_reply * status)3248 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3249 		struct drm_dp_mst_port *port,
3250 		struct drm_dp_query_stream_enc_status_ack_reply *status)
3251 {
3252 	struct drm_dp_sideband_msg_tx *txmsg;
3253 	u8 nonce[7];
3254 	int ret;
3255 
3256 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3257 	if (!txmsg)
3258 		return -ENOMEM;
3259 
3260 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3261 	if (!port) {
3262 		ret = -EINVAL;
3263 		goto out_get_port;
3264 	}
3265 
3266 	get_random_bytes(nonce, sizeof(nonce));
3267 
3268 	/*
3269 	 * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3270 	 *  transaction at the MST Branch device directly connected to the
3271 	 *  Source"
3272 	 */
3273 	txmsg->dst = mgr->mst_primary;
3274 
3275 	build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
3276 
3277 	drm_dp_queue_down_tx(mgr, txmsg);
3278 
3279 	ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3280 	if (ret < 0) {
3281 		goto out;
3282 	} else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3283 		drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3284 		ret = -ENXIO;
3285 		goto out;
3286 	}
3287 
3288 	ret = 0;
3289 	memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3290 
3291 out:
3292 	drm_dp_mst_topology_put_port(port);
3293 out_get_port:
3294 	kfree(txmsg);
3295 	return ret;
3296 }
3297 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3298 
drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr * mgr,int id,struct drm_dp_payload * payload)3299 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3300 				       int id,
3301 				       struct drm_dp_payload *payload)
3302 {
3303 	int ret;
3304 
3305 	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
3306 	if (ret < 0) {
3307 		payload->payload_state = 0;
3308 		return ret;
3309 	}
3310 	payload->payload_state = DP_PAYLOAD_LOCAL;
3311 	return 0;
3312 }
3313 
drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int id,struct drm_dp_payload * payload)3314 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3315 				       struct drm_dp_mst_port *port,
3316 				       int id,
3317 				       struct drm_dp_payload *payload)
3318 {
3319 	int ret;
3320 
3321 	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
3322 	if (ret < 0)
3323 		return ret;
3324 	payload->payload_state = DP_PAYLOAD_REMOTE;
3325 	return ret;
3326 }
3327 
drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int id,struct drm_dp_payload * payload)3328 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3329 					struct drm_dp_mst_port *port,
3330 					int id,
3331 					struct drm_dp_payload *payload)
3332 {
3333 	drm_dbg_kms(mgr->dev, "\n");
3334 	/* it's okay for these to fail */
3335 	if (port) {
3336 		drm_dp_payload_send_msg(mgr, port, id, 0);
3337 	}
3338 
3339 	drm_dp_dpcd_write_payload(mgr, id, payload);
3340 	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
3341 	return 0;
3342 }
3343 
drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr * mgr,int id,struct drm_dp_payload * payload)3344 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3345 					int id,
3346 					struct drm_dp_payload *payload)
3347 {
3348 	payload->payload_state = 0;
3349 	return 0;
3350 }
3351 
3352 /**
3353  * drm_dp_update_payload_part1() - Execute payload update part 1
3354  * @mgr: manager to use.
3355  * @start_slot: this is the cur slot
3356  *
3357  * NOTE: start_slot is a temporary workaround for non-atomic drivers,
3358  * this will be removed when non-atomic mst helpers are moved out of the helper
3359  *
3360  * This iterates over all proposed virtual channels, and tries to
3361  * allocate space in the link for them. For 0->slots transitions,
3362  * this step just writes the VCPI to the MST device. For slots->0
3363  * transitions, this writes the updated VCPIs and removes the
3364  * remote VC payloads.
3365  *
3366  * after calling this the driver should generate ACT and payload
3367  * packets.
3368  */
drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr * mgr,int start_slot)3369 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr, int start_slot)
3370 {
3371 	struct drm_dp_payload req_payload;
3372 	struct drm_dp_mst_port *port;
3373 	int i, j;
3374 	int cur_slots = start_slot;
3375 	bool skip;
3376 
3377 	mutex_lock(&mgr->payload_lock);
3378 	for (i = 0; i < mgr->max_payloads; i++) {
3379 		struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
3380 		struct drm_dp_payload *payload = &mgr->payloads[i];
3381 		bool put_port = false;
3382 
3383 		/* solve the current payloads - compare to the hw ones
3384 		   - update the hw view */
3385 		req_payload.start_slot = cur_slots;
3386 		if (vcpi) {
3387 			port = container_of(vcpi, struct drm_dp_mst_port,
3388 					    vcpi);
3389 
3390 			mutex_lock(&mgr->lock);
3391 			skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3392 			mutex_unlock(&mgr->lock);
3393 
3394 			if (skip) {
3395 				drm_dbg_kms(mgr->dev,
3396 					    "Virtual channel %d is not in current topology\n",
3397 					    i);
3398 				continue;
3399 			}
3400 			/* Validated ports don't matter if we're releasing
3401 			 * VCPI
3402 			 */
3403 			if (vcpi->num_slots) {
3404 				port = drm_dp_mst_topology_get_port_validated(
3405 				    mgr, port);
3406 				if (!port) {
3407 					if (vcpi->num_slots == payload->num_slots) {
3408 						cur_slots += vcpi->num_slots;
3409 						payload->start_slot = req_payload.start_slot;
3410 						continue;
3411 					} else {
3412 						drm_dbg_kms(mgr->dev,
3413 							    "Fail:set payload to invalid sink");
3414 						mutex_unlock(&mgr->payload_lock);
3415 						return -EINVAL;
3416 					}
3417 				}
3418 				put_port = true;
3419 			}
3420 
3421 			req_payload.num_slots = vcpi->num_slots;
3422 			req_payload.vcpi = vcpi->vcpi;
3423 		} else {
3424 			port = NULL;
3425 			req_payload.num_slots = 0;
3426 		}
3427 
3428 		payload->start_slot = req_payload.start_slot;
3429 		/* work out what is required to happen with this payload */
3430 		if (payload->num_slots != req_payload.num_slots) {
3431 
3432 			/* need to push an update for this payload */
3433 			if (req_payload.num_slots) {
3434 				drm_dp_create_payload_step1(mgr, vcpi->vcpi,
3435 							    &req_payload);
3436 				payload->num_slots = req_payload.num_slots;
3437 				payload->vcpi = req_payload.vcpi;
3438 
3439 			} else if (payload->num_slots) {
3440 				payload->num_slots = 0;
3441 				drm_dp_destroy_payload_step1(mgr, port,
3442 							     payload->vcpi,
3443 							     payload);
3444 				req_payload.payload_state =
3445 					payload->payload_state;
3446 				payload->start_slot = 0;
3447 			}
3448 			payload->payload_state = req_payload.payload_state;
3449 		}
3450 		cur_slots += req_payload.num_slots;
3451 
3452 		if (put_port)
3453 			drm_dp_mst_topology_put_port(port);
3454 	}
3455 
3456 	for (i = 0; i < mgr->max_payloads; /* do nothing */) {
3457 		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
3458 			i++;
3459 			continue;
3460 		}
3461 
3462 		drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
3463 		for (j = i; j < mgr->max_payloads - 1; j++) {
3464 			mgr->payloads[j] = mgr->payloads[j + 1];
3465 			mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
3466 
3467 			if (mgr->proposed_vcpis[j] &&
3468 			    mgr->proposed_vcpis[j]->num_slots) {
3469 				set_bit(j + 1, &mgr->payload_mask);
3470 			} else {
3471 				clear_bit(j + 1, &mgr->payload_mask);
3472 			}
3473 		}
3474 
3475 		memset(&mgr->payloads[mgr->max_payloads - 1], 0,
3476 		       sizeof(struct drm_dp_payload));
3477 		mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
3478 		clear_bit(mgr->max_payloads, &mgr->payload_mask);
3479 	}
3480 	mutex_unlock(&mgr->payload_lock);
3481 
3482 	return 0;
3483 }
3484 EXPORT_SYMBOL(drm_dp_update_payload_part1);
3485 
3486 /**
3487  * drm_dp_update_payload_part2() - Execute payload update part 2
3488  * @mgr: manager to use.
3489  *
3490  * This iterates over all proposed virtual channels, and tries to
3491  * allocate space in the link for them. For 0->slots transitions,
3492  * this step writes the remote VC payload commands. For slots->0
3493  * this just resets some internal state.
3494  */
drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr * mgr)3495 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
3496 {
3497 	struct drm_dp_mst_port *port;
3498 	int i;
3499 	int ret = 0;
3500 	bool skip;
3501 
3502 	mutex_lock(&mgr->payload_lock);
3503 	for (i = 0; i < mgr->max_payloads; i++) {
3504 
3505 		if (!mgr->proposed_vcpis[i])
3506 			continue;
3507 
3508 		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3509 
3510 		mutex_lock(&mgr->lock);
3511 		skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3512 		mutex_unlock(&mgr->lock);
3513 
3514 		if (skip)
3515 			continue;
3516 
3517 		drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
3518 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
3519 			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3520 		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
3521 			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3522 		}
3523 		if (ret) {
3524 			mutex_unlock(&mgr->payload_lock);
3525 			return ret;
3526 		}
3527 	}
3528 	mutex_unlock(&mgr->payload_lock);
3529 	return 0;
3530 }
3531 EXPORT_SYMBOL(drm_dp_update_payload_part2);
3532 
drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int offset,int size,u8 * bytes)3533 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3534 				 struct drm_dp_mst_port *port,
3535 				 int offset, int size, u8 *bytes)
3536 {
3537 	int ret = 0;
3538 	struct drm_dp_sideband_msg_tx *txmsg;
3539 	struct drm_dp_mst_branch *mstb;
3540 
3541 	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3542 	if (!mstb)
3543 		return -EINVAL;
3544 
3545 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3546 	if (!txmsg) {
3547 		ret = -ENOMEM;
3548 		goto fail_put;
3549 	}
3550 
3551 	build_dpcd_read(txmsg, port->port_num, offset, size);
3552 	txmsg->dst = port->parent;
3553 
3554 	drm_dp_queue_down_tx(mgr, txmsg);
3555 
3556 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3557 	if (ret < 0)
3558 		goto fail_free;
3559 
3560 	if (txmsg->reply.reply_type == 1) {
3561 		drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3562 			    mstb, port->port_num, offset, size);
3563 		ret = -EIO;
3564 		goto fail_free;
3565 	}
3566 
3567 	if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3568 		ret = -EPROTO;
3569 		goto fail_free;
3570 	}
3571 
3572 	ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3573 		    size);
3574 	memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3575 
3576 fail_free:
3577 	kfree(txmsg);
3578 fail_put:
3579 	drm_dp_mst_topology_put_mstb(mstb);
3580 
3581 	return ret;
3582 }
3583 
drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int offset,int size,u8 * bytes)3584 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3585 				  struct drm_dp_mst_port *port,
3586 				  int offset, int size, u8 *bytes)
3587 {
3588 	int ret;
3589 	struct drm_dp_sideband_msg_tx *txmsg;
3590 	struct drm_dp_mst_branch *mstb;
3591 
3592 	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3593 	if (!mstb)
3594 		return -EINVAL;
3595 
3596 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3597 	if (!txmsg) {
3598 		ret = -ENOMEM;
3599 		goto fail_put;
3600 	}
3601 
3602 	build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3603 	txmsg->dst = mstb;
3604 
3605 	drm_dp_queue_down_tx(mgr, txmsg);
3606 
3607 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3608 	if (ret > 0) {
3609 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3610 			ret = -EIO;
3611 		else
3612 			ret = size;
3613 	}
3614 
3615 	kfree(txmsg);
3616 fail_put:
3617 	drm_dp_mst_topology_put_mstb(mstb);
3618 	return ret;
3619 }
3620 
drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx * msg,u8 req_type)3621 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3622 {
3623 	struct drm_dp_sideband_msg_reply_body reply;
3624 
3625 	reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3626 	reply.req_type = req_type;
3627 	drm_dp_encode_sideband_reply(&reply, msg);
3628 	return 0;
3629 }
3630 
drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,int req_type,bool broadcast)3631 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3632 				    struct drm_dp_mst_branch *mstb,
3633 				    int req_type, bool broadcast)
3634 {
3635 	struct drm_dp_sideband_msg_tx *txmsg;
3636 
3637 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3638 	if (!txmsg)
3639 		return -ENOMEM;
3640 
3641 	txmsg->dst = mstb;
3642 	drm_dp_encode_up_ack_reply(txmsg, req_type);
3643 
3644 	mutex_lock(&mgr->qlock);
3645 	/* construct a chunk from the first msg in the tx_msg queue */
3646 	process_single_tx_qlock(mgr, txmsg, true);
3647 	mutex_unlock(&mgr->qlock);
3648 
3649 	kfree(txmsg);
3650 	return 0;
3651 }
3652 
3653 /**
3654  * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3655  * @mgr: The &drm_dp_mst_topology_mgr to use
3656  * @link_rate: link rate in 10kbits/s units
3657  * @link_lane_count: lane count
3658  *
3659  * Calculate the total bandwidth of a MultiStream Transport link. The returned
3660  * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3661  * convert the number of PBNs required for a given stream to the number of
3662  * timeslots this stream requires in each MTP.
3663  */
drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr * mgr,int link_rate,int link_lane_count)3664 int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3665 			     int link_rate, int link_lane_count)
3666 {
3667 	if (link_rate == 0 || link_lane_count == 0)
3668 		drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3669 			    link_rate, link_lane_count);
3670 
3671 	/* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3672 	return link_rate * link_lane_count / 54000;
3673 }
3674 EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3675 
3676 /**
3677  * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3678  * @aux: The DP AUX channel to use
3679  * @dpcd: A cached copy of the DPCD capabilities for this sink
3680  *
3681  * Returns: %True if the sink supports MST, %false otherwise
3682  */
drm_dp_read_mst_cap(struct drm_dp_aux * aux,const u8 dpcd[DP_RECEIVER_CAP_SIZE])3683 bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3684 			 const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3685 {
3686 	u8 mstm_cap;
3687 
3688 	if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3689 		return false;
3690 
3691 	if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3692 		return false;
3693 
3694 	return mstm_cap & DP_MST_CAP;
3695 }
3696 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3697 
3698 /**
3699  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3700  * @mgr: manager to set state for
3701  * @mst_state: true to enable MST on this connector - false to disable.
3702  *
3703  * This is called by the driver when it detects an MST capable device plugged
3704  * into a DP MST capable port, or when a DP MST capable device is unplugged.
3705  */
drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr * mgr,bool mst_state)3706 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3707 {
3708 	int ret = 0;
3709 	struct drm_dp_mst_branch *mstb = NULL;
3710 
3711 	mutex_lock(&mgr->payload_lock);
3712 	mutex_lock(&mgr->lock);
3713 	if (mst_state == mgr->mst_state)
3714 		goto out_unlock;
3715 
3716 	mgr->mst_state = mst_state;
3717 	/* set the device into MST mode */
3718 	if (mst_state) {
3719 		struct drm_dp_payload reset_pay;
3720 		int lane_count;
3721 		int link_rate;
3722 
3723 		WARN_ON(mgr->mst_primary);
3724 
3725 		/* get dpcd info */
3726 		ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3727 		if (ret < 0) {
3728 			drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3729 				    mgr->aux->name, ret);
3730 			goto out_unlock;
3731 		}
3732 
3733 		lane_count = min_t(int, mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
3734 		link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr->dpcd[1]), mgr->max_link_rate);
3735 		mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
3736 							link_rate,
3737 							lane_count);
3738 		if (mgr->pbn_div == 0) {
3739 			ret = -EINVAL;
3740 			goto out_unlock;
3741 		}
3742 
3743 		/* add initial branch device at LCT 1 */
3744 		mstb = drm_dp_add_mst_branch_device(1, NULL);
3745 		if (mstb == NULL) {
3746 			ret = -ENOMEM;
3747 			goto out_unlock;
3748 		}
3749 		mstb->mgr = mgr;
3750 
3751 		/* give this the main reference */
3752 		mgr->mst_primary = mstb;
3753 		drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3754 
3755 		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3756 					 DP_MST_EN |
3757 					 DP_UP_REQ_EN |
3758 					 DP_UPSTREAM_IS_SRC);
3759 		if (ret < 0)
3760 			goto out_unlock;
3761 
3762 		reset_pay.start_slot = 0;
3763 		reset_pay.num_slots = 0x3f;
3764 		drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
3765 
3766 		queue_work(system_long_wq, &mgr->work);
3767 
3768 		ret = 0;
3769 	} else {
3770 		/* disable MST on the device */
3771 		mstb = mgr->mst_primary;
3772 		mgr->mst_primary = NULL;
3773 		/* this can fail if the device is gone */
3774 		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3775 		ret = 0;
3776 		memset(mgr->payloads, 0,
3777 		       mgr->max_payloads * sizeof(mgr->payloads[0]));
3778 		memset(mgr->proposed_vcpis, 0,
3779 		       mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
3780 		mgr->payload_mask = 0;
3781 		set_bit(0, &mgr->payload_mask);
3782 		mgr->vcpi_mask = 0;
3783 		mgr->payload_id_table_cleared = false;
3784 	}
3785 
3786 out_unlock:
3787 	mutex_unlock(&mgr->lock);
3788 	mutex_unlock(&mgr->payload_lock);
3789 	if (mstb)
3790 		drm_dp_mst_topology_put_mstb(mstb);
3791 	return ret;
3792 
3793 }
3794 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3795 
3796 static void
drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch * mstb)3797 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3798 {
3799 	struct drm_dp_mst_port *port;
3800 
3801 	/* The link address will need to be re-sent on resume */
3802 	mstb->link_address_sent = false;
3803 
3804 	list_for_each_entry(port, &mstb->ports, next)
3805 		if (port->mstb)
3806 			drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3807 }
3808 
3809 /**
3810  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3811  * @mgr: manager to suspend
3812  *
3813  * This function tells the MST device that we can't handle UP messages
3814  * anymore. This should stop it from sending any since we are suspended.
3815  */
drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr * mgr)3816 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3817 {
3818 	mutex_lock(&mgr->lock);
3819 	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3820 			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
3821 	mutex_unlock(&mgr->lock);
3822 	flush_work(&mgr->up_req_work);
3823 	flush_work(&mgr->work);
3824 	flush_work(&mgr->delayed_destroy_work);
3825 
3826 	mutex_lock(&mgr->lock);
3827 	if (mgr->mst_state && mgr->mst_primary)
3828 		drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3829 	mutex_unlock(&mgr->lock);
3830 }
3831 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3832 
3833 /**
3834  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3835  * @mgr: manager to resume
3836  * @sync: whether or not to perform topology reprobing synchronously
3837  *
3838  * This will fetch DPCD and see if the device is still there,
3839  * if it is, it will rewrite the MSTM control bits, and return.
3840  *
3841  * If the device fails this returns -1, and the driver should do
3842  * a full MST reprobe, in case we were undocked.
3843  *
3844  * During system resume (where it is assumed that the driver will be calling
3845  * drm_atomic_helper_resume()) this function should be called beforehand with
3846  * @sync set to true. In contexts like runtime resume where the driver is not
3847  * expected to be calling drm_atomic_helper_resume(), this function should be
3848  * called with @sync set to false in order to avoid deadlocking.
3849  *
3850  * Returns: -1 if the MST topology was removed while we were suspended, 0
3851  * otherwise.
3852  */
drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr * mgr,bool sync)3853 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3854 				   bool sync)
3855 {
3856 	int ret;
3857 	u8 guid[16];
3858 
3859 	mutex_lock(&mgr->lock);
3860 	if (!mgr->mst_primary)
3861 		goto out_fail;
3862 
3863 	if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
3864 		drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3865 		goto out_fail;
3866 	}
3867 
3868 	ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3869 				 DP_MST_EN |
3870 				 DP_UP_REQ_EN |
3871 				 DP_UPSTREAM_IS_SRC);
3872 	if (ret < 0) {
3873 		drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3874 		goto out_fail;
3875 	}
3876 
3877 	/* Some hubs forget their guids after they resume */
3878 	ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3879 	if (ret != 16) {
3880 		drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3881 		goto out_fail;
3882 	}
3883 
3884 	ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3885 	if (ret) {
3886 		drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3887 		goto out_fail;
3888 	}
3889 
3890 	/*
3891 	 * For the final step of resuming the topology, we need to bring the
3892 	 * state of our in-memory topology back into sync with reality. So,
3893 	 * restart the probing process as if we're probing a new hub
3894 	 */
3895 	queue_work(system_long_wq, &mgr->work);
3896 	mutex_unlock(&mgr->lock);
3897 
3898 	if (sync) {
3899 		drm_dbg_kms(mgr->dev,
3900 			    "Waiting for link probe work to finish re-syncing topology...\n");
3901 		flush_work(&mgr->work);
3902 	}
3903 
3904 	return 0;
3905 
3906 out_fail:
3907 	mutex_unlock(&mgr->lock);
3908 	return -1;
3909 }
3910 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3911 
3912 static bool
drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr * mgr,bool up,struct drm_dp_mst_branch ** mstb)3913 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3914 		      struct drm_dp_mst_branch **mstb)
3915 {
3916 	int len;
3917 	u8 replyblock[32];
3918 	int replylen, curreply;
3919 	int ret;
3920 	u8 hdrlen;
3921 	struct drm_dp_sideband_msg_hdr hdr;
3922 	struct drm_dp_sideband_msg_rx *msg =
3923 		up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3924 	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3925 			   DP_SIDEBAND_MSG_DOWN_REP_BASE;
3926 
3927 	if (!up)
3928 		*mstb = NULL;
3929 
3930 	len = min(mgr->max_dpcd_transaction_bytes, 16);
3931 	ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3932 	if (ret != len) {
3933 		drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3934 		return false;
3935 	}
3936 
3937 	ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3938 	if (ret == false) {
3939 		print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3940 			       1, replyblock, len, false);
3941 		drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3942 		return false;
3943 	}
3944 
3945 	if (!up) {
3946 		/* Caller is responsible for giving back this reference */
3947 		*mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3948 		if (!*mstb) {
3949 			drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3950 			return false;
3951 		}
3952 	}
3953 
3954 	if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3955 		drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3956 		return false;
3957 	}
3958 
3959 	replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3960 	ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3961 	if (!ret) {
3962 		drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3963 		return false;
3964 	}
3965 
3966 	replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3967 	curreply = len;
3968 	while (replylen > 0) {
3969 		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3970 		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3971 				    replyblock, len);
3972 		if (ret != len) {
3973 			drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3974 				    len, ret);
3975 			return false;
3976 		}
3977 
3978 		ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3979 		if (!ret) {
3980 			drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3981 			return false;
3982 		}
3983 
3984 		curreply += len;
3985 		replylen -= len;
3986 	}
3987 	return true;
3988 }
3989 
drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr * mgr)3990 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3991 {
3992 	struct drm_dp_sideband_msg_tx *txmsg;
3993 	struct drm_dp_mst_branch *mstb = NULL;
3994 	struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3995 
3996 	if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3997 		goto out;
3998 
3999 	/* Multi-packet message transmission, don't clear the reply */
4000 	if (!msg->have_eomt)
4001 		goto out;
4002 
4003 	/* find the message */
4004 	mutex_lock(&mgr->qlock);
4005 	txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
4006 					 struct drm_dp_sideband_msg_tx, next);
4007 	mutex_unlock(&mgr->qlock);
4008 
4009 	/* Were we actually expecting a response, and from this mstb? */
4010 	if (!txmsg || txmsg->dst != mstb) {
4011 		struct drm_dp_sideband_msg_hdr *hdr;
4012 
4013 		hdr = &msg->initial_hdr;
4014 		drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
4015 			    mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
4016 		goto out_clear_reply;
4017 	}
4018 
4019 	drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
4020 
4021 	if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
4022 		drm_dbg_kms(mgr->dev,
4023 			    "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
4024 			    txmsg->reply.req_type,
4025 			    drm_dp_mst_req_type_str(txmsg->reply.req_type),
4026 			    txmsg->reply.u.nak.reason,
4027 			    drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
4028 			    txmsg->reply.u.nak.nak_data);
4029 	}
4030 
4031 	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4032 	drm_dp_mst_topology_put_mstb(mstb);
4033 
4034 	mutex_lock(&mgr->qlock);
4035 	txmsg->state = DRM_DP_SIDEBAND_TX_RX;
4036 	list_del(&txmsg->next);
4037 	mutex_unlock(&mgr->qlock);
4038 
4039 	wake_up_all(&mgr->tx_waitq);
4040 
4041 	return 0;
4042 
4043 out_clear_reply:
4044 	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4045 out:
4046 	if (mstb)
4047 		drm_dp_mst_topology_put_mstb(mstb);
4048 
4049 	return 0;
4050 }
4051 
4052 static inline bool
drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_pending_up_req * up_req)4053 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
4054 			  struct drm_dp_pending_up_req *up_req)
4055 {
4056 	struct drm_dp_mst_branch *mstb = NULL;
4057 	struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
4058 	struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
4059 	bool hotplug = false;
4060 
4061 	if (hdr->broadcast) {
4062 		const u8 *guid = NULL;
4063 
4064 		if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
4065 			guid = msg->u.conn_stat.guid;
4066 		else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
4067 			guid = msg->u.resource_stat.guid;
4068 
4069 		if (guid)
4070 			mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
4071 	} else {
4072 		mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
4073 	}
4074 
4075 	if (!mstb) {
4076 		drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
4077 		return false;
4078 	}
4079 
4080 	/* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
4081 	if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
4082 		drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
4083 		hotplug = true;
4084 	}
4085 
4086 	drm_dp_mst_topology_put_mstb(mstb);
4087 	return hotplug;
4088 }
4089 
drm_dp_mst_up_req_work(struct work_struct * work)4090 static void drm_dp_mst_up_req_work(struct work_struct *work)
4091 {
4092 	struct drm_dp_mst_topology_mgr *mgr =
4093 		container_of(work, struct drm_dp_mst_topology_mgr,
4094 			     up_req_work);
4095 	struct drm_dp_pending_up_req *up_req;
4096 	bool send_hotplug = false;
4097 
4098 	mutex_lock(&mgr->probe_lock);
4099 	while (true) {
4100 		mutex_lock(&mgr->up_req_lock);
4101 		up_req = list_first_entry_or_null(&mgr->up_req_list,
4102 						  struct drm_dp_pending_up_req,
4103 						  next);
4104 		if (up_req)
4105 			list_del(&up_req->next);
4106 		mutex_unlock(&mgr->up_req_lock);
4107 
4108 		if (!up_req)
4109 			break;
4110 
4111 		send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4112 		kfree(up_req);
4113 	}
4114 	mutex_unlock(&mgr->probe_lock);
4115 
4116 	if (send_hotplug)
4117 		drm_kms_helper_hotplug_event(mgr->dev);
4118 }
4119 
drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr * mgr)4120 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4121 {
4122 	struct drm_dp_pending_up_req *up_req;
4123 
4124 	if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4125 		goto out;
4126 
4127 	if (!mgr->up_req_recv.have_eomt)
4128 		return 0;
4129 
4130 	up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4131 	if (!up_req)
4132 		return -ENOMEM;
4133 
4134 	INIT_LIST_HEAD(&up_req->next);
4135 
4136 	drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4137 
4138 	if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4139 	    up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4140 		drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4141 			    up_req->msg.req_type);
4142 		kfree(up_req);
4143 		goto out;
4144 	}
4145 
4146 	drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4147 				 false);
4148 
4149 	if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4150 		const struct drm_dp_connection_status_notify *conn_stat =
4151 			&up_req->msg.u.conn_stat;
4152 
4153 		drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4154 			    conn_stat->port_number,
4155 			    conn_stat->legacy_device_plug_status,
4156 			    conn_stat->displayport_device_plug_status,
4157 			    conn_stat->message_capability_status,
4158 			    conn_stat->input_port,
4159 			    conn_stat->peer_device_type);
4160 	} else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4161 		const struct drm_dp_resource_status_notify *res_stat =
4162 			&up_req->msg.u.resource_stat;
4163 
4164 		drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4165 			    res_stat->port_number,
4166 			    res_stat->available_pbn);
4167 	}
4168 
4169 	up_req->hdr = mgr->up_req_recv.initial_hdr;
4170 	mutex_lock(&mgr->up_req_lock);
4171 	list_add_tail(&up_req->next, &mgr->up_req_list);
4172 	mutex_unlock(&mgr->up_req_lock);
4173 	queue_work(system_long_wq, &mgr->up_req_work);
4174 
4175 out:
4176 	memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4177 	return 0;
4178 }
4179 
4180 /**
4181  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
4182  * @mgr: manager to notify irq for.
4183  * @esi: 4 bytes from SINK_COUNT_ESI
4184  * @handled: whether the hpd interrupt was consumed or not
4185  *
4186  * This should be called from the driver when it detects a short IRQ,
4187  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4188  * topology manager will process the sideband messages received as a result
4189  * of this.
4190  */
drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr * mgr,u8 * esi,bool * handled)4191 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
4192 {
4193 	int ret = 0;
4194 	int sc;
4195 	*handled = false;
4196 	sc = DP_GET_SINK_COUNT(esi[0]);
4197 
4198 	if (sc != mgr->sink_count) {
4199 		mgr->sink_count = sc;
4200 		*handled = true;
4201 	}
4202 
4203 	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4204 		ret = drm_dp_mst_handle_down_rep(mgr);
4205 		*handled = true;
4206 	}
4207 
4208 	if (esi[1] & DP_UP_REQ_MSG_RDY) {
4209 		ret |= drm_dp_mst_handle_up_req(mgr);
4210 		*handled = true;
4211 	}
4212 
4213 	drm_dp_mst_kick_tx(mgr);
4214 	return ret;
4215 }
4216 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
4217 
4218 /**
4219  * drm_dp_mst_detect_port() - get connection status for an MST port
4220  * @connector: DRM connector for this port
4221  * @ctx: The acquisition context to use for grabbing locks
4222  * @mgr: manager for this port
4223  * @port: pointer to a port
4224  *
4225  * This returns the current connection state for a port.
4226  */
4227 int
drm_dp_mst_detect_port(struct drm_connector * connector,struct drm_modeset_acquire_ctx * ctx,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4228 drm_dp_mst_detect_port(struct drm_connector *connector,
4229 		       struct drm_modeset_acquire_ctx *ctx,
4230 		       struct drm_dp_mst_topology_mgr *mgr,
4231 		       struct drm_dp_mst_port *port)
4232 {
4233 	int ret;
4234 
4235 	/* we need to search for the port in the mgr in case it's gone */
4236 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4237 	if (!port)
4238 		return connector_status_disconnected;
4239 
4240 	ret = drm_modeset_lock(&mgr->base.lock, ctx);
4241 	if (ret)
4242 		goto out;
4243 
4244 	ret = connector_status_disconnected;
4245 
4246 	if (!port->ddps)
4247 		goto out;
4248 
4249 	switch (port->pdt) {
4250 	case DP_PEER_DEVICE_NONE:
4251 		break;
4252 	case DP_PEER_DEVICE_MST_BRANCHING:
4253 		if (!port->mcs)
4254 			ret = connector_status_connected;
4255 		break;
4256 
4257 	case DP_PEER_DEVICE_SST_SINK:
4258 		ret = connector_status_connected;
4259 		/* for logical ports - cache the EDID */
4260 		if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4261 			port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4262 		break;
4263 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
4264 		if (port->ldps)
4265 			ret = connector_status_connected;
4266 		break;
4267 	}
4268 out:
4269 	drm_dp_mst_topology_put_port(port);
4270 	return ret;
4271 }
4272 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4273 
4274 /**
4275  * drm_dp_mst_get_edid() - get EDID for an MST port
4276  * @connector: toplevel connector to get EDID for
4277  * @mgr: manager for this port
4278  * @port: unverified pointer to a port.
4279  *
4280  * This returns an EDID for the port connected to a connector,
4281  * It validates the pointer still exists so the caller doesn't require a
4282  * reference.
4283  */
drm_dp_mst_get_edid(struct drm_connector * connector,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4284 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4285 {
4286 	struct edid *edid = NULL;
4287 
4288 	/* we need to search for the port in the mgr in case it's gone */
4289 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4290 	if (!port)
4291 		return NULL;
4292 
4293 	if (port->cached_edid)
4294 		edid = drm_edid_duplicate(port->cached_edid);
4295 	else {
4296 		edid = drm_get_edid(connector, &port->aux.ddc);
4297 	}
4298 	port->has_audio = drm_detect_monitor_audio(edid);
4299 	drm_dp_mst_topology_put_port(port);
4300 	return edid;
4301 }
4302 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4303 
4304 /**
4305  * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
4306  * @mgr: manager to use
4307  * @pbn: payload bandwidth to convert into slots.
4308  *
4309  * Calculate the number of VCPI slots that will be required for the given PBN
4310  * value. This function is deprecated, and should not be used in atomic
4311  * drivers.
4312  *
4313  * RETURNS:
4314  * The total slots required for this port, or error.
4315  */
drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr * mgr,int pbn)4316 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
4317 			   int pbn)
4318 {
4319 	int num_slots;
4320 
4321 	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
4322 
4323 	/* max. time slots - one slot for MTP header */
4324 	if (num_slots > 63)
4325 		return -ENOSPC;
4326 	return num_slots;
4327 }
4328 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
4329 
drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_vcpi * vcpi,int pbn,int slots)4330 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4331 			    struct drm_dp_vcpi *vcpi, int pbn, int slots)
4332 {
4333 	int ret;
4334 
4335 	vcpi->pbn = pbn;
4336 	vcpi->aligned_pbn = slots * mgr->pbn_div;
4337 	vcpi->num_slots = slots;
4338 
4339 	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
4340 	if (ret < 0)
4341 		return ret;
4342 	return 0;
4343 }
4344 
4345 /**
4346  * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
4347  * @state: global atomic state
4348  * @mgr: MST topology manager for the port
4349  * @port: port to find vcpi slots for
4350  * @pbn: bandwidth required for the mode in PBN
4351  * @pbn_div: divider for DSC mode that takes FEC into account
4352  *
4353  * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
4354  * may have had. Any atomic drivers which support MST must call this function
4355  * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
4356  * current VCPI allocation for the new state, but only when
4357  * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
4358  * to ensure compatibility with userspace applications that still use the
4359  * legacy modesetting UAPI.
4360  *
4361  * Allocations set by this function are not checked against the bandwidth
4362  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4363  *
4364  * Additionally, it is OK to call this function multiple times on the same
4365  * @port as needed. It is not OK however, to call this function and
4366  * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
4367  *
4368  * See also:
4369  * drm_dp_atomic_release_vcpi_slots()
4370  * drm_dp_mst_atomic_check()
4371  *
4372  * Returns:
4373  * Total slots in the atomic state assigned for this port, or a negative error
4374  * code if the port no longer exists
4375  */
drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int pbn,int pbn_div)4376 int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
4377 				  struct drm_dp_mst_topology_mgr *mgr,
4378 				  struct drm_dp_mst_port *port, int pbn,
4379 				  int pbn_div)
4380 {
4381 	struct drm_dp_mst_topology_state *topology_state;
4382 	struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
4383 	int prev_slots, prev_bw, req_slots;
4384 
4385 	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4386 	if (IS_ERR(topology_state))
4387 		return PTR_ERR(topology_state);
4388 
4389 	/* Find the current allocation for this port, if any */
4390 	list_for_each_entry(pos, &topology_state->vcpis, next) {
4391 		if (pos->port == port) {
4392 			vcpi = pos;
4393 			prev_slots = vcpi->vcpi;
4394 			prev_bw = vcpi->pbn;
4395 
4396 			/*
4397 			 * This should never happen, unless the driver tries
4398 			 * releasing and allocating the same VCPI allocation,
4399 			 * which is an error
4400 			 */
4401 			if (WARN_ON(!prev_slots)) {
4402 				drm_err(mgr->dev,
4403 					"cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
4404 					port);
4405 				return -EINVAL;
4406 			}
4407 
4408 			break;
4409 		}
4410 	}
4411 	if (!vcpi) {
4412 		prev_slots = 0;
4413 		prev_bw = 0;
4414 	}
4415 
4416 	if (pbn_div <= 0)
4417 		pbn_div = mgr->pbn_div;
4418 
4419 	req_slots = DIV_ROUND_UP(pbn, pbn_div);
4420 
4421 	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
4422 		       port->connector->base.id, port->connector->name,
4423 		       port, prev_slots, req_slots);
4424 	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4425 		       port->connector->base.id, port->connector->name,
4426 		       port, prev_bw, pbn);
4427 
4428 	/* Add the new allocation to the state */
4429 	if (!vcpi) {
4430 		vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
4431 		if (!vcpi)
4432 			return -ENOMEM;
4433 
4434 		drm_dp_mst_get_port_malloc(port);
4435 		vcpi->port = port;
4436 		list_add(&vcpi->next, &topology_state->vcpis);
4437 	}
4438 	vcpi->vcpi = req_slots;
4439 	vcpi->pbn = pbn;
4440 
4441 	return req_slots;
4442 }
4443 EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
4444 
4445 /**
4446  * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
4447  * @state: global atomic state
4448  * @mgr: MST topology manager for the port
4449  * @port: The port to release the VCPI slots from
4450  *
4451  * Releases any VCPI slots that have been allocated to a port in the atomic
4452  * state. Any atomic drivers which support MST must call this function in
4453  * their &drm_connector_helper_funcs.atomic_check() callback when the
4454  * connector will no longer have VCPI allocated (e.g. because its CRTC was
4455  * removed) when it had VCPI allocated in the previous atomic state.
4456  *
4457  * It is OK to call this even if @port has been removed from the system.
4458  * Additionally, it is OK to call this function multiple times on the same
4459  * @port as needed. It is not OK however, to call this function and
4460  * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
4461  * phase.
4462  *
4463  * See also:
4464  * drm_dp_atomic_find_vcpi_slots()
4465  * drm_dp_mst_atomic_check()
4466  *
4467  * Returns:
4468  * 0 if all slots for this port were added back to
4469  * &drm_dp_mst_topology_state.avail_slots or negative error code
4470  */
drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4471 int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
4472 				     struct drm_dp_mst_topology_mgr *mgr,
4473 				     struct drm_dp_mst_port *port)
4474 {
4475 	struct drm_dp_mst_topology_state *topology_state;
4476 	struct drm_dp_vcpi_allocation *pos;
4477 	bool found = false;
4478 
4479 	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4480 	if (IS_ERR(topology_state))
4481 		return PTR_ERR(topology_state);
4482 
4483 	list_for_each_entry(pos, &topology_state->vcpis, next) {
4484 		if (pos->port == port) {
4485 			found = true;
4486 			break;
4487 		}
4488 	}
4489 	if (WARN_ON(!found)) {
4490 		drm_err(mgr->dev, "no VCPI for [MST PORT:%p] found in mst state %p\n",
4491 			port, &topology_state->base);
4492 		return -EINVAL;
4493 	}
4494 
4495 	drm_dbg_atomic(mgr->dev, "[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
4496 	if (pos->vcpi) {
4497 		drm_dp_mst_put_port_malloc(port);
4498 		pos->vcpi = 0;
4499 		pos->pbn = 0;
4500 	}
4501 
4502 	return 0;
4503 }
4504 EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
4505 
4506 /**
4507  * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
4508  * @mst_state: mst_state to update
4509  * @link_encoding_cap: the ecoding format on the link
4510  */
drm_dp_mst_update_slots(struct drm_dp_mst_topology_state * mst_state,uint8_t link_encoding_cap)4511 void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap)
4512 {
4513 	if (link_encoding_cap == DP_CAP_ANSI_128B132B) {
4514 		mst_state->total_avail_slots = 64;
4515 		mst_state->start_slot = 0;
4516 	} else {
4517 		mst_state->total_avail_slots = 63;
4518 		mst_state->start_slot = 1;
4519 	}
4520 
4521 	DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n",
4522 		      (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b",
4523 		      mst_state);
4524 }
4525 EXPORT_SYMBOL(drm_dp_mst_update_slots);
4526 
4527 /**
4528  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
4529  * @mgr: manager for this port
4530  * @port: port to allocate a virtual channel for.
4531  * @pbn: payload bandwidth number to request
4532  * @slots: returned number of slots for this PBN.
4533  */
drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int pbn,int slots)4534 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4535 			      struct drm_dp_mst_port *port, int pbn, int slots)
4536 {
4537 	int ret;
4538 
4539 	if (slots < 0)
4540 		return false;
4541 
4542 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4543 	if (!port)
4544 		return false;
4545 
4546 	if (port->vcpi.vcpi > 0) {
4547 		drm_dbg_kms(mgr->dev,
4548 			    "payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
4549 			    port->vcpi.vcpi, port->vcpi.pbn, pbn);
4550 		if (pbn == port->vcpi.pbn) {
4551 			drm_dp_mst_topology_put_port(port);
4552 			return true;
4553 		}
4554 	}
4555 
4556 	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
4557 	if (ret) {
4558 		drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d ret=%d\n",
4559 			    DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
4560 		drm_dp_mst_topology_put_port(port);
4561 		goto out;
4562 	}
4563 	drm_dbg_kms(mgr->dev, "initing vcpi for pbn=%d slots=%d\n", pbn, port->vcpi.num_slots);
4564 
4565 	/* Keep port allocated until its payload has been removed */
4566 	drm_dp_mst_get_port_malloc(port);
4567 	drm_dp_mst_topology_put_port(port);
4568 	return true;
4569 out:
4570 	return false;
4571 }
4572 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
4573 
drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4574 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4575 {
4576 	int slots = 0;
4577 
4578 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4579 	if (!port)
4580 		return slots;
4581 
4582 	slots = port->vcpi.num_slots;
4583 	drm_dp_mst_topology_put_port(port);
4584 	return slots;
4585 }
4586 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
4587 
4588 /**
4589  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
4590  * @mgr: manager for this port
4591  * @port: unverified pointer to a port.
4592  *
4593  * This just resets the number of slots for the ports VCPI for later programming.
4594  */
drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4595 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4596 {
4597 	/*
4598 	 * A port with VCPI will remain allocated until its VCPI is
4599 	 * released, no verified ref needed
4600 	 */
4601 
4602 	port->vcpi.num_slots = 0;
4603 }
4604 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
4605 
4606 /**
4607  * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
4608  * @mgr: manager for this port
4609  * @port: port to deallocate vcpi for
4610  *
4611  * This can be called unconditionally, regardless of whether
4612  * drm_dp_mst_allocate_vcpi() succeeded or not.
4613  */
drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4614 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4615 				struct drm_dp_mst_port *port)
4616 {
4617 	bool skip;
4618 
4619 	if (!port->vcpi.vcpi)
4620 		return;
4621 
4622 	mutex_lock(&mgr->lock);
4623 	skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
4624 	mutex_unlock(&mgr->lock);
4625 
4626 	if (skip)
4627 		return;
4628 
4629 	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
4630 	port->vcpi.num_slots = 0;
4631 	port->vcpi.pbn = 0;
4632 	port->vcpi.aligned_pbn = 0;
4633 	port->vcpi.vcpi = 0;
4634 	drm_dp_mst_put_port_malloc(port);
4635 }
4636 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
4637 
drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr * mgr,int id,struct drm_dp_payload * payload)4638 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4639 				     int id, struct drm_dp_payload *payload)
4640 {
4641 	u8 payload_alloc[3], status;
4642 	int ret;
4643 	int retries = 0;
4644 
4645 	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4646 			   DP_PAYLOAD_TABLE_UPDATED);
4647 
4648 	payload_alloc[0] = id;
4649 	payload_alloc[1] = payload->start_slot;
4650 	payload_alloc[2] = payload->num_slots;
4651 
4652 	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4653 	if (ret != 3) {
4654 		drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4655 		goto fail;
4656 	}
4657 
4658 retry:
4659 	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4660 	if (ret < 0) {
4661 		drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4662 		goto fail;
4663 	}
4664 
4665 	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4666 		retries++;
4667 		if (retries < 20) {
4668 			usleep_range(10000, 20000);
4669 			goto retry;
4670 		}
4671 		drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4672 			    status);
4673 		ret = -EINVAL;
4674 		goto fail;
4675 	}
4676 	ret = 0;
4677 fail:
4678 	return ret;
4679 }
4680 
do_get_act_status(struct drm_dp_aux * aux)4681 static int do_get_act_status(struct drm_dp_aux *aux)
4682 {
4683 	int ret;
4684 	u8 status;
4685 
4686 	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4687 	if (ret < 0)
4688 		return ret;
4689 
4690 	return status;
4691 }
4692 
4693 /**
4694  * drm_dp_check_act_status() - Polls for ACT handled status.
4695  * @mgr: manager to use
4696  *
4697  * Tries waiting for the MST hub to finish updating it's payload table by
4698  * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4699  * take that long).
4700  *
4701  * Returns:
4702  * 0 if the ACT was handled in time, negative error code on failure.
4703  */
drm_dp_check_act_status(struct drm_dp_mst_topology_mgr * mgr)4704 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4705 {
4706 	/*
4707 	 * There doesn't seem to be any recommended retry count or timeout in
4708 	 * the MST specification. Since some hubs have been observed to take
4709 	 * over 1 second to update their payload allocations under certain
4710 	 * conditions, we use a rather large timeout value.
4711 	 */
4712 	const int timeout_ms = 3000;
4713 	int ret, status;
4714 
4715 	ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4716 				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4717 				 200, timeout_ms * USEC_PER_MSEC);
4718 	if (ret < 0 && status >= 0) {
4719 		drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4720 			timeout_ms, status);
4721 		return -EINVAL;
4722 	} else if (status < 0) {
4723 		/*
4724 		 * Failure here isn't unexpected - the hub may have
4725 		 * just been unplugged
4726 		 */
4727 		drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4728 		return status;
4729 	}
4730 
4731 	return 0;
4732 }
4733 EXPORT_SYMBOL(drm_dp_check_act_status);
4734 
4735 /**
4736  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4737  * @clock: dot clock for the mode
4738  * @bpp: bpp for the mode.
4739  * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4740  *
4741  * This uses the formula in the spec to calculate the PBN value for a mode.
4742  */
drm_dp_calc_pbn_mode(int clock,int bpp,bool dsc)4743 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4744 {
4745 	/*
4746 	 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4747 	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4748 	 * common multiplier to render an integer PBN for all link rate/lane
4749 	 * counts combinations
4750 	 * calculate
4751 	 * peak_kbps *= (1006/1000)
4752 	 * peak_kbps *= (64/54)
4753 	 * peak_kbps *= 8    convert to bytes
4754 	 *
4755 	 * If the bpp is in units of 1/16, further divide by 16. Put this
4756 	 * factor in the numerator rather than the denominator to avoid
4757 	 * integer overflow
4758 	 */
4759 
4760 	if (dsc)
4761 		return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4762 					8 * 54 * 1000 * 1000);
4763 
4764 	return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4765 				8 * 54 * 1000 * 1000);
4766 }
4767 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4768 
4769 /* we want to kick the TX after we've ack the up/down IRQs. */
drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr * mgr)4770 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4771 {
4772 	queue_work(system_long_wq, &mgr->tx_work);
4773 }
4774 
4775 /*
4776  * Helper function for parsing DP device types into convenient strings
4777  * for use with dp_mst_topology
4778  */
pdt_to_string(u8 pdt)4779 static const char *pdt_to_string(u8 pdt)
4780 {
4781 	switch (pdt) {
4782 	case DP_PEER_DEVICE_NONE:
4783 		return "NONE";
4784 	case DP_PEER_DEVICE_SOURCE_OR_SST:
4785 		return "SOURCE OR SST";
4786 	case DP_PEER_DEVICE_MST_BRANCHING:
4787 		return "MST BRANCHING";
4788 	case DP_PEER_DEVICE_SST_SINK:
4789 		return "SST SINK";
4790 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
4791 		return "DP LEGACY CONV";
4792 	default:
4793 		return "ERR";
4794 	}
4795 }
4796 
drm_dp_mst_dump_mstb(struct seq_file * m,struct drm_dp_mst_branch * mstb)4797 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4798 				 struct drm_dp_mst_branch *mstb)
4799 {
4800 	struct drm_dp_mst_port *port;
4801 	int tabs = mstb->lct;
4802 	char prefix[10];
4803 	int i;
4804 
4805 	for (i = 0; i < tabs; i++)
4806 		prefix[i] = '\t';
4807 	prefix[i] = '\0';
4808 
4809 	seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4810 	list_for_each_entry(port, &mstb->ports, next) {
4811 		seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4812 			   prefix,
4813 			   port->port_num,
4814 			   port,
4815 			   port->input ? "input" : "output",
4816 			   pdt_to_string(port->pdt),
4817 			   port->ddps,
4818 			   port->ldps,
4819 			   port->num_sdp_streams,
4820 			   port->num_sdp_stream_sinks,
4821 			   port->fec_capable ? "true" : "false",
4822 			   port->connector);
4823 		if (port->mstb)
4824 			drm_dp_mst_dump_mstb(m, port->mstb);
4825 	}
4826 }
4827 
4828 #define DP_PAYLOAD_TABLE_SIZE		64
4829 
dump_dp_payload_table(struct drm_dp_mst_topology_mgr * mgr,char * buf)4830 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4831 				  char *buf)
4832 {
4833 	int i;
4834 
4835 	for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4836 		if (drm_dp_dpcd_read(mgr->aux,
4837 				     DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4838 				     &buf[i], 16) != 16)
4839 			return false;
4840 	}
4841 	return true;
4842 }
4843 
fetch_monitor_name(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,char * name,int namelen)4844 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4845 			       struct drm_dp_mst_port *port, char *name,
4846 			       int namelen)
4847 {
4848 	struct edid *mst_edid;
4849 
4850 	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4851 	drm_edid_get_monitor_name(mst_edid, name, namelen);
4852 	kfree(mst_edid);
4853 }
4854 
4855 /**
4856  * drm_dp_mst_dump_topology(): dump topology to seq file.
4857  * @m: seq_file to dump output to
4858  * @mgr: manager to dump current topology for.
4859  *
4860  * helper to dump MST topology to a seq file for debugfs.
4861  */
drm_dp_mst_dump_topology(struct seq_file * m,struct drm_dp_mst_topology_mgr * mgr)4862 void drm_dp_mst_dump_topology(struct seq_file *m,
4863 			      struct drm_dp_mst_topology_mgr *mgr)
4864 {
4865 	int i;
4866 	struct drm_dp_mst_port *port;
4867 
4868 	mutex_lock(&mgr->lock);
4869 	if (mgr->mst_primary)
4870 		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4871 
4872 	/* dump VCPIs */
4873 	mutex_unlock(&mgr->lock);
4874 
4875 	mutex_lock(&mgr->payload_lock);
4876 	seq_printf(m, "\n*** VCPI Info ***\n");
4877 	seq_printf(m, "payload_mask: %lx, vcpi_mask: %lx, max_payloads: %d\n", mgr->payload_mask, mgr->vcpi_mask, mgr->max_payloads);
4878 
4879 	seq_printf(m, "\n|   idx   |  port # |  vcp_id | # slots |     sink name     |\n");
4880 	for (i = 0; i < mgr->max_payloads; i++) {
4881 		if (mgr->proposed_vcpis[i]) {
4882 			char name[14];
4883 
4884 			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
4885 			fetch_monitor_name(mgr, port, name, sizeof(name));
4886 			seq_printf(m, "%10d%10d%10d%10d%20s\n",
4887 				   i,
4888 				   port->port_num,
4889 				   port->vcpi.vcpi,
4890 				   port->vcpi.num_slots,
4891 				   (*name != 0) ? name : "Unknown");
4892 		} else
4893 			seq_printf(m, "%6d - Unused\n", i);
4894 	}
4895 	seq_printf(m, "\n*** Payload Info ***\n");
4896 	seq_printf(m, "|   idx   |  state  |  start slot  | # slots |\n");
4897 	for (i = 0; i < mgr->max_payloads; i++) {
4898 		seq_printf(m, "%10d%10d%15d%10d\n",
4899 			   i,
4900 			   mgr->payloads[i].payload_state,
4901 			   mgr->payloads[i].start_slot,
4902 			   mgr->payloads[i].num_slots);
4903 	}
4904 	mutex_unlock(&mgr->payload_lock);
4905 
4906 	seq_printf(m, "\n*** DPCD Info ***\n");
4907 	mutex_lock(&mgr->lock);
4908 	if (mgr->mst_primary) {
4909 		u8 buf[DP_PAYLOAD_TABLE_SIZE];
4910 		int ret;
4911 
4912 		if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
4913 			seq_printf(m, "dpcd read failed\n");
4914 			goto out;
4915 		}
4916 		seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4917 
4918 		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4919 		if (ret) {
4920 			seq_printf(m, "faux/mst read failed\n");
4921 			goto out;
4922 		}
4923 		seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4924 
4925 		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4926 		if (ret) {
4927 			seq_printf(m, "mst ctrl read failed\n");
4928 			goto out;
4929 		}
4930 		seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4931 
4932 		/* dump the standard OUI branch header */
4933 		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4934 		if (ret) {
4935 			seq_printf(m, "branch oui read failed\n");
4936 			goto out;
4937 		}
4938 		seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4939 
4940 		for (i = 0x3; i < 0x8 && buf[i]; i++)
4941 			seq_printf(m, "%c", buf[i]);
4942 		seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4943 			   buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4944 		if (dump_dp_payload_table(mgr, buf))
4945 			seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4946 	}
4947 
4948 out:
4949 	mutex_unlock(&mgr->lock);
4950 
4951 }
4952 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4953 
drm_dp_tx_work(struct work_struct * work)4954 static void drm_dp_tx_work(struct work_struct *work)
4955 {
4956 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4957 
4958 	mutex_lock(&mgr->qlock);
4959 	if (!list_empty(&mgr->tx_msg_downq))
4960 		process_single_down_tx_qlock(mgr);
4961 	mutex_unlock(&mgr->qlock);
4962 }
4963 
4964 static inline void
drm_dp_delayed_destroy_port(struct drm_dp_mst_port * port)4965 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4966 {
4967 	drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4968 
4969 	if (port->connector) {
4970 		drm_connector_unregister(port->connector);
4971 		drm_connector_put(port->connector);
4972 	}
4973 
4974 	drm_dp_mst_put_port_malloc(port);
4975 }
4976 
4977 static inline void
drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch * mstb)4978 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4979 {
4980 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4981 	struct drm_dp_mst_port *port, *port_tmp;
4982 	struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4983 	bool wake_tx = false;
4984 
4985 	mutex_lock(&mgr->lock);
4986 	list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4987 		list_del(&port->next);
4988 		drm_dp_mst_topology_put_port(port);
4989 	}
4990 	mutex_unlock(&mgr->lock);
4991 
4992 	/* drop any tx slot msg */
4993 	mutex_lock(&mstb->mgr->qlock);
4994 	list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4995 		if (txmsg->dst != mstb)
4996 			continue;
4997 
4998 		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4999 		list_del(&txmsg->next);
5000 		wake_tx = true;
5001 	}
5002 	mutex_unlock(&mstb->mgr->qlock);
5003 
5004 	if (wake_tx)
5005 		wake_up_all(&mstb->mgr->tx_waitq);
5006 
5007 	drm_dp_mst_put_mstb_malloc(mstb);
5008 }
5009 
drm_dp_delayed_destroy_work(struct work_struct * work)5010 static void drm_dp_delayed_destroy_work(struct work_struct *work)
5011 {
5012 	struct drm_dp_mst_topology_mgr *mgr =
5013 		container_of(work, struct drm_dp_mst_topology_mgr,
5014 			     delayed_destroy_work);
5015 	bool send_hotplug = false, go_again;
5016 
5017 	/*
5018 	 * Not a regular list traverse as we have to drop the destroy
5019 	 * connector lock before destroying the mstb/port, to avoid AB->BA
5020 	 * ordering between this lock and the config mutex.
5021 	 */
5022 	do {
5023 		go_again = false;
5024 
5025 		for (;;) {
5026 			struct drm_dp_mst_branch *mstb;
5027 
5028 			mutex_lock(&mgr->delayed_destroy_lock);
5029 			mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
5030 							struct drm_dp_mst_branch,
5031 							destroy_next);
5032 			if (mstb)
5033 				list_del(&mstb->destroy_next);
5034 			mutex_unlock(&mgr->delayed_destroy_lock);
5035 
5036 			if (!mstb)
5037 				break;
5038 
5039 			drm_dp_delayed_destroy_mstb(mstb);
5040 			go_again = true;
5041 		}
5042 
5043 		for (;;) {
5044 			struct drm_dp_mst_port *port;
5045 
5046 			mutex_lock(&mgr->delayed_destroy_lock);
5047 			port = list_first_entry_or_null(&mgr->destroy_port_list,
5048 							struct drm_dp_mst_port,
5049 							next);
5050 			if (port)
5051 				list_del(&port->next);
5052 			mutex_unlock(&mgr->delayed_destroy_lock);
5053 
5054 			if (!port)
5055 				break;
5056 
5057 			drm_dp_delayed_destroy_port(port);
5058 			send_hotplug = true;
5059 			go_again = true;
5060 		}
5061 	} while (go_again);
5062 
5063 	if (send_hotplug)
5064 		drm_kms_helper_hotplug_event(mgr->dev);
5065 }
5066 
5067 static struct drm_private_state *
drm_dp_mst_duplicate_state(struct drm_private_obj * obj)5068 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5069 {
5070 	struct drm_dp_mst_topology_state *state, *old_state =
5071 		to_dp_mst_topology_state(obj->state);
5072 	struct drm_dp_vcpi_allocation *pos, *vcpi;
5073 
5074 	state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5075 	if (!state)
5076 		return NULL;
5077 
5078 	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5079 
5080 	INIT_LIST_HEAD(&state->vcpis);
5081 
5082 	list_for_each_entry(pos, &old_state->vcpis, next) {
5083 		/* Prune leftover freed VCPI allocations */
5084 		if (!pos->vcpi)
5085 			continue;
5086 
5087 		vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
5088 		if (!vcpi)
5089 			goto fail;
5090 
5091 		drm_dp_mst_get_port_malloc(vcpi->port);
5092 		list_add(&vcpi->next, &state->vcpis);
5093 	}
5094 
5095 	return &state->base;
5096 
5097 fail:
5098 	list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
5099 		drm_dp_mst_put_port_malloc(pos->port);
5100 		kfree(pos);
5101 	}
5102 	kfree(state);
5103 
5104 	return NULL;
5105 }
5106 
drm_dp_mst_destroy_state(struct drm_private_obj * obj,struct drm_private_state * state)5107 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5108 				     struct drm_private_state *state)
5109 {
5110 	struct drm_dp_mst_topology_state *mst_state =
5111 		to_dp_mst_topology_state(state);
5112 	struct drm_dp_vcpi_allocation *pos, *tmp;
5113 
5114 	list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
5115 		/* We only keep references to ports with non-zero VCPIs */
5116 		if (pos->vcpi)
5117 			drm_dp_mst_put_port_malloc(pos->port);
5118 		kfree(pos);
5119 	}
5120 
5121 	kfree(mst_state);
5122 }
5123 
drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port * port,struct drm_dp_mst_branch * branch)5124 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5125 						 struct drm_dp_mst_branch *branch)
5126 {
5127 	while (port->parent) {
5128 		if (port->parent == branch)
5129 			return true;
5130 
5131 		if (port->parent->port_parent)
5132 			port = port->parent->port_parent;
5133 		else
5134 			break;
5135 	}
5136 	return false;
5137 }
5138 
5139 static int
5140 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5141 				      struct drm_dp_mst_topology_state *state);
5142 
5143 static int
drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_topology_state * state)5144 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5145 				      struct drm_dp_mst_topology_state *state)
5146 {
5147 	struct drm_dp_vcpi_allocation *vcpi;
5148 	struct drm_dp_mst_port *port;
5149 	int pbn_used = 0, ret;
5150 	bool found = false;
5151 
5152 	/* Check that we have at least one port in our state that's downstream
5153 	 * of this branch, otherwise we can skip this branch
5154 	 */
5155 	list_for_each_entry(vcpi, &state->vcpis, next) {
5156 		if (!vcpi->pbn ||
5157 		    !drm_dp_mst_port_downstream_of_branch(vcpi->port, mstb))
5158 			continue;
5159 
5160 		found = true;
5161 		break;
5162 	}
5163 	if (!found)
5164 		return 0;
5165 
5166 	if (mstb->port_parent)
5167 		drm_dbg_atomic(mstb->mgr->dev,
5168 			       "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5169 			       mstb->port_parent->parent, mstb->port_parent, mstb);
5170 	else
5171 		drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5172 
5173 	list_for_each_entry(port, &mstb->ports, next) {
5174 		ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
5175 		if (ret < 0)
5176 			return ret;
5177 
5178 		pbn_used += ret;
5179 	}
5180 
5181 	return pbn_used;
5182 }
5183 
5184 static int
drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port * port,struct drm_dp_mst_topology_state * state)5185 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5186 				      struct drm_dp_mst_topology_state *state)
5187 {
5188 	struct drm_dp_vcpi_allocation *vcpi;
5189 	int pbn_used = 0;
5190 
5191 	if (port->pdt == DP_PEER_DEVICE_NONE)
5192 		return 0;
5193 
5194 	if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5195 		bool found = false;
5196 
5197 		list_for_each_entry(vcpi, &state->vcpis, next) {
5198 			if (vcpi->port != port)
5199 				continue;
5200 			if (!vcpi->pbn)
5201 				return 0;
5202 
5203 			found = true;
5204 			break;
5205 		}
5206 		if (!found)
5207 			return 0;
5208 
5209 		/*
5210 		 * This could happen if the sink deasserted its HPD line, but
5211 		 * the branch device still reports it as attached (PDT != NONE).
5212 		 */
5213 		if (!port->full_pbn) {
5214 			drm_dbg_atomic(port->mgr->dev,
5215 				       "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5216 				       port->parent, port);
5217 			return -EINVAL;
5218 		}
5219 
5220 		pbn_used = vcpi->pbn;
5221 	} else {
5222 		pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5223 								 state);
5224 		if (pbn_used <= 0)
5225 			return pbn_used;
5226 	}
5227 
5228 	if (pbn_used > port->full_pbn) {
5229 		drm_dbg_atomic(port->mgr->dev,
5230 			       "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5231 			       port->parent, port, pbn_used, port->full_pbn);
5232 		return -ENOSPC;
5233 	}
5234 
5235 	drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5236 		       port->parent, port, pbn_used, port->full_pbn);
5237 
5238 	return pbn_used;
5239 }
5240 
5241 static inline int
drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_state * mst_state)5242 drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
5243 					 struct drm_dp_mst_topology_state *mst_state)
5244 {
5245 	struct drm_dp_vcpi_allocation *vcpi;
5246 	int avail_slots = mst_state->total_avail_slots, payload_count = 0;
5247 
5248 	list_for_each_entry(vcpi, &mst_state->vcpis, next) {
5249 		/* Releasing VCPI is always OK-even if the port is gone */
5250 		if (!vcpi->vcpi) {
5251 			drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all VCPI slots\n",
5252 				       vcpi->port);
5253 			continue;
5254 		}
5255 
5256 		drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d vcpi slots\n",
5257 			       vcpi->port, vcpi->vcpi);
5258 
5259 		avail_slots -= vcpi->vcpi;
5260 		if (avail_slots < 0) {
5261 			drm_dbg_atomic(mgr->dev,
5262 				       "[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
5263 				       vcpi->port, mst_state, avail_slots + vcpi->vcpi);
5264 			return -ENOSPC;
5265 		}
5266 
5267 		if (++payload_count > mgr->max_payloads) {
5268 			drm_dbg_atomic(mgr->dev,
5269 				       "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5270 				       mgr, mst_state, mgr->max_payloads);
5271 			return -EINVAL;
5272 		}
5273 	}
5274 	drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
5275 		       mgr, mst_state, avail_slots, mst_state->total_avail_slots - avail_slots);
5276 
5277 	return 0;
5278 }
5279 
5280 /**
5281  * drm_dp_mst_add_affected_dsc_crtcs
5282  * @state: Pointer to the new struct drm_dp_mst_topology_state
5283  * @mgr: MST topology manager
5284  *
5285  * Whenever there is a change in mst topology
5286  * DSC configuration would have to be recalculated
5287  * therefore we need to trigger modeset on all affected
5288  * CRTCs in that topology
5289  *
5290  * See also:
5291  * drm_dp_mst_atomic_enable_dsc()
5292  */
drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr)5293 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5294 {
5295 	struct drm_dp_mst_topology_state *mst_state;
5296 	struct drm_dp_vcpi_allocation *pos;
5297 	struct drm_connector *connector;
5298 	struct drm_connector_state *conn_state;
5299 	struct drm_crtc *crtc;
5300 	struct drm_crtc_state *crtc_state;
5301 
5302 	mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5303 
5304 	if (IS_ERR(mst_state))
5305 		return -EINVAL;
5306 
5307 	list_for_each_entry(pos, &mst_state->vcpis, next) {
5308 
5309 		connector = pos->port->connector;
5310 
5311 		if (!connector)
5312 			return -EINVAL;
5313 
5314 		conn_state = drm_atomic_get_connector_state(state, connector);
5315 
5316 		if (IS_ERR(conn_state))
5317 			return PTR_ERR(conn_state);
5318 
5319 		crtc = conn_state->crtc;
5320 
5321 		if (!crtc)
5322 			continue;
5323 
5324 		if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5325 			continue;
5326 
5327 		crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5328 
5329 		if (IS_ERR(crtc_state))
5330 			return PTR_ERR(crtc_state);
5331 
5332 		drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5333 			       mgr, crtc);
5334 
5335 		crtc_state->mode_changed = true;
5336 	}
5337 	return 0;
5338 }
5339 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5340 
5341 /**
5342  * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5343  * @state: Pointer to the new drm_atomic_state
5344  * @port: Pointer to the affected MST Port
5345  * @pbn: Newly recalculated bw required for link with DSC enabled
5346  * @pbn_div: Divider to calculate correct number of pbn per slot
5347  * @enable: Boolean flag to enable or disable DSC on the port
5348  *
5349  * This function enables DSC on the given Port
5350  * by recalculating its vcpi from pbn provided
5351  * and sets dsc_enable flag to keep track of which
5352  * ports have DSC enabled
5353  *
5354  */
drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state * state,struct drm_dp_mst_port * port,int pbn,int pbn_div,bool enable)5355 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5356 				 struct drm_dp_mst_port *port,
5357 				 int pbn, int pbn_div,
5358 				 bool enable)
5359 {
5360 	struct drm_dp_mst_topology_state *mst_state;
5361 	struct drm_dp_vcpi_allocation *pos;
5362 	bool found = false;
5363 	int vcpi = 0;
5364 
5365 	mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5366 
5367 	if (IS_ERR(mst_state))
5368 		return PTR_ERR(mst_state);
5369 
5370 	list_for_each_entry(pos, &mst_state->vcpis, next) {
5371 		if (pos->port == port) {
5372 			found = true;
5373 			break;
5374 		}
5375 	}
5376 
5377 	if (!found) {
5378 		drm_dbg_atomic(state->dev,
5379 			       "[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
5380 			       port, mst_state);
5381 		return -EINVAL;
5382 	}
5383 
5384 	if (pos->dsc_enabled == enable) {
5385 		drm_dbg_atomic(state->dev,
5386 			       "[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
5387 			       port, enable, pos->vcpi);
5388 		vcpi = pos->vcpi;
5389 	}
5390 
5391 	if (enable) {
5392 		vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
5393 		drm_dbg_atomic(state->dev,
5394 			       "[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
5395 			       port, vcpi);
5396 		if (vcpi < 0)
5397 			return -EINVAL;
5398 	}
5399 
5400 	pos->dsc_enabled = enable;
5401 
5402 	return vcpi;
5403 }
5404 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5405 /**
5406  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5407  * atomic update is valid
5408  * @state: Pointer to the new &struct drm_dp_mst_topology_state
5409  *
5410  * Checks the given topology state for an atomic update to ensure that it's
5411  * valid. This includes checking whether there's enough bandwidth to support
5412  * the new VCPI allocations in the atomic update.
5413  *
5414  * Any atomic drivers supporting DP MST must make sure to call this after
5415  * checking the rest of their state in their
5416  * &drm_mode_config_funcs.atomic_check() callback.
5417  *
5418  * See also:
5419  * drm_dp_atomic_find_vcpi_slots()
5420  * drm_dp_atomic_release_vcpi_slots()
5421  *
5422  * Returns:
5423  *
5424  * 0 if the new state is valid, negative error code otherwise.
5425  */
drm_dp_mst_atomic_check(struct drm_atomic_state * state)5426 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5427 {
5428 	struct drm_dp_mst_topology_mgr *mgr;
5429 	struct drm_dp_mst_topology_state *mst_state;
5430 	int i, ret = 0;
5431 
5432 	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5433 		if (!mgr->mst_state)
5434 			continue;
5435 
5436 		ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
5437 		if (ret)
5438 			break;
5439 
5440 		mutex_lock(&mgr->lock);
5441 		ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5442 							    mst_state);
5443 		mutex_unlock(&mgr->lock);
5444 		if (ret < 0)
5445 			break;
5446 		else
5447 			ret = 0;
5448 	}
5449 
5450 	return ret;
5451 }
5452 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5453 
5454 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5455 	.atomic_duplicate_state = drm_dp_mst_duplicate_state,
5456 	.atomic_destroy_state = drm_dp_mst_destroy_state,
5457 };
5458 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5459 
5460 /**
5461  * drm_atomic_get_mst_topology_state: get MST topology state
5462  *
5463  * @state: global atomic state
5464  * @mgr: MST topology manager, also the private object in this case
5465  *
5466  * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5467  * state vtable so that the private object state returned is that of a MST
5468  * topology object. Also, drm_atomic_get_private_obj_state() expects the caller
5469  * to care of the locking, so warn if don't hold the connection_mutex.
5470  *
5471  * RETURNS:
5472  *
5473  * The MST topology state or error pointer.
5474  */
drm_atomic_get_mst_topology_state(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr)5475 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5476 								    struct drm_dp_mst_topology_mgr *mgr)
5477 {
5478 	return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5479 }
5480 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5481 
5482 /**
5483  * drm_dp_mst_topology_mgr_init - initialise a topology manager
5484  * @mgr: manager struct to initialise
5485  * @dev: device providing this structure - for i2c addition.
5486  * @aux: DP helper aux channel to talk to this device
5487  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5488  * @max_payloads: maximum number of payloads this GPU can source
5489  * @max_lane_count: maximum number of lanes this GPU supports
5490  * @max_link_rate: maximum link rate per lane this GPU supports in kHz
5491  * @conn_base_id: the connector object ID the MST device is connected to.
5492  *
5493  * Return 0 for success, or negative error code on failure
5494  */
drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr * mgr,struct drm_device * dev,struct drm_dp_aux * aux,int max_dpcd_transaction_bytes,int max_payloads,int max_lane_count,int max_link_rate,int conn_base_id)5495 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5496 				 struct drm_device *dev, struct drm_dp_aux *aux,
5497 				 int max_dpcd_transaction_bytes, int max_payloads,
5498 				 int max_lane_count, int max_link_rate,
5499 				 int conn_base_id)
5500 {
5501 	struct drm_dp_mst_topology_state *mst_state;
5502 
5503 	mutex_init(&mgr->lock);
5504 	mutex_init(&mgr->qlock);
5505 	mutex_init(&mgr->payload_lock);
5506 	mutex_init(&mgr->delayed_destroy_lock);
5507 	mutex_init(&mgr->up_req_lock);
5508 	mutex_init(&mgr->probe_lock);
5509 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5510 	mutex_init(&mgr->topology_ref_history_lock);
5511 	stack_depot_init();
5512 #endif
5513 	INIT_LIST_HEAD(&mgr->tx_msg_downq);
5514 	INIT_LIST_HEAD(&mgr->destroy_port_list);
5515 	INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5516 	INIT_LIST_HEAD(&mgr->up_req_list);
5517 
5518 	/*
5519 	 * delayed_destroy_work will be queued on a dedicated WQ, so that any
5520 	 * requeuing will be also flushed when deiniting the topology manager.
5521 	 */
5522 	mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5523 	if (mgr->delayed_destroy_wq == NULL)
5524 		return -ENOMEM;
5525 
5526 	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5527 	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5528 	INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5529 	INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5530 	init_waitqueue_head(&mgr->tx_waitq);
5531 	mgr->dev = dev;
5532 	mgr->aux = aux;
5533 	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5534 	mgr->max_payloads = max_payloads;
5535 	mgr->max_lane_count = max_lane_count;
5536 	mgr->max_link_rate = max_link_rate;
5537 	mgr->conn_base_id = conn_base_id;
5538 	if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
5539 	    max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
5540 		return -EINVAL;
5541 	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
5542 	if (!mgr->payloads)
5543 		return -ENOMEM;
5544 	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
5545 	if (!mgr->proposed_vcpis)
5546 		return -ENOMEM;
5547 	set_bit(0, &mgr->payload_mask);
5548 
5549 	mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5550 	if (mst_state == NULL)
5551 		return -ENOMEM;
5552 
5553 	mst_state->total_avail_slots = 63;
5554 	mst_state->start_slot = 1;
5555 
5556 	mst_state->mgr = mgr;
5557 	INIT_LIST_HEAD(&mst_state->vcpis);
5558 
5559 	drm_atomic_private_obj_init(dev, &mgr->base,
5560 				    &mst_state->base,
5561 				    &drm_dp_mst_topology_state_funcs);
5562 
5563 	return 0;
5564 }
5565 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5566 
5567 /**
5568  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5569  * @mgr: manager to destroy
5570  */
drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr * mgr)5571 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5572 {
5573 	drm_dp_mst_topology_mgr_set_mst(mgr, false);
5574 	flush_work(&mgr->work);
5575 	/* The following will also drain any requeued work on the WQ. */
5576 	if (mgr->delayed_destroy_wq) {
5577 		destroy_workqueue(mgr->delayed_destroy_wq);
5578 		mgr->delayed_destroy_wq = NULL;
5579 	}
5580 	mutex_lock(&mgr->payload_lock);
5581 	kfree(mgr->payloads);
5582 	mgr->payloads = NULL;
5583 	kfree(mgr->proposed_vcpis);
5584 	mgr->proposed_vcpis = NULL;
5585 	mutex_unlock(&mgr->payload_lock);
5586 	mgr->dev = NULL;
5587 	mgr->aux = NULL;
5588 	drm_atomic_private_obj_fini(&mgr->base);
5589 	mgr->funcs = NULL;
5590 
5591 	mutex_destroy(&mgr->delayed_destroy_lock);
5592 	mutex_destroy(&mgr->payload_lock);
5593 	mutex_destroy(&mgr->qlock);
5594 	mutex_destroy(&mgr->lock);
5595 	mutex_destroy(&mgr->up_req_lock);
5596 	mutex_destroy(&mgr->probe_lock);
5597 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5598 	mutex_destroy(&mgr->topology_ref_history_lock);
5599 #endif
5600 }
5601 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5602 
remote_i2c_read_ok(const struct i2c_msg msgs[],int num)5603 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5604 {
5605 	int i;
5606 
5607 	if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5608 		return false;
5609 
5610 	for (i = 0; i < num - 1; i++) {
5611 		if (msgs[i].flags & I2C_M_RD ||
5612 		    msgs[i].len > 0xff)
5613 			return false;
5614 	}
5615 
5616 	return msgs[num - 1].flags & I2C_M_RD &&
5617 		msgs[num - 1].len <= 0xff;
5618 }
5619 
remote_i2c_write_ok(const struct i2c_msg msgs[],int num)5620 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5621 {
5622 	int i;
5623 
5624 	for (i = 0; i < num - 1; i++) {
5625 		if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5626 		    msgs[i].len > 0xff)
5627 			return false;
5628 	}
5629 
5630 	return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5631 }
5632 
drm_dp_mst_i2c_read(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port,struct i2c_msg * msgs,int num)5633 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5634 			       struct drm_dp_mst_port *port,
5635 			       struct i2c_msg *msgs, int num)
5636 {
5637 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5638 	unsigned int i;
5639 	struct drm_dp_sideband_msg_req_body msg;
5640 	struct drm_dp_sideband_msg_tx *txmsg = NULL;
5641 	int ret;
5642 
5643 	memset(&msg, 0, sizeof(msg));
5644 	msg.req_type = DP_REMOTE_I2C_READ;
5645 	msg.u.i2c_read.num_transactions = num - 1;
5646 	msg.u.i2c_read.port_number = port->port_num;
5647 	for (i = 0; i < num - 1; i++) {
5648 		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5649 		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5650 		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5651 		msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5652 	}
5653 	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5654 	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5655 
5656 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5657 	if (!txmsg) {
5658 		ret = -ENOMEM;
5659 		goto out;
5660 	}
5661 
5662 	txmsg->dst = mstb;
5663 	drm_dp_encode_sideband_req(&msg, txmsg);
5664 
5665 	drm_dp_queue_down_tx(mgr, txmsg);
5666 
5667 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5668 	if (ret > 0) {
5669 
5670 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5671 			ret = -EREMOTEIO;
5672 			goto out;
5673 		}
5674 		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5675 			ret = -EIO;
5676 			goto out;
5677 		}
5678 		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5679 		ret = num;
5680 	}
5681 out:
5682 	kfree(txmsg);
5683 	return ret;
5684 }
5685 
drm_dp_mst_i2c_write(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port,struct i2c_msg * msgs,int num)5686 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5687 				struct drm_dp_mst_port *port,
5688 				struct i2c_msg *msgs, int num)
5689 {
5690 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5691 	unsigned int i;
5692 	struct drm_dp_sideband_msg_req_body msg;
5693 	struct drm_dp_sideband_msg_tx *txmsg = NULL;
5694 	int ret;
5695 
5696 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5697 	if (!txmsg) {
5698 		ret = -ENOMEM;
5699 		goto out;
5700 	}
5701 	for (i = 0; i < num; i++) {
5702 		memset(&msg, 0, sizeof(msg));
5703 		msg.req_type = DP_REMOTE_I2C_WRITE;
5704 		msg.u.i2c_write.port_number = port->port_num;
5705 		msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5706 		msg.u.i2c_write.num_bytes = msgs[i].len;
5707 		msg.u.i2c_write.bytes = msgs[i].buf;
5708 
5709 		memset(txmsg, 0, sizeof(*txmsg));
5710 		txmsg->dst = mstb;
5711 
5712 		drm_dp_encode_sideband_req(&msg, txmsg);
5713 		drm_dp_queue_down_tx(mgr, txmsg);
5714 
5715 		ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5716 		if (ret > 0) {
5717 			if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5718 				ret = -EREMOTEIO;
5719 				goto out;
5720 			}
5721 		} else {
5722 			goto out;
5723 		}
5724 	}
5725 	ret = num;
5726 out:
5727 	kfree(txmsg);
5728 	return ret;
5729 }
5730 
5731 /* I2C device */
drm_dp_mst_i2c_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int num)5732 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5733 			       struct i2c_msg *msgs, int num)
5734 {
5735 	struct drm_dp_aux *aux = adapter->algo_data;
5736 	struct drm_dp_mst_port *port =
5737 		container_of(aux, struct drm_dp_mst_port, aux);
5738 	struct drm_dp_mst_branch *mstb;
5739 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5740 	int ret;
5741 
5742 	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5743 	if (!mstb)
5744 		return -EREMOTEIO;
5745 
5746 	if (remote_i2c_read_ok(msgs, num)) {
5747 		ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5748 	} else if (remote_i2c_write_ok(msgs, num)) {
5749 		ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5750 	} else {
5751 		drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5752 		ret = -EIO;
5753 	}
5754 
5755 	drm_dp_mst_topology_put_mstb(mstb);
5756 	return ret;
5757 }
5758 
drm_dp_mst_i2c_functionality(struct i2c_adapter * adapter)5759 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5760 {
5761 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5762 	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5763 	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5764 	       I2C_FUNC_10BIT_ADDR;
5765 }
5766 
5767 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5768 	.functionality = drm_dp_mst_i2c_functionality,
5769 	.master_xfer = drm_dp_mst_i2c_xfer,
5770 };
5771 
5772 /**
5773  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5774  * @port: The port to add the I2C bus on
5775  *
5776  * Returns 0 on success or a negative error code on failure.
5777  */
drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port * port)5778 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5779 {
5780 	struct drm_dp_aux *aux = &port->aux;
5781 	struct device *parent_dev = port->mgr->dev->dev;
5782 
5783 	aux->ddc.algo = &drm_dp_mst_i2c_algo;
5784 	aux->ddc.algo_data = aux;
5785 	aux->ddc.retries = 3;
5786 
5787 	aux->ddc.class = I2C_CLASS_DDC;
5788 	aux->ddc.owner = THIS_MODULE;
5789 	/* FIXME: set the kdev of the port's connector as parent */
5790 	aux->ddc.dev.parent = parent_dev;
5791 	aux->ddc.dev.of_node = parent_dev->of_node;
5792 
5793 	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5794 		sizeof(aux->ddc.name));
5795 
5796 	return i2c_add_adapter(&aux->ddc);
5797 }
5798 
5799 /**
5800  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5801  * @port: The port to remove the I2C bus from
5802  */
drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port * port)5803 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5804 {
5805 	i2c_del_adapter(&port->aux.ddc);
5806 }
5807 
5808 /**
5809  * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5810  * @port: The port to check
5811  *
5812  * A single physical MST hub object can be represented in the topology
5813  * by multiple branches, with virtual ports between those branches.
5814  *
5815  * As of DP1.4, An MST hub with internal (virtual) ports must expose
5816  * certain DPCD registers over those ports. See sections 2.6.1.1.1
5817  * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5818  *
5819  * May acquire mgr->lock
5820  *
5821  * Returns:
5822  * true if the port is a virtual DP peer device, false otherwise
5823  */
drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port * port)5824 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5825 {
5826 	struct drm_dp_mst_port *downstream_port;
5827 
5828 	if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5829 		return false;
5830 
5831 	/* Virtual DP Sink (Internal Display Panel) */
5832 	if (port->port_num >= 8)
5833 		return true;
5834 
5835 	/* DP-to-HDMI Protocol Converter */
5836 	if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5837 	    !port->mcs &&
5838 	    port->ldps)
5839 		return true;
5840 
5841 	/* DP-to-DP */
5842 	mutex_lock(&port->mgr->lock);
5843 	if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5844 	    port->mstb &&
5845 	    port->mstb->num_ports == 2) {
5846 		list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5847 			if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5848 			    !downstream_port->input) {
5849 				mutex_unlock(&port->mgr->lock);
5850 				return true;
5851 			}
5852 		}
5853 	}
5854 	mutex_unlock(&port->mgr->lock);
5855 
5856 	return false;
5857 }
5858 
5859 /**
5860  * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5861  * @port: The port to check. A leaf of the MST tree with an attached display.
5862  *
5863  * Depending on the situation, DSC may be enabled via the endpoint aux,
5864  * the immediately upstream aux, or the connector's physical aux.
5865  *
5866  * This is both the correct aux to read DSC_CAPABILITY and the
5867  * correct aux to write DSC_ENABLED.
5868  *
5869  * This operation can be expensive (up to four aux reads), so
5870  * the caller should cache the return.
5871  *
5872  * Returns:
5873  * NULL if DSC cannot be enabled on this port, otherwise the aux device
5874  */
drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port * port)5875 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5876 {
5877 	struct drm_dp_mst_port *immediate_upstream_port;
5878 	struct drm_dp_mst_port *fec_port;
5879 	struct drm_dp_desc desc = {};
5880 	u8 endpoint_fec;
5881 	u8 endpoint_dsc;
5882 
5883 	if (!port)
5884 		return NULL;
5885 
5886 	if (port->parent->port_parent)
5887 		immediate_upstream_port = port->parent->port_parent;
5888 	else
5889 		immediate_upstream_port = NULL;
5890 
5891 	fec_port = immediate_upstream_port;
5892 	while (fec_port) {
5893 		/*
5894 		 * Each physical link (i.e. not a virtual port) between the
5895 		 * output and the primary device must support FEC
5896 		 */
5897 		if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5898 		    !fec_port->fec_capable)
5899 			return NULL;
5900 
5901 		fec_port = fec_port->parent->port_parent;
5902 	}
5903 
5904 	/* DP-to-DP peer device */
5905 	if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5906 		u8 upstream_dsc;
5907 
5908 		if (drm_dp_dpcd_read(&port->aux,
5909 				     DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5910 			return NULL;
5911 		if (drm_dp_dpcd_read(&port->aux,
5912 				     DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5913 			return NULL;
5914 		if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5915 				     DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5916 			return NULL;
5917 
5918 		/* Enpoint decompression with DP-to-DP peer device */
5919 		if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5920 		    (endpoint_fec & DP_FEC_CAPABLE) &&
5921 		    (upstream_dsc & 0x2) /* DSC passthrough */)
5922 			return &port->aux;
5923 
5924 		/* Virtual DPCD decompression with DP-to-DP peer device */
5925 		return &immediate_upstream_port->aux;
5926 	}
5927 
5928 	/* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5929 	if (drm_dp_mst_is_virtual_dpcd(port))
5930 		return &port->aux;
5931 
5932 	/*
5933 	 * Synaptics quirk
5934 	 * Applies to ports for which:
5935 	 * - Physical aux has Synaptics OUI
5936 	 * - DPv1.4 or higher
5937 	 * - Port is on primary branch device
5938 	 * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5939 	 */
5940 	if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5941 		return NULL;
5942 
5943 	if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5944 	    port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5945 	    port->parent == port->mgr->mst_primary) {
5946 		u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
5947 
5948 		if (drm_dp_read_dpcd_caps(port->mgr->aux, dpcd_ext) < 0)
5949 			return NULL;
5950 
5951 		if ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
5952 		    ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
5953 		     != DP_DWN_STRM_PORT_TYPE_ANALOG))
5954 			return port->mgr->aux;
5955 	}
5956 
5957 	/*
5958 	 * The check below verifies if the MST sink
5959 	 * connected to the GPU is capable of DSC -
5960 	 * therefore the endpoint needs to be
5961 	 * both DSC and FEC capable.
5962 	 */
5963 	if (drm_dp_dpcd_read(&port->aux,
5964 	   DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5965 		return NULL;
5966 	if (drm_dp_dpcd_read(&port->aux,
5967 	   DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5968 		return NULL;
5969 	if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5970 	   (endpoint_fec & DP_FEC_CAPABLE))
5971 		return &port->aux;
5972 
5973 	return NULL;
5974 }
5975 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);
5976