1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Thunderbolt driver - control channel and configuration commands
4  *
5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
6  * Copyright (C) 2018, Intel Corporation
7  */
8 
9 #include <linux/crc32.h>
10 #include <linux/delay.h>
11 #include <linux/slab.h>
12 #include <linux/pci.h>
13 #include <linux/dmapool.h>
14 #include <linux/workqueue.h>
15 
16 #include "ctl.h"
17 
18 
19 #define TB_CTL_RX_PKG_COUNT	10
20 #define TB_CTL_RETRIES		4
21 
22 /**
23  * struct tb_ctl - Thunderbolt control channel
24  * @nhi: Pointer to the NHI structure
25  * @tx: Transmit ring
26  * @rx: Receive ring
27  * @frame_pool: DMA pool for control messages
28  * @rx_packets: Received control messages
29  * @request_queue_lock: Lock protecting @request_queue
30  * @request_queue: List of outstanding requests
31  * @running: Is the control channel running at the moment
32  * @timeout_msec: Default timeout for non-raw control messages
33  * @callback: Callback called when hotplug message is received
34  * @callback_data: Data passed to @callback
35  */
36 struct tb_ctl {
37 	struct tb_nhi *nhi;
38 	struct tb_ring *tx;
39 	struct tb_ring *rx;
40 
41 	struct dma_pool *frame_pool;
42 	struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
43 	struct mutex request_queue_lock;
44 	struct list_head request_queue;
45 	bool running;
46 
47 	int timeout_msec;
48 	event_cb callback;
49 	void *callback_data;
50 };
51 
52 
53 #define tb_ctl_WARN(ctl, format, arg...) \
54 	dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)
55 
56 #define tb_ctl_err(ctl, format, arg...) \
57 	dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)
58 
59 #define tb_ctl_warn(ctl, format, arg...) \
60 	dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)
61 
62 #define tb_ctl_info(ctl, format, arg...) \
63 	dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)
64 
65 #define tb_ctl_dbg(ctl, format, arg...) \
66 	dev_dbg(&(ctl)->nhi->pdev->dev, format, ## arg)
67 
68 static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
69 /* Serializes access to request kref_get/put */
70 static DEFINE_MUTEX(tb_cfg_request_lock);
71 
72 /**
73  * tb_cfg_request_alloc() - Allocates a new config request
74  *
75  * This is refcounted object so when you are done with this, call
76  * tb_cfg_request_put() to it.
77  */
tb_cfg_request_alloc(void)78 struct tb_cfg_request *tb_cfg_request_alloc(void)
79 {
80 	struct tb_cfg_request *req;
81 
82 	req = kzalloc(sizeof(*req), GFP_KERNEL);
83 	if (!req)
84 		return NULL;
85 
86 	kref_init(&req->kref);
87 
88 	return req;
89 }
90 
91 /**
92  * tb_cfg_request_get() - Increase refcount of a request
93  * @req: Request whose refcount is increased
94  */
tb_cfg_request_get(struct tb_cfg_request * req)95 void tb_cfg_request_get(struct tb_cfg_request *req)
96 {
97 	mutex_lock(&tb_cfg_request_lock);
98 	kref_get(&req->kref);
99 	mutex_unlock(&tb_cfg_request_lock);
100 }
101 
tb_cfg_request_destroy(struct kref * kref)102 static void tb_cfg_request_destroy(struct kref *kref)
103 {
104 	struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
105 
106 	kfree(req);
107 }
108 
109 /**
110  * tb_cfg_request_put() - Decrease refcount and possibly release the request
111  * @req: Request whose refcount is decreased
112  *
113  * Call this function when you are done with the request. When refcount
114  * goes to %0 the object is released.
115  */
tb_cfg_request_put(struct tb_cfg_request * req)116 void tb_cfg_request_put(struct tb_cfg_request *req)
117 {
118 	mutex_lock(&tb_cfg_request_lock);
119 	kref_put(&req->kref, tb_cfg_request_destroy);
120 	mutex_unlock(&tb_cfg_request_lock);
121 }
122 
tb_cfg_request_enqueue(struct tb_ctl * ctl,struct tb_cfg_request * req)123 static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
124 				  struct tb_cfg_request *req)
125 {
126 	WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
127 	WARN_ON(req->ctl);
128 
129 	mutex_lock(&ctl->request_queue_lock);
130 	if (!ctl->running) {
131 		mutex_unlock(&ctl->request_queue_lock);
132 		return -ENOTCONN;
133 	}
134 	req->ctl = ctl;
135 	list_add_tail(&req->list, &ctl->request_queue);
136 	set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
137 	mutex_unlock(&ctl->request_queue_lock);
138 	return 0;
139 }
140 
tb_cfg_request_dequeue(struct tb_cfg_request * req)141 static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
142 {
143 	struct tb_ctl *ctl = req->ctl;
144 
145 	mutex_lock(&ctl->request_queue_lock);
146 	list_del(&req->list);
147 	clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
148 	if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
149 		wake_up(&tb_cfg_request_cancel_queue);
150 	mutex_unlock(&ctl->request_queue_lock);
151 }
152 
tb_cfg_request_is_active(struct tb_cfg_request * req)153 static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
154 {
155 	return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
156 }
157 
158 static struct tb_cfg_request *
tb_cfg_request_find(struct tb_ctl * ctl,struct ctl_pkg * pkg)159 tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
160 {
161 	struct tb_cfg_request *req = NULL, *iter;
162 
163 	mutex_lock(&pkg->ctl->request_queue_lock);
164 	list_for_each_entry(iter, &pkg->ctl->request_queue, list) {
165 		tb_cfg_request_get(iter);
166 		if (iter->match(iter, pkg)) {
167 			req = iter;
168 			break;
169 		}
170 		tb_cfg_request_put(iter);
171 	}
172 	mutex_unlock(&pkg->ctl->request_queue_lock);
173 
174 	return req;
175 }
176 
177 /* utility functions */
178 
179 
check_header(const struct ctl_pkg * pkg,u32 len,enum tb_cfg_pkg_type type,u64 route)180 static int check_header(const struct ctl_pkg *pkg, u32 len,
181 			enum tb_cfg_pkg_type type, u64 route)
182 {
183 	struct tb_cfg_header *header = pkg->buffer;
184 
185 	/* check frame, TODO: frame flags */
186 	if (WARN(len != pkg->frame.size,
187 			"wrong framesize (expected %#x, got %#x)\n",
188 			len, pkg->frame.size))
189 		return -EIO;
190 	if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
191 			type, pkg->frame.eof))
192 		return -EIO;
193 	if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
194 			pkg->frame.sof))
195 		return -EIO;
196 
197 	/* check header */
198 	if (WARN(header->unknown != 1 << 9,
199 			"header->unknown is %#x\n", header->unknown))
200 		return -EIO;
201 	if (WARN(route != tb_cfg_get_route(header),
202 			"wrong route (expected %llx, got %llx)",
203 			route, tb_cfg_get_route(header)))
204 		return -EIO;
205 	return 0;
206 }
207 
check_config_address(struct tb_cfg_address addr,enum tb_cfg_space space,u32 offset,u32 length)208 static int check_config_address(struct tb_cfg_address addr,
209 				enum tb_cfg_space space, u32 offset,
210 				u32 length)
211 {
212 	if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
213 		return -EIO;
214 	if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
215 			space, addr.space))
216 		return -EIO;
217 	if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
218 			offset, addr.offset))
219 		return -EIO;
220 	if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
221 			length, addr.length))
222 		return -EIO;
223 	/*
224 	 * We cannot check addr->port as it is set to the upstream port of the
225 	 * sender.
226 	 */
227 	return 0;
228 }
229 
decode_error(const struct ctl_pkg * response)230 static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
231 {
232 	struct cfg_error_pkg *pkg = response->buffer;
233 	struct tb_ctl *ctl = response->ctl;
234 	struct tb_cfg_result res = { 0 };
235 	res.response_route = tb_cfg_get_route(&pkg->header);
236 	res.response_port = 0;
237 	res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
238 			       tb_cfg_get_route(&pkg->header));
239 	if (res.err)
240 		return res;
241 
242 	if (pkg->zero1)
243 		tb_ctl_warn(ctl, "pkg->zero1 is %#x\n", pkg->zero1);
244 	if (pkg->zero2)
245 		tb_ctl_warn(ctl, "pkg->zero2 is %#x\n", pkg->zero2);
246 	if (pkg->zero3)
247 		tb_ctl_warn(ctl, "pkg->zero3 is %#x\n", pkg->zero3);
248 
249 	res.err = 1;
250 	res.tb_error = pkg->error;
251 	res.response_port = pkg->port;
252 	return res;
253 
254 }
255 
parse_header(const struct ctl_pkg * pkg,u32 len,enum tb_cfg_pkg_type type,u64 route)256 static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
257 					 enum tb_cfg_pkg_type type, u64 route)
258 {
259 	struct tb_cfg_header *header = pkg->buffer;
260 	struct tb_cfg_result res = { 0 };
261 
262 	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
263 		return decode_error(pkg);
264 
265 	res.response_port = 0; /* will be updated later for cfg_read/write */
266 	res.response_route = tb_cfg_get_route(header);
267 	res.err = check_header(pkg, len, type, route);
268 	return res;
269 }
270 
tb_cfg_print_error(struct tb_ctl * ctl,const struct tb_cfg_result * res)271 static void tb_cfg_print_error(struct tb_ctl *ctl,
272 			       const struct tb_cfg_result *res)
273 {
274 	WARN_ON(res->err != 1);
275 	switch (res->tb_error) {
276 	case TB_CFG_ERROR_PORT_NOT_CONNECTED:
277 		/* Port is not connected. This can happen during surprise
278 		 * removal. Do not warn. */
279 		return;
280 	case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
281 		/*
282 		 * Invalid cfg_space/offset/length combination in
283 		 * cfg_read/cfg_write.
284 		 */
285 		tb_ctl_dbg(ctl, "%llx:%x: invalid config space or offset\n",
286 			   res->response_route, res->response_port);
287 		return;
288 	case TB_CFG_ERROR_NO_SUCH_PORT:
289 		/*
290 		 * - The route contains a non-existent port.
291 		 * - The route contains a non-PHY port (e.g. PCIe).
292 		 * - The port in cfg_read/cfg_write does not exist.
293 		 */
294 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
295 			res->response_route, res->response_port);
296 		return;
297 	case TB_CFG_ERROR_LOOP:
298 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
299 			res->response_route, res->response_port);
300 		return;
301 	case TB_CFG_ERROR_LOCK:
302 		tb_ctl_warn(ctl, "%llx:%x: downstream port is locked\n",
303 			    res->response_route, res->response_port);
304 		return;
305 	default:
306 		/* 5,6,7,9 and 11 are also valid error codes */
307 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
308 			res->response_route, res->response_port);
309 		return;
310 	}
311 }
312 
tb_crc(const void * data,size_t len)313 static __be32 tb_crc(const void *data, size_t len)
314 {
315 	return cpu_to_be32(~__crc32c_le(~0, data, len));
316 }
317 
tb_ctl_pkg_free(struct ctl_pkg * pkg)318 static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
319 {
320 	if (pkg) {
321 		dma_pool_free(pkg->ctl->frame_pool,
322 			      pkg->buffer, pkg->frame.buffer_phy);
323 		kfree(pkg);
324 	}
325 }
326 
tb_ctl_pkg_alloc(struct tb_ctl * ctl)327 static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
328 {
329 	struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
330 	if (!pkg)
331 		return NULL;
332 	pkg->ctl = ctl;
333 	pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
334 				     &pkg->frame.buffer_phy);
335 	if (!pkg->buffer) {
336 		kfree(pkg);
337 		return NULL;
338 	}
339 	return pkg;
340 }
341 
342 
343 /* RX/TX handling */
344 
tb_ctl_tx_callback(struct tb_ring * ring,struct ring_frame * frame,bool canceled)345 static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
346 			       bool canceled)
347 {
348 	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
349 	tb_ctl_pkg_free(pkg);
350 }
351 
352 /*
353  * tb_cfg_tx() - transmit a packet on the control channel
354  *
355  * len must be a multiple of four.
356  *
357  * Return: Returns 0 on success or an error code on failure.
358  */
tb_ctl_tx(struct tb_ctl * ctl,const void * data,size_t len,enum tb_cfg_pkg_type type)359 static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
360 		     enum tb_cfg_pkg_type type)
361 {
362 	int res;
363 	struct ctl_pkg *pkg;
364 	if (len % 4 != 0) { /* required for le->be conversion */
365 		tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
366 		return -EINVAL;
367 	}
368 	if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
369 		tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
370 			    len, TB_FRAME_SIZE - 4);
371 		return -EINVAL;
372 	}
373 	pkg = tb_ctl_pkg_alloc(ctl);
374 	if (!pkg)
375 		return -ENOMEM;
376 	pkg->frame.callback = tb_ctl_tx_callback;
377 	pkg->frame.size = len + 4;
378 	pkg->frame.sof = type;
379 	pkg->frame.eof = type;
380 	cpu_to_be32_array(pkg->buffer, data, len / 4);
381 	*(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
382 
383 	res = tb_ring_tx(ctl->tx, &pkg->frame);
384 	if (res) /* ring is stopped */
385 		tb_ctl_pkg_free(pkg);
386 	return res;
387 }
388 
389 /*
390  * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
391  */
tb_ctl_handle_event(struct tb_ctl * ctl,enum tb_cfg_pkg_type type,struct ctl_pkg * pkg,size_t size)392 static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
393 				struct ctl_pkg *pkg, size_t size)
394 {
395 	return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
396 }
397 
tb_ctl_rx_submit(struct ctl_pkg * pkg)398 static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
399 {
400 	tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
401 					     * We ignore failures during stop.
402 					     * All rx packets are referenced
403 					     * from ctl->rx_packets, so we do
404 					     * not loose them.
405 					     */
406 }
407 
tb_async_error(const struct ctl_pkg * pkg)408 static int tb_async_error(const struct ctl_pkg *pkg)
409 {
410 	const struct cfg_error_pkg *error = pkg->buffer;
411 
412 	if (pkg->frame.eof != TB_CFG_PKG_ERROR)
413 		return false;
414 
415 	switch (error->error) {
416 	case TB_CFG_ERROR_LINK_ERROR:
417 	case TB_CFG_ERROR_HEC_ERROR_DETECTED:
418 	case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
419 		return true;
420 
421 	default:
422 		return false;
423 	}
424 }
425 
tb_ctl_rx_callback(struct tb_ring * ring,struct ring_frame * frame,bool canceled)426 static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
427 			       bool canceled)
428 {
429 	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
430 	struct tb_cfg_request *req;
431 	__be32 crc32;
432 
433 	if (canceled)
434 		return; /*
435 			 * ring is stopped, packet is referenced from
436 			 * ctl->rx_packets.
437 			 */
438 
439 	if (frame->size < 4 || frame->size % 4 != 0) {
440 		tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
441 			   frame->size);
442 		goto rx;
443 	}
444 
445 	frame->size -= 4; /* remove checksum */
446 	crc32 = tb_crc(pkg->buffer, frame->size);
447 	be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
448 
449 	switch (frame->eof) {
450 	case TB_CFG_PKG_READ:
451 	case TB_CFG_PKG_WRITE:
452 	case TB_CFG_PKG_ERROR:
453 	case TB_CFG_PKG_OVERRIDE:
454 	case TB_CFG_PKG_RESET:
455 		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
456 			tb_ctl_err(pkg->ctl,
457 				   "RX: checksum mismatch, dropping packet\n");
458 			goto rx;
459 		}
460 		if (tb_async_error(pkg)) {
461 			tb_ctl_handle_event(pkg->ctl, frame->eof,
462 					    pkg, frame->size);
463 			goto rx;
464 		}
465 		break;
466 
467 	case TB_CFG_PKG_EVENT:
468 	case TB_CFG_PKG_XDOMAIN_RESP:
469 	case TB_CFG_PKG_XDOMAIN_REQ:
470 		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
471 			tb_ctl_err(pkg->ctl,
472 				   "RX: checksum mismatch, dropping packet\n");
473 			goto rx;
474 		}
475 		fallthrough;
476 	case TB_CFG_PKG_ICM_EVENT:
477 		if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
478 			goto rx;
479 		break;
480 
481 	default:
482 		break;
483 	}
484 
485 	/*
486 	 * The received packet will be processed only if there is an
487 	 * active request and that the packet is what is expected. This
488 	 * prevents packets such as replies coming after timeout has
489 	 * triggered from messing with the active requests.
490 	 */
491 	req = tb_cfg_request_find(pkg->ctl, pkg);
492 	if (req) {
493 		if (req->copy(req, pkg))
494 			schedule_work(&req->work);
495 		tb_cfg_request_put(req);
496 	}
497 
498 rx:
499 	tb_ctl_rx_submit(pkg);
500 }
501 
tb_cfg_request_work(struct work_struct * work)502 static void tb_cfg_request_work(struct work_struct *work)
503 {
504 	struct tb_cfg_request *req = container_of(work, typeof(*req), work);
505 
506 	if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
507 		req->callback(req->callback_data);
508 
509 	tb_cfg_request_dequeue(req);
510 	tb_cfg_request_put(req);
511 }
512 
513 /**
514  * tb_cfg_request() - Start control request not waiting for it to complete
515  * @ctl: Control channel to use
516  * @req: Request to start
517  * @callback: Callback called when the request is completed
518  * @callback_data: Data to be passed to @callback
519  *
520  * This queues @req on the given control channel without waiting for it
521  * to complete. When the request completes @callback is called.
522  */
tb_cfg_request(struct tb_ctl * ctl,struct tb_cfg_request * req,void (* callback)(void *),void * callback_data)523 int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
524 		   void (*callback)(void *), void *callback_data)
525 {
526 	int ret;
527 
528 	req->flags = 0;
529 	req->callback = callback;
530 	req->callback_data = callback_data;
531 	INIT_WORK(&req->work, tb_cfg_request_work);
532 	INIT_LIST_HEAD(&req->list);
533 
534 	tb_cfg_request_get(req);
535 	ret = tb_cfg_request_enqueue(ctl, req);
536 	if (ret)
537 		goto err_put;
538 
539 	ret = tb_ctl_tx(ctl, req->request, req->request_size,
540 			req->request_type);
541 	if (ret)
542 		goto err_dequeue;
543 
544 	if (!req->response)
545 		schedule_work(&req->work);
546 
547 	return 0;
548 
549 err_dequeue:
550 	tb_cfg_request_dequeue(req);
551 err_put:
552 	tb_cfg_request_put(req);
553 
554 	return ret;
555 }
556 
557 /**
558  * tb_cfg_request_cancel() - Cancel a control request
559  * @req: Request to cancel
560  * @err: Error to assign to the request
561  *
562  * This function can be used to cancel ongoing request. It will wait
563  * until the request is not active anymore.
564  */
tb_cfg_request_cancel(struct tb_cfg_request * req,int err)565 void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
566 {
567 	set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
568 	schedule_work(&req->work);
569 	wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
570 	req->result.err = err;
571 }
572 
tb_cfg_request_complete(void * data)573 static void tb_cfg_request_complete(void *data)
574 {
575 	complete(data);
576 }
577 
578 /**
579  * tb_cfg_request_sync() - Start control request and wait until it completes
580  * @ctl: Control channel to use
581  * @req: Request to start
582  * @timeout_msec: Timeout how long to wait @req to complete
583  *
584  * Starts a control request and waits until it completes. If timeout
585  * triggers the request is canceled before function returns. Note the
586  * caller needs to make sure only one message for given switch is active
587  * at a time.
588  */
tb_cfg_request_sync(struct tb_ctl * ctl,struct tb_cfg_request * req,int timeout_msec)589 struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
590 					 struct tb_cfg_request *req,
591 					 int timeout_msec)
592 {
593 	unsigned long timeout = msecs_to_jiffies(timeout_msec);
594 	struct tb_cfg_result res = { 0 };
595 	DECLARE_COMPLETION_ONSTACK(done);
596 	int ret;
597 
598 	ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
599 	if (ret) {
600 		res.err = ret;
601 		return res;
602 	}
603 
604 	if (!wait_for_completion_timeout(&done, timeout))
605 		tb_cfg_request_cancel(req, -ETIMEDOUT);
606 
607 	flush_work(&req->work);
608 
609 	return req->result;
610 }
611 
612 /* public interface, alloc/start/stop/free */
613 
614 /**
615  * tb_ctl_alloc() - allocate a control channel
616  * @nhi: Pointer to NHI
617  * @timeout_msec: Default timeout used with non-raw control messages
618  * @cb: Callback called for plug events
619  * @cb_data: Data passed to @cb
620  *
621  * cb will be invoked once for every hot plug event.
622  *
623  * Return: Returns a pointer on success or NULL on failure.
624  */
tb_ctl_alloc(struct tb_nhi * nhi,int timeout_msec,event_cb cb,void * cb_data)625 struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int timeout_msec, event_cb cb,
626 			    void *cb_data)
627 {
628 	int i;
629 	struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
630 	if (!ctl)
631 		return NULL;
632 	ctl->nhi = nhi;
633 	ctl->timeout_msec = timeout_msec;
634 	ctl->callback = cb;
635 	ctl->callback_data = cb_data;
636 
637 	mutex_init(&ctl->request_queue_lock);
638 	INIT_LIST_HEAD(&ctl->request_queue);
639 	ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
640 					 TB_FRAME_SIZE, 4, 0);
641 	if (!ctl->frame_pool)
642 		goto err;
643 
644 	ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
645 	if (!ctl->tx)
646 		goto err;
647 
648 	ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0, 0xffff,
649 				   0xffff, NULL, NULL);
650 	if (!ctl->rx)
651 		goto err;
652 
653 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
654 		ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
655 		if (!ctl->rx_packets[i])
656 			goto err;
657 		ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
658 	}
659 
660 	tb_ctl_dbg(ctl, "control channel created\n");
661 	return ctl;
662 err:
663 	tb_ctl_free(ctl);
664 	return NULL;
665 }
666 
667 /**
668  * tb_ctl_free() - free a control channel
669  * @ctl: Control channel to free
670  *
671  * Must be called after tb_ctl_stop.
672  *
673  * Must NOT be called from ctl->callback.
674  */
tb_ctl_free(struct tb_ctl * ctl)675 void tb_ctl_free(struct tb_ctl *ctl)
676 {
677 	int i;
678 
679 	if (!ctl)
680 		return;
681 
682 	if (ctl->rx)
683 		tb_ring_free(ctl->rx);
684 	if (ctl->tx)
685 		tb_ring_free(ctl->tx);
686 
687 	/* free RX packets */
688 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
689 		tb_ctl_pkg_free(ctl->rx_packets[i]);
690 
691 
692 	dma_pool_destroy(ctl->frame_pool);
693 	kfree(ctl);
694 }
695 
696 /**
697  * tb_ctl_start() - start/resume the control channel
698  * @ctl: Control channel to start
699  */
tb_ctl_start(struct tb_ctl * ctl)700 void tb_ctl_start(struct tb_ctl *ctl)
701 {
702 	int i;
703 	tb_ctl_dbg(ctl, "control channel starting...\n");
704 	tb_ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
705 	tb_ring_start(ctl->rx);
706 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
707 		tb_ctl_rx_submit(ctl->rx_packets[i]);
708 
709 	ctl->running = true;
710 }
711 
712 /**
713  * tb_ctl_stop() - pause the control channel
714  * @ctl: Control channel to stop
715  *
716  * All invocations of ctl->callback will have finished after this method
717  * returns.
718  *
719  * Must NOT be called from ctl->callback.
720  */
tb_ctl_stop(struct tb_ctl * ctl)721 void tb_ctl_stop(struct tb_ctl *ctl)
722 {
723 	mutex_lock(&ctl->request_queue_lock);
724 	ctl->running = false;
725 	mutex_unlock(&ctl->request_queue_lock);
726 
727 	tb_ring_stop(ctl->rx);
728 	tb_ring_stop(ctl->tx);
729 
730 	if (!list_empty(&ctl->request_queue))
731 		tb_ctl_WARN(ctl, "dangling request in request_queue\n");
732 	INIT_LIST_HEAD(&ctl->request_queue);
733 	tb_ctl_dbg(ctl, "control channel stopped\n");
734 }
735 
736 /* public interface, commands */
737 
738 /**
739  * tb_cfg_ack_plug() - Ack hot plug/unplug event
740  * @ctl: Control channel to use
741  * @route: Router that originated the event
742  * @port: Port where the hot plug/unplug happened
743  * @unplug: Ack hot plug or unplug
744  *
745  * Call this as response for hot plug/unplug event to ack it.
746  * Returns %0 on success or an error code on failure.
747  */
tb_cfg_ack_plug(struct tb_ctl * ctl,u64 route,u32 port,bool unplug)748 int tb_cfg_ack_plug(struct tb_ctl *ctl, u64 route, u32 port, bool unplug)
749 {
750 	struct cfg_error_pkg pkg = {
751 		.header = tb_cfg_make_header(route),
752 		.port = port,
753 		.error = TB_CFG_ERROR_ACK_PLUG_EVENT,
754 		.pg = unplug ? TB_CFG_ERROR_PG_HOT_UNPLUG
755 			     : TB_CFG_ERROR_PG_HOT_PLUG,
756 	};
757 	tb_ctl_dbg(ctl, "acking hot %splug event on %llx:%x\n",
758 		   unplug ? "un" : "", route, port);
759 	return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
760 }
761 
tb_cfg_match(const struct tb_cfg_request * req,const struct ctl_pkg * pkg)762 static bool tb_cfg_match(const struct tb_cfg_request *req,
763 			 const struct ctl_pkg *pkg)
764 {
765 	u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
766 
767 	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
768 		return true;
769 
770 	if (pkg->frame.eof != req->response_type)
771 		return false;
772 	if (route != tb_cfg_get_route(req->request))
773 		return false;
774 	if (pkg->frame.size != req->response_size)
775 		return false;
776 
777 	if (pkg->frame.eof == TB_CFG_PKG_READ ||
778 	    pkg->frame.eof == TB_CFG_PKG_WRITE) {
779 		const struct cfg_read_pkg *req_hdr = req->request;
780 		const struct cfg_read_pkg *res_hdr = pkg->buffer;
781 
782 		if (req_hdr->addr.seq != res_hdr->addr.seq)
783 			return false;
784 	}
785 
786 	return true;
787 }
788 
tb_cfg_copy(struct tb_cfg_request * req,const struct ctl_pkg * pkg)789 static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
790 {
791 	struct tb_cfg_result res;
792 
793 	/* Now make sure it is in expected format */
794 	res = parse_header(pkg, req->response_size, req->response_type,
795 			   tb_cfg_get_route(req->request));
796 	if (!res.err)
797 		memcpy(req->response, pkg->buffer, req->response_size);
798 
799 	req->result = res;
800 
801 	/* Always complete when first response is received */
802 	return true;
803 }
804 
805 /**
806  * tb_cfg_reset() - send a reset packet and wait for a response
807  * @ctl: Control channel pointer
808  * @route: Router string for the router to send reset
809  *
810  * If the switch at route is incorrectly configured then we will not receive a
811  * reply (even though the switch will reset). The caller should check for
812  * -ETIMEDOUT and attempt to reconfigure the switch.
813  */
tb_cfg_reset(struct tb_ctl * ctl,u64 route)814 struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route)
815 {
816 	struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
817 	struct tb_cfg_result res = { 0 };
818 	struct tb_cfg_header reply;
819 	struct tb_cfg_request *req;
820 
821 	req = tb_cfg_request_alloc();
822 	if (!req) {
823 		res.err = -ENOMEM;
824 		return res;
825 	}
826 
827 	req->match = tb_cfg_match;
828 	req->copy = tb_cfg_copy;
829 	req->request = &request;
830 	req->request_size = sizeof(request);
831 	req->request_type = TB_CFG_PKG_RESET;
832 	req->response = &reply;
833 	req->response_size = sizeof(reply);
834 	req->response_type = TB_CFG_PKG_RESET;
835 
836 	res = tb_cfg_request_sync(ctl, req, ctl->timeout_msec);
837 
838 	tb_cfg_request_put(req);
839 
840 	return res;
841 }
842 
843 /**
844  * tb_cfg_read_raw() - read from config space into buffer
845  * @ctl: Pointer to the control channel
846  * @buffer: Buffer where the data is read
847  * @route: Route string of the router
848  * @port: Port number when reading from %TB_CFG_PORT, %0 otherwise
849  * @space: Config space selector
850  * @offset: Dword word offset of the register to start reading
851  * @length: Number of dwords to read
852  * @timeout_msec: Timeout in ms how long to wait for the response
853  *
854  * Reads from router config space without translating the possible error.
855  */
tb_cfg_read_raw(struct tb_ctl * ctl,void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length,int timeout_msec)856 struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
857 		u64 route, u32 port, enum tb_cfg_space space,
858 		u32 offset, u32 length, int timeout_msec)
859 {
860 	struct tb_cfg_result res = { 0 };
861 	struct cfg_read_pkg request = {
862 		.header = tb_cfg_make_header(route),
863 		.addr = {
864 			.port = port,
865 			.space = space,
866 			.offset = offset,
867 			.length = length,
868 		},
869 	};
870 	struct cfg_write_pkg reply;
871 	int retries = 0;
872 
873 	while (retries < TB_CTL_RETRIES) {
874 		struct tb_cfg_request *req;
875 
876 		req = tb_cfg_request_alloc();
877 		if (!req) {
878 			res.err = -ENOMEM;
879 			return res;
880 		}
881 
882 		request.addr.seq = retries++;
883 
884 		req->match = tb_cfg_match;
885 		req->copy = tb_cfg_copy;
886 		req->request = &request;
887 		req->request_size = sizeof(request);
888 		req->request_type = TB_CFG_PKG_READ;
889 		req->response = &reply;
890 		req->response_size = 12 + 4 * length;
891 		req->response_type = TB_CFG_PKG_READ;
892 
893 		res = tb_cfg_request_sync(ctl, req, timeout_msec);
894 
895 		tb_cfg_request_put(req);
896 
897 		if (res.err != -ETIMEDOUT)
898 			break;
899 
900 		/* Wait a bit (arbitrary time) until we send a retry */
901 		usleep_range(10, 100);
902 	}
903 
904 	if (res.err)
905 		return res;
906 
907 	res.response_port = reply.addr.port;
908 	res.err = check_config_address(reply.addr, space, offset, length);
909 	if (!res.err)
910 		memcpy(buffer, &reply.data, 4 * length);
911 	return res;
912 }
913 
914 /**
915  * tb_cfg_write_raw() - write from buffer into config space
916  * @ctl: Pointer to the control channel
917  * @buffer: Data to write
918  * @route: Route string of the router
919  * @port: Port number when writing to %TB_CFG_PORT, %0 otherwise
920  * @space: Config space selector
921  * @offset: Dword word offset of the register to start writing
922  * @length: Number of dwords to write
923  * @timeout_msec: Timeout in ms how long to wait for the response
924  *
925  * Writes to router config space without translating the possible error.
926  */
tb_cfg_write_raw(struct tb_ctl * ctl,const void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length,int timeout_msec)927 struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
928 		u64 route, u32 port, enum tb_cfg_space space,
929 		u32 offset, u32 length, int timeout_msec)
930 {
931 	struct tb_cfg_result res = { 0 };
932 	struct cfg_write_pkg request = {
933 		.header = tb_cfg_make_header(route),
934 		.addr = {
935 			.port = port,
936 			.space = space,
937 			.offset = offset,
938 			.length = length,
939 		},
940 	};
941 	struct cfg_read_pkg reply;
942 	int retries = 0;
943 
944 	memcpy(&request.data, buffer, length * 4);
945 
946 	while (retries < TB_CTL_RETRIES) {
947 		struct tb_cfg_request *req;
948 
949 		req = tb_cfg_request_alloc();
950 		if (!req) {
951 			res.err = -ENOMEM;
952 			return res;
953 		}
954 
955 		request.addr.seq = retries++;
956 
957 		req->match = tb_cfg_match;
958 		req->copy = tb_cfg_copy;
959 		req->request = &request;
960 		req->request_size = 12 + 4 * length;
961 		req->request_type = TB_CFG_PKG_WRITE;
962 		req->response = &reply;
963 		req->response_size = sizeof(reply);
964 		req->response_type = TB_CFG_PKG_WRITE;
965 
966 		res = tb_cfg_request_sync(ctl, req, timeout_msec);
967 
968 		tb_cfg_request_put(req);
969 
970 		if (res.err != -ETIMEDOUT)
971 			break;
972 
973 		/* Wait a bit (arbitrary time) until we send a retry */
974 		usleep_range(10, 100);
975 	}
976 
977 	if (res.err)
978 		return res;
979 
980 	res.response_port = reply.addr.port;
981 	res.err = check_config_address(reply.addr, space, offset, length);
982 	return res;
983 }
984 
tb_cfg_get_error(struct tb_ctl * ctl,enum tb_cfg_space space,const struct tb_cfg_result * res)985 static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
986 			    const struct tb_cfg_result *res)
987 {
988 	/*
989 	 * For unimplemented ports access to port config space may return
990 	 * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
991 	 * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
992 	 * that the caller can mark the port as disabled.
993 	 */
994 	if (space == TB_CFG_PORT &&
995 	    res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
996 		return -ENODEV;
997 
998 	tb_cfg_print_error(ctl, res);
999 
1000 	if (res->tb_error == TB_CFG_ERROR_LOCK)
1001 		return -EACCES;
1002 	else if (res->tb_error == TB_CFG_ERROR_PORT_NOT_CONNECTED)
1003 		return -ENOTCONN;
1004 
1005 	return -EIO;
1006 }
1007 
tb_cfg_read(struct tb_ctl * ctl,void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length)1008 int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
1009 		enum tb_cfg_space space, u32 offset, u32 length)
1010 {
1011 	struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
1012 			space, offset, length, ctl->timeout_msec);
1013 	switch (res.err) {
1014 	case 0:
1015 		/* Success */
1016 		break;
1017 
1018 	case 1:
1019 		/* Thunderbolt error, tb_error holds the actual number */
1020 		return tb_cfg_get_error(ctl, space, &res);
1021 
1022 	case -ETIMEDOUT:
1023 		tb_ctl_warn(ctl, "%llx: timeout reading config space %u from %#x\n",
1024 			    route, space, offset);
1025 		break;
1026 
1027 	default:
1028 		WARN(1, "tb_cfg_read: %d\n", res.err);
1029 		break;
1030 	}
1031 	return res.err;
1032 }
1033 
tb_cfg_write(struct tb_ctl * ctl,const void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length)1034 int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
1035 		 enum tb_cfg_space space, u32 offset, u32 length)
1036 {
1037 	struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
1038 			space, offset, length, ctl->timeout_msec);
1039 	switch (res.err) {
1040 	case 0:
1041 		/* Success */
1042 		break;
1043 
1044 	case 1:
1045 		/* Thunderbolt error, tb_error holds the actual number */
1046 		return tb_cfg_get_error(ctl, space, &res);
1047 
1048 	case -ETIMEDOUT:
1049 		tb_ctl_warn(ctl, "%llx: timeout writing config space %u to %#x\n",
1050 			    route, space, offset);
1051 		break;
1052 
1053 	default:
1054 		WARN(1, "tb_cfg_write: %d\n", res.err);
1055 		break;
1056 	}
1057 	return res.err;
1058 }
1059 
1060 /**
1061  * tb_cfg_get_upstream_port() - get upstream port number of switch at route
1062  * @ctl: Pointer to the control channel
1063  * @route: Route string of the router
1064  *
1065  * Reads the first dword from the switches TB_CFG_SWITCH config area and
1066  * returns the port number from which the reply originated.
1067  *
1068  * Return: Returns the upstream port number on success or an error code on
1069  * failure.
1070  */
tb_cfg_get_upstream_port(struct tb_ctl * ctl,u64 route)1071 int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
1072 {
1073 	u32 dummy;
1074 	struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
1075 						   TB_CFG_SWITCH, 0, 1,
1076 						   ctl->timeout_msec);
1077 	if (res.err == 1)
1078 		return -EIO;
1079 	if (res.err)
1080 		return res.err;
1081 	return res.response_port;
1082 }
1083