1 // SPDX-License-Identifier: GPL-2.0
2 
3 /* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
4  * Copyright (C) 2018-2023 Linaro Ltd.
5  */
6 
7 #include <linux/types.h>
8 #include <linux/bits.h>
9 #include <linux/bitfield.h>
10 #include <linux/mutex.h>
11 #include <linux/completion.h>
12 #include <linux/io.h>
13 #include <linux/bug.h>
14 #include <linux/interrupt.h>
15 #include <linux/platform_device.h>
16 #include <linux/netdevice.h>
17 
18 #include "gsi.h"
19 #include "reg.h"
20 #include "gsi_reg.h"
21 #include "gsi_private.h"
22 #include "gsi_trans.h"
23 #include "ipa_gsi.h"
24 #include "ipa_data.h"
25 #include "ipa_version.h"
26 
27 /**
28  * DOC: The IPA Generic Software Interface
29  *
30  * The generic software interface (GSI) is an integral component of the IPA,
31  * providing a well-defined communication layer between the AP subsystem
32  * and the IPA core.  The modem uses the GSI layer as well.
33  *
34  *	--------	     ---------
35  *	|      |	     |	     |
36  *	|  AP  +<---.	.----+ Modem |
37  *	|      +--. |	| .->+	     |
38  *	|      |  | |	| |  |	     |
39  *	--------  | |	| |  ---------
40  *		  v |	v |
41  *		--+-+---+-+--
42  *		|    GSI    |
43  *		|-----------|
44  *		|	    |
45  *		|    IPA    |
46  *		|	    |
47  *		-------------
48  *
49  * In the above diagram, the AP and Modem represent "execution environments"
50  * (EEs), which are independent operating environments that use the IPA for
51  * data transfer.
52  *
53  * Each EE uses a set of unidirectional GSI "channels," which allow transfer
54  * of data to or from the IPA.  A channel is implemented as a ring buffer,
55  * with a DRAM-resident array of "transfer elements" (TREs) available to
56  * describe transfers to or from other EEs through the IPA.  A transfer
57  * element can also contain an immediate command, requesting the IPA perform
58  * actions other than data transfer.
59  *
60  * Each TRE refers to a block of data--also located in DRAM.  After writing
61  * one or more TREs to a channel, the writer (either the IPA or an EE) writes
62  * a doorbell register to inform the receiving side how many elements have
63  * been written.
64  *
65  * Each channel has a GSI "event ring" associated with it.  An event ring
66  * is implemented very much like a channel ring, but is always directed from
67  * the IPA to an EE.  The IPA notifies an EE (such as the AP) about channel
68  * events by adding an entry to the event ring associated with the channel.
69  * The GSI then writes its doorbell for the event ring, causing the target
70  * EE to be interrupted.  Each entry in an event ring contains a pointer
71  * to the channel TRE whose completion the event represents.
72  *
73  * Each TRE in a channel ring has a set of flags.  One flag indicates whether
74  * the completion of the transfer operation generates an entry (and possibly
75  * an interrupt) in the channel's event ring.  Other flags allow transfer
76  * elements to be chained together, forming a single logical transaction.
77  * TRE flags are used to control whether and when interrupts are generated
78  * to signal completion of channel transfers.
79  *
80  * Elements in channel and event rings are completed (or consumed) strictly
81  * in order.  Completion of one entry implies the completion of all preceding
82  * entries.  A single completion interrupt can therefore communicate the
83  * completion of many transfers.
84  *
85  * Note that all GSI registers are little-endian, which is the assumed
86  * endianness of I/O space accesses.  The accessor functions perform byte
87  * swapping if needed (i.e., for a big endian CPU).
88  */
89 
90 /* Delay period for interrupt moderation (in 32KHz IPA internal timer ticks) */
91 #define GSI_EVT_RING_INT_MODT		(32 * 1) /* 1ms under 32KHz clock */
92 
93 #define GSI_CMD_TIMEOUT			50	/* milliseconds */
94 
95 #define GSI_CHANNEL_STOP_RETRIES	10
96 #define GSI_CHANNEL_MODEM_HALT_RETRIES	10
97 #define GSI_CHANNEL_MODEM_FLOW_RETRIES	5	/* disable flow control only */
98 
99 #define GSI_MHI_EVENT_ID_START		10	/* 1st reserved event id */
100 #define GSI_MHI_EVENT_ID_END		16	/* Last reserved event id */
101 
102 #define GSI_ISR_MAX_ITER		50	/* Detect interrupt storms */
103 
104 /* An entry in an event ring */
105 struct gsi_event {
106 	__le64 xfer_ptr;
107 	__le16 len;
108 	u8 reserved1;
109 	u8 code;
110 	__le16 reserved2;
111 	u8 type;
112 	u8 chid;
113 };
114 
115 /** gsi_channel_scratch_gpi - GPI protocol scratch register
116  * @max_outstanding_tre:
117  *	Defines the maximum number of TREs allowed in a single transaction
118  *	on a channel (in bytes).  This determines the amount of prefetch
119  *	performed by the hardware.  We configure this to equal the size of
120  *	the TLV FIFO for the channel.
121  * @outstanding_threshold:
122  *	Defines the threshold (in bytes) determining when the sequencer
123  *	should update the channel doorbell.  We configure this to equal
124  *	the size of two TREs.
125  */
126 struct gsi_channel_scratch_gpi {
127 	u64 reserved1;
128 	u16 reserved2;
129 	u16 max_outstanding_tre;
130 	u16 reserved3;
131 	u16 outstanding_threshold;
132 };
133 
134 /** gsi_channel_scratch - channel scratch configuration area
135  *
136  * The exact interpretation of this register is protocol-specific.
137  * We only use GPI channels; see struct gsi_channel_scratch_gpi, above.
138  */
139 union gsi_channel_scratch {
140 	struct gsi_channel_scratch_gpi gpi;
141 	struct {
142 		u32 word1;
143 		u32 word2;
144 		u32 word3;
145 		u32 word4;
146 	} data;
147 };
148 
149 /* Check things that can be validated at build time. */
gsi_validate_build(void)150 static void gsi_validate_build(void)
151 {
152 	/* This is used as a divisor */
153 	BUILD_BUG_ON(!GSI_RING_ELEMENT_SIZE);
154 
155 	/* Code assumes the size of channel and event ring element are
156 	 * the same (and fixed).  Make sure the size of an event ring
157 	 * element is what's expected.
158 	 */
159 	BUILD_BUG_ON(sizeof(struct gsi_event) != GSI_RING_ELEMENT_SIZE);
160 
161 	/* Hardware requires a 2^n ring size.  We ensure the number of
162 	 * elements in an event ring is a power of 2 elsewhere; this
163 	 * ensure the elements themselves meet the requirement.
164 	 */
165 	BUILD_BUG_ON(!is_power_of_2(GSI_RING_ELEMENT_SIZE));
166 }
167 
168 /* Return the channel id associated with a given channel */
gsi_channel_id(struct gsi_channel * channel)169 static u32 gsi_channel_id(struct gsi_channel *channel)
170 {
171 	return channel - &channel->gsi->channel[0];
172 }
173 
174 /* An initialized channel has a non-null GSI pointer */
gsi_channel_initialized(struct gsi_channel * channel)175 static bool gsi_channel_initialized(struct gsi_channel *channel)
176 {
177 	return !!channel->gsi;
178 }
179 
180 /* Encode the channel protocol for the CH_C_CNTXT_0 register */
ch_c_cntxt_0_type_encode(enum ipa_version version,const struct reg * reg,enum gsi_channel_type type)181 static u32 ch_c_cntxt_0_type_encode(enum ipa_version version,
182 				    const struct reg *reg,
183 				    enum gsi_channel_type type)
184 {
185 	u32 val;
186 
187 	val = reg_encode(reg, CHTYPE_PROTOCOL, type);
188 	if (version < IPA_VERSION_4_5 || version >= IPA_VERSION_5_0)
189 		return val;
190 
191 	type >>= hweight32(reg_fmask(reg, CHTYPE_PROTOCOL));
192 
193 	return val | reg_encode(reg, CHTYPE_PROTOCOL_MSB, type);
194 }
195 
196 /* Update the GSI IRQ type register with the cached value */
gsi_irq_type_update(struct gsi * gsi,u32 val)197 static void gsi_irq_type_update(struct gsi *gsi, u32 val)
198 {
199 	const struct reg *reg = gsi_reg(gsi, CNTXT_TYPE_IRQ_MSK);
200 
201 	gsi->type_enabled_bitmap = val;
202 	iowrite32(val, gsi->virt + reg_offset(reg));
203 }
204 
gsi_irq_type_enable(struct gsi * gsi,enum gsi_irq_type_id type_id)205 static void gsi_irq_type_enable(struct gsi *gsi, enum gsi_irq_type_id type_id)
206 {
207 	gsi_irq_type_update(gsi, gsi->type_enabled_bitmap | type_id);
208 }
209 
gsi_irq_type_disable(struct gsi * gsi,enum gsi_irq_type_id type_id)210 static void gsi_irq_type_disable(struct gsi *gsi, enum gsi_irq_type_id type_id)
211 {
212 	gsi_irq_type_update(gsi, gsi->type_enabled_bitmap & ~type_id);
213 }
214 
215 /* Event ring commands are performed one at a time.  Their completion
216  * is signaled by the event ring control GSI interrupt type, which is
217  * only enabled when we issue an event ring command.  Only the event
218  * ring being operated on has this interrupt enabled.
219  */
gsi_irq_ev_ctrl_enable(struct gsi * gsi,u32 evt_ring_id)220 static void gsi_irq_ev_ctrl_enable(struct gsi *gsi, u32 evt_ring_id)
221 {
222 	u32 val = BIT(evt_ring_id);
223 	const struct reg *reg;
224 
225 	/* There's a small chance that a previous command completed
226 	 * after the interrupt was disabled, so make sure we have no
227 	 * pending interrupts before we enable them.
228 	 */
229 	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_CLR);
230 	iowrite32(~0, gsi->virt + reg_offset(reg));
231 
232 	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_MSK);
233 	iowrite32(val, gsi->virt + reg_offset(reg));
234 	gsi_irq_type_enable(gsi, GSI_EV_CTRL);
235 }
236 
237 /* Disable event ring control interrupts */
gsi_irq_ev_ctrl_disable(struct gsi * gsi)238 static void gsi_irq_ev_ctrl_disable(struct gsi *gsi)
239 {
240 	const struct reg *reg;
241 
242 	gsi_irq_type_disable(gsi, GSI_EV_CTRL);
243 
244 	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_MSK);
245 	iowrite32(0, gsi->virt + reg_offset(reg));
246 }
247 
248 /* Channel commands are performed one at a time.  Their completion is
249  * signaled by the channel control GSI interrupt type, which is only
250  * enabled when we issue a channel command.  Only the channel being
251  * operated on has this interrupt enabled.
252  */
gsi_irq_ch_ctrl_enable(struct gsi * gsi,u32 channel_id)253 static void gsi_irq_ch_ctrl_enable(struct gsi *gsi, u32 channel_id)
254 {
255 	u32 val = BIT(channel_id);
256 	const struct reg *reg;
257 
258 	/* There's a small chance that a previous command completed
259 	 * after the interrupt was disabled, so make sure we have no
260 	 * pending interrupts before we enable them.
261 	 */
262 	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_CLR);
263 	iowrite32(~0, gsi->virt + reg_offset(reg));
264 
265 	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_MSK);
266 	iowrite32(val, gsi->virt + reg_offset(reg));
267 
268 	gsi_irq_type_enable(gsi, GSI_CH_CTRL);
269 }
270 
271 /* Disable channel control interrupts */
gsi_irq_ch_ctrl_disable(struct gsi * gsi)272 static void gsi_irq_ch_ctrl_disable(struct gsi *gsi)
273 {
274 	const struct reg *reg;
275 
276 	gsi_irq_type_disable(gsi, GSI_CH_CTRL);
277 
278 	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_MSK);
279 	iowrite32(0, gsi->virt + reg_offset(reg));
280 }
281 
gsi_irq_ieob_enable_one(struct gsi * gsi,u32 evt_ring_id)282 static void gsi_irq_ieob_enable_one(struct gsi *gsi, u32 evt_ring_id)
283 {
284 	bool enable_ieob = !gsi->ieob_enabled_bitmap;
285 	const struct reg *reg;
286 	u32 val;
287 
288 	gsi->ieob_enabled_bitmap |= BIT(evt_ring_id);
289 
290 	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ_MSK);
291 	val = gsi->ieob_enabled_bitmap;
292 	iowrite32(val, gsi->virt + reg_offset(reg));
293 
294 	/* Enable the interrupt type if this is the first channel enabled */
295 	if (enable_ieob)
296 		gsi_irq_type_enable(gsi, GSI_IEOB);
297 }
298 
gsi_irq_ieob_disable(struct gsi * gsi,u32 event_mask)299 static void gsi_irq_ieob_disable(struct gsi *gsi, u32 event_mask)
300 {
301 	const struct reg *reg;
302 	u32 val;
303 
304 	gsi->ieob_enabled_bitmap &= ~event_mask;
305 
306 	/* Disable the interrupt type if this was the last enabled channel */
307 	if (!gsi->ieob_enabled_bitmap)
308 		gsi_irq_type_disable(gsi, GSI_IEOB);
309 
310 	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ_MSK);
311 	val = gsi->ieob_enabled_bitmap;
312 	iowrite32(val, gsi->virt + reg_offset(reg));
313 }
314 
gsi_irq_ieob_disable_one(struct gsi * gsi,u32 evt_ring_id)315 static void gsi_irq_ieob_disable_one(struct gsi *gsi, u32 evt_ring_id)
316 {
317 	gsi_irq_ieob_disable(gsi, BIT(evt_ring_id));
318 }
319 
320 /* Enable all GSI_interrupt types */
gsi_irq_enable(struct gsi * gsi)321 static void gsi_irq_enable(struct gsi *gsi)
322 {
323 	const struct reg *reg;
324 	u32 val;
325 
326 	/* Global interrupts include hardware error reports.  Enable
327 	 * that so we can at least report the error should it occur.
328 	 */
329 	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
330 	iowrite32(ERROR_INT, gsi->virt + reg_offset(reg));
331 
332 	gsi_irq_type_update(gsi, gsi->type_enabled_bitmap | GSI_GLOB_EE);
333 
334 	/* General GSI interrupts are reported to all EEs; if they occur
335 	 * they are unrecoverable (without reset).  A breakpoint interrupt
336 	 * also exists, but we don't support that.  We want to be notified
337 	 * of errors so we can report them, even if they can't be handled.
338 	 */
339 	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_EN);
340 	val = BUS_ERROR;
341 	val |= CMD_FIFO_OVRFLOW;
342 	val |= MCS_STACK_OVRFLOW;
343 	iowrite32(val, gsi->virt + reg_offset(reg));
344 
345 	gsi_irq_type_update(gsi, gsi->type_enabled_bitmap | GSI_GENERAL);
346 }
347 
348 /* Disable all GSI interrupt types */
gsi_irq_disable(struct gsi * gsi)349 static void gsi_irq_disable(struct gsi *gsi)
350 {
351 	const struct reg *reg;
352 
353 	gsi_irq_type_update(gsi, 0);
354 
355 	/* Clear the type-specific interrupt masks set by gsi_irq_enable() */
356 	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_EN);
357 	iowrite32(0, gsi->virt + reg_offset(reg));
358 
359 	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
360 	iowrite32(0, gsi->virt + reg_offset(reg));
361 }
362 
363 /* Return the virtual address associated with a ring index */
gsi_ring_virt(struct gsi_ring * ring,u32 index)364 void *gsi_ring_virt(struct gsi_ring *ring, u32 index)
365 {
366 	/* Note: index *must* be used modulo the ring count here */
367 	return ring->virt + (index % ring->count) * GSI_RING_ELEMENT_SIZE;
368 }
369 
370 /* Return the 32-bit DMA address associated with a ring index */
gsi_ring_addr(struct gsi_ring * ring,u32 index)371 static u32 gsi_ring_addr(struct gsi_ring *ring, u32 index)
372 {
373 	return lower_32_bits(ring->addr) + index * GSI_RING_ELEMENT_SIZE;
374 }
375 
376 /* Return the ring index of a 32-bit ring offset */
gsi_ring_index(struct gsi_ring * ring,u32 offset)377 static u32 gsi_ring_index(struct gsi_ring *ring, u32 offset)
378 {
379 	return (offset - gsi_ring_addr(ring, 0)) / GSI_RING_ELEMENT_SIZE;
380 }
381 
382 /* Issue a GSI command by writing a value to a register, then wait for
383  * completion to be signaled.  Returns true if the command completes
384  * or false if it times out.
385  */
gsi_command(struct gsi * gsi,u32 reg,u32 val)386 static bool gsi_command(struct gsi *gsi, u32 reg, u32 val)
387 {
388 	unsigned long timeout = msecs_to_jiffies(GSI_CMD_TIMEOUT);
389 	struct completion *completion = &gsi->completion;
390 
391 	reinit_completion(completion);
392 
393 	iowrite32(val, gsi->virt + reg);
394 
395 	return !!wait_for_completion_timeout(completion, timeout);
396 }
397 
398 /* Return the hardware's notion of the current state of an event ring */
399 static enum gsi_evt_ring_state
gsi_evt_ring_state(struct gsi * gsi,u32 evt_ring_id)400 gsi_evt_ring_state(struct gsi *gsi, u32 evt_ring_id)
401 {
402 	const struct reg *reg = gsi_reg(gsi, EV_CH_E_CNTXT_0);
403 	u32 val;
404 
405 	val = ioread32(gsi->virt + reg_n_offset(reg, evt_ring_id));
406 
407 	return reg_decode(reg, EV_CHSTATE, val);
408 }
409 
410 /* Issue an event ring command and wait for it to complete */
gsi_evt_ring_command(struct gsi * gsi,u32 evt_ring_id,enum gsi_evt_cmd_opcode opcode)411 static void gsi_evt_ring_command(struct gsi *gsi, u32 evt_ring_id,
412 				 enum gsi_evt_cmd_opcode opcode)
413 {
414 	struct device *dev = gsi->dev;
415 	const struct reg *reg;
416 	bool timeout;
417 	u32 val;
418 
419 	/* Enable the completion interrupt for the command */
420 	gsi_irq_ev_ctrl_enable(gsi, evt_ring_id);
421 
422 	reg = gsi_reg(gsi, EV_CH_CMD);
423 	val = reg_encode(reg, EV_CHID, evt_ring_id);
424 	val |= reg_encode(reg, EV_OPCODE, opcode);
425 
426 	timeout = !gsi_command(gsi, reg_offset(reg), val);
427 
428 	gsi_irq_ev_ctrl_disable(gsi);
429 
430 	if (!timeout)
431 		return;
432 
433 	dev_err(dev, "GSI command %u for event ring %u timed out, state %u\n",
434 		opcode, evt_ring_id, gsi_evt_ring_state(gsi, evt_ring_id));
435 }
436 
437 /* Allocate an event ring in NOT_ALLOCATED state */
gsi_evt_ring_alloc_command(struct gsi * gsi,u32 evt_ring_id)438 static int gsi_evt_ring_alloc_command(struct gsi *gsi, u32 evt_ring_id)
439 {
440 	enum gsi_evt_ring_state state;
441 
442 	/* Get initial event ring state */
443 	state = gsi_evt_ring_state(gsi, evt_ring_id);
444 	if (state != GSI_EVT_RING_STATE_NOT_ALLOCATED) {
445 		dev_err(gsi->dev, "event ring %u bad state %u before alloc\n",
446 			evt_ring_id, state);
447 		return -EINVAL;
448 	}
449 
450 	gsi_evt_ring_command(gsi, evt_ring_id, GSI_EVT_ALLOCATE);
451 
452 	/* If successful the event ring state will have changed */
453 	state = gsi_evt_ring_state(gsi, evt_ring_id);
454 	if (state == GSI_EVT_RING_STATE_ALLOCATED)
455 		return 0;
456 
457 	dev_err(gsi->dev, "event ring %u bad state %u after alloc\n",
458 		evt_ring_id, state);
459 
460 	return -EIO;
461 }
462 
463 /* Reset a GSI event ring in ALLOCATED or ERROR state. */
gsi_evt_ring_reset_command(struct gsi * gsi,u32 evt_ring_id)464 static void gsi_evt_ring_reset_command(struct gsi *gsi, u32 evt_ring_id)
465 {
466 	enum gsi_evt_ring_state state;
467 
468 	state = gsi_evt_ring_state(gsi, evt_ring_id);
469 	if (state != GSI_EVT_RING_STATE_ALLOCATED &&
470 	    state != GSI_EVT_RING_STATE_ERROR) {
471 		dev_err(gsi->dev, "event ring %u bad state %u before reset\n",
472 			evt_ring_id, state);
473 		return;
474 	}
475 
476 	gsi_evt_ring_command(gsi, evt_ring_id, GSI_EVT_RESET);
477 
478 	/* If successful the event ring state will have changed */
479 	state = gsi_evt_ring_state(gsi, evt_ring_id);
480 	if (state == GSI_EVT_RING_STATE_ALLOCATED)
481 		return;
482 
483 	dev_err(gsi->dev, "event ring %u bad state %u after reset\n",
484 		evt_ring_id, state);
485 }
486 
487 /* Issue a hardware de-allocation request for an allocated event ring */
gsi_evt_ring_de_alloc_command(struct gsi * gsi,u32 evt_ring_id)488 static void gsi_evt_ring_de_alloc_command(struct gsi *gsi, u32 evt_ring_id)
489 {
490 	enum gsi_evt_ring_state state;
491 
492 	state = gsi_evt_ring_state(gsi, evt_ring_id);
493 	if (state != GSI_EVT_RING_STATE_ALLOCATED) {
494 		dev_err(gsi->dev, "event ring %u state %u before dealloc\n",
495 			evt_ring_id, state);
496 		return;
497 	}
498 
499 	gsi_evt_ring_command(gsi, evt_ring_id, GSI_EVT_DE_ALLOC);
500 
501 	/* If successful the event ring state will have changed */
502 	state = gsi_evt_ring_state(gsi, evt_ring_id);
503 	if (state == GSI_EVT_RING_STATE_NOT_ALLOCATED)
504 		return;
505 
506 	dev_err(gsi->dev, "event ring %u bad state %u after dealloc\n",
507 		evt_ring_id, state);
508 }
509 
510 /* Fetch the current state of a channel from hardware */
gsi_channel_state(struct gsi_channel * channel)511 static enum gsi_channel_state gsi_channel_state(struct gsi_channel *channel)
512 {
513 	const struct reg *reg = gsi_reg(channel->gsi, CH_C_CNTXT_0);
514 	u32 channel_id = gsi_channel_id(channel);
515 	struct gsi *gsi = channel->gsi;
516 	void __iomem *virt = gsi->virt;
517 	u32 val;
518 
519 	reg = gsi_reg(gsi, CH_C_CNTXT_0);
520 	val = ioread32(virt + reg_n_offset(reg, channel_id));
521 
522 	return reg_decode(reg, CHSTATE, val);
523 }
524 
525 /* Issue a channel command and wait for it to complete */
526 static void
gsi_channel_command(struct gsi_channel * channel,enum gsi_ch_cmd_opcode opcode)527 gsi_channel_command(struct gsi_channel *channel, enum gsi_ch_cmd_opcode opcode)
528 {
529 	u32 channel_id = gsi_channel_id(channel);
530 	struct gsi *gsi = channel->gsi;
531 	struct device *dev = gsi->dev;
532 	const struct reg *reg;
533 	bool timeout;
534 	u32 val;
535 
536 	/* Enable the completion interrupt for the command */
537 	gsi_irq_ch_ctrl_enable(gsi, channel_id);
538 
539 	reg = gsi_reg(gsi, CH_CMD);
540 	val = reg_encode(reg, CH_CHID, channel_id);
541 	val |= reg_encode(reg, CH_OPCODE, opcode);
542 
543 	timeout = !gsi_command(gsi, reg_offset(reg), val);
544 
545 	gsi_irq_ch_ctrl_disable(gsi);
546 
547 	if (!timeout)
548 		return;
549 
550 	dev_err(dev, "GSI command %u for channel %u timed out, state %u\n",
551 		opcode, channel_id, gsi_channel_state(channel));
552 }
553 
554 /* Allocate GSI channel in NOT_ALLOCATED state */
gsi_channel_alloc_command(struct gsi * gsi,u32 channel_id)555 static int gsi_channel_alloc_command(struct gsi *gsi, u32 channel_id)
556 {
557 	struct gsi_channel *channel = &gsi->channel[channel_id];
558 	struct device *dev = gsi->dev;
559 	enum gsi_channel_state state;
560 
561 	/* Get initial channel state */
562 	state = gsi_channel_state(channel);
563 	if (state != GSI_CHANNEL_STATE_NOT_ALLOCATED) {
564 		dev_err(dev, "channel %u bad state %u before alloc\n",
565 			channel_id, state);
566 		return -EINVAL;
567 	}
568 
569 	gsi_channel_command(channel, GSI_CH_ALLOCATE);
570 
571 	/* If successful the channel state will have changed */
572 	state = gsi_channel_state(channel);
573 	if (state == GSI_CHANNEL_STATE_ALLOCATED)
574 		return 0;
575 
576 	dev_err(dev, "channel %u bad state %u after alloc\n",
577 		channel_id, state);
578 
579 	return -EIO;
580 }
581 
582 /* Start an ALLOCATED channel */
gsi_channel_start_command(struct gsi_channel * channel)583 static int gsi_channel_start_command(struct gsi_channel *channel)
584 {
585 	struct device *dev = channel->gsi->dev;
586 	enum gsi_channel_state state;
587 
588 	state = gsi_channel_state(channel);
589 	if (state != GSI_CHANNEL_STATE_ALLOCATED &&
590 	    state != GSI_CHANNEL_STATE_STOPPED) {
591 		dev_err(dev, "channel %u bad state %u before start\n",
592 			gsi_channel_id(channel), state);
593 		return -EINVAL;
594 	}
595 
596 	gsi_channel_command(channel, GSI_CH_START);
597 
598 	/* If successful the channel state will have changed */
599 	state = gsi_channel_state(channel);
600 	if (state == GSI_CHANNEL_STATE_STARTED)
601 		return 0;
602 
603 	dev_err(dev, "channel %u bad state %u after start\n",
604 		gsi_channel_id(channel), state);
605 
606 	return -EIO;
607 }
608 
609 /* Stop a GSI channel in STARTED state */
gsi_channel_stop_command(struct gsi_channel * channel)610 static int gsi_channel_stop_command(struct gsi_channel *channel)
611 {
612 	struct device *dev = channel->gsi->dev;
613 	enum gsi_channel_state state;
614 
615 	state = gsi_channel_state(channel);
616 
617 	/* Channel could have entered STOPPED state since last call
618 	 * if it timed out.  If so, we're done.
619 	 */
620 	if (state == GSI_CHANNEL_STATE_STOPPED)
621 		return 0;
622 
623 	if (state != GSI_CHANNEL_STATE_STARTED &&
624 	    state != GSI_CHANNEL_STATE_STOP_IN_PROC) {
625 		dev_err(dev, "channel %u bad state %u before stop\n",
626 			gsi_channel_id(channel), state);
627 		return -EINVAL;
628 	}
629 
630 	gsi_channel_command(channel, GSI_CH_STOP);
631 
632 	/* If successful the channel state will have changed */
633 	state = gsi_channel_state(channel);
634 	if (state == GSI_CHANNEL_STATE_STOPPED)
635 		return 0;
636 
637 	/* We may have to try again if stop is in progress */
638 	if (state == GSI_CHANNEL_STATE_STOP_IN_PROC)
639 		return -EAGAIN;
640 
641 	dev_err(dev, "channel %u bad state %u after stop\n",
642 		gsi_channel_id(channel), state);
643 
644 	return -EIO;
645 }
646 
647 /* Reset a GSI channel in ALLOCATED or ERROR state. */
gsi_channel_reset_command(struct gsi_channel * channel)648 static void gsi_channel_reset_command(struct gsi_channel *channel)
649 {
650 	struct device *dev = channel->gsi->dev;
651 	enum gsi_channel_state state;
652 
653 	/* A short delay is required before a RESET command */
654 	usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
655 
656 	state = gsi_channel_state(channel);
657 	if (state != GSI_CHANNEL_STATE_STOPPED &&
658 	    state != GSI_CHANNEL_STATE_ERROR) {
659 		/* No need to reset a channel already in ALLOCATED state */
660 		if (state != GSI_CHANNEL_STATE_ALLOCATED)
661 			dev_err(dev, "channel %u bad state %u before reset\n",
662 				gsi_channel_id(channel), state);
663 		return;
664 	}
665 
666 	gsi_channel_command(channel, GSI_CH_RESET);
667 
668 	/* If successful the channel state will have changed */
669 	state = gsi_channel_state(channel);
670 	if (state != GSI_CHANNEL_STATE_ALLOCATED)
671 		dev_err(dev, "channel %u bad state %u after reset\n",
672 			gsi_channel_id(channel), state);
673 }
674 
675 /* Deallocate an ALLOCATED GSI channel */
gsi_channel_de_alloc_command(struct gsi * gsi,u32 channel_id)676 static void gsi_channel_de_alloc_command(struct gsi *gsi, u32 channel_id)
677 {
678 	struct gsi_channel *channel = &gsi->channel[channel_id];
679 	struct device *dev = gsi->dev;
680 	enum gsi_channel_state state;
681 
682 	state = gsi_channel_state(channel);
683 	if (state != GSI_CHANNEL_STATE_ALLOCATED) {
684 		dev_err(dev, "channel %u bad state %u before dealloc\n",
685 			channel_id, state);
686 		return;
687 	}
688 
689 	gsi_channel_command(channel, GSI_CH_DE_ALLOC);
690 
691 	/* If successful the channel state will have changed */
692 	state = gsi_channel_state(channel);
693 
694 	if (state != GSI_CHANNEL_STATE_NOT_ALLOCATED)
695 		dev_err(dev, "channel %u bad state %u after dealloc\n",
696 			channel_id, state);
697 }
698 
699 /* Ring an event ring doorbell, reporting the last entry processed by the AP.
700  * The index argument (modulo the ring count) is the first unfilled entry, so
701  * we supply one less than that with the doorbell.  Update the event ring
702  * index field with the value provided.
703  */
gsi_evt_ring_doorbell(struct gsi * gsi,u32 evt_ring_id,u32 index)704 static void gsi_evt_ring_doorbell(struct gsi *gsi, u32 evt_ring_id, u32 index)
705 {
706 	const struct reg *reg = gsi_reg(gsi, EV_CH_E_DOORBELL_0);
707 	struct gsi_ring *ring = &gsi->evt_ring[evt_ring_id].ring;
708 	u32 val;
709 
710 	ring->index = index;	/* Next unused entry */
711 
712 	/* Note: index *must* be used modulo the ring count here */
713 	val = gsi_ring_addr(ring, (index - 1) % ring->count);
714 	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
715 }
716 
717 /* Program an event ring for use */
gsi_evt_ring_program(struct gsi * gsi,u32 evt_ring_id)718 static void gsi_evt_ring_program(struct gsi *gsi, u32 evt_ring_id)
719 {
720 	struct gsi_evt_ring *evt_ring = &gsi->evt_ring[evt_ring_id];
721 	struct gsi_ring *ring = &evt_ring->ring;
722 	const struct reg *reg;
723 	u32 val;
724 
725 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_0);
726 	/* We program all event rings as GPI type/protocol */
727 	val = reg_encode(reg, EV_CHTYPE, GSI_CHANNEL_TYPE_GPI);
728 	/* EV_EE field is 0 (GSI_EE_AP) */
729 	val |= reg_bit(reg, EV_INTYPE);
730 	val |= reg_encode(reg, EV_ELEMENT_SIZE, GSI_RING_ELEMENT_SIZE);
731 	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
732 
733 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_1);
734 	val = reg_encode(reg, R_LENGTH, ring->count * GSI_RING_ELEMENT_SIZE);
735 	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
736 
737 	/* The context 2 and 3 registers store the low-order and
738 	 * high-order 32 bits of the address of the event ring,
739 	 * respectively.
740 	 */
741 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_2);
742 	val = lower_32_bits(ring->addr);
743 	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
744 
745 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_3);
746 	val = upper_32_bits(ring->addr);
747 	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
748 
749 	/* Enable interrupt moderation by setting the moderation delay */
750 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_8);
751 	val = reg_encode(reg, EV_MODT, GSI_EVT_RING_INT_MODT);
752 	val |= reg_encode(reg, EV_MODC, 1);	/* comes from channel */
753 	/* EV_MOD_CNT is 0 (no counter-based interrupt coalescing) */
754 	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
755 
756 	/* No MSI write data, and MSI high and low address is 0 */
757 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_9);
758 	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
759 
760 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_10);
761 	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
762 
763 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_11);
764 	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
765 
766 	/* We don't need to get event read pointer updates */
767 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_12);
768 	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
769 
770 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_13);
771 	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
772 
773 	/* Finally, tell the hardware our "last processed" event (arbitrary) */
774 	gsi_evt_ring_doorbell(gsi, evt_ring_id, ring->index);
775 }
776 
777 /* Find the transaction whose completion indicates a channel is quiesced */
gsi_channel_trans_last(struct gsi_channel * channel)778 static struct gsi_trans *gsi_channel_trans_last(struct gsi_channel *channel)
779 {
780 	struct gsi_trans_info *trans_info = &channel->trans_info;
781 	u32 pending_id = trans_info->pending_id;
782 	struct gsi_trans *trans;
783 	u16 trans_id;
784 
785 	if (channel->toward_ipa && pending_id != trans_info->free_id) {
786 		/* There is a small chance a TX transaction got allocated
787 		 * just before we disabled transmits, so check for that.
788 		 * The last allocated, committed, or pending transaction
789 		 * precedes the first free transaction.
790 		 */
791 		trans_id = trans_info->free_id - 1;
792 	} else if (trans_info->polled_id != pending_id) {
793 		/* Otherwise (TX or RX) we want to wait for anything that
794 		 * has completed, or has been polled but not released yet.
795 		 *
796 		 * The last completed or polled transaction precedes the
797 		 * first pending transaction.
798 		 */
799 		trans_id = pending_id - 1;
800 	} else {
801 		return NULL;
802 	}
803 
804 	/* Caller will wait for this, so take a reference */
805 	trans = &trans_info->trans[trans_id % channel->tre_count];
806 	refcount_inc(&trans->refcount);
807 
808 	return trans;
809 }
810 
811 /* Wait for transaction activity on a channel to complete */
gsi_channel_trans_quiesce(struct gsi_channel * channel)812 static void gsi_channel_trans_quiesce(struct gsi_channel *channel)
813 {
814 	struct gsi_trans *trans;
815 
816 	/* Get the last transaction, and wait for it to complete */
817 	trans = gsi_channel_trans_last(channel);
818 	if (trans) {
819 		wait_for_completion(&trans->completion);
820 		gsi_trans_free(trans);
821 	}
822 }
823 
824 /* Program a channel for use; there is no gsi_channel_deprogram() */
gsi_channel_program(struct gsi_channel * channel,bool doorbell)825 static void gsi_channel_program(struct gsi_channel *channel, bool doorbell)
826 {
827 	size_t size = channel->tre_ring.count * GSI_RING_ELEMENT_SIZE;
828 	u32 channel_id = gsi_channel_id(channel);
829 	union gsi_channel_scratch scr = { };
830 	struct gsi_channel_scratch_gpi *gpi;
831 	struct gsi *gsi = channel->gsi;
832 	const struct reg *reg;
833 	u32 wrr_weight = 0;
834 	u32 offset;
835 	u32 val;
836 
837 	reg = gsi_reg(gsi, CH_C_CNTXT_0);
838 
839 	/* We program all channels as GPI type/protocol */
840 	val = ch_c_cntxt_0_type_encode(gsi->version, reg, GSI_CHANNEL_TYPE_GPI);
841 	if (channel->toward_ipa)
842 		val |= reg_bit(reg, CHTYPE_DIR);
843 	if (gsi->version < IPA_VERSION_5_0)
844 		val |= reg_encode(reg, ERINDEX, channel->evt_ring_id);
845 	val |= reg_encode(reg, ELEMENT_SIZE, GSI_RING_ELEMENT_SIZE);
846 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
847 
848 	reg = gsi_reg(gsi, CH_C_CNTXT_1);
849 	val = reg_encode(reg, CH_R_LENGTH, size);
850 	if (gsi->version >= IPA_VERSION_5_0)
851 		val |= reg_encode(reg, CH_ERINDEX, channel->evt_ring_id);
852 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
853 
854 	/* The context 2 and 3 registers store the low-order and
855 	 * high-order 32 bits of the address of the channel ring,
856 	 * respectively.
857 	 */
858 	reg = gsi_reg(gsi, CH_C_CNTXT_2);
859 	val = lower_32_bits(channel->tre_ring.addr);
860 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
861 
862 	reg = gsi_reg(gsi, CH_C_CNTXT_3);
863 	val = upper_32_bits(channel->tre_ring.addr);
864 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
865 
866 	reg = gsi_reg(gsi, CH_C_QOS);
867 
868 	/* Command channel gets low weighted round-robin priority */
869 	if (channel->command)
870 		wrr_weight = reg_field_max(reg, WRR_WEIGHT);
871 	val = reg_encode(reg, WRR_WEIGHT, wrr_weight);
872 
873 	/* Max prefetch is 1 segment (do not set MAX_PREFETCH_FMASK) */
874 
875 	/* No need to use the doorbell engine starting at IPA v4.0 */
876 	if (gsi->version < IPA_VERSION_4_0 && doorbell)
877 		val |= reg_bit(reg, USE_DB_ENG);
878 
879 	/* v4.0 introduces an escape buffer for prefetch.  We use it
880 	 * on all but the AP command channel.
881 	 */
882 	if (gsi->version >= IPA_VERSION_4_0 && !channel->command) {
883 		/* If not otherwise set, prefetch buffers are used */
884 		if (gsi->version < IPA_VERSION_4_5)
885 			val |= reg_bit(reg, USE_ESCAPE_BUF_ONLY);
886 		else
887 			val |= reg_encode(reg, PREFETCH_MODE, ESCAPE_BUF_ONLY);
888 	}
889 	/* All channels set DB_IN_BYTES */
890 	if (gsi->version >= IPA_VERSION_4_9)
891 		val |= reg_bit(reg, DB_IN_BYTES);
892 
893 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
894 
895 	/* Now update the scratch registers for GPI protocol */
896 	gpi = &scr.gpi;
897 	gpi->max_outstanding_tre = channel->trans_tre_max *
898 					GSI_RING_ELEMENT_SIZE;
899 	gpi->outstanding_threshold = 2 * GSI_RING_ELEMENT_SIZE;
900 
901 	reg = gsi_reg(gsi, CH_C_SCRATCH_0);
902 	val = scr.data.word1;
903 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
904 
905 	reg = gsi_reg(gsi, CH_C_SCRATCH_1);
906 	val = scr.data.word2;
907 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
908 
909 	reg = gsi_reg(gsi, CH_C_SCRATCH_2);
910 	val = scr.data.word3;
911 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
912 
913 	/* We must preserve the upper 16 bits of the last scratch register.
914 	 * The next sequence assumes those bits remain unchanged between the
915 	 * read and the write.
916 	 */
917 	reg = gsi_reg(gsi, CH_C_SCRATCH_3);
918 	offset = reg_n_offset(reg, channel_id);
919 	val = ioread32(gsi->virt + offset);
920 	val = (scr.data.word4 & GENMASK(31, 16)) | (val & GENMASK(15, 0));
921 	iowrite32(val, gsi->virt + offset);
922 
923 	/* All done! */
924 }
925 
__gsi_channel_start(struct gsi_channel * channel,bool resume)926 static int __gsi_channel_start(struct gsi_channel *channel, bool resume)
927 {
928 	struct gsi *gsi = channel->gsi;
929 	int ret;
930 
931 	/* Prior to IPA v4.0 suspend/resume is not implemented by GSI */
932 	if (resume && gsi->version < IPA_VERSION_4_0)
933 		return 0;
934 
935 	mutex_lock(&gsi->mutex);
936 
937 	ret = gsi_channel_start_command(channel);
938 
939 	mutex_unlock(&gsi->mutex);
940 
941 	return ret;
942 }
943 
944 /* Start an allocated GSI channel */
gsi_channel_start(struct gsi * gsi,u32 channel_id)945 int gsi_channel_start(struct gsi *gsi, u32 channel_id)
946 {
947 	struct gsi_channel *channel = &gsi->channel[channel_id];
948 	int ret;
949 
950 	/* Enable NAPI and the completion interrupt */
951 	napi_enable(&channel->napi);
952 	gsi_irq_ieob_enable_one(gsi, channel->evt_ring_id);
953 
954 	ret = __gsi_channel_start(channel, false);
955 	if (ret) {
956 		gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
957 		napi_disable(&channel->napi);
958 	}
959 
960 	return ret;
961 }
962 
gsi_channel_stop_retry(struct gsi_channel * channel)963 static int gsi_channel_stop_retry(struct gsi_channel *channel)
964 {
965 	u32 retries = GSI_CHANNEL_STOP_RETRIES;
966 	int ret;
967 
968 	do {
969 		ret = gsi_channel_stop_command(channel);
970 		if (ret != -EAGAIN)
971 			break;
972 		usleep_range(3 * USEC_PER_MSEC, 5 * USEC_PER_MSEC);
973 	} while (retries--);
974 
975 	return ret;
976 }
977 
__gsi_channel_stop(struct gsi_channel * channel,bool suspend)978 static int __gsi_channel_stop(struct gsi_channel *channel, bool suspend)
979 {
980 	struct gsi *gsi = channel->gsi;
981 	int ret;
982 
983 	/* Wait for any underway transactions to complete before stopping. */
984 	gsi_channel_trans_quiesce(channel);
985 
986 	/* Prior to IPA v4.0 suspend/resume is not implemented by GSI */
987 	if (suspend && gsi->version < IPA_VERSION_4_0)
988 		return 0;
989 
990 	mutex_lock(&gsi->mutex);
991 
992 	ret = gsi_channel_stop_retry(channel);
993 
994 	mutex_unlock(&gsi->mutex);
995 
996 	return ret;
997 }
998 
999 /* Stop a started channel */
gsi_channel_stop(struct gsi * gsi,u32 channel_id)1000 int gsi_channel_stop(struct gsi *gsi, u32 channel_id)
1001 {
1002 	struct gsi_channel *channel = &gsi->channel[channel_id];
1003 	int ret;
1004 
1005 	ret = __gsi_channel_stop(channel, false);
1006 	if (ret)
1007 		return ret;
1008 
1009 	/* Disable the completion interrupt and NAPI if successful */
1010 	gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
1011 	napi_disable(&channel->napi);
1012 
1013 	return 0;
1014 }
1015 
1016 /* Reset and reconfigure a channel, (possibly) enabling the doorbell engine */
gsi_channel_reset(struct gsi * gsi,u32 channel_id,bool doorbell)1017 void gsi_channel_reset(struct gsi *gsi, u32 channel_id, bool doorbell)
1018 {
1019 	struct gsi_channel *channel = &gsi->channel[channel_id];
1020 
1021 	mutex_lock(&gsi->mutex);
1022 
1023 	gsi_channel_reset_command(channel);
1024 	/* Due to a hardware quirk we may need to reset RX channels twice. */
1025 	if (gsi->version < IPA_VERSION_4_0 && !channel->toward_ipa)
1026 		gsi_channel_reset_command(channel);
1027 
1028 	/* Hardware assumes this is 0 following reset */
1029 	channel->tre_ring.index = 0;
1030 	gsi_channel_program(channel, doorbell);
1031 	gsi_channel_trans_cancel_pending(channel);
1032 
1033 	mutex_unlock(&gsi->mutex);
1034 }
1035 
1036 /* Stop a started channel for suspend */
gsi_channel_suspend(struct gsi * gsi,u32 channel_id)1037 int gsi_channel_suspend(struct gsi *gsi, u32 channel_id)
1038 {
1039 	struct gsi_channel *channel = &gsi->channel[channel_id];
1040 	int ret;
1041 
1042 	ret = __gsi_channel_stop(channel, true);
1043 	if (ret)
1044 		return ret;
1045 
1046 	/* Ensure NAPI polling has finished. */
1047 	napi_synchronize(&channel->napi);
1048 
1049 	return 0;
1050 }
1051 
1052 /* Resume a suspended channel (starting if stopped) */
gsi_channel_resume(struct gsi * gsi,u32 channel_id)1053 int gsi_channel_resume(struct gsi *gsi, u32 channel_id)
1054 {
1055 	struct gsi_channel *channel = &gsi->channel[channel_id];
1056 
1057 	return __gsi_channel_start(channel, true);
1058 }
1059 
1060 /* Prevent all GSI interrupts while suspended */
gsi_suspend(struct gsi * gsi)1061 void gsi_suspend(struct gsi *gsi)
1062 {
1063 	disable_irq(gsi->irq);
1064 }
1065 
1066 /* Allow all GSI interrupts again when resuming */
gsi_resume(struct gsi * gsi)1067 void gsi_resume(struct gsi *gsi)
1068 {
1069 	enable_irq(gsi->irq);
1070 }
1071 
gsi_trans_tx_committed(struct gsi_trans * trans)1072 void gsi_trans_tx_committed(struct gsi_trans *trans)
1073 {
1074 	struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id];
1075 
1076 	channel->trans_count++;
1077 	channel->byte_count += trans->len;
1078 
1079 	trans->trans_count = channel->trans_count;
1080 	trans->byte_count = channel->byte_count;
1081 }
1082 
gsi_trans_tx_queued(struct gsi_trans * trans)1083 void gsi_trans_tx_queued(struct gsi_trans *trans)
1084 {
1085 	u32 channel_id = trans->channel_id;
1086 	struct gsi *gsi = trans->gsi;
1087 	struct gsi_channel *channel;
1088 	u32 trans_count;
1089 	u32 byte_count;
1090 
1091 	channel = &gsi->channel[channel_id];
1092 
1093 	byte_count = channel->byte_count - channel->queued_byte_count;
1094 	trans_count = channel->trans_count - channel->queued_trans_count;
1095 	channel->queued_byte_count = channel->byte_count;
1096 	channel->queued_trans_count = channel->trans_count;
1097 
1098 	ipa_gsi_channel_tx_queued(gsi, channel_id, trans_count, byte_count);
1099 }
1100 
1101 /**
1102  * gsi_trans_tx_completed() - Report completed TX transactions
1103  * @trans:	TX channel transaction that has completed
1104  *
1105  * Report that a transaction on a TX channel has completed.  At the time a
1106  * transaction is committed, we record *in the transaction* its channel's
1107  * committed transaction and byte counts.  Transactions are completed in
1108  * order, and the difference between the channel's byte/transaction count
1109  * when the transaction was committed and when it completes tells us
1110  * exactly how much data has been transferred while the transaction was
1111  * pending.
1112  *
1113  * We report this information to the network stack, which uses it to manage
1114  * the rate at which data is sent to hardware.
1115  */
gsi_trans_tx_completed(struct gsi_trans * trans)1116 static void gsi_trans_tx_completed(struct gsi_trans *trans)
1117 {
1118 	u32 channel_id = trans->channel_id;
1119 	struct gsi *gsi = trans->gsi;
1120 	struct gsi_channel *channel;
1121 	u32 trans_count;
1122 	u32 byte_count;
1123 
1124 	channel = &gsi->channel[channel_id];
1125 	trans_count = trans->trans_count - channel->compl_trans_count;
1126 	byte_count = trans->byte_count - channel->compl_byte_count;
1127 
1128 	channel->compl_trans_count += trans_count;
1129 	channel->compl_byte_count += byte_count;
1130 
1131 	ipa_gsi_channel_tx_completed(gsi, channel_id, trans_count, byte_count);
1132 }
1133 
1134 /* Channel control interrupt handler */
gsi_isr_chan_ctrl(struct gsi * gsi)1135 static void gsi_isr_chan_ctrl(struct gsi *gsi)
1136 {
1137 	const struct reg *reg;
1138 	u32 channel_mask;
1139 
1140 	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ);
1141 	channel_mask = ioread32(gsi->virt + reg_offset(reg));
1142 
1143 	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_CLR);
1144 	iowrite32(channel_mask, gsi->virt + reg_offset(reg));
1145 
1146 	while (channel_mask) {
1147 		u32 channel_id = __ffs(channel_mask);
1148 
1149 		channel_mask ^= BIT(channel_id);
1150 
1151 		complete(&gsi->completion);
1152 	}
1153 }
1154 
1155 /* Event ring control interrupt handler */
gsi_isr_evt_ctrl(struct gsi * gsi)1156 static void gsi_isr_evt_ctrl(struct gsi *gsi)
1157 {
1158 	const struct reg *reg;
1159 	u32 event_mask;
1160 
1161 	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ);
1162 	event_mask = ioread32(gsi->virt + reg_offset(reg));
1163 
1164 	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_CLR);
1165 	iowrite32(event_mask, gsi->virt + reg_offset(reg));
1166 
1167 	while (event_mask) {
1168 		u32 evt_ring_id = __ffs(event_mask);
1169 
1170 		event_mask ^= BIT(evt_ring_id);
1171 
1172 		complete(&gsi->completion);
1173 	}
1174 }
1175 
1176 /* Global channel error interrupt handler */
1177 static void
gsi_isr_glob_chan_err(struct gsi * gsi,u32 err_ee,u32 channel_id,u32 code)1178 gsi_isr_glob_chan_err(struct gsi *gsi, u32 err_ee, u32 channel_id, u32 code)
1179 {
1180 	if (code == GSI_OUT_OF_RESOURCES) {
1181 		dev_err(gsi->dev, "channel %u out of resources\n", channel_id);
1182 		complete(&gsi->completion);
1183 		return;
1184 	}
1185 
1186 	/* Report, but otherwise ignore all other error codes */
1187 	dev_err(gsi->dev, "channel %u global error ee 0x%08x code 0x%08x\n",
1188 		channel_id, err_ee, code);
1189 }
1190 
1191 /* Global event error interrupt handler */
1192 static void
gsi_isr_glob_evt_err(struct gsi * gsi,u32 err_ee,u32 evt_ring_id,u32 code)1193 gsi_isr_glob_evt_err(struct gsi *gsi, u32 err_ee, u32 evt_ring_id, u32 code)
1194 {
1195 	if (code == GSI_OUT_OF_RESOURCES) {
1196 		struct gsi_evt_ring *evt_ring = &gsi->evt_ring[evt_ring_id];
1197 		u32 channel_id = gsi_channel_id(evt_ring->channel);
1198 
1199 		complete(&gsi->completion);
1200 		dev_err(gsi->dev, "evt_ring for channel %u out of resources\n",
1201 			channel_id);
1202 		return;
1203 	}
1204 
1205 	/* Report, but otherwise ignore all other error codes */
1206 	dev_err(gsi->dev, "event ring %u global error ee %u code 0x%08x\n",
1207 		evt_ring_id, err_ee, code);
1208 }
1209 
1210 /* Global error interrupt handler */
gsi_isr_glob_err(struct gsi * gsi)1211 static void gsi_isr_glob_err(struct gsi *gsi)
1212 {
1213 	const struct reg *log_reg;
1214 	const struct reg *clr_reg;
1215 	enum gsi_err_type type;
1216 	enum gsi_err_code code;
1217 	u32 offset;
1218 	u32 which;
1219 	u32 val;
1220 	u32 ee;
1221 
1222 	/* Get the logged error, then reinitialize the log */
1223 	log_reg = gsi_reg(gsi, ERROR_LOG);
1224 	offset = reg_offset(log_reg);
1225 	val = ioread32(gsi->virt + offset);
1226 	iowrite32(0, gsi->virt + offset);
1227 
1228 	clr_reg = gsi_reg(gsi, ERROR_LOG_CLR);
1229 	iowrite32(~0, gsi->virt + reg_offset(clr_reg));
1230 
1231 	/* Parse the error value */
1232 	ee = reg_decode(log_reg, ERR_EE, val);
1233 	type = reg_decode(log_reg, ERR_TYPE, val);
1234 	which = reg_decode(log_reg, ERR_VIRT_IDX, val);
1235 	code = reg_decode(log_reg, ERR_CODE, val);
1236 
1237 	if (type == GSI_ERR_TYPE_CHAN)
1238 		gsi_isr_glob_chan_err(gsi, ee, which, code);
1239 	else if (type == GSI_ERR_TYPE_EVT)
1240 		gsi_isr_glob_evt_err(gsi, ee, which, code);
1241 	else	/* type GSI_ERR_TYPE_GLOB should be fatal */
1242 		dev_err(gsi->dev, "unexpected global error 0x%08x\n", type);
1243 }
1244 
1245 /* Generic EE interrupt handler */
gsi_isr_gp_int1(struct gsi * gsi)1246 static void gsi_isr_gp_int1(struct gsi *gsi)
1247 {
1248 	const struct reg *reg;
1249 	u32 result;
1250 	u32 val;
1251 
1252 	/* This interrupt is used to handle completions of GENERIC GSI
1253 	 * commands.  We use these to allocate and halt channels on the
1254 	 * modem's behalf due to a hardware quirk on IPA v4.2.  The modem
1255 	 * "owns" channels even when the AP allocates them, and have no
1256 	 * way of knowing whether a modem channel's state has been changed.
1257 	 *
1258 	 * We also use GENERIC commands to enable/disable channel flow
1259 	 * control for IPA v4.2+.
1260 	 *
1261 	 * It is recommended that we halt the modem channels we allocated
1262 	 * when shutting down, but it's possible the channel isn't running
1263 	 * at the time we issue the HALT command.  We'll get an error in
1264 	 * that case, but it's harmless (the channel is already halted).
1265 	 * Similarly, we could get an error back when updating flow control
1266 	 * on a channel because it's not in the proper state.
1267 	 *
1268 	 * In either case, we silently ignore a INCORRECT_CHANNEL_STATE
1269 	 * error if we receive it.
1270 	 */
1271 	reg = gsi_reg(gsi, CNTXT_SCRATCH_0);
1272 	val = ioread32(gsi->virt + reg_offset(reg));
1273 	result = reg_decode(reg, GENERIC_EE_RESULT, val);
1274 
1275 	switch (result) {
1276 	case GENERIC_EE_SUCCESS:
1277 	case GENERIC_EE_INCORRECT_CHANNEL_STATE:
1278 		gsi->result = 0;
1279 		break;
1280 
1281 	case GENERIC_EE_RETRY:
1282 		gsi->result = -EAGAIN;
1283 		break;
1284 
1285 	default:
1286 		dev_err(gsi->dev, "global INT1 generic result %u\n", result);
1287 		gsi->result = -EIO;
1288 		break;
1289 	}
1290 
1291 	complete(&gsi->completion);
1292 }
1293 
1294 /* Inter-EE interrupt handler */
gsi_isr_glob_ee(struct gsi * gsi)1295 static void gsi_isr_glob_ee(struct gsi *gsi)
1296 {
1297 	const struct reg *reg;
1298 	u32 val;
1299 
1300 	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_STTS);
1301 	val = ioread32(gsi->virt + reg_offset(reg));
1302 
1303 	if (val & ERROR_INT)
1304 		gsi_isr_glob_err(gsi);
1305 
1306 	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_CLR);
1307 	iowrite32(val, gsi->virt + reg_offset(reg));
1308 
1309 	val &= ~ERROR_INT;
1310 
1311 	if (val & GP_INT1) {
1312 		val ^= GP_INT1;
1313 		gsi_isr_gp_int1(gsi);
1314 	}
1315 
1316 	if (val)
1317 		dev_err(gsi->dev, "unexpected global interrupt 0x%08x\n", val);
1318 }
1319 
1320 /* I/O completion interrupt event */
gsi_isr_ieob(struct gsi * gsi)1321 static void gsi_isr_ieob(struct gsi *gsi)
1322 {
1323 	const struct reg *reg;
1324 	u32 event_mask;
1325 
1326 	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ);
1327 	event_mask = ioread32(gsi->virt + reg_offset(reg));
1328 
1329 	gsi_irq_ieob_disable(gsi, event_mask);
1330 
1331 	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ_CLR);
1332 	iowrite32(event_mask, gsi->virt + reg_offset(reg));
1333 
1334 	while (event_mask) {
1335 		u32 evt_ring_id = __ffs(event_mask);
1336 
1337 		event_mask ^= BIT(evt_ring_id);
1338 
1339 		napi_schedule(&gsi->evt_ring[evt_ring_id].channel->napi);
1340 	}
1341 }
1342 
1343 /* General event interrupts represent serious problems, so report them */
gsi_isr_general(struct gsi * gsi)1344 static void gsi_isr_general(struct gsi *gsi)
1345 {
1346 	struct device *dev = gsi->dev;
1347 	const struct reg *reg;
1348 	u32 val;
1349 
1350 	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_STTS);
1351 	val = ioread32(gsi->virt + reg_offset(reg));
1352 
1353 	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_CLR);
1354 	iowrite32(val, gsi->virt + reg_offset(reg));
1355 
1356 	dev_err(dev, "unexpected general interrupt 0x%08x\n", val);
1357 }
1358 
1359 /**
1360  * gsi_isr() - Top level GSI interrupt service routine
1361  * @irq:	Interrupt number (ignored)
1362  * @dev_id:	GSI pointer supplied to request_irq()
1363  *
1364  * This is the main handler function registered for the GSI IRQ. Each type
1365  * of interrupt has a separate handler function that is called from here.
1366  */
gsi_isr(int irq,void * dev_id)1367 static irqreturn_t gsi_isr(int irq, void *dev_id)
1368 {
1369 	struct gsi *gsi = dev_id;
1370 	const struct reg *reg;
1371 	u32 intr_mask;
1372 	u32 cnt = 0;
1373 	u32 offset;
1374 
1375 	reg = gsi_reg(gsi, CNTXT_TYPE_IRQ);
1376 	offset = reg_offset(reg);
1377 
1378 	/* enum gsi_irq_type_id defines GSI interrupt types */
1379 	while ((intr_mask = ioread32(gsi->virt + offset))) {
1380 		/* intr_mask contains bitmask of pending GSI interrupts */
1381 		do {
1382 			u32 gsi_intr = BIT(__ffs(intr_mask));
1383 
1384 			intr_mask ^= gsi_intr;
1385 
1386 			/* Note: the IRQ condition for each type is cleared
1387 			 * when the type-specific register is updated.
1388 			 */
1389 			switch (gsi_intr) {
1390 			case GSI_CH_CTRL:
1391 				gsi_isr_chan_ctrl(gsi);
1392 				break;
1393 			case GSI_EV_CTRL:
1394 				gsi_isr_evt_ctrl(gsi);
1395 				break;
1396 			case GSI_GLOB_EE:
1397 				gsi_isr_glob_ee(gsi);
1398 				break;
1399 			case GSI_IEOB:
1400 				gsi_isr_ieob(gsi);
1401 				break;
1402 			case GSI_GENERAL:
1403 				gsi_isr_general(gsi);
1404 				break;
1405 			default:
1406 				dev_err(gsi->dev,
1407 					"unrecognized interrupt type 0x%08x\n",
1408 					gsi_intr);
1409 				break;
1410 			}
1411 		} while (intr_mask);
1412 
1413 		if (++cnt > GSI_ISR_MAX_ITER) {
1414 			dev_err(gsi->dev, "interrupt flood\n");
1415 			break;
1416 		}
1417 	}
1418 
1419 	return IRQ_HANDLED;
1420 }
1421 
1422 /* Init function for GSI IRQ lookup; there is no gsi_irq_exit() */
gsi_irq_init(struct gsi * gsi,struct platform_device * pdev)1423 static int gsi_irq_init(struct gsi *gsi, struct platform_device *pdev)
1424 {
1425 	int ret;
1426 
1427 	ret = platform_get_irq_byname(pdev, "gsi");
1428 	if (ret <= 0)
1429 		return ret ? : -EINVAL;
1430 
1431 	gsi->irq = ret;
1432 
1433 	return 0;
1434 }
1435 
1436 /* Return the transaction associated with a transfer completion event */
1437 static struct gsi_trans *
gsi_event_trans(struct gsi * gsi,struct gsi_event * event)1438 gsi_event_trans(struct gsi *gsi, struct gsi_event *event)
1439 {
1440 	u32 channel_id = event->chid;
1441 	struct gsi_channel *channel;
1442 	struct gsi_trans *trans;
1443 	u32 tre_offset;
1444 	u32 tre_index;
1445 
1446 	channel = &gsi->channel[channel_id];
1447 	if (WARN(!channel->gsi, "event has bad channel %u\n", channel_id))
1448 		return NULL;
1449 
1450 	/* Event xfer_ptr records the TRE it's associated with */
1451 	tre_offset = lower_32_bits(le64_to_cpu(event->xfer_ptr));
1452 	tre_index = gsi_ring_index(&channel->tre_ring, tre_offset);
1453 
1454 	trans = gsi_channel_trans_mapped(channel, tre_index);
1455 
1456 	if (WARN(!trans, "channel %u event with no transaction\n", channel_id))
1457 		return NULL;
1458 
1459 	return trans;
1460 }
1461 
1462 /**
1463  * gsi_evt_ring_update() - Update transaction state from hardware
1464  * @gsi:		GSI pointer
1465  * @evt_ring_id:	Event ring ID
1466  * @index:		Event index in ring reported by hardware
1467  *
1468  * Events for RX channels contain the actual number of bytes received into
1469  * the buffer.  Every event has a transaction associated with it, and here
1470  * we update transactions to record their actual received lengths.
1471  *
1472  * When an event for a TX channel arrives we use information in the
1473  * transaction to report the number of requests and bytes that have
1474  * been transferred.
1475  *
1476  * This function is called whenever we learn that the GSI hardware has filled
1477  * new events since the last time we checked.  The ring's index field tells
1478  * the first entry in need of processing.  The index provided is the
1479  * first *unfilled* event in the ring (following the last filled one).
1480  *
1481  * Events are sequential within the event ring, and transactions are
1482  * sequential within the transaction array.
1483  *
1484  * Note that @index always refers to an element *within* the event ring.
1485  */
gsi_evt_ring_update(struct gsi * gsi,u32 evt_ring_id,u32 index)1486 static void gsi_evt_ring_update(struct gsi *gsi, u32 evt_ring_id, u32 index)
1487 {
1488 	struct gsi_evt_ring *evt_ring = &gsi->evt_ring[evt_ring_id];
1489 	struct gsi_ring *ring = &evt_ring->ring;
1490 	struct gsi_event *event_done;
1491 	struct gsi_event *event;
1492 	u32 event_avail;
1493 	u32 old_index;
1494 
1495 	/* Starting with the oldest un-processed event, determine which
1496 	 * transaction (and which channel) is associated with the event.
1497 	 * For RX channels, update each completed transaction with the
1498 	 * number of bytes that were actually received.  For TX channels
1499 	 * associated with a network device, report to the network stack
1500 	 * the number of transfers and bytes this completion represents.
1501 	 */
1502 	old_index = ring->index;
1503 	event = gsi_ring_virt(ring, old_index);
1504 
1505 	/* Compute the number of events to process before we wrap,
1506 	 * and determine when we'll be done processing events.
1507 	 */
1508 	event_avail = ring->count - old_index % ring->count;
1509 	event_done = gsi_ring_virt(ring, index);
1510 	do {
1511 		struct gsi_trans *trans;
1512 
1513 		trans = gsi_event_trans(gsi, event);
1514 		if (!trans)
1515 			return;
1516 
1517 		if (trans->direction == DMA_FROM_DEVICE)
1518 			trans->len = __le16_to_cpu(event->len);
1519 		else
1520 			gsi_trans_tx_completed(trans);
1521 
1522 		gsi_trans_move_complete(trans);
1523 
1524 		/* Move on to the next event and transaction */
1525 		if (--event_avail)
1526 			event++;
1527 		else
1528 			event = gsi_ring_virt(ring, 0);
1529 	} while (event != event_done);
1530 
1531 	/* Tell the hardware we've handled these events */
1532 	gsi_evt_ring_doorbell(gsi, evt_ring_id, index);
1533 }
1534 
1535 /* Initialize a ring, including allocating DMA memory for its entries */
gsi_ring_alloc(struct gsi * gsi,struct gsi_ring * ring,u32 count)1536 static int gsi_ring_alloc(struct gsi *gsi, struct gsi_ring *ring, u32 count)
1537 {
1538 	u32 size = count * GSI_RING_ELEMENT_SIZE;
1539 	struct device *dev = gsi->dev;
1540 	dma_addr_t addr;
1541 
1542 	/* Hardware requires a 2^n ring size, with alignment equal to size.
1543 	 * The DMA address returned by dma_alloc_coherent() is guaranteed to
1544 	 * be a power-of-2 number of pages, which satisfies the requirement.
1545 	 */
1546 	ring->virt = dma_alloc_coherent(dev, size, &addr, GFP_KERNEL);
1547 	if (!ring->virt)
1548 		return -ENOMEM;
1549 
1550 	ring->addr = addr;
1551 	ring->count = count;
1552 	ring->index = 0;
1553 
1554 	return 0;
1555 }
1556 
1557 /* Free a previously-allocated ring */
gsi_ring_free(struct gsi * gsi,struct gsi_ring * ring)1558 static void gsi_ring_free(struct gsi *gsi, struct gsi_ring *ring)
1559 {
1560 	size_t size = ring->count * GSI_RING_ELEMENT_SIZE;
1561 
1562 	dma_free_coherent(gsi->dev, size, ring->virt, ring->addr);
1563 }
1564 
1565 /* Allocate an available event ring id */
gsi_evt_ring_id_alloc(struct gsi * gsi)1566 static int gsi_evt_ring_id_alloc(struct gsi *gsi)
1567 {
1568 	u32 evt_ring_id;
1569 
1570 	if (gsi->event_bitmap == ~0U) {
1571 		dev_err(gsi->dev, "event rings exhausted\n");
1572 		return -ENOSPC;
1573 	}
1574 
1575 	evt_ring_id = ffz(gsi->event_bitmap);
1576 	gsi->event_bitmap |= BIT(evt_ring_id);
1577 
1578 	return (int)evt_ring_id;
1579 }
1580 
1581 /* Free a previously-allocated event ring id */
gsi_evt_ring_id_free(struct gsi * gsi,u32 evt_ring_id)1582 static void gsi_evt_ring_id_free(struct gsi *gsi, u32 evt_ring_id)
1583 {
1584 	gsi->event_bitmap &= ~BIT(evt_ring_id);
1585 }
1586 
1587 /* Ring a channel doorbell, reporting the first un-filled entry */
gsi_channel_doorbell(struct gsi_channel * channel)1588 void gsi_channel_doorbell(struct gsi_channel *channel)
1589 {
1590 	struct gsi_ring *tre_ring = &channel->tre_ring;
1591 	u32 channel_id = gsi_channel_id(channel);
1592 	struct gsi *gsi = channel->gsi;
1593 	const struct reg *reg;
1594 	u32 val;
1595 
1596 	reg = gsi_reg(gsi, CH_C_DOORBELL_0);
1597 	/* Note: index *must* be used modulo the ring count here */
1598 	val = gsi_ring_addr(tre_ring, tre_ring->index % tre_ring->count);
1599 	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
1600 }
1601 
1602 /* Consult hardware, move newly completed transactions to completed state */
gsi_channel_update(struct gsi_channel * channel)1603 void gsi_channel_update(struct gsi_channel *channel)
1604 {
1605 	u32 evt_ring_id = channel->evt_ring_id;
1606 	struct gsi *gsi = channel->gsi;
1607 	struct gsi_evt_ring *evt_ring;
1608 	struct gsi_trans *trans;
1609 	struct gsi_ring *ring;
1610 	const struct reg *reg;
1611 	u32 offset;
1612 	u32 index;
1613 
1614 	evt_ring = &gsi->evt_ring[evt_ring_id];
1615 	ring = &evt_ring->ring;
1616 
1617 	/* See if there's anything new to process; if not, we're done.  Note
1618 	 * that index always refers to an entry *within* the event ring.
1619 	 */
1620 	reg = gsi_reg(gsi, EV_CH_E_CNTXT_4);
1621 	offset = reg_n_offset(reg, evt_ring_id);
1622 	index = gsi_ring_index(ring, ioread32(gsi->virt + offset));
1623 	if (index == ring->index % ring->count)
1624 		return;
1625 
1626 	/* Get the transaction for the latest completed event. */
1627 	trans = gsi_event_trans(gsi, gsi_ring_virt(ring, index - 1));
1628 	if (!trans)
1629 		return;
1630 
1631 	/* For RX channels, update each completed transaction with the number
1632 	 * of bytes that were actually received.  For TX channels, report
1633 	 * the number of transactions and bytes this completion represents
1634 	 * up the network stack.
1635 	 */
1636 	gsi_evt_ring_update(gsi, evt_ring_id, index);
1637 }
1638 
1639 /**
1640  * gsi_channel_poll_one() - Return a single completed transaction on a channel
1641  * @channel:	Channel to be polled
1642  *
1643  * Return:	Transaction pointer, or null if none are available
1644  *
1645  * This function returns the first of a channel's completed transactions.
1646  * If no transactions are in completed state, the hardware is consulted to
1647  * determine whether any new transactions have completed.  If so, they're
1648  * moved to completed state and the first such transaction is returned.
1649  * If there are no more completed transactions, a null pointer is returned.
1650  */
gsi_channel_poll_one(struct gsi_channel * channel)1651 static struct gsi_trans *gsi_channel_poll_one(struct gsi_channel *channel)
1652 {
1653 	struct gsi_trans *trans;
1654 
1655 	/* Get the first completed transaction */
1656 	trans = gsi_channel_trans_complete(channel);
1657 	if (trans)
1658 		gsi_trans_move_polled(trans);
1659 
1660 	return trans;
1661 }
1662 
1663 /**
1664  * gsi_channel_poll() - NAPI poll function for a channel
1665  * @napi:	NAPI structure for the channel
1666  * @budget:	Budget supplied by NAPI core
1667  *
1668  * Return:	Number of items polled (<= budget)
1669  *
1670  * Single transactions completed by hardware are polled until either
1671  * the budget is exhausted, or there are no more.  Each transaction
1672  * polled is passed to gsi_trans_complete(), to perform remaining
1673  * completion processing and retire/free the transaction.
1674  */
gsi_channel_poll(struct napi_struct * napi,int budget)1675 static int gsi_channel_poll(struct napi_struct *napi, int budget)
1676 {
1677 	struct gsi_channel *channel;
1678 	int count;
1679 
1680 	channel = container_of(napi, struct gsi_channel, napi);
1681 	for (count = 0; count < budget; count++) {
1682 		struct gsi_trans *trans;
1683 
1684 		trans = gsi_channel_poll_one(channel);
1685 		if (!trans)
1686 			break;
1687 		gsi_trans_complete(trans);
1688 	}
1689 
1690 	if (count < budget && napi_complete(napi))
1691 		gsi_irq_ieob_enable_one(channel->gsi, channel->evt_ring_id);
1692 
1693 	return count;
1694 }
1695 
1696 /* The event bitmap represents which event ids are available for allocation.
1697  * Set bits are not available, clear bits can be used.  This function
1698  * initializes the map so all events supported by the hardware are available,
1699  * then precludes any reserved events from being allocated.
1700  */
gsi_event_bitmap_init(u32 evt_ring_max)1701 static u32 gsi_event_bitmap_init(u32 evt_ring_max)
1702 {
1703 	u32 event_bitmap = GENMASK(BITS_PER_LONG - 1, evt_ring_max);
1704 
1705 	event_bitmap |= GENMASK(GSI_MHI_EVENT_ID_END, GSI_MHI_EVENT_ID_START);
1706 
1707 	return event_bitmap;
1708 }
1709 
1710 /* Setup function for a single channel */
gsi_channel_setup_one(struct gsi * gsi,u32 channel_id)1711 static int gsi_channel_setup_one(struct gsi *gsi, u32 channel_id)
1712 {
1713 	struct gsi_channel *channel = &gsi->channel[channel_id];
1714 	u32 evt_ring_id = channel->evt_ring_id;
1715 	int ret;
1716 
1717 	if (!gsi_channel_initialized(channel))
1718 		return 0;
1719 
1720 	ret = gsi_evt_ring_alloc_command(gsi, evt_ring_id);
1721 	if (ret)
1722 		return ret;
1723 
1724 	gsi_evt_ring_program(gsi, evt_ring_id);
1725 
1726 	ret = gsi_channel_alloc_command(gsi, channel_id);
1727 	if (ret)
1728 		goto err_evt_ring_de_alloc;
1729 
1730 	gsi_channel_program(channel, true);
1731 
1732 	if (channel->toward_ipa)
1733 		netif_napi_add_tx(&gsi->dummy_dev, &channel->napi,
1734 				  gsi_channel_poll);
1735 	else
1736 		netif_napi_add(&gsi->dummy_dev, &channel->napi,
1737 			       gsi_channel_poll);
1738 
1739 	return 0;
1740 
1741 err_evt_ring_de_alloc:
1742 	/* We've done nothing with the event ring yet so don't reset */
1743 	gsi_evt_ring_de_alloc_command(gsi, evt_ring_id);
1744 
1745 	return ret;
1746 }
1747 
1748 /* Inverse of gsi_channel_setup_one() */
gsi_channel_teardown_one(struct gsi * gsi,u32 channel_id)1749 static void gsi_channel_teardown_one(struct gsi *gsi, u32 channel_id)
1750 {
1751 	struct gsi_channel *channel = &gsi->channel[channel_id];
1752 	u32 evt_ring_id = channel->evt_ring_id;
1753 
1754 	if (!gsi_channel_initialized(channel))
1755 		return;
1756 
1757 	netif_napi_del(&channel->napi);
1758 
1759 	gsi_channel_de_alloc_command(gsi, channel_id);
1760 	gsi_evt_ring_reset_command(gsi, evt_ring_id);
1761 	gsi_evt_ring_de_alloc_command(gsi, evt_ring_id);
1762 }
1763 
1764 /* We use generic commands only to operate on modem channels.  We don't have
1765  * the ability to determine channel state for a modem channel, so we simply
1766  * issue the command and wait for it to complete.
1767  */
gsi_generic_command(struct gsi * gsi,u32 channel_id,enum gsi_generic_cmd_opcode opcode,u8 params)1768 static int gsi_generic_command(struct gsi *gsi, u32 channel_id,
1769 			       enum gsi_generic_cmd_opcode opcode,
1770 			       u8 params)
1771 {
1772 	const struct reg *reg;
1773 	bool timeout;
1774 	u32 offset;
1775 	u32 val;
1776 
1777 	/* The error global interrupt type is always enabled (until we tear
1778 	 * down), so we will keep it enabled.
1779 	 *
1780 	 * A generic EE command completes with a GSI global interrupt of
1781 	 * type GP_INT1.  We only perform one generic command at a time
1782 	 * (to allocate, halt, or enable/disable flow control on a modem
1783 	 * channel), and only from this function.  So we enable the GP_INT1
1784 	 * IRQ type here, and disable it again after the command completes.
1785 	 */
1786 	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
1787 	val = ERROR_INT | GP_INT1;
1788 	iowrite32(val, gsi->virt + reg_offset(reg));
1789 
1790 	/* First zero the result code field */
1791 	reg = gsi_reg(gsi, CNTXT_SCRATCH_0);
1792 	offset = reg_offset(reg);
1793 	val = ioread32(gsi->virt + offset);
1794 
1795 	val &= ~reg_fmask(reg, GENERIC_EE_RESULT);
1796 	iowrite32(val, gsi->virt + offset);
1797 
1798 	/* Now issue the command */
1799 	reg = gsi_reg(gsi, GENERIC_CMD);
1800 	val = reg_encode(reg, GENERIC_OPCODE, opcode);
1801 	val |= reg_encode(reg, GENERIC_CHID, channel_id);
1802 	val |= reg_encode(reg, GENERIC_EE, GSI_EE_MODEM);
1803 	if (gsi->version >= IPA_VERSION_4_11)
1804 		val |= reg_encode(reg, GENERIC_PARAMS, params);
1805 
1806 	timeout = !gsi_command(gsi, reg_offset(reg), val);
1807 
1808 	/* Disable the GP_INT1 IRQ type again */
1809 	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
1810 	iowrite32(ERROR_INT, gsi->virt + reg_offset(reg));
1811 
1812 	if (!timeout)
1813 		return gsi->result;
1814 
1815 	dev_err(gsi->dev, "GSI generic command %u to channel %u timed out\n",
1816 		opcode, channel_id);
1817 
1818 	return -ETIMEDOUT;
1819 }
1820 
gsi_modem_channel_alloc(struct gsi * gsi,u32 channel_id)1821 static int gsi_modem_channel_alloc(struct gsi *gsi, u32 channel_id)
1822 {
1823 	return gsi_generic_command(gsi, channel_id,
1824 				   GSI_GENERIC_ALLOCATE_CHANNEL, 0);
1825 }
1826 
gsi_modem_channel_halt(struct gsi * gsi,u32 channel_id)1827 static void gsi_modem_channel_halt(struct gsi *gsi, u32 channel_id)
1828 {
1829 	u32 retries = GSI_CHANNEL_MODEM_HALT_RETRIES;
1830 	int ret;
1831 
1832 	do
1833 		ret = gsi_generic_command(gsi, channel_id,
1834 					  GSI_GENERIC_HALT_CHANNEL, 0);
1835 	while (ret == -EAGAIN && retries--);
1836 
1837 	if (ret)
1838 		dev_err(gsi->dev, "error %d halting modem channel %u\n",
1839 			ret, channel_id);
1840 }
1841 
1842 /* Enable or disable flow control for a modem GSI TX channel (IPA v4.2+) */
1843 void
gsi_modem_channel_flow_control(struct gsi * gsi,u32 channel_id,bool enable)1844 gsi_modem_channel_flow_control(struct gsi *gsi, u32 channel_id, bool enable)
1845 {
1846 	u32 retries = 0;
1847 	u32 command;
1848 	int ret;
1849 
1850 	command = enable ? GSI_GENERIC_ENABLE_FLOW_CONTROL
1851 			 : GSI_GENERIC_DISABLE_FLOW_CONTROL;
1852 	/* Disabling flow control on IPA v4.11+ can return -EAGAIN if enable
1853 	 * is underway.  In this case we need to retry the command.
1854 	 */
1855 	if (!enable && gsi->version >= IPA_VERSION_4_11)
1856 		retries = GSI_CHANNEL_MODEM_FLOW_RETRIES;
1857 
1858 	do
1859 		ret = gsi_generic_command(gsi, channel_id, command, 0);
1860 	while (ret == -EAGAIN && retries--);
1861 
1862 	if (ret)
1863 		dev_err(gsi->dev,
1864 			"error %d %sabling mode channel %u flow control\n",
1865 			ret, enable ? "en" : "dis", channel_id);
1866 }
1867 
1868 /* Setup function for channels */
gsi_channel_setup(struct gsi * gsi)1869 static int gsi_channel_setup(struct gsi *gsi)
1870 {
1871 	u32 channel_id = 0;
1872 	u32 mask;
1873 	int ret;
1874 
1875 	gsi_irq_enable(gsi);
1876 
1877 	mutex_lock(&gsi->mutex);
1878 
1879 	do {
1880 		ret = gsi_channel_setup_one(gsi, channel_id);
1881 		if (ret)
1882 			goto err_unwind;
1883 	} while (++channel_id < gsi->channel_count);
1884 
1885 	/* Make sure no channels were defined that hardware does not support */
1886 	while (channel_id < GSI_CHANNEL_COUNT_MAX) {
1887 		struct gsi_channel *channel = &gsi->channel[channel_id++];
1888 
1889 		if (!gsi_channel_initialized(channel))
1890 			continue;
1891 
1892 		ret = -EINVAL;
1893 		dev_err(gsi->dev, "channel %u not supported by hardware\n",
1894 			channel_id - 1);
1895 		channel_id = gsi->channel_count;
1896 		goto err_unwind;
1897 	}
1898 
1899 	/* Allocate modem channels if necessary */
1900 	mask = gsi->modem_channel_bitmap;
1901 	while (mask) {
1902 		u32 modem_channel_id = __ffs(mask);
1903 
1904 		ret = gsi_modem_channel_alloc(gsi, modem_channel_id);
1905 		if (ret)
1906 			goto err_unwind_modem;
1907 
1908 		/* Clear bit from mask only after success (for unwind) */
1909 		mask ^= BIT(modem_channel_id);
1910 	}
1911 
1912 	mutex_unlock(&gsi->mutex);
1913 
1914 	return 0;
1915 
1916 err_unwind_modem:
1917 	/* Compute which modem channels need to be deallocated */
1918 	mask ^= gsi->modem_channel_bitmap;
1919 	while (mask) {
1920 		channel_id = __fls(mask);
1921 
1922 		mask ^= BIT(channel_id);
1923 
1924 		gsi_modem_channel_halt(gsi, channel_id);
1925 	}
1926 
1927 err_unwind:
1928 	while (channel_id--)
1929 		gsi_channel_teardown_one(gsi, channel_id);
1930 
1931 	mutex_unlock(&gsi->mutex);
1932 
1933 	gsi_irq_disable(gsi);
1934 
1935 	return ret;
1936 }
1937 
1938 /* Inverse of gsi_channel_setup() */
gsi_channel_teardown(struct gsi * gsi)1939 static void gsi_channel_teardown(struct gsi *gsi)
1940 {
1941 	u32 mask = gsi->modem_channel_bitmap;
1942 	u32 channel_id;
1943 
1944 	mutex_lock(&gsi->mutex);
1945 
1946 	while (mask) {
1947 		channel_id = __fls(mask);
1948 
1949 		mask ^= BIT(channel_id);
1950 
1951 		gsi_modem_channel_halt(gsi, channel_id);
1952 	}
1953 
1954 	channel_id = gsi->channel_count - 1;
1955 	do
1956 		gsi_channel_teardown_one(gsi, channel_id);
1957 	while (channel_id--);
1958 
1959 	mutex_unlock(&gsi->mutex);
1960 
1961 	gsi_irq_disable(gsi);
1962 }
1963 
1964 /* Turn off all GSI interrupts initially */
gsi_irq_setup(struct gsi * gsi)1965 static int gsi_irq_setup(struct gsi *gsi)
1966 {
1967 	const struct reg *reg;
1968 	int ret;
1969 
1970 	/* Writing 1 indicates IRQ interrupts; 0 would be MSI */
1971 	reg = gsi_reg(gsi, CNTXT_INTSET);
1972 	iowrite32(reg_bit(reg, INTYPE), gsi->virt + reg_offset(reg));
1973 
1974 	/* Disable all interrupt types */
1975 	gsi_irq_type_update(gsi, 0);
1976 
1977 	/* Clear all type-specific interrupt masks */
1978 	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_MSK);
1979 	iowrite32(0, gsi->virt + reg_offset(reg));
1980 
1981 	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_MSK);
1982 	iowrite32(0, gsi->virt + reg_offset(reg));
1983 
1984 	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
1985 	iowrite32(0, gsi->virt + reg_offset(reg));
1986 
1987 	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ_MSK);
1988 	iowrite32(0, gsi->virt + reg_offset(reg));
1989 
1990 	/* The inter-EE interrupts are not supported for IPA v3.0-v3.1 */
1991 	if (gsi->version > IPA_VERSION_3_1) {
1992 		reg = gsi_reg(gsi, INTER_EE_SRC_CH_IRQ_MSK);
1993 		iowrite32(0, gsi->virt + reg_offset(reg));
1994 
1995 		reg = gsi_reg(gsi, INTER_EE_SRC_EV_CH_IRQ_MSK);
1996 		iowrite32(0, gsi->virt + reg_offset(reg));
1997 	}
1998 
1999 	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_EN);
2000 	iowrite32(0, gsi->virt + reg_offset(reg));
2001 
2002 	ret = request_irq(gsi->irq, gsi_isr, 0, "gsi", gsi);
2003 	if (ret)
2004 		dev_err(gsi->dev, "error %d requesting \"gsi\" IRQ\n", ret);
2005 
2006 	return ret;
2007 }
2008 
gsi_irq_teardown(struct gsi * gsi)2009 static void gsi_irq_teardown(struct gsi *gsi)
2010 {
2011 	free_irq(gsi->irq, gsi);
2012 }
2013 
2014 /* Get # supported channel and event rings; there is no gsi_ring_teardown() */
gsi_ring_setup(struct gsi * gsi)2015 static int gsi_ring_setup(struct gsi *gsi)
2016 {
2017 	struct device *dev = gsi->dev;
2018 	const struct reg *reg;
2019 	u32 count;
2020 	u32 val;
2021 
2022 	if (gsi->version < IPA_VERSION_3_5_1) {
2023 		/* No HW_PARAM_2 register prior to IPA v3.5.1, assume the max */
2024 		gsi->channel_count = GSI_CHANNEL_COUNT_MAX;
2025 		gsi->evt_ring_count = GSI_EVT_RING_COUNT_MAX;
2026 
2027 		return 0;
2028 	}
2029 
2030 	reg = gsi_reg(gsi, HW_PARAM_2);
2031 	val = ioread32(gsi->virt + reg_offset(reg));
2032 
2033 	count = reg_decode(reg, NUM_CH_PER_EE, val);
2034 	if (!count) {
2035 		dev_err(dev, "GSI reports zero channels supported\n");
2036 		return -EINVAL;
2037 	}
2038 	if (count > GSI_CHANNEL_COUNT_MAX) {
2039 		dev_warn(dev, "limiting to %u channels; hardware supports %u\n",
2040 			 GSI_CHANNEL_COUNT_MAX, count);
2041 		count = GSI_CHANNEL_COUNT_MAX;
2042 	}
2043 	gsi->channel_count = count;
2044 
2045 	if (gsi->version < IPA_VERSION_5_0) {
2046 		count = reg_decode(reg, NUM_EV_PER_EE, val);
2047 	} else {
2048 		reg = gsi_reg(gsi, HW_PARAM_4);
2049 		count = reg_decode(reg, EV_PER_EE, val);
2050 	}
2051 	if (!count) {
2052 		dev_err(dev, "GSI reports zero event rings supported\n");
2053 		return -EINVAL;
2054 	}
2055 	if (count > GSI_EVT_RING_COUNT_MAX) {
2056 		dev_warn(dev,
2057 			 "limiting to %u event rings; hardware supports %u\n",
2058 			 GSI_EVT_RING_COUNT_MAX, count);
2059 		count = GSI_EVT_RING_COUNT_MAX;
2060 	}
2061 	gsi->evt_ring_count = count;
2062 
2063 	return 0;
2064 }
2065 
2066 /* Setup function for GSI.  GSI firmware must be loaded and initialized */
gsi_setup(struct gsi * gsi)2067 int gsi_setup(struct gsi *gsi)
2068 {
2069 	const struct reg *reg;
2070 	u32 val;
2071 	int ret;
2072 
2073 	/* Here is where we first touch the GSI hardware */
2074 	reg = gsi_reg(gsi, GSI_STATUS);
2075 	val = ioread32(gsi->virt + reg_offset(reg));
2076 	if (!(val & reg_bit(reg, ENABLED))) {
2077 		dev_err(gsi->dev, "GSI has not been enabled\n");
2078 		return -EIO;
2079 	}
2080 
2081 	ret = gsi_irq_setup(gsi);
2082 	if (ret)
2083 		return ret;
2084 
2085 	ret = gsi_ring_setup(gsi);	/* No matching teardown required */
2086 	if (ret)
2087 		goto err_irq_teardown;
2088 
2089 	/* Initialize the error log */
2090 	reg = gsi_reg(gsi, ERROR_LOG);
2091 	iowrite32(0, gsi->virt + reg_offset(reg));
2092 
2093 	ret = gsi_channel_setup(gsi);
2094 	if (ret)
2095 		goto err_irq_teardown;
2096 
2097 	return 0;
2098 
2099 err_irq_teardown:
2100 	gsi_irq_teardown(gsi);
2101 
2102 	return ret;
2103 }
2104 
2105 /* Inverse of gsi_setup() */
gsi_teardown(struct gsi * gsi)2106 void gsi_teardown(struct gsi *gsi)
2107 {
2108 	gsi_channel_teardown(gsi);
2109 	gsi_irq_teardown(gsi);
2110 }
2111 
2112 /* Initialize a channel's event ring */
gsi_channel_evt_ring_init(struct gsi_channel * channel)2113 static int gsi_channel_evt_ring_init(struct gsi_channel *channel)
2114 {
2115 	struct gsi *gsi = channel->gsi;
2116 	struct gsi_evt_ring *evt_ring;
2117 	int ret;
2118 
2119 	ret = gsi_evt_ring_id_alloc(gsi);
2120 	if (ret < 0)
2121 		return ret;
2122 	channel->evt_ring_id = ret;
2123 
2124 	evt_ring = &gsi->evt_ring[channel->evt_ring_id];
2125 	evt_ring->channel = channel;
2126 
2127 	ret = gsi_ring_alloc(gsi, &evt_ring->ring, channel->event_count);
2128 	if (!ret)
2129 		return 0;	/* Success! */
2130 
2131 	dev_err(gsi->dev, "error %d allocating channel %u event ring\n",
2132 		ret, gsi_channel_id(channel));
2133 
2134 	gsi_evt_ring_id_free(gsi, channel->evt_ring_id);
2135 
2136 	return ret;
2137 }
2138 
2139 /* Inverse of gsi_channel_evt_ring_init() */
gsi_channel_evt_ring_exit(struct gsi_channel * channel)2140 static void gsi_channel_evt_ring_exit(struct gsi_channel *channel)
2141 {
2142 	u32 evt_ring_id = channel->evt_ring_id;
2143 	struct gsi *gsi = channel->gsi;
2144 	struct gsi_evt_ring *evt_ring;
2145 
2146 	evt_ring = &gsi->evt_ring[evt_ring_id];
2147 	gsi_ring_free(gsi, &evt_ring->ring);
2148 	gsi_evt_ring_id_free(gsi, evt_ring_id);
2149 }
2150 
gsi_channel_data_valid(struct gsi * gsi,bool command,const struct ipa_gsi_endpoint_data * data)2151 static bool gsi_channel_data_valid(struct gsi *gsi, bool command,
2152 				   const struct ipa_gsi_endpoint_data *data)
2153 {
2154 	const struct gsi_channel_data *channel_data;
2155 	u32 channel_id = data->channel_id;
2156 	struct device *dev = gsi->dev;
2157 
2158 	/* Make sure channel ids are in the range driver supports */
2159 	if (channel_id >= GSI_CHANNEL_COUNT_MAX) {
2160 		dev_err(dev, "bad channel id %u; must be less than %u\n",
2161 			channel_id, GSI_CHANNEL_COUNT_MAX);
2162 		return false;
2163 	}
2164 
2165 	if (data->ee_id != GSI_EE_AP && data->ee_id != GSI_EE_MODEM) {
2166 		dev_err(dev, "bad EE id %u; not AP or modem\n", data->ee_id);
2167 		return false;
2168 	}
2169 
2170 	if (command && !data->toward_ipa) {
2171 		dev_err(dev, "command channel %u is not TX\n", channel_id);
2172 		return false;
2173 	}
2174 
2175 	channel_data = &data->channel;
2176 
2177 	if (!channel_data->tlv_count ||
2178 	    channel_data->tlv_count > GSI_TLV_MAX) {
2179 		dev_err(dev, "channel %u bad tlv_count %u; must be 1..%u\n",
2180 			channel_id, channel_data->tlv_count, GSI_TLV_MAX);
2181 		return false;
2182 	}
2183 
2184 	if (command && IPA_COMMAND_TRANS_TRE_MAX > channel_data->tlv_count) {
2185 		dev_err(dev, "command TRE max too big for channel %u (%u > %u)\n",
2186 			channel_id, IPA_COMMAND_TRANS_TRE_MAX,
2187 			channel_data->tlv_count);
2188 		return false;
2189 	}
2190 
2191 	/* We have to allow at least one maximally-sized transaction to
2192 	 * be outstanding (which would use tlv_count TREs).  Given how
2193 	 * gsi_channel_tre_max() is computed, tre_count has to be almost
2194 	 * twice the TLV FIFO size to satisfy this requirement.
2195 	 */
2196 	if (channel_data->tre_count < 2 * channel_data->tlv_count - 1) {
2197 		dev_err(dev, "channel %u TLV count %u exceeds TRE count %u\n",
2198 			channel_id, channel_data->tlv_count,
2199 			channel_data->tre_count);
2200 		return false;
2201 	}
2202 
2203 	if (!is_power_of_2(channel_data->tre_count)) {
2204 		dev_err(dev, "channel %u bad tre_count %u; not power of 2\n",
2205 			channel_id, channel_data->tre_count);
2206 		return false;
2207 	}
2208 
2209 	if (!is_power_of_2(channel_data->event_count)) {
2210 		dev_err(dev, "channel %u bad event_count %u; not power of 2\n",
2211 			channel_id, channel_data->event_count);
2212 		return false;
2213 	}
2214 
2215 	return true;
2216 }
2217 
2218 /* Init function for a single channel */
gsi_channel_init_one(struct gsi * gsi,const struct ipa_gsi_endpoint_data * data,bool command)2219 static int gsi_channel_init_one(struct gsi *gsi,
2220 				const struct ipa_gsi_endpoint_data *data,
2221 				bool command)
2222 {
2223 	struct gsi_channel *channel;
2224 	u32 tre_count;
2225 	int ret;
2226 
2227 	if (!gsi_channel_data_valid(gsi, command, data))
2228 		return -EINVAL;
2229 
2230 	/* Worst case we need an event for every outstanding TRE */
2231 	if (data->channel.tre_count > data->channel.event_count) {
2232 		tre_count = data->channel.event_count;
2233 		dev_warn(gsi->dev, "channel %u limited to %u TREs\n",
2234 			 data->channel_id, tre_count);
2235 	} else {
2236 		tre_count = data->channel.tre_count;
2237 	}
2238 
2239 	channel = &gsi->channel[data->channel_id];
2240 	memset(channel, 0, sizeof(*channel));
2241 
2242 	channel->gsi = gsi;
2243 	channel->toward_ipa = data->toward_ipa;
2244 	channel->command = command;
2245 	channel->trans_tre_max = data->channel.tlv_count;
2246 	channel->tre_count = tre_count;
2247 	channel->event_count = data->channel.event_count;
2248 
2249 	ret = gsi_channel_evt_ring_init(channel);
2250 	if (ret)
2251 		goto err_clear_gsi;
2252 
2253 	ret = gsi_ring_alloc(gsi, &channel->tre_ring, data->channel.tre_count);
2254 	if (ret) {
2255 		dev_err(gsi->dev, "error %d allocating channel %u ring\n",
2256 			ret, data->channel_id);
2257 		goto err_channel_evt_ring_exit;
2258 	}
2259 
2260 	ret = gsi_channel_trans_init(gsi, data->channel_id);
2261 	if (ret)
2262 		goto err_ring_free;
2263 
2264 	if (command) {
2265 		u32 tre_max = gsi_channel_tre_max(gsi, data->channel_id);
2266 
2267 		ret = ipa_cmd_pool_init(channel, tre_max);
2268 	}
2269 	if (!ret)
2270 		return 0;	/* Success! */
2271 
2272 	gsi_channel_trans_exit(channel);
2273 err_ring_free:
2274 	gsi_ring_free(gsi, &channel->tre_ring);
2275 err_channel_evt_ring_exit:
2276 	gsi_channel_evt_ring_exit(channel);
2277 err_clear_gsi:
2278 	channel->gsi = NULL;	/* Mark it not (fully) initialized */
2279 
2280 	return ret;
2281 }
2282 
2283 /* Inverse of gsi_channel_init_one() */
gsi_channel_exit_one(struct gsi_channel * channel)2284 static void gsi_channel_exit_one(struct gsi_channel *channel)
2285 {
2286 	if (!gsi_channel_initialized(channel))
2287 		return;
2288 
2289 	if (channel->command)
2290 		ipa_cmd_pool_exit(channel);
2291 	gsi_channel_trans_exit(channel);
2292 	gsi_ring_free(channel->gsi, &channel->tre_ring);
2293 	gsi_channel_evt_ring_exit(channel);
2294 }
2295 
2296 /* Init function for channels */
gsi_channel_init(struct gsi * gsi,u32 count,const struct ipa_gsi_endpoint_data * data)2297 static int gsi_channel_init(struct gsi *gsi, u32 count,
2298 			    const struct ipa_gsi_endpoint_data *data)
2299 {
2300 	bool modem_alloc;
2301 	int ret = 0;
2302 	u32 i;
2303 
2304 	/* IPA v4.2 requires the AP to allocate channels for the modem */
2305 	modem_alloc = gsi->version == IPA_VERSION_4_2;
2306 
2307 	gsi->event_bitmap = gsi_event_bitmap_init(GSI_EVT_RING_COUNT_MAX);
2308 	gsi->ieob_enabled_bitmap = 0;
2309 
2310 	/* The endpoint data array is indexed by endpoint name */
2311 	for (i = 0; i < count; i++) {
2312 		bool command = i == IPA_ENDPOINT_AP_COMMAND_TX;
2313 
2314 		if (ipa_gsi_endpoint_data_empty(&data[i]))
2315 			continue;	/* Skip over empty slots */
2316 
2317 		/* Mark modem channels to be allocated (hardware workaround) */
2318 		if (data[i].ee_id == GSI_EE_MODEM) {
2319 			if (modem_alloc)
2320 				gsi->modem_channel_bitmap |=
2321 						BIT(data[i].channel_id);
2322 			continue;
2323 		}
2324 
2325 		ret = gsi_channel_init_one(gsi, &data[i], command);
2326 		if (ret)
2327 			goto err_unwind;
2328 	}
2329 
2330 	return ret;
2331 
2332 err_unwind:
2333 	while (i--) {
2334 		if (ipa_gsi_endpoint_data_empty(&data[i]))
2335 			continue;
2336 		if (modem_alloc && data[i].ee_id == GSI_EE_MODEM) {
2337 			gsi->modem_channel_bitmap &= ~BIT(data[i].channel_id);
2338 			continue;
2339 		}
2340 		gsi_channel_exit_one(&gsi->channel[data->channel_id]);
2341 	}
2342 
2343 	return ret;
2344 }
2345 
2346 /* Inverse of gsi_channel_init() */
gsi_channel_exit(struct gsi * gsi)2347 static void gsi_channel_exit(struct gsi *gsi)
2348 {
2349 	u32 channel_id = GSI_CHANNEL_COUNT_MAX - 1;
2350 
2351 	do
2352 		gsi_channel_exit_one(&gsi->channel[channel_id]);
2353 	while (channel_id--);
2354 	gsi->modem_channel_bitmap = 0;
2355 }
2356 
2357 /* Init function for GSI.  GSI hardware does not need to be "ready" */
gsi_init(struct gsi * gsi,struct platform_device * pdev,enum ipa_version version,u32 count,const struct ipa_gsi_endpoint_data * data)2358 int gsi_init(struct gsi *gsi, struct platform_device *pdev,
2359 	     enum ipa_version version, u32 count,
2360 	     const struct ipa_gsi_endpoint_data *data)
2361 {
2362 	int ret;
2363 
2364 	gsi_validate_build();
2365 
2366 	gsi->dev = &pdev->dev;
2367 	gsi->version = version;
2368 
2369 	/* GSI uses NAPI on all channels.  Create a dummy network device
2370 	 * for the channel NAPI contexts to be associated with.
2371 	 */
2372 	init_dummy_netdev(&gsi->dummy_dev);
2373 	init_completion(&gsi->completion);
2374 
2375 	ret = gsi_reg_init(gsi, pdev);
2376 	if (ret)
2377 		return ret;
2378 
2379 	ret = gsi_irq_init(gsi, pdev);	/* No matching exit required */
2380 	if (ret)
2381 		goto err_reg_exit;
2382 
2383 	ret = gsi_channel_init(gsi, count, data);
2384 	if (ret)
2385 		goto err_reg_exit;
2386 
2387 	mutex_init(&gsi->mutex);
2388 
2389 	return 0;
2390 
2391 err_reg_exit:
2392 	gsi_reg_exit(gsi);
2393 
2394 	return ret;
2395 }
2396 
2397 /* Inverse of gsi_init() */
gsi_exit(struct gsi * gsi)2398 void gsi_exit(struct gsi *gsi)
2399 {
2400 	mutex_destroy(&gsi->mutex);
2401 	gsi_channel_exit(gsi);
2402 	gsi_reg_exit(gsi);
2403 }
2404 
2405 /* The maximum number of outstanding TREs on a channel.  This limits
2406  * a channel's maximum number of transactions outstanding (worst case
2407  * is one TRE per transaction).
2408  *
2409  * The absolute limit is the number of TREs in the channel's TRE ring,
2410  * and in theory we should be able use all of them.  But in practice,
2411  * doing that led to the hardware reporting exhaustion of event ring
2412  * slots for writing completion information.  So the hardware limit
2413  * would be (tre_count - 1).
2414  *
2415  * We reduce it a bit further though.  Transaction resource pools are
2416  * sized to be a little larger than this maximum, to allow resource
2417  * allocations to always be contiguous.  The number of entries in a
2418  * TRE ring buffer is a power of 2, and the extra resources in a pool
2419  * tends to nearly double the memory allocated for it.  Reducing the
2420  * maximum number of outstanding TREs allows the number of entries in
2421  * a pool to avoid crossing that power-of-2 boundary, and this can
2422  * substantially reduce pool memory requirements.  The number we
2423  * reduce it by matches the number added in gsi_trans_pool_init().
2424  */
gsi_channel_tre_max(struct gsi * gsi,u32 channel_id)2425 u32 gsi_channel_tre_max(struct gsi *gsi, u32 channel_id)
2426 {
2427 	struct gsi_channel *channel = &gsi->channel[channel_id];
2428 
2429 	/* Hardware limit is channel->tre_count - 1 */
2430 	return channel->tre_count - (channel->trans_tre_max - 1);
2431 }
2432