xref: /openbmc/linux/drivers/gpu/host1x/syncpt.c (revision e5bd61e8)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Tegra host1x Syncpoints
4  *
5  * Copyright (c) 2010-2015, NVIDIA Corporation.
6  */
7 
8 #include <linux/module.h>
9 #include <linux/device.h>
10 #include <linux/slab.h>
11 
12 #include <trace/events/host1x.h>
13 
14 #include "syncpt.h"
15 #include "dev.h"
16 #include "intr.h"
17 #include "debug.h"
18 
19 #define SYNCPT_CHECK_PERIOD (2 * HZ)
20 #define MAX_STUCK_CHECK_COUNT 15
21 
22 static struct host1x_syncpt_base *
23 host1x_syncpt_base_request(struct host1x *host)
24 {
25 	struct host1x_syncpt_base *bases = host->bases;
26 	unsigned int i;
27 
28 	for (i = 0; i < host->info->nb_bases; i++)
29 		if (!bases[i].requested)
30 			break;
31 
32 	if (i >= host->info->nb_bases)
33 		return NULL;
34 
35 	bases[i].requested = true;
36 	return &bases[i];
37 }
38 
39 static void host1x_syncpt_base_free(struct host1x_syncpt_base *base)
40 {
41 	if (base)
42 		base->requested = false;
43 }
44 
45 /**
46  * host1x_syncpt_alloc() - allocate a syncpoint
47  * @host: host1x device data
48  * @flags: bitfield of HOST1X_SYNCPT_* flags
49  * @name: name for the syncpoint for use in debug prints
50  *
51  * Allocates a hardware syncpoint for the caller's use. The caller then has
52  * the sole authority to mutate the syncpoint's value until it is freed again.
53  *
54  * If no free syncpoints are available, or a NULL name was specified, returns
55  * NULL.
56  */
57 struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
58 					  unsigned long flags,
59 					  const char *name)
60 {
61 	struct host1x_syncpt *sp = host->syncpt;
62 	char *full_name;
63 	unsigned int i;
64 
65 	if (!name)
66 		return NULL;
67 
68 	mutex_lock(&host->syncpt_mutex);
69 
70 	for (i = 0; i < host->info->nb_pts && kref_read(&sp->ref); i++, sp++)
71 		;
72 
73 	if (i >= host->info->nb_pts)
74 		goto unlock;
75 
76 	if (flags & HOST1X_SYNCPT_HAS_BASE) {
77 		sp->base = host1x_syncpt_base_request(host);
78 		if (!sp->base)
79 			goto unlock;
80 	}
81 
82 	full_name = kasprintf(GFP_KERNEL, "%u-%s", sp->id, name);
83 	if (!full_name)
84 		goto free_base;
85 
86 	sp->name = full_name;
87 
88 	if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
89 		sp->client_managed = true;
90 	else
91 		sp->client_managed = false;
92 
93 	kref_init(&sp->ref);
94 
95 	mutex_unlock(&host->syncpt_mutex);
96 	return sp;
97 
98 free_base:
99 	host1x_syncpt_base_free(sp->base);
100 	sp->base = NULL;
101 unlock:
102 	mutex_unlock(&host->syncpt_mutex);
103 	return NULL;
104 }
105 EXPORT_SYMBOL(host1x_syncpt_alloc);
106 
107 /**
108  * host1x_syncpt_id() - retrieve syncpoint ID
109  * @sp: host1x syncpoint
110  *
111  * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
112  * often used as a value to program into registers that control how hardware
113  * blocks interact with syncpoints.
114  */
115 u32 host1x_syncpt_id(struct host1x_syncpt *sp)
116 {
117 	return sp->id;
118 }
119 EXPORT_SYMBOL(host1x_syncpt_id);
120 
121 /**
122  * host1x_syncpt_incr_max() - update the value sent to hardware
123  * @sp: host1x syncpoint
124  * @incrs: number of increments
125  */
126 u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
127 {
128 	return (u32)atomic_add_return(incrs, &sp->max_val);
129 }
130 EXPORT_SYMBOL(host1x_syncpt_incr_max);
131 
132  /*
133  * Write cached syncpoint and waitbase values to hardware.
134  */
135 void host1x_syncpt_restore(struct host1x *host)
136 {
137 	struct host1x_syncpt *sp_base = host->syncpt;
138 	unsigned int i;
139 
140 	for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
141 		host1x_hw_syncpt_restore(host, sp_base + i);
142 
143 	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
144 		host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
145 
146 	wmb();
147 }
148 
149 /*
150  * Update the cached syncpoint and waitbase values by reading them
151  * from the registers.
152   */
153 void host1x_syncpt_save(struct host1x *host)
154 {
155 	struct host1x_syncpt *sp_base = host->syncpt;
156 	unsigned int i;
157 
158 	for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
159 		if (host1x_syncpt_client_managed(sp_base + i))
160 			host1x_hw_syncpt_load(host, sp_base + i);
161 		else
162 			WARN_ON(!host1x_syncpt_idle(sp_base + i));
163 	}
164 
165 	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
166 		host1x_hw_syncpt_load_wait_base(host, sp_base + i);
167 }
168 
169 /*
170  * Updates the cached syncpoint value by reading a new value from the hardware
171  * register
172  */
173 u32 host1x_syncpt_load(struct host1x_syncpt *sp)
174 {
175 	u32 val;
176 
177 	val = host1x_hw_syncpt_load(sp->host, sp);
178 	trace_host1x_syncpt_load_min(sp->id, val);
179 
180 	return val;
181 }
182 
183 /*
184  * Get the current syncpoint base
185  */
186 u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
187 {
188 	host1x_hw_syncpt_load_wait_base(sp->host, sp);
189 
190 	return sp->base_val;
191 }
192 
193 /**
194  * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
195  * @sp: host1x syncpoint
196  */
197 int host1x_syncpt_incr(struct host1x_syncpt *sp)
198 {
199 	return host1x_hw_syncpt_cpu_incr(sp->host, sp);
200 }
201 EXPORT_SYMBOL(host1x_syncpt_incr);
202 
203 /*
204  * Updated sync point form hardware, and returns true if syncpoint is expired,
205  * false if we may need to wait
206  */
207 static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
208 {
209 	host1x_hw_syncpt_load(sp->host, sp);
210 
211 	return host1x_syncpt_is_expired(sp, thresh);
212 }
213 
214 /**
215  * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
216  * @sp: host1x syncpoint
217  * @thresh: threshold
218  * @timeout: maximum time to wait for the syncpoint to reach the given value
219  * @value: return location for the syncpoint value
220  */
221 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
222 		       u32 *value)
223 {
224 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
225 	void *ref;
226 	struct host1x_waitlist *waiter;
227 	int err = 0, check_count = 0;
228 	u32 val;
229 
230 	if (value)
231 		*value = 0;
232 
233 	/* first check cache */
234 	if (host1x_syncpt_is_expired(sp, thresh)) {
235 		if (value)
236 			*value = host1x_syncpt_load(sp);
237 
238 		return 0;
239 	}
240 
241 	/* try to read from register */
242 	val = host1x_hw_syncpt_load(sp->host, sp);
243 	if (host1x_syncpt_is_expired(sp, thresh)) {
244 		if (value)
245 			*value = val;
246 
247 		goto done;
248 	}
249 
250 	if (!timeout) {
251 		err = -EAGAIN;
252 		goto done;
253 	}
254 
255 	/* allocate a waiter */
256 	waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
257 	if (!waiter) {
258 		err = -ENOMEM;
259 		goto done;
260 	}
261 
262 	/* schedule a wakeup when the syncpoint value is reached */
263 	err = host1x_intr_add_action(sp->host, sp, thresh,
264 				     HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
265 				     &wq, waiter, &ref);
266 	if (err)
267 		goto done;
268 
269 	err = -EAGAIN;
270 	/* Caller-specified timeout may be impractically low */
271 	if (timeout < 0)
272 		timeout = LONG_MAX;
273 
274 	/* wait for the syncpoint, or timeout, or signal */
275 	while (timeout) {
276 		long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
277 		int remain;
278 
279 		remain = wait_event_interruptible_timeout(wq,
280 				syncpt_load_min_is_expired(sp, thresh),
281 				check);
282 		if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
283 			if (value)
284 				*value = host1x_syncpt_load(sp);
285 
286 			err = 0;
287 
288 			break;
289 		}
290 
291 		if (remain < 0) {
292 			err = remain;
293 			break;
294 		}
295 
296 		timeout -= check;
297 
298 		if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
299 			dev_warn(sp->host->dev,
300 				"%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
301 				 current->comm, sp->id, sp->name,
302 				 thresh, timeout);
303 
304 			host1x_debug_dump_syncpts(sp->host);
305 
306 			if (check_count == MAX_STUCK_CHECK_COUNT)
307 				host1x_debug_dump(sp->host);
308 
309 			check_count++;
310 		}
311 	}
312 
313 	host1x_intr_put_ref(sp->host, sp->id, ref, true);
314 
315 done:
316 	return err;
317 }
318 EXPORT_SYMBOL(host1x_syncpt_wait);
319 
320 /*
321  * Returns true if syncpoint is expired, false if we may need to wait
322  */
323 bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
324 {
325 	u32 current_val;
326 
327 	smp_rmb();
328 
329 	current_val = (u32)atomic_read(&sp->min_val);
330 
331 	return ((current_val - thresh) & 0x80000000U) == 0U;
332 }
333 
334 int host1x_syncpt_init(struct host1x *host)
335 {
336 	struct host1x_syncpt_base *bases;
337 	struct host1x_syncpt *syncpt;
338 	unsigned int i;
339 
340 	syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
341 			      GFP_KERNEL);
342 	if (!syncpt)
343 		return -ENOMEM;
344 
345 	bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
346 			     GFP_KERNEL);
347 	if (!bases)
348 		return -ENOMEM;
349 
350 	for (i = 0; i < host->info->nb_pts; i++) {
351 		syncpt[i].id = i;
352 		syncpt[i].host = host;
353 
354 		/*
355 		 * Unassign syncpt from channels for purposes of Tegra186
356 		 * syncpoint protection. This prevents any channel from
357 		 * accessing it until it is reassigned.
358 		 */
359 		host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
360 	}
361 
362 	for (i = 0; i < host->info->nb_bases; i++)
363 		bases[i].id = i;
364 
365 	mutex_init(&host->syncpt_mutex);
366 	host->syncpt = syncpt;
367 	host->bases = bases;
368 
369 	host1x_syncpt_restore(host);
370 	host1x_hw_syncpt_enable_protection(host);
371 
372 	/* Allocate sync point to use for clearing waits for expired fences */
373 	host->nop_sp = host1x_syncpt_alloc(host, 0, "reserved-nop");
374 	if (!host->nop_sp)
375 		return -ENOMEM;
376 
377 	if (host->info->reserve_vblank_syncpts) {
378 		kref_init(&host->syncpt[26].ref);
379 		kref_init(&host->syncpt[27].ref);
380 	}
381 
382 	return 0;
383 }
384 
385 /**
386  * host1x_syncpt_request() - request a syncpoint
387  * @client: client requesting the syncpoint
388  * @flags: flags
389  *
390  * host1x client drivers can use this function to allocate a syncpoint for
391  * subsequent use. A syncpoint returned by this function will be reserved for
392  * use by the client exclusively. When no longer using a syncpoint, a host1x
393  * client driver needs to release it using host1x_syncpt_put().
394  */
395 struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
396 					    unsigned long flags)
397 {
398 	struct host1x *host = dev_get_drvdata(client->host->parent);
399 
400 	return host1x_syncpt_alloc(host, flags, dev_name(client->dev));
401 }
402 EXPORT_SYMBOL(host1x_syncpt_request);
403 
404 static void syncpt_release(struct kref *ref)
405 {
406 	struct host1x_syncpt *sp = container_of(ref, struct host1x_syncpt, ref);
407 
408 	atomic_set(&sp->max_val, host1x_syncpt_read(sp));
409 
410 	mutex_lock(&sp->host->syncpt_mutex);
411 
412 	host1x_syncpt_base_free(sp->base);
413 	kfree(sp->name);
414 	sp->base = NULL;
415 	sp->name = NULL;
416 	sp->client_managed = false;
417 
418 	mutex_unlock(&sp->host->syncpt_mutex);
419 }
420 
421 /**
422  * host1x_syncpt_put() - free a requested syncpoint
423  * @sp: host1x syncpoint
424  *
425  * Release a syncpoint previously allocated using host1x_syncpt_request(). A
426  * host1x client driver should call this when the syncpoint is no longer in
427  * use.
428  */
429 void host1x_syncpt_put(struct host1x_syncpt *sp)
430 {
431 	if (!sp)
432 		return;
433 
434 	kref_put(&sp->ref, syncpt_release);
435 }
436 EXPORT_SYMBOL(host1x_syncpt_put);
437 
438 void host1x_syncpt_deinit(struct host1x *host)
439 {
440 	struct host1x_syncpt *sp = host->syncpt;
441 	unsigned int i;
442 
443 	for (i = 0; i < host->info->nb_pts; i++, sp++)
444 		kfree(sp->name);
445 }
446 
447 /**
448  * host1x_syncpt_read_max() - read maximum syncpoint value
449  * @sp: host1x syncpoint
450  *
451  * The maximum syncpoint value indicates how many operations there are in
452  * queue, either in channel or in a software thread.
453  */
454 u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
455 {
456 	smp_rmb();
457 
458 	return (u32)atomic_read(&sp->max_val);
459 }
460 EXPORT_SYMBOL(host1x_syncpt_read_max);
461 
462 /**
463  * host1x_syncpt_read_min() - read minimum syncpoint value
464  * @sp: host1x syncpoint
465  *
466  * The minimum syncpoint value is a shadow of the current sync point value in
467  * hardware.
468  */
469 u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
470 {
471 	smp_rmb();
472 
473 	return (u32)atomic_read(&sp->min_val);
474 }
475 EXPORT_SYMBOL(host1x_syncpt_read_min);
476 
477 /**
478  * host1x_syncpt_read() - read the current syncpoint value
479  * @sp: host1x syncpoint
480  */
481 u32 host1x_syncpt_read(struct host1x_syncpt *sp)
482 {
483 	return host1x_syncpt_load(sp);
484 }
485 EXPORT_SYMBOL(host1x_syncpt_read);
486 
487 unsigned int host1x_syncpt_nb_pts(struct host1x *host)
488 {
489 	return host->info->nb_pts;
490 }
491 
492 unsigned int host1x_syncpt_nb_bases(struct host1x *host)
493 {
494 	return host->info->nb_bases;
495 }
496 
497 unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
498 {
499 	return host->info->nb_mlocks;
500 }
501 
502 /**
503  * host1x_syncpt_get_by_id() - obtain a syncpoint by ID
504  * @host: host1x controller
505  * @id: syncpoint ID
506  */
507 struct host1x_syncpt *host1x_syncpt_get_by_id(struct host1x *host,
508 					      unsigned int id)
509 {
510 	if (id >= host->info->nb_pts)
511 		return NULL;
512 
513 	if (kref_get_unless_zero(&host->syncpt[id].ref))
514 		return &host->syncpt[id];
515 	else
516 		return NULL;
517 }
518 EXPORT_SYMBOL(host1x_syncpt_get_by_id);
519 
520 /**
521  * host1x_syncpt_get_by_id_noref() - obtain a syncpoint by ID but don't
522  * 	increase the refcount.
523  * @host: host1x controller
524  * @id: syncpoint ID
525  */
526 struct host1x_syncpt *host1x_syncpt_get_by_id_noref(struct host1x *host,
527 						    unsigned int id)
528 {
529 	if (id >= host->info->nb_pts)
530 		return NULL;
531 
532 	return &host->syncpt[id];
533 }
534 EXPORT_SYMBOL(host1x_syncpt_get_by_id_noref);
535 
536 /**
537  * host1x_syncpt_get() - increment syncpoint refcount
538  * @sp: syncpoint
539  */
540 struct host1x_syncpt *host1x_syncpt_get(struct host1x_syncpt *sp)
541 {
542 	kref_get(&sp->ref);
543 
544 	return sp;
545 }
546 EXPORT_SYMBOL(host1x_syncpt_get);
547 
548 /**
549  * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
550  * @sp: host1x syncpoint
551  */
552 struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
553 {
554 	return sp ? sp->base : NULL;
555 }
556 EXPORT_SYMBOL(host1x_syncpt_get_base);
557 
558 /**
559  * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
560  * @base: host1x syncpoint wait base
561  */
562 u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
563 {
564 	return base->id;
565 }
566 EXPORT_SYMBOL(host1x_syncpt_base_id);
567 
568 static void do_nothing(struct kref *ref)
569 {
570 }
571 
572 /**
573  * host1x_syncpt_release_vblank_reservation() - Make VBLANK syncpoint
574  *   available for allocation
575  *
576  * @client: host1x bus client
577  * @syncpt_id: syncpoint ID to make available
578  *
579  * Makes VBLANK<i> syncpoint available for allocatation if it was
580  * reserved at initialization time. This should be called by the display
581  * driver after it has ensured that any VBLANK increment programming configured
582  * by the boot chain has been disabled.
583  */
584 void host1x_syncpt_release_vblank_reservation(struct host1x_client *client,
585 					      u32 syncpt_id)
586 {
587 	struct host1x *host = dev_get_drvdata(client->host->parent);
588 
589 	if (!host->info->reserve_vblank_syncpts)
590 		return;
591 
592 	kref_put(&host->syncpt[syncpt_id].ref, do_nothing);
593 }
594 EXPORT_SYMBOL(host1x_syncpt_release_vblank_reservation);
595