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 *
host1x_syncpt_base_request(struct host1x * host)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 
host1x_syncpt_base_free(struct host1x_syncpt_base * base)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  */
host1x_syncpt_alloc(struct host1x * host,unsigned long flags,const char * name)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  */
host1x_syncpt_id(struct host1x_syncpt * sp)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  */
host1x_syncpt_incr_max(struct host1x_syncpt * sp,u32 incrs)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  */
host1x_syncpt_restore(struct host1x * host)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 		/*
142 		 * Unassign syncpt from channels for purposes of Tegra186
143 		 * syncpoint protection. This prevents any channel from
144 		 * accessing it until it is reassigned.
145 		 */
146 		host1x_hw_syncpt_assign_to_channel(host, sp_base + i, NULL);
147 		host1x_hw_syncpt_restore(host, sp_base + i);
148 	}
149 
150 	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
151 		host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
152 
153 	host1x_hw_syncpt_enable_protection(host);
154 
155 	wmb();
156 }
157 
158 /*
159  * Update the cached syncpoint and waitbase values by reading them
160  * from the registers.
161   */
host1x_syncpt_save(struct host1x * host)162 void host1x_syncpt_save(struct host1x *host)
163 {
164 	struct host1x_syncpt *sp_base = host->syncpt;
165 	unsigned int i;
166 
167 	for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
168 		if (host1x_syncpt_client_managed(sp_base + i))
169 			host1x_hw_syncpt_load(host, sp_base + i);
170 		else
171 			WARN_ON(!host1x_syncpt_idle(sp_base + i));
172 	}
173 
174 	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
175 		host1x_hw_syncpt_load_wait_base(host, sp_base + i);
176 }
177 
178 /*
179  * Updates the cached syncpoint value by reading a new value from the hardware
180  * register
181  */
host1x_syncpt_load(struct host1x_syncpt * sp)182 u32 host1x_syncpt_load(struct host1x_syncpt *sp)
183 {
184 	u32 val;
185 
186 	val = host1x_hw_syncpt_load(sp->host, sp);
187 	trace_host1x_syncpt_load_min(sp->id, val);
188 
189 	return val;
190 }
191 
192 /*
193  * Get the current syncpoint base
194  */
host1x_syncpt_load_wait_base(struct host1x_syncpt * sp)195 u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
196 {
197 	host1x_hw_syncpt_load_wait_base(sp->host, sp);
198 
199 	return sp->base_val;
200 }
201 
202 /**
203  * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
204  * @sp: host1x syncpoint
205  */
host1x_syncpt_incr(struct host1x_syncpt * sp)206 int host1x_syncpt_incr(struct host1x_syncpt *sp)
207 {
208 	return host1x_hw_syncpt_cpu_incr(sp->host, sp);
209 }
210 EXPORT_SYMBOL(host1x_syncpt_incr);
211 
212 /*
213  * Updated sync point form hardware, and returns true if syncpoint is expired,
214  * false if we may need to wait
215  */
syncpt_load_min_is_expired(struct host1x_syncpt * sp,u32 thresh)216 static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
217 {
218 	host1x_hw_syncpt_load(sp->host, sp);
219 
220 	return host1x_syncpt_is_expired(sp, thresh);
221 }
222 
223 /**
224  * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
225  * @sp: host1x syncpoint
226  * @thresh: threshold
227  * @timeout: maximum time to wait for the syncpoint to reach the given value
228  * @value: return location for the syncpoint value
229  */
host1x_syncpt_wait(struct host1x_syncpt * sp,u32 thresh,long timeout,u32 * value)230 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
231 		       u32 *value)
232 {
233 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
234 	void *ref;
235 	struct host1x_waitlist *waiter;
236 	int err = 0, check_count = 0;
237 
238 	if (value)
239 		*value = host1x_syncpt_load(sp);
240 
241 	if (host1x_syncpt_is_expired(sp, thresh))
242 		return 0;
243 
244 	if (!timeout) {
245 		err = -EAGAIN;
246 		goto done;
247 	}
248 
249 	/* allocate a waiter */
250 	waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
251 	if (!waiter) {
252 		err = -ENOMEM;
253 		goto done;
254 	}
255 
256 	/* schedule a wakeup when the syncpoint value is reached */
257 	err = host1x_intr_add_action(sp->host, sp, thresh,
258 				     HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
259 				     &wq, waiter, &ref);
260 	if (err)
261 		goto done;
262 
263 	err = -EAGAIN;
264 	/* Caller-specified timeout may be impractically low */
265 	if (timeout < 0)
266 		timeout = LONG_MAX;
267 
268 	/* wait for the syncpoint, or timeout, or signal */
269 	while (timeout) {
270 		long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
271 		int remain;
272 
273 		remain = wait_event_interruptible_timeout(wq,
274 				syncpt_load_min_is_expired(sp, thresh),
275 				check);
276 		if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
277 			if (value)
278 				*value = host1x_syncpt_load(sp);
279 
280 			err = 0;
281 
282 			break;
283 		}
284 
285 		if (remain < 0) {
286 			err = remain;
287 			break;
288 		}
289 
290 		timeout -= check;
291 
292 		if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
293 			dev_warn(sp->host->dev,
294 				"%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
295 				 current->comm, sp->id, sp->name,
296 				 thresh, timeout);
297 
298 			host1x_debug_dump_syncpts(sp->host);
299 
300 			if (check_count == MAX_STUCK_CHECK_COUNT)
301 				host1x_debug_dump(sp->host);
302 
303 			check_count++;
304 		}
305 	}
306 
307 	host1x_intr_put_ref(sp->host, sp->id, ref, true);
308 
309 done:
310 	return err;
311 }
312 EXPORT_SYMBOL(host1x_syncpt_wait);
313 
314 /*
315  * Returns true if syncpoint is expired, false if we may need to wait
316  */
host1x_syncpt_is_expired(struct host1x_syncpt * sp,u32 thresh)317 bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
318 {
319 	u32 current_val;
320 
321 	smp_rmb();
322 
323 	current_val = (u32)atomic_read(&sp->min_val);
324 
325 	return ((current_val - thresh) & 0x80000000U) == 0U;
326 }
327 
host1x_syncpt_init(struct host1x * host)328 int host1x_syncpt_init(struct host1x *host)
329 {
330 	struct host1x_syncpt_base *bases;
331 	struct host1x_syncpt *syncpt;
332 	unsigned int i;
333 
334 	syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
335 			      GFP_KERNEL);
336 	if (!syncpt)
337 		return -ENOMEM;
338 
339 	bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
340 			     GFP_KERNEL);
341 	if (!bases)
342 		return -ENOMEM;
343 
344 	for (i = 0; i < host->info->nb_pts; i++) {
345 		syncpt[i].id = i;
346 		syncpt[i].host = host;
347 	}
348 
349 	for (i = 0; i < host->info->nb_bases; i++)
350 		bases[i].id = i;
351 
352 	mutex_init(&host->syncpt_mutex);
353 	host->syncpt = syncpt;
354 	host->bases = bases;
355 
356 	/* Allocate sync point to use for clearing waits for expired fences */
357 	host->nop_sp = host1x_syncpt_alloc(host, 0, "reserved-nop");
358 	if (!host->nop_sp)
359 		return -ENOMEM;
360 
361 	if (host->info->reserve_vblank_syncpts) {
362 		kref_init(&host->syncpt[26].ref);
363 		kref_init(&host->syncpt[27].ref);
364 	}
365 
366 	return 0;
367 }
368 
369 /**
370  * host1x_syncpt_request() - request a syncpoint
371  * @client: client requesting the syncpoint
372  * @flags: flags
373  *
374  * host1x client drivers can use this function to allocate a syncpoint for
375  * subsequent use. A syncpoint returned by this function will be reserved for
376  * use by the client exclusively. When no longer using a syncpoint, a host1x
377  * client driver needs to release it using host1x_syncpt_put().
378  */
host1x_syncpt_request(struct host1x_client * client,unsigned long flags)379 struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
380 					    unsigned long flags)
381 {
382 	struct host1x *host = dev_get_drvdata(client->host->parent);
383 
384 	return host1x_syncpt_alloc(host, flags, dev_name(client->dev));
385 }
386 EXPORT_SYMBOL(host1x_syncpt_request);
387 
syncpt_release(struct kref * ref)388 static void syncpt_release(struct kref *ref)
389 {
390 	struct host1x_syncpt *sp = container_of(ref, struct host1x_syncpt, ref);
391 
392 	atomic_set(&sp->max_val, host1x_syncpt_read(sp));
393 
394 	sp->locked = false;
395 
396 	mutex_lock(&sp->host->syncpt_mutex);
397 
398 	host1x_syncpt_base_free(sp->base);
399 	kfree(sp->name);
400 	sp->base = NULL;
401 	sp->name = NULL;
402 	sp->client_managed = false;
403 
404 	mutex_unlock(&sp->host->syncpt_mutex);
405 }
406 
407 /**
408  * host1x_syncpt_put() - free a requested syncpoint
409  * @sp: host1x syncpoint
410  *
411  * Release a syncpoint previously allocated using host1x_syncpt_request(). A
412  * host1x client driver should call this when the syncpoint is no longer in
413  * use.
414  */
host1x_syncpt_put(struct host1x_syncpt * sp)415 void host1x_syncpt_put(struct host1x_syncpt *sp)
416 {
417 	if (!sp)
418 		return;
419 
420 	kref_put(&sp->ref, syncpt_release);
421 }
422 EXPORT_SYMBOL(host1x_syncpt_put);
423 
host1x_syncpt_deinit(struct host1x * host)424 void host1x_syncpt_deinit(struct host1x *host)
425 {
426 	struct host1x_syncpt *sp = host->syncpt;
427 	unsigned int i;
428 
429 	for (i = 0; i < host->info->nb_pts; i++, sp++)
430 		kfree(sp->name);
431 }
432 
433 /**
434  * host1x_syncpt_read_max() - read maximum syncpoint value
435  * @sp: host1x syncpoint
436  *
437  * The maximum syncpoint value indicates how many operations there are in
438  * queue, either in channel or in a software thread.
439  */
host1x_syncpt_read_max(struct host1x_syncpt * sp)440 u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
441 {
442 	smp_rmb();
443 
444 	return (u32)atomic_read(&sp->max_val);
445 }
446 EXPORT_SYMBOL(host1x_syncpt_read_max);
447 
448 /**
449  * host1x_syncpt_read_min() - read minimum syncpoint value
450  * @sp: host1x syncpoint
451  *
452  * The minimum syncpoint value is a shadow of the current sync point value in
453  * hardware.
454  */
host1x_syncpt_read_min(struct host1x_syncpt * sp)455 u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
456 {
457 	smp_rmb();
458 
459 	return (u32)atomic_read(&sp->min_val);
460 }
461 EXPORT_SYMBOL(host1x_syncpt_read_min);
462 
463 /**
464  * host1x_syncpt_read() - read the current syncpoint value
465  * @sp: host1x syncpoint
466  */
host1x_syncpt_read(struct host1x_syncpt * sp)467 u32 host1x_syncpt_read(struct host1x_syncpt *sp)
468 {
469 	return host1x_syncpt_load(sp);
470 }
471 EXPORT_SYMBOL(host1x_syncpt_read);
472 
host1x_syncpt_nb_pts(struct host1x * host)473 unsigned int host1x_syncpt_nb_pts(struct host1x *host)
474 {
475 	return host->info->nb_pts;
476 }
477 
host1x_syncpt_nb_bases(struct host1x * host)478 unsigned int host1x_syncpt_nb_bases(struct host1x *host)
479 {
480 	return host->info->nb_bases;
481 }
482 
host1x_syncpt_nb_mlocks(struct host1x * host)483 unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
484 {
485 	return host->info->nb_mlocks;
486 }
487 
488 /**
489  * host1x_syncpt_get_by_id() - obtain a syncpoint by ID
490  * @host: host1x controller
491  * @id: syncpoint ID
492  */
host1x_syncpt_get_by_id(struct host1x * host,unsigned int id)493 struct host1x_syncpt *host1x_syncpt_get_by_id(struct host1x *host,
494 					      unsigned int id)
495 {
496 	if (id >= host->info->nb_pts)
497 		return NULL;
498 
499 	if (kref_get_unless_zero(&host->syncpt[id].ref))
500 		return &host->syncpt[id];
501 	else
502 		return NULL;
503 }
504 EXPORT_SYMBOL(host1x_syncpt_get_by_id);
505 
506 /**
507  * host1x_syncpt_get_by_id_noref() - obtain a syncpoint by ID but don't
508  * 	increase the refcount.
509  * @host: host1x controller
510  * @id: syncpoint ID
511  */
host1x_syncpt_get_by_id_noref(struct host1x * host,unsigned int id)512 struct host1x_syncpt *host1x_syncpt_get_by_id_noref(struct host1x *host,
513 						    unsigned int id)
514 {
515 	if (id >= host->info->nb_pts)
516 		return NULL;
517 
518 	return &host->syncpt[id];
519 }
520 EXPORT_SYMBOL(host1x_syncpt_get_by_id_noref);
521 
522 /**
523  * host1x_syncpt_get() - increment syncpoint refcount
524  * @sp: syncpoint
525  */
host1x_syncpt_get(struct host1x_syncpt * sp)526 struct host1x_syncpt *host1x_syncpt_get(struct host1x_syncpt *sp)
527 {
528 	kref_get(&sp->ref);
529 
530 	return sp;
531 }
532 EXPORT_SYMBOL(host1x_syncpt_get);
533 
534 /**
535  * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
536  * @sp: host1x syncpoint
537  */
host1x_syncpt_get_base(struct host1x_syncpt * sp)538 struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
539 {
540 	return sp ? sp->base : NULL;
541 }
542 EXPORT_SYMBOL(host1x_syncpt_get_base);
543 
544 /**
545  * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
546  * @base: host1x syncpoint wait base
547  */
host1x_syncpt_base_id(struct host1x_syncpt_base * base)548 u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
549 {
550 	return base->id;
551 }
552 EXPORT_SYMBOL(host1x_syncpt_base_id);
553 
do_nothing(struct kref * ref)554 static void do_nothing(struct kref *ref)
555 {
556 }
557 
558 /**
559  * host1x_syncpt_release_vblank_reservation() - Make VBLANK syncpoint
560  *   available for allocation
561  *
562  * @client: host1x bus client
563  * @syncpt_id: syncpoint ID to make available
564  *
565  * Makes VBLANK<i> syncpoint available for allocatation if it was
566  * reserved at initialization time. This should be called by the display
567  * driver after it has ensured that any VBLANK increment programming configured
568  * by the boot chain has been disabled.
569  */
host1x_syncpt_release_vblank_reservation(struct host1x_client * client,u32 syncpt_id)570 void host1x_syncpt_release_vblank_reservation(struct host1x_client *client,
571 					      u32 syncpt_id)
572 {
573 	struct host1x *host = dev_get_drvdata(client->host->parent);
574 
575 	if (!host->info->reserve_vblank_syncpts)
576 		return;
577 
578 	kref_put(&host->syncpt[syncpt_id].ref, do_nothing);
579 }
580 EXPORT_SYMBOL(host1x_syncpt_release_vblank_reservation);
581