xref: /openbmc/linux/drivers/gpu/host1x/syncpt.c (revision 98ddec80)
1 /*
2  * Tegra host1x Syncpoints
3  *
4  * Copyright (c) 2010-2015, NVIDIA Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include <linux/module.h>
20 #include <linux/device.h>
21 #include <linux/slab.h>
22 
23 #include <trace/events/host1x.h>
24 
25 #include "syncpt.h"
26 #include "dev.h"
27 #include "intr.h"
28 #include "debug.h"
29 
30 #define SYNCPT_CHECK_PERIOD (2 * HZ)
31 #define MAX_STUCK_CHECK_COUNT 15
32 
33 static struct host1x_syncpt_base *
34 host1x_syncpt_base_request(struct host1x *host)
35 {
36 	struct host1x_syncpt_base *bases = host->bases;
37 	unsigned int i;
38 
39 	for (i = 0; i < host->info->nb_bases; i++)
40 		if (!bases[i].requested)
41 			break;
42 
43 	if (i >= host->info->nb_bases)
44 		return NULL;
45 
46 	bases[i].requested = true;
47 	return &bases[i];
48 }
49 
50 static void host1x_syncpt_base_free(struct host1x_syncpt_base *base)
51 {
52 	if (base)
53 		base->requested = false;
54 }
55 
56 static struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
57 						 struct host1x_client *client,
58 						 unsigned long flags)
59 {
60 	struct host1x_syncpt *sp = host->syncpt;
61 	unsigned int i;
62 	char *name;
63 
64 	mutex_lock(&host->syncpt_mutex);
65 
66 	for (i = 0; i < host->info->nb_pts && sp->name; i++, sp++)
67 		;
68 
69 	if (i >= host->info->nb_pts)
70 		goto unlock;
71 
72 	if (flags & HOST1X_SYNCPT_HAS_BASE) {
73 		sp->base = host1x_syncpt_base_request(host);
74 		if (!sp->base)
75 			goto unlock;
76 	}
77 
78 	name = kasprintf(GFP_KERNEL, "%02u-%s", sp->id,
79 			 client ? dev_name(client->dev) : NULL);
80 	if (!name)
81 		goto free_base;
82 
83 	sp->client = client;
84 	sp->name = name;
85 
86 	if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
87 		sp->client_managed = true;
88 	else
89 		sp->client_managed = false;
90 
91 	mutex_unlock(&host->syncpt_mutex);
92 	return sp;
93 
94 free_base:
95 	host1x_syncpt_base_free(sp->base);
96 	sp->base = NULL;
97 unlock:
98 	mutex_unlock(&host->syncpt_mutex);
99 	return NULL;
100 }
101 
102 /**
103  * host1x_syncpt_id() - retrieve syncpoint ID
104  * @sp: host1x syncpoint
105  *
106  * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
107  * often used as a value to program into registers that control how hardware
108  * blocks interact with syncpoints.
109  */
110 u32 host1x_syncpt_id(struct host1x_syncpt *sp)
111 {
112 	return sp->id;
113 }
114 EXPORT_SYMBOL(host1x_syncpt_id);
115 
116 /**
117  * host1x_syncpt_incr_max() - update the value sent to hardware
118  * @sp: host1x syncpoint
119  * @incrs: number of increments
120  */
121 u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
122 {
123 	return (u32)atomic_add_return(incrs, &sp->max_val);
124 }
125 EXPORT_SYMBOL(host1x_syncpt_incr_max);
126 
127  /*
128  * Write cached syncpoint and waitbase values to hardware.
129  */
130 void host1x_syncpt_restore(struct host1x *host)
131 {
132 	struct host1x_syncpt *sp_base = host->syncpt;
133 	unsigned int i;
134 
135 	for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
136 		host1x_hw_syncpt_restore(host, sp_base + i);
137 
138 	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
139 		host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
140 
141 	wmb();
142 }
143 
144 /*
145  * Update the cached syncpoint and waitbase values by reading them
146  * from the registers.
147   */
148 void host1x_syncpt_save(struct host1x *host)
149 {
150 	struct host1x_syncpt *sp_base = host->syncpt;
151 	unsigned int i;
152 
153 	for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
154 		if (host1x_syncpt_client_managed(sp_base + i))
155 			host1x_hw_syncpt_load(host, sp_base + i);
156 		else
157 			WARN_ON(!host1x_syncpt_idle(sp_base + i));
158 	}
159 
160 	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
161 		host1x_hw_syncpt_load_wait_base(host, sp_base + i);
162 }
163 
164 /*
165  * Updates the cached syncpoint value by reading a new value from the hardware
166  * register
167  */
168 u32 host1x_syncpt_load(struct host1x_syncpt *sp)
169 {
170 	u32 val;
171 
172 	val = host1x_hw_syncpt_load(sp->host, sp);
173 	trace_host1x_syncpt_load_min(sp->id, val);
174 
175 	return val;
176 }
177 
178 /*
179  * Get the current syncpoint base
180  */
181 u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
182 {
183 	host1x_hw_syncpt_load_wait_base(sp->host, sp);
184 
185 	return sp->base_val;
186 }
187 
188 /**
189  * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
190  * @sp: host1x syncpoint
191  */
192 int host1x_syncpt_incr(struct host1x_syncpt *sp)
193 {
194 	return host1x_hw_syncpt_cpu_incr(sp->host, sp);
195 }
196 EXPORT_SYMBOL(host1x_syncpt_incr);
197 
198 /*
199  * Updated sync point form hardware, and returns true if syncpoint is expired,
200  * false if we may need to wait
201  */
202 static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
203 {
204 	host1x_hw_syncpt_load(sp->host, sp);
205 
206 	return host1x_syncpt_is_expired(sp, thresh);
207 }
208 
209 /**
210  * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
211  * @sp: host1x syncpoint
212  * @thresh: threshold
213  * @timeout: maximum time to wait for the syncpoint to reach the given value
214  * @value: return location for the syncpoint value
215  */
216 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
217 		       u32 *value)
218 {
219 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
220 	void *ref;
221 	struct host1x_waitlist *waiter;
222 	int err = 0, check_count = 0;
223 	u32 val;
224 
225 	if (value)
226 		*value = 0;
227 
228 	/* first check cache */
229 	if (host1x_syncpt_is_expired(sp, thresh)) {
230 		if (value)
231 			*value = host1x_syncpt_load(sp);
232 
233 		return 0;
234 	}
235 
236 	/* try to read from register */
237 	val = host1x_hw_syncpt_load(sp->host, sp);
238 	if (host1x_syncpt_is_expired(sp, thresh)) {
239 		if (value)
240 			*value = val;
241 
242 		goto done;
243 	}
244 
245 	if (!timeout) {
246 		err = -EAGAIN;
247 		goto done;
248 	}
249 
250 	/* allocate a waiter */
251 	waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
252 	if (!waiter) {
253 		err = -ENOMEM;
254 		goto done;
255 	}
256 
257 	/* schedule a wakeup when the syncpoint value is reached */
258 	err = host1x_intr_add_action(sp->host, sp, thresh,
259 				     HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
260 				     &wq, waiter, &ref);
261 	if (err)
262 		goto done;
263 
264 	err = -EAGAIN;
265 	/* Caller-specified timeout may be impractically low */
266 	if (timeout < 0)
267 		timeout = LONG_MAX;
268 
269 	/* wait for the syncpoint, or timeout, or signal */
270 	while (timeout) {
271 		long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
272 		int remain;
273 
274 		remain = wait_event_interruptible_timeout(wq,
275 				syncpt_load_min_is_expired(sp, thresh),
276 				check);
277 		if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
278 			if (value)
279 				*value = host1x_syncpt_load(sp);
280 
281 			err = 0;
282 
283 			break;
284 		}
285 
286 		if (remain < 0) {
287 			err = remain;
288 			break;
289 		}
290 
291 		timeout -= check;
292 
293 		if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
294 			dev_warn(sp->host->dev,
295 				"%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
296 				 current->comm, sp->id, sp->name,
297 				 thresh, timeout);
298 
299 			host1x_debug_dump_syncpts(sp->host);
300 
301 			if (check_count == MAX_STUCK_CHECK_COUNT)
302 				host1x_debug_dump(sp->host);
303 
304 			check_count++;
305 		}
306 	}
307 
308 	host1x_intr_put_ref(sp->host, sp->id, ref);
309 
310 done:
311 	return err;
312 }
313 EXPORT_SYMBOL(host1x_syncpt_wait);
314 
315 /*
316  * Returns true if syncpoint is expired, false if we may need to wait
317  */
318 bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
319 {
320 	u32 current_val;
321 	u32 future_val;
322 
323 	smp_rmb();
324 
325 	current_val = (u32)atomic_read(&sp->min_val);
326 	future_val = (u32)atomic_read(&sp->max_val);
327 
328 	/* Note the use of unsigned arithmetic here (mod 1<<32).
329 	 *
330 	 * c = current_val = min_val	= the current value of the syncpoint.
331 	 * t = thresh			= the value we are checking
332 	 * f = future_val  = max_val	= the value c will reach when all
333 	 *				  outstanding increments have completed.
334 	 *
335 	 * Note that c always chases f until it reaches f.
336 	 *
337 	 * Dtf = (f - t)
338 	 * Dtc = (c - t)
339 	 *
340 	 *  Consider all cases:
341 	 *
342 	 *	A) .....c..t..f.....	Dtf < Dtc	need to wait
343 	 *	B) .....c.....f..t..	Dtf > Dtc	expired
344 	 *	C) ..t..c.....f.....	Dtf > Dtc	expired	   (Dct very large)
345 	 *
346 	 *  Any case where f==c: always expired (for any t).	Dtf == Dcf
347 	 *  Any case where t==c: always expired (for any f).	Dtf >= Dtc (because Dtc==0)
348 	 *  Any case where t==f!=c: always wait.		Dtf <  Dtc (because Dtf==0,
349 	 *							Dtc!=0)
350 	 *
351 	 *  Other cases:
352 	 *
353 	 *	A) .....t..f..c.....	Dtf < Dtc	need to wait
354 	 *	A) .....f..c..t.....	Dtf < Dtc	need to wait
355 	 *	A) .....f..t..c.....	Dtf > Dtc	expired
356 	 *
357 	 *   So:
358 	 *	   Dtf >= Dtc implies EXPIRED	(return true)
359 	 *	   Dtf <  Dtc implies WAIT	(return false)
360 	 *
361 	 * Note: If t is expired then we *cannot* wait on it. We would wait
362 	 * forever (hang the system).
363 	 *
364 	 * Note: do NOT get clever and remove the -thresh from both sides. It
365 	 * is NOT the same.
366 	 *
367 	 * If future valueis zero, we have a client managed sync point. In that
368 	 * case we do a direct comparison.
369 	 */
370 	if (!host1x_syncpt_client_managed(sp))
371 		return future_val - thresh >= current_val - thresh;
372 	else
373 		return (s32)(current_val - thresh) >= 0;
374 }
375 
376 int host1x_syncpt_init(struct host1x *host)
377 {
378 	struct host1x_syncpt_base *bases;
379 	struct host1x_syncpt *syncpt;
380 	unsigned int i;
381 
382 	syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
383 			      GFP_KERNEL);
384 	if (!syncpt)
385 		return -ENOMEM;
386 
387 	bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
388 			     GFP_KERNEL);
389 	if (!bases)
390 		return -ENOMEM;
391 
392 	for (i = 0; i < host->info->nb_pts; i++) {
393 		syncpt[i].id = i;
394 		syncpt[i].host = host;
395 
396 		/*
397 		 * Unassign syncpt from channels for purposes of Tegra186
398 		 * syncpoint protection. This prevents any channel from
399 		 * accessing it until it is reassigned.
400 		 */
401 		host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
402 	}
403 
404 	for (i = 0; i < host->info->nb_bases; i++)
405 		bases[i].id = i;
406 
407 	mutex_init(&host->syncpt_mutex);
408 	host->syncpt = syncpt;
409 	host->bases = bases;
410 
411 	host1x_syncpt_restore(host);
412 	host1x_hw_syncpt_enable_protection(host);
413 
414 	/* Allocate sync point to use for clearing waits for expired fences */
415 	host->nop_sp = host1x_syncpt_alloc(host, NULL, 0);
416 	if (!host->nop_sp)
417 		return -ENOMEM;
418 
419 	return 0;
420 }
421 
422 /**
423  * host1x_syncpt_request() - request a syncpoint
424  * @client: client requesting the syncpoint
425  * @flags: flags
426  *
427  * host1x client drivers can use this function to allocate a syncpoint for
428  * subsequent use. A syncpoint returned by this function will be reserved for
429  * use by the client exclusively. When no longer using a syncpoint, a host1x
430  * client driver needs to release it using host1x_syncpt_free().
431  */
432 struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
433 					    unsigned long flags)
434 {
435 	struct host1x *host = dev_get_drvdata(client->parent->parent);
436 
437 	return host1x_syncpt_alloc(host, client, flags);
438 }
439 EXPORT_SYMBOL(host1x_syncpt_request);
440 
441 /**
442  * host1x_syncpt_free() - free a requested syncpoint
443  * @sp: host1x syncpoint
444  *
445  * Release a syncpoint previously allocated using host1x_syncpt_request(). A
446  * host1x client driver should call this when the syncpoint is no longer in
447  * use. Note that client drivers must ensure that the syncpoint doesn't remain
448  * under the control of hardware after calling this function, otherwise two
449  * clients may end up trying to access the same syncpoint concurrently.
450  */
451 void host1x_syncpt_free(struct host1x_syncpt *sp)
452 {
453 	if (!sp)
454 		return;
455 
456 	mutex_lock(&sp->host->syncpt_mutex);
457 
458 	host1x_syncpt_base_free(sp->base);
459 	kfree(sp->name);
460 	sp->base = NULL;
461 	sp->client = NULL;
462 	sp->name = NULL;
463 	sp->client_managed = false;
464 
465 	mutex_unlock(&sp->host->syncpt_mutex);
466 }
467 EXPORT_SYMBOL(host1x_syncpt_free);
468 
469 void host1x_syncpt_deinit(struct host1x *host)
470 {
471 	struct host1x_syncpt *sp = host->syncpt;
472 	unsigned int i;
473 
474 	for (i = 0; i < host->info->nb_pts; i++, sp++)
475 		kfree(sp->name);
476 }
477 
478 /**
479  * host1x_syncpt_read_max() - read maximum syncpoint value
480  * @sp: host1x syncpoint
481  *
482  * The maximum syncpoint value indicates how many operations there are in
483  * queue, either in channel or in a software thread.
484  */
485 u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
486 {
487 	smp_rmb();
488 
489 	return (u32)atomic_read(&sp->max_val);
490 }
491 EXPORT_SYMBOL(host1x_syncpt_read_max);
492 
493 /**
494  * host1x_syncpt_read_min() - read minimum syncpoint value
495  * @sp: host1x syncpoint
496  *
497  * The minimum syncpoint value is a shadow of the current sync point value in
498  * hardware.
499  */
500 u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
501 {
502 	smp_rmb();
503 
504 	return (u32)atomic_read(&sp->min_val);
505 }
506 EXPORT_SYMBOL(host1x_syncpt_read_min);
507 
508 /**
509  * host1x_syncpt_read() - read the current syncpoint value
510  * @sp: host1x syncpoint
511  */
512 u32 host1x_syncpt_read(struct host1x_syncpt *sp)
513 {
514 	return host1x_syncpt_load(sp);
515 }
516 EXPORT_SYMBOL(host1x_syncpt_read);
517 
518 unsigned int host1x_syncpt_nb_pts(struct host1x *host)
519 {
520 	return host->info->nb_pts;
521 }
522 
523 unsigned int host1x_syncpt_nb_bases(struct host1x *host)
524 {
525 	return host->info->nb_bases;
526 }
527 
528 unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
529 {
530 	return host->info->nb_mlocks;
531 }
532 
533 /**
534  * host1x_syncpt_get() - obtain a syncpoint by ID
535  * @host: host1x controller
536  * @id: syncpoint ID
537  */
538 struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
539 {
540 	if (id >= host->info->nb_pts)
541 		return NULL;
542 
543 	return host->syncpt + id;
544 }
545 EXPORT_SYMBOL(host1x_syncpt_get);
546 
547 /**
548  * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
549  * @sp: host1x syncpoint
550  */
551 struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
552 {
553 	return sp ? sp->base : NULL;
554 }
555 EXPORT_SYMBOL(host1x_syncpt_get_base);
556 
557 /**
558  * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
559  * @base: host1x syncpoint wait base
560  */
561 u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
562 {
563 	return base->id;
564 }
565 EXPORT_SYMBOL(host1x_syncpt_base_id);
566