1 /*
2  * Copyright (C) 2007 Ben Skeggs.
3  * All Rights Reserved.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining
6  * a copy of this software and associated documentation files (the
7  * "Software"), to deal in the Software without restriction, including
8  * without limitation the rights to use, copy, modify, merge, publish,
9  * distribute, sublicense, and/or sell copies of the Software, and to
10  * permit persons to whom the Software is furnished to do so, subject to
11  * the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the
14  * next paragraph) shall be included in all copies or substantial
15  * portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
20  * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
21  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
22  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
23  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24  *
25  */
26 
27 #include <linux/ktime.h>
28 #include <linux/hrtimer.h>
29 #include <linux/sched/signal.h>
30 #include <trace/events/dma_fence.h>
31 
32 #include <nvif/cl826e.h>
33 #include <nvif/notify.h>
34 #include <nvif/event.h>
35 
36 #include "nouveau_drv.h"
37 #include "nouveau_dma.h"
38 #include "nouveau_fence.h"
39 
40 static const struct dma_fence_ops nouveau_fence_ops_uevent;
41 static const struct dma_fence_ops nouveau_fence_ops_legacy;
42 
43 static inline struct nouveau_fence *
44 from_fence(struct dma_fence *fence)
45 {
46 	return container_of(fence, struct nouveau_fence, base);
47 }
48 
49 static inline struct nouveau_fence_chan *
50 nouveau_fctx(struct nouveau_fence *fence)
51 {
52 	return container_of(fence->base.lock, struct nouveau_fence_chan, lock);
53 }
54 
55 static int
56 nouveau_fence_signal(struct nouveau_fence *fence)
57 {
58 	int drop = 0;
59 
60 	dma_fence_signal_locked(&fence->base);
61 	list_del(&fence->head);
62 	rcu_assign_pointer(fence->channel, NULL);
63 
64 	if (test_bit(DMA_FENCE_FLAG_USER_BITS, &fence->base.flags)) {
65 		struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
66 
67 		if (!--fctx->notify_ref)
68 			drop = 1;
69 	}
70 
71 	dma_fence_put(&fence->base);
72 	return drop;
73 }
74 
75 static struct nouveau_fence *
76 nouveau_local_fence(struct dma_fence *fence, struct nouveau_drm *drm)
77 {
78 	if (fence->ops != &nouveau_fence_ops_legacy &&
79 	    fence->ops != &nouveau_fence_ops_uevent)
80 		return NULL;
81 
82 	if (fence->context < drm->chan.context_base ||
83 	    fence->context >= drm->chan.context_base + drm->chan.nr)
84 		return NULL;
85 
86 	return from_fence(fence);
87 }
88 
89 void
90 nouveau_fence_context_kill(struct nouveau_fence_chan *fctx, int error)
91 {
92 	struct nouveau_fence *fence;
93 
94 	spin_lock_irq(&fctx->lock);
95 	while (!list_empty(&fctx->pending)) {
96 		fence = list_entry(fctx->pending.next, typeof(*fence), head);
97 
98 		if (error)
99 			dma_fence_set_error(&fence->base, error);
100 
101 		if (nouveau_fence_signal(fence))
102 			nvif_notify_put(&fctx->notify);
103 	}
104 	spin_unlock_irq(&fctx->lock);
105 }
106 
107 void
108 nouveau_fence_context_del(struct nouveau_fence_chan *fctx)
109 {
110 	nouveau_fence_context_kill(fctx, 0);
111 	nvif_notify_dtor(&fctx->notify);
112 	fctx->dead = 1;
113 
114 	/*
115 	 * Ensure that all accesses to fence->channel complete before freeing
116 	 * the channel.
117 	 */
118 	synchronize_rcu();
119 }
120 
121 static void
122 nouveau_fence_context_put(struct kref *fence_ref)
123 {
124 	kfree(container_of(fence_ref, struct nouveau_fence_chan, fence_ref));
125 }
126 
127 void
128 nouveau_fence_context_free(struct nouveau_fence_chan *fctx)
129 {
130 	kref_put(&fctx->fence_ref, nouveau_fence_context_put);
131 }
132 
133 static int
134 nouveau_fence_update(struct nouveau_channel *chan, struct nouveau_fence_chan *fctx)
135 {
136 	struct nouveau_fence *fence;
137 	int drop = 0;
138 	u32 seq = fctx->read(chan);
139 
140 	while (!list_empty(&fctx->pending)) {
141 		fence = list_entry(fctx->pending.next, typeof(*fence), head);
142 
143 		if ((int)(seq - fence->base.seqno) < 0)
144 			break;
145 
146 		drop |= nouveau_fence_signal(fence);
147 	}
148 
149 	return drop;
150 }
151 
152 static int
153 nouveau_fence_wait_uevent_handler(struct nvif_notify *notify)
154 {
155 	struct nouveau_fence_chan *fctx =
156 		container_of(notify, typeof(*fctx), notify);
157 	unsigned long flags;
158 	int ret = NVIF_NOTIFY_KEEP;
159 
160 	spin_lock_irqsave(&fctx->lock, flags);
161 	if (!list_empty(&fctx->pending)) {
162 		struct nouveau_fence *fence;
163 		struct nouveau_channel *chan;
164 
165 		fence = list_entry(fctx->pending.next, typeof(*fence), head);
166 		chan = rcu_dereference_protected(fence->channel, lockdep_is_held(&fctx->lock));
167 		if (nouveau_fence_update(chan, fctx))
168 			ret = NVIF_NOTIFY_DROP;
169 	}
170 	spin_unlock_irqrestore(&fctx->lock, flags);
171 
172 	return ret;
173 }
174 
175 void
176 nouveau_fence_context_new(struct nouveau_channel *chan, struct nouveau_fence_chan *fctx)
177 {
178 	struct nouveau_fence_priv *priv = (void*)chan->drm->fence;
179 	struct nouveau_cli *cli = (void *)chan->user.client;
180 	int ret;
181 
182 	INIT_LIST_HEAD(&fctx->flip);
183 	INIT_LIST_HEAD(&fctx->pending);
184 	spin_lock_init(&fctx->lock);
185 	fctx->context = chan->drm->chan.context_base + chan->chid;
186 
187 	if (chan == chan->drm->cechan)
188 		strcpy(fctx->name, "copy engine channel");
189 	else if (chan == chan->drm->channel)
190 		strcpy(fctx->name, "generic kernel channel");
191 	else
192 		strcpy(fctx->name, nvxx_client(&cli->base)->name);
193 
194 	kref_init(&fctx->fence_ref);
195 	if (!priv->uevent)
196 		return;
197 
198 	ret = nvif_notify_ctor(&chan->user, "fenceNonStallIntr",
199 			       nouveau_fence_wait_uevent_handler,
200 			       false, NV826E_V0_NTFY_NON_STALL_INTERRUPT,
201 			       &(struct nvif_notify_uevent_req) { },
202 			       sizeof(struct nvif_notify_uevent_req),
203 			       sizeof(struct nvif_notify_uevent_rep),
204 			       &fctx->notify);
205 
206 	WARN_ON(ret);
207 }
208 
209 int
210 nouveau_fence_emit(struct nouveau_fence *fence, struct nouveau_channel *chan)
211 {
212 	struct nouveau_fence_chan *fctx = chan->fence;
213 	struct nouveau_fence_priv *priv = (void*)chan->drm->fence;
214 	int ret;
215 
216 	fence->channel  = chan;
217 	fence->timeout  = jiffies + (15 * HZ);
218 
219 	if (priv->uevent)
220 		dma_fence_init(&fence->base, &nouveau_fence_ops_uevent,
221 			       &fctx->lock, fctx->context, ++fctx->sequence);
222 	else
223 		dma_fence_init(&fence->base, &nouveau_fence_ops_legacy,
224 			       &fctx->lock, fctx->context, ++fctx->sequence);
225 	kref_get(&fctx->fence_ref);
226 
227 	ret = fctx->emit(fence);
228 	if (!ret) {
229 		dma_fence_get(&fence->base);
230 		spin_lock_irq(&fctx->lock);
231 
232 		if (nouveau_fence_update(chan, fctx))
233 			nvif_notify_put(&fctx->notify);
234 
235 		list_add_tail(&fence->head, &fctx->pending);
236 		spin_unlock_irq(&fctx->lock);
237 	}
238 
239 	return ret;
240 }
241 
242 bool
243 nouveau_fence_done(struct nouveau_fence *fence)
244 {
245 	if (fence->base.ops == &nouveau_fence_ops_legacy ||
246 	    fence->base.ops == &nouveau_fence_ops_uevent) {
247 		struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
248 		struct nouveau_channel *chan;
249 		unsigned long flags;
250 
251 		if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags))
252 			return true;
253 
254 		spin_lock_irqsave(&fctx->lock, flags);
255 		chan = rcu_dereference_protected(fence->channel, lockdep_is_held(&fctx->lock));
256 		if (chan && nouveau_fence_update(chan, fctx))
257 			nvif_notify_put(&fctx->notify);
258 		spin_unlock_irqrestore(&fctx->lock, flags);
259 	}
260 	return dma_fence_is_signaled(&fence->base);
261 }
262 
263 static long
264 nouveau_fence_wait_legacy(struct dma_fence *f, bool intr, long wait)
265 {
266 	struct nouveau_fence *fence = from_fence(f);
267 	unsigned long sleep_time = NSEC_PER_MSEC / 1000;
268 	unsigned long t = jiffies, timeout = t + wait;
269 
270 	while (!nouveau_fence_done(fence)) {
271 		ktime_t kt;
272 
273 		t = jiffies;
274 
275 		if (wait != MAX_SCHEDULE_TIMEOUT && time_after_eq(t, timeout)) {
276 			__set_current_state(TASK_RUNNING);
277 			return 0;
278 		}
279 
280 		__set_current_state(intr ? TASK_INTERRUPTIBLE :
281 					   TASK_UNINTERRUPTIBLE);
282 
283 		kt = sleep_time;
284 		schedule_hrtimeout(&kt, HRTIMER_MODE_REL);
285 		sleep_time *= 2;
286 		if (sleep_time > NSEC_PER_MSEC)
287 			sleep_time = NSEC_PER_MSEC;
288 
289 		if (intr && signal_pending(current))
290 			return -ERESTARTSYS;
291 	}
292 
293 	__set_current_state(TASK_RUNNING);
294 
295 	return timeout - t;
296 }
297 
298 static int
299 nouveau_fence_wait_busy(struct nouveau_fence *fence, bool intr)
300 {
301 	int ret = 0;
302 
303 	while (!nouveau_fence_done(fence)) {
304 		if (time_after_eq(jiffies, fence->timeout)) {
305 			ret = -EBUSY;
306 			break;
307 		}
308 
309 		__set_current_state(intr ?
310 				    TASK_INTERRUPTIBLE :
311 				    TASK_UNINTERRUPTIBLE);
312 
313 		if (intr && signal_pending(current)) {
314 			ret = -ERESTARTSYS;
315 			break;
316 		}
317 	}
318 
319 	__set_current_state(TASK_RUNNING);
320 	return ret;
321 }
322 
323 int
324 nouveau_fence_wait(struct nouveau_fence *fence, bool lazy, bool intr)
325 {
326 	long ret;
327 
328 	if (!lazy)
329 		return nouveau_fence_wait_busy(fence, intr);
330 
331 	ret = dma_fence_wait_timeout(&fence->base, intr, 15 * HZ);
332 	if (ret < 0)
333 		return ret;
334 	else if (!ret)
335 		return -EBUSY;
336 	else
337 		return 0;
338 }
339 
340 int
341 nouveau_fence_sync(struct nouveau_bo *nvbo, struct nouveau_channel *chan,
342 		   bool exclusive, bool intr)
343 {
344 	struct nouveau_fence_chan *fctx = chan->fence;
345 	struct dma_resv *resv = nvbo->bo.base.resv;
346 	int i, ret;
347 
348 	ret = dma_resv_reserve_fences(resv, 1);
349 	if (ret)
350 		return ret;
351 
352 	/* Waiting for the writes first causes performance regressions
353 	 * under some circumstances. So manually wait for the reads first.
354 	 */
355 	for (i = 0; i < 2; ++i) {
356 		struct dma_resv_iter cursor;
357 		struct dma_fence *fence;
358 
359 		dma_resv_for_each_fence(&cursor, resv,
360 					dma_resv_usage_rw(exclusive),
361 					fence) {
362 			enum dma_resv_usage usage;
363 			struct nouveau_fence *f;
364 
365 			usage = dma_resv_iter_usage(&cursor);
366 			if (i == 0 && usage == DMA_RESV_USAGE_WRITE)
367 				continue;
368 
369 			f = nouveau_local_fence(fence, chan->drm);
370 			if (f) {
371 				struct nouveau_channel *prev;
372 				bool must_wait = true;
373 
374 				rcu_read_lock();
375 				prev = rcu_dereference(f->channel);
376 				if (prev && (prev == chan ||
377 					     fctx->sync(f, prev, chan) == 0))
378 					must_wait = false;
379 				rcu_read_unlock();
380 				if (!must_wait)
381 					continue;
382 			}
383 
384 			ret = dma_fence_wait(fence, intr);
385 			if (ret)
386 				return ret;
387 		}
388 	}
389 
390 	return 0;
391 }
392 
393 void
394 nouveau_fence_unref(struct nouveau_fence **pfence)
395 {
396 	if (*pfence)
397 		dma_fence_put(&(*pfence)->base);
398 	*pfence = NULL;
399 }
400 
401 int
402 nouveau_fence_new(struct nouveau_channel *chan, bool sysmem,
403 		  struct nouveau_fence **pfence)
404 {
405 	struct nouveau_fence *fence;
406 	int ret = 0;
407 
408 	if (unlikely(!chan->fence))
409 		return -ENODEV;
410 
411 	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
412 	if (!fence)
413 		return -ENOMEM;
414 
415 	ret = nouveau_fence_emit(fence, chan);
416 	if (ret)
417 		nouveau_fence_unref(&fence);
418 
419 	*pfence = fence;
420 	return ret;
421 }
422 
423 static const char *nouveau_fence_get_get_driver_name(struct dma_fence *fence)
424 {
425 	return "nouveau";
426 }
427 
428 static const char *nouveau_fence_get_timeline_name(struct dma_fence *f)
429 {
430 	struct nouveau_fence *fence = from_fence(f);
431 	struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
432 
433 	return !fctx->dead ? fctx->name : "dead channel";
434 }
435 
436 /*
437  * In an ideal world, read would not assume the channel context is still alive.
438  * This function may be called from another device, running into free memory as a
439  * result. The drm node should still be there, so we can derive the index from
440  * the fence context.
441  */
442 static bool nouveau_fence_is_signaled(struct dma_fence *f)
443 {
444 	struct nouveau_fence *fence = from_fence(f);
445 	struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
446 	struct nouveau_channel *chan;
447 	bool ret = false;
448 
449 	rcu_read_lock();
450 	chan = rcu_dereference(fence->channel);
451 	if (chan)
452 		ret = (int)(fctx->read(chan) - fence->base.seqno) >= 0;
453 	rcu_read_unlock();
454 
455 	return ret;
456 }
457 
458 static bool nouveau_fence_no_signaling(struct dma_fence *f)
459 {
460 	struct nouveau_fence *fence = from_fence(f);
461 
462 	/*
463 	 * caller should have a reference on the fence,
464 	 * else fence could get freed here
465 	 */
466 	WARN_ON(kref_read(&fence->base.refcount) <= 1);
467 
468 	/*
469 	 * This needs uevents to work correctly, but dma_fence_add_callback relies on
470 	 * being able to enable signaling. It will still get signaled eventually,
471 	 * just not right away.
472 	 */
473 	if (nouveau_fence_is_signaled(f)) {
474 		list_del(&fence->head);
475 
476 		dma_fence_put(&fence->base);
477 		return false;
478 	}
479 
480 	return true;
481 }
482 
483 static void nouveau_fence_release(struct dma_fence *f)
484 {
485 	struct nouveau_fence *fence = from_fence(f);
486 	struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
487 
488 	kref_put(&fctx->fence_ref, nouveau_fence_context_put);
489 	dma_fence_free(&fence->base);
490 }
491 
492 static const struct dma_fence_ops nouveau_fence_ops_legacy = {
493 	.get_driver_name = nouveau_fence_get_get_driver_name,
494 	.get_timeline_name = nouveau_fence_get_timeline_name,
495 	.enable_signaling = nouveau_fence_no_signaling,
496 	.signaled = nouveau_fence_is_signaled,
497 	.wait = nouveau_fence_wait_legacy,
498 	.release = nouveau_fence_release
499 };
500 
501 static bool nouveau_fence_enable_signaling(struct dma_fence *f)
502 {
503 	struct nouveau_fence *fence = from_fence(f);
504 	struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
505 	bool ret;
506 
507 	if (!fctx->notify_ref++)
508 		nvif_notify_get(&fctx->notify);
509 
510 	ret = nouveau_fence_no_signaling(f);
511 	if (ret)
512 		set_bit(DMA_FENCE_FLAG_USER_BITS, &fence->base.flags);
513 	else if (!--fctx->notify_ref)
514 		nvif_notify_put(&fctx->notify);
515 
516 	return ret;
517 }
518 
519 static const struct dma_fence_ops nouveau_fence_ops_uevent = {
520 	.get_driver_name = nouveau_fence_get_get_driver_name,
521 	.get_timeline_name = nouveau_fence_get_timeline_name,
522 	.enable_signaling = nouveau_fence_enable_signaling,
523 	.signaled = nouveau_fence_is_signaled,
524 	.release = nouveau_fence_release
525 };
526