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 	trace_dma_fence_emit(&fence->base);
228 	ret = fctx->emit(fence);
229 	if (!ret) {
230 		dma_fence_get(&fence->base);
231 		spin_lock_irq(&fctx->lock);
232 
233 		if (nouveau_fence_update(chan, fctx))
234 			nvif_notify_put(&fctx->notify);
235 
236 		list_add_tail(&fence->head, &fctx->pending);
237 		spin_unlock_irq(&fctx->lock);
238 	}
239 
240 	return ret;
241 }
242 
243 bool
244 nouveau_fence_done(struct nouveau_fence *fence)
245 {
246 	if (fence->base.ops == &nouveau_fence_ops_legacy ||
247 	    fence->base.ops == &nouveau_fence_ops_uevent) {
248 		struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
249 		struct nouveau_channel *chan;
250 		unsigned long flags;
251 
252 		if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags))
253 			return true;
254 
255 		spin_lock_irqsave(&fctx->lock, flags);
256 		chan = rcu_dereference_protected(fence->channel, lockdep_is_held(&fctx->lock));
257 		if (chan && nouveau_fence_update(chan, fctx))
258 			nvif_notify_put(&fctx->notify);
259 		spin_unlock_irqrestore(&fctx->lock, flags);
260 	}
261 	return dma_fence_is_signaled(&fence->base);
262 }
263 
264 static long
265 nouveau_fence_wait_legacy(struct dma_fence *f, bool intr, long wait)
266 {
267 	struct nouveau_fence *fence = from_fence(f);
268 	unsigned long sleep_time = NSEC_PER_MSEC / 1000;
269 	unsigned long t = jiffies, timeout = t + wait;
270 
271 	while (!nouveau_fence_done(fence)) {
272 		ktime_t kt;
273 
274 		t = jiffies;
275 
276 		if (wait != MAX_SCHEDULE_TIMEOUT && time_after_eq(t, timeout)) {
277 			__set_current_state(TASK_RUNNING);
278 			return 0;
279 		}
280 
281 		__set_current_state(intr ? TASK_INTERRUPTIBLE :
282 					   TASK_UNINTERRUPTIBLE);
283 
284 		kt = sleep_time;
285 		schedule_hrtimeout(&kt, HRTIMER_MODE_REL);
286 		sleep_time *= 2;
287 		if (sleep_time > NSEC_PER_MSEC)
288 			sleep_time = NSEC_PER_MSEC;
289 
290 		if (intr && signal_pending(current))
291 			return -ERESTARTSYS;
292 	}
293 
294 	__set_current_state(TASK_RUNNING);
295 
296 	return timeout - t;
297 }
298 
299 static int
300 nouveau_fence_wait_busy(struct nouveau_fence *fence, bool intr)
301 {
302 	int ret = 0;
303 
304 	while (!nouveau_fence_done(fence)) {
305 		if (time_after_eq(jiffies, fence->timeout)) {
306 			ret = -EBUSY;
307 			break;
308 		}
309 
310 		__set_current_state(intr ?
311 				    TASK_INTERRUPTIBLE :
312 				    TASK_UNINTERRUPTIBLE);
313 
314 		if (intr && signal_pending(current)) {
315 			ret = -ERESTARTSYS;
316 			break;
317 		}
318 	}
319 
320 	__set_current_state(TASK_RUNNING);
321 	return ret;
322 }
323 
324 int
325 nouveau_fence_wait(struct nouveau_fence *fence, bool lazy, bool intr)
326 {
327 	long ret;
328 
329 	if (!lazy)
330 		return nouveau_fence_wait_busy(fence, intr);
331 
332 	ret = dma_fence_wait_timeout(&fence->base, intr, 15 * HZ);
333 	if (ret < 0)
334 		return ret;
335 	else if (!ret)
336 		return -EBUSY;
337 	else
338 		return 0;
339 }
340 
341 int
342 nouveau_fence_sync(struct nouveau_bo *nvbo, struct nouveau_channel *chan,
343 		   bool exclusive, bool intr)
344 {
345 	struct nouveau_fence_chan *fctx = chan->fence;
346 	struct dma_resv *resv = nvbo->bo.base.resv;
347 	int i, ret;
348 
349 	ret = dma_resv_reserve_fences(resv, 1);
350 	if (ret)
351 		return ret;
352 
353 	/* Waiting for the writes first causes performance regressions
354 	 * under some circumstances. So manually wait for the reads first.
355 	 */
356 	for (i = 0; i < 2; ++i) {
357 		struct dma_resv_iter cursor;
358 		struct dma_fence *fence;
359 
360 		dma_resv_for_each_fence(&cursor, resv,
361 					dma_resv_usage_rw(exclusive),
362 					fence) {
363 			enum dma_resv_usage usage;
364 			struct nouveau_fence *f;
365 
366 			usage = dma_resv_iter_usage(&cursor);
367 			if (i == 0 && usage == DMA_RESV_USAGE_WRITE)
368 				continue;
369 
370 			f = nouveau_local_fence(fence, chan->drm);
371 			if (f) {
372 				struct nouveau_channel *prev;
373 				bool must_wait = true;
374 
375 				rcu_read_lock();
376 				prev = rcu_dereference(f->channel);
377 				if (prev && (prev == chan ||
378 					     fctx->sync(f, prev, chan) == 0))
379 					must_wait = false;
380 				rcu_read_unlock();
381 				if (!must_wait)
382 					continue;
383 			}
384 
385 			ret = dma_fence_wait(fence, intr);
386 			if (ret)
387 				return ret;
388 		}
389 	}
390 
391 	return 0;
392 }
393 
394 void
395 nouveau_fence_unref(struct nouveau_fence **pfence)
396 {
397 	if (*pfence)
398 		dma_fence_put(&(*pfence)->base);
399 	*pfence = NULL;
400 }
401 
402 int
403 nouveau_fence_new(struct nouveau_channel *chan, bool sysmem,
404 		  struct nouveau_fence **pfence)
405 {
406 	struct nouveau_fence *fence;
407 	int ret = 0;
408 
409 	if (unlikely(!chan->fence))
410 		return -ENODEV;
411 
412 	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
413 	if (!fence)
414 		return -ENOMEM;
415 
416 	ret = nouveau_fence_emit(fence, chan);
417 	if (ret)
418 		nouveau_fence_unref(&fence);
419 
420 	*pfence = fence;
421 	return ret;
422 }
423 
424 static const char *nouveau_fence_get_get_driver_name(struct dma_fence *fence)
425 {
426 	return "nouveau";
427 }
428 
429 static const char *nouveau_fence_get_timeline_name(struct dma_fence *f)
430 {
431 	struct nouveau_fence *fence = from_fence(f);
432 	struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
433 
434 	return !fctx->dead ? fctx->name : "dead channel";
435 }
436 
437 /*
438  * In an ideal world, read would not assume the channel context is still alive.
439  * This function may be called from another device, running into free memory as a
440  * result. The drm node should still be there, so we can derive the index from
441  * the fence context.
442  */
443 static bool nouveau_fence_is_signaled(struct dma_fence *f)
444 {
445 	struct nouveau_fence *fence = from_fence(f);
446 	struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
447 	struct nouveau_channel *chan;
448 	bool ret = false;
449 
450 	rcu_read_lock();
451 	chan = rcu_dereference(fence->channel);
452 	if (chan)
453 		ret = (int)(fctx->read(chan) - fence->base.seqno) >= 0;
454 	rcu_read_unlock();
455 
456 	return ret;
457 }
458 
459 static bool nouveau_fence_no_signaling(struct dma_fence *f)
460 {
461 	struct nouveau_fence *fence = from_fence(f);
462 
463 	/*
464 	 * caller should have a reference on the fence,
465 	 * else fence could get freed here
466 	 */
467 	WARN_ON(kref_read(&fence->base.refcount) <= 1);
468 
469 	/*
470 	 * This needs uevents to work correctly, but dma_fence_add_callback relies on
471 	 * being able to enable signaling. It will still get signaled eventually,
472 	 * just not right away.
473 	 */
474 	if (nouveau_fence_is_signaled(f)) {
475 		list_del(&fence->head);
476 
477 		dma_fence_put(&fence->base);
478 		return false;
479 	}
480 
481 	return true;
482 }
483 
484 static void nouveau_fence_release(struct dma_fence *f)
485 {
486 	struct nouveau_fence *fence = from_fence(f);
487 	struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
488 
489 	kref_put(&fctx->fence_ref, nouveau_fence_context_put);
490 	dma_fence_free(&fence->base);
491 }
492 
493 static const struct dma_fence_ops nouveau_fence_ops_legacy = {
494 	.get_driver_name = nouveau_fence_get_get_driver_name,
495 	.get_timeline_name = nouveau_fence_get_timeline_name,
496 	.enable_signaling = nouveau_fence_no_signaling,
497 	.signaled = nouveau_fence_is_signaled,
498 	.wait = nouveau_fence_wait_legacy,
499 	.release = nouveau_fence_release
500 };
501 
502 static bool nouveau_fence_enable_signaling(struct dma_fence *f)
503 {
504 	struct nouveau_fence *fence = from_fence(f);
505 	struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
506 	bool ret;
507 
508 	if (!fctx->notify_ref++)
509 		nvif_notify_get(&fctx->notify);
510 
511 	ret = nouveau_fence_no_signaling(f);
512 	if (ret)
513 		set_bit(DMA_FENCE_FLAG_USER_BITS, &fence->base.flags);
514 	else if (!--fctx->notify_ref)
515 		nvif_notify_put(&fctx->notify);
516 
517 	return ret;
518 }
519 
520 static const struct dma_fence_ops nouveau_fence_ops_uevent = {
521 	.get_driver_name = nouveau_fence_get_get_driver_name,
522 	.get_timeline_name = nouveau_fence_get_timeline_name,
523 	.enable_signaling = nouveau_fence_enable_signaling,
524 	.signaled = nouveau_fence_is_signaled,
525 	.release = nouveau_fence_release
526 };
527