xref: /linux/drivers/gpu/drm/vc4/vc4_gem.c (revision a8b70ccf10e38775785d9cb12ead916474549f99)
1 /*
2  * Copyright © 2014 Broadcom
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the next
12  * paragraph) shall be included in all copies or substantial portions of the
13  * Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21  * IN THE SOFTWARE.
22  */
23 
24 #include <linux/module.h>
25 #include <linux/platform_device.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/device.h>
28 #include <linux/io.h>
29 #include <linux/sched/signal.h>
30 
31 #include "uapi/drm/vc4_drm.h"
32 #include "vc4_drv.h"
33 #include "vc4_regs.h"
34 #include "vc4_trace.h"
35 
36 static void
37 vc4_queue_hangcheck(struct drm_device *dev)
38 {
39 	struct vc4_dev *vc4 = to_vc4_dev(dev);
40 
41 	mod_timer(&vc4->hangcheck.timer,
42 		  round_jiffies_up(jiffies + msecs_to_jiffies(100)));
43 }
44 
45 struct vc4_hang_state {
46 	struct drm_vc4_get_hang_state user_state;
47 
48 	u32 bo_count;
49 	struct drm_gem_object **bo;
50 };
51 
52 static void
53 vc4_free_hang_state(struct drm_device *dev, struct vc4_hang_state *state)
54 {
55 	unsigned int i;
56 
57 	for (i = 0; i < state->user_state.bo_count; i++)
58 		drm_gem_object_put_unlocked(state->bo[i]);
59 
60 	kfree(state);
61 }
62 
63 int
64 vc4_get_hang_state_ioctl(struct drm_device *dev, void *data,
65 			 struct drm_file *file_priv)
66 {
67 	struct drm_vc4_get_hang_state *get_state = data;
68 	struct drm_vc4_get_hang_state_bo *bo_state;
69 	struct vc4_hang_state *kernel_state;
70 	struct drm_vc4_get_hang_state *state;
71 	struct vc4_dev *vc4 = to_vc4_dev(dev);
72 	unsigned long irqflags;
73 	u32 i;
74 	int ret = 0;
75 
76 	spin_lock_irqsave(&vc4->job_lock, irqflags);
77 	kernel_state = vc4->hang_state;
78 	if (!kernel_state) {
79 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
80 		return -ENOENT;
81 	}
82 	state = &kernel_state->user_state;
83 
84 	/* If the user's array isn't big enough, just return the
85 	 * required array size.
86 	 */
87 	if (get_state->bo_count < state->bo_count) {
88 		get_state->bo_count = state->bo_count;
89 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
90 		return 0;
91 	}
92 
93 	vc4->hang_state = NULL;
94 	spin_unlock_irqrestore(&vc4->job_lock, irqflags);
95 
96 	/* Save the user's BO pointer, so we don't stomp it with the memcpy. */
97 	state->bo = get_state->bo;
98 	memcpy(get_state, state, sizeof(*state));
99 
100 	bo_state = kcalloc(state->bo_count, sizeof(*bo_state), GFP_KERNEL);
101 	if (!bo_state) {
102 		ret = -ENOMEM;
103 		goto err_free;
104 	}
105 
106 	for (i = 0; i < state->bo_count; i++) {
107 		struct vc4_bo *vc4_bo = to_vc4_bo(kernel_state->bo[i]);
108 		u32 handle;
109 
110 		ret = drm_gem_handle_create(file_priv, kernel_state->bo[i],
111 					    &handle);
112 
113 		if (ret) {
114 			state->bo_count = i;
115 			goto err_delete_handle;
116 		}
117 		bo_state[i].handle = handle;
118 		bo_state[i].paddr = vc4_bo->base.paddr;
119 		bo_state[i].size = vc4_bo->base.base.size;
120 	}
121 
122 	if (copy_to_user(u64_to_user_ptr(get_state->bo),
123 			 bo_state,
124 			 state->bo_count * sizeof(*bo_state)))
125 		ret = -EFAULT;
126 
127 err_delete_handle:
128 	if (ret) {
129 		for (i = 0; i < state->bo_count; i++)
130 			drm_gem_handle_delete(file_priv, bo_state[i].handle);
131 	}
132 
133 err_free:
134 	vc4_free_hang_state(dev, kernel_state);
135 	kfree(bo_state);
136 
137 	return ret;
138 }
139 
140 static void
141 vc4_save_hang_state(struct drm_device *dev)
142 {
143 	struct vc4_dev *vc4 = to_vc4_dev(dev);
144 	struct drm_vc4_get_hang_state *state;
145 	struct vc4_hang_state *kernel_state;
146 	struct vc4_exec_info *exec[2];
147 	struct vc4_bo *bo;
148 	unsigned long irqflags;
149 	unsigned int i, j, k, unref_list_count;
150 
151 	kernel_state = kcalloc(1, sizeof(*kernel_state), GFP_KERNEL);
152 	if (!kernel_state)
153 		return;
154 
155 	state = &kernel_state->user_state;
156 
157 	spin_lock_irqsave(&vc4->job_lock, irqflags);
158 	exec[0] = vc4_first_bin_job(vc4);
159 	exec[1] = vc4_first_render_job(vc4);
160 	if (!exec[0] && !exec[1]) {
161 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
162 		return;
163 	}
164 
165 	/* Get the bos from both binner and renderer into hang state. */
166 	state->bo_count = 0;
167 	for (i = 0; i < 2; i++) {
168 		if (!exec[i])
169 			continue;
170 
171 		unref_list_count = 0;
172 		list_for_each_entry(bo, &exec[i]->unref_list, unref_head)
173 			unref_list_count++;
174 		state->bo_count += exec[i]->bo_count + unref_list_count;
175 	}
176 
177 	kernel_state->bo = kcalloc(state->bo_count,
178 				   sizeof(*kernel_state->bo), GFP_ATOMIC);
179 
180 	if (!kernel_state->bo) {
181 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
182 		return;
183 	}
184 
185 	k = 0;
186 	for (i = 0; i < 2; i++) {
187 		if (!exec[i])
188 			continue;
189 
190 		for (j = 0; j < exec[i]->bo_count; j++) {
191 			bo = to_vc4_bo(&exec[i]->bo[j]->base);
192 
193 			/* Retain BOs just in case they were marked purgeable.
194 			 * This prevents the BO from being purged before
195 			 * someone had a chance to dump the hang state.
196 			 */
197 			WARN_ON(!refcount_read(&bo->usecnt));
198 			refcount_inc(&bo->usecnt);
199 			drm_gem_object_get(&exec[i]->bo[j]->base);
200 			kernel_state->bo[k++] = &exec[i]->bo[j]->base;
201 		}
202 
203 		list_for_each_entry(bo, &exec[i]->unref_list, unref_head) {
204 			/* No need to retain BOs coming from the ->unref_list
205 			 * because they are naturally unpurgeable.
206 			 */
207 			drm_gem_object_get(&bo->base.base);
208 			kernel_state->bo[k++] = &bo->base.base;
209 		}
210 	}
211 
212 	WARN_ON_ONCE(k != state->bo_count);
213 
214 	if (exec[0])
215 		state->start_bin = exec[0]->ct0ca;
216 	if (exec[1])
217 		state->start_render = exec[1]->ct1ca;
218 
219 	spin_unlock_irqrestore(&vc4->job_lock, irqflags);
220 
221 	state->ct0ca = V3D_READ(V3D_CTNCA(0));
222 	state->ct0ea = V3D_READ(V3D_CTNEA(0));
223 
224 	state->ct1ca = V3D_READ(V3D_CTNCA(1));
225 	state->ct1ea = V3D_READ(V3D_CTNEA(1));
226 
227 	state->ct0cs = V3D_READ(V3D_CTNCS(0));
228 	state->ct1cs = V3D_READ(V3D_CTNCS(1));
229 
230 	state->ct0ra0 = V3D_READ(V3D_CT00RA0);
231 	state->ct1ra0 = V3D_READ(V3D_CT01RA0);
232 
233 	state->bpca = V3D_READ(V3D_BPCA);
234 	state->bpcs = V3D_READ(V3D_BPCS);
235 	state->bpoa = V3D_READ(V3D_BPOA);
236 	state->bpos = V3D_READ(V3D_BPOS);
237 
238 	state->vpmbase = V3D_READ(V3D_VPMBASE);
239 
240 	state->dbge = V3D_READ(V3D_DBGE);
241 	state->fdbgo = V3D_READ(V3D_FDBGO);
242 	state->fdbgb = V3D_READ(V3D_FDBGB);
243 	state->fdbgr = V3D_READ(V3D_FDBGR);
244 	state->fdbgs = V3D_READ(V3D_FDBGS);
245 	state->errstat = V3D_READ(V3D_ERRSTAT);
246 
247 	/* We need to turn purgeable BOs into unpurgeable ones so that
248 	 * userspace has a chance to dump the hang state before the kernel
249 	 * decides to purge those BOs.
250 	 * Note that BO consistency at dump time cannot be guaranteed. For
251 	 * example, if the owner of these BOs decides to re-use them or mark
252 	 * them purgeable again there's nothing we can do to prevent it.
253 	 */
254 	for (i = 0; i < kernel_state->user_state.bo_count; i++) {
255 		struct vc4_bo *bo = to_vc4_bo(kernel_state->bo[i]);
256 
257 		if (bo->madv == __VC4_MADV_NOTSUPP)
258 			continue;
259 
260 		mutex_lock(&bo->madv_lock);
261 		if (!WARN_ON(bo->madv == __VC4_MADV_PURGED))
262 			bo->madv = VC4_MADV_WILLNEED;
263 		refcount_dec(&bo->usecnt);
264 		mutex_unlock(&bo->madv_lock);
265 	}
266 
267 	spin_lock_irqsave(&vc4->job_lock, irqflags);
268 	if (vc4->hang_state) {
269 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
270 		vc4_free_hang_state(dev, kernel_state);
271 	} else {
272 		vc4->hang_state = kernel_state;
273 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
274 	}
275 }
276 
277 static void
278 vc4_reset(struct drm_device *dev)
279 {
280 	struct vc4_dev *vc4 = to_vc4_dev(dev);
281 
282 	DRM_INFO("Resetting GPU.\n");
283 
284 	mutex_lock(&vc4->power_lock);
285 	if (vc4->power_refcount) {
286 		/* Power the device off and back on the by dropping the
287 		 * reference on runtime PM.
288 		 */
289 		pm_runtime_put_sync_suspend(&vc4->v3d->pdev->dev);
290 		pm_runtime_get_sync(&vc4->v3d->pdev->dev);
291 	}
292 	mutex_unlock(&vc4->power_lock);
293 
294 	vc4_irq_reset(dev);
295 
296 	/* Rearm the hangcheck -- another job might have been waiting
297 	 * for our hung one to get kicked off, and vc4_irq_reset()
298 	 * would have started it.
299 	 */
300 	vc4_queue_hangcheck(dev);
301 }
302 
303 static void
304 vc4_reset_work(struct work_struct *work)
305 {
306 	struct vc4_dev *vc4 =
307 		container_of(work, struct vc4_dev, hangcheck.reset_work);
308 
309 	vc4_save_hang_state(vc4->dev);
310 
311 	vc4_reset(vc4->dev);
312 }
313 
314 static void
315 vc4_hangcheck_elapsed(struct timer_list *t)
316 {
317 	struct vc4_dev *vc4 = from_timer(vc4, t, hangcheck.timer);
318 	struct drm_device *dev = vc4->dev;
319 	uint32_t ct0ca, ct1ca;
320 	unsigned long irqflags;
321 	struct vc4_exec_info *bin_exec, *render_exec;
322 
323 	spin_lock_irqsave(&vc4->job_lock, irqflags);
324 
325 	bin_exec = vc4_first_bin_job(vc4);
326 	render_exec = vc4_first_render_job(vc4);
327 
328 	/* If idle, we can stop watching for hangs. */
329 	if (!bin_exec && !render_exec) {
330 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
331 		return;
332 	}
333 
334 	ct0ca = V3D_READ(V3D_CTNCA(0));
335 	ct1ca = V3D_READ(V3D_CTNCA(1));
336 
337 	/* If we've made any progress in execution, rearm the timer
338 	 * and wait.
339 	 */
340 	if ((bin_exec && ct0ca != bin_exec->last_ct0ca) ||
341 	    (render_exec && ct1ca != render_exec->last_ct1ca)) {
342 		if (bin_exec)
343 			bin_exec->last_ct0ca = ct0ca;
344 		if (render_exec)
345 			render_exec->last_ct1ca = ct1ca;
346 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
347 		vc4_queue_hangcheck(dev);
348 		return;
349 	}
350 
351 	spin_unlock_irqrestore(&vc4->job_lock, irqflags);
352 
353 	/* We've gone too long with no progress, reset.  This has to
354 	 * be done from a work struct, since resetting can sleep and
355 	 * this timer hook isn't allowed to.
356 	 */
357 	schedule_work(&vc4->hangcheck.reset_work);
358 }
359 
360 static void
361 submit_cl(struct drm_device *dev, uint32_t thread, uint32_t start, uint32_t end)
362 {
363 	struct vc4_dev *vc4 = to_vc4_dev(dev);
364 
365 	/* Set the current and end address of the control list.
366 	 * Writing the end register is what starts the job.
367 	 */
368 	V3D_WRITE(V3D_CTNCA(thread), start);
369 	V3D_WRITE(V3D_CTNEA(thread), end);
370 }
371 
372 int
373 vc4_wait_for_seqno(struct drm_device *dev, uint64_t seqno, uint64_t timeout_ns,
374 		   bool interruptible)
375 {
376 	struct vc4_dev *vc4 = to_vc4_dev(dev);
377 	int ret = 0;
378 	unsigned long timeout_expire;
379 	DEFINE_WAIT(wait);
380 
381 	if (vc4->finished_seqno >= seqno)
382 		return 0;
383 
384 	if (timeout_ns == 0)
385 		return -ETIME;
386 
387 	timeout_expire = jiffies + nsecs_to_jiffies(timeout_ns);
388 
389 	trace_vc4_wait_for_seqno_begin(dev, seqno, timeout_ns);
390 	for (;;) {
391 		prepare_to_wait(&vc4->job_wait_queue, &wait,
392 				interruptible ? TASK_INTERRUPTIBLE :
393 				TASK_UNINTERRUPTIBLE);
394 
395 		if (interruptible && signal_pending(current)) {
396 			ret = -ERESTARTSYS;
397 			break;
398 		}
399 
400 		if (vc4->finished_seqno >= seqno)
401 			break;
402 
403 		if (timeout_ns != ~0ull) {
404 			if (time_after_eq(jiffies, timeout_expire)) {
405 				ret = -ETIME;
406 				break;
407 			}
408 			schedule_timeout(timeout_expire - jiffies);
409 		} else {
410 			schedule();
411 		}
412 	}
413 
414 	finish_wait(&vc4->job_wait_queue, &wait);
415 	trace_vc4_wait_for_seqno_end(dev, seqno);
416 
417 	return ret;
418 }
419 
420 static void
421 vc4_flush_caches(struct drm_device *dev)
422 {
423 	struct vc4_dev *vc4 = to_vc4_dev(dev);
424 
425 	/* Flush the GPU L2 caches.  These caches sit on top of system
426 	 * L3 (the 128kb or so shared with the CPU), and are
427 	 * non-allocating in the L3.
428 	 */
429 	V3D_WRITE(V3D_L2CACTL,
430 		  V3D_L2CACTL_L2CCLR);
431 
432 	V3D_WRITE(V3D_SLCACTL,
433 		  VC4_SET_FIELD(0xf, V3D_SLCACTL_T1CC) |
434 		  VC4_SET_FIELD(0xf, V3D_SLCACTL_T0CC) |
435 		  VC4_SET_FIELD(0xf, V3D_SLCACTL_UCC) |
436 		  VC4_SET_FIELD(0xf, V3D_SLCACTL_ICC));
437 }
438 
439 static void
440 vc4_flush_texture_caches(struct drm_device *dev)
441 {
442 	struct vc4_dev *vc4 = to_vc4_dev(dev);
443 
444 	V3D_WRITE(V3D_L2CACTL,
445 		  V3D_L2CACTL_L2CCLR);
446 
447 	V3D_WRITE(V3D_SLCACTL,
448 		  VC4_SET_FIELD(0xf, V3D_SLCACTL_T1CC) |
449 		  VC4_SET_FIELD(0xf, V3D_SLCACTL_T0CC));
450 }
451 
452 /* Sets the registers for the next job to be actually be executed in
453  * the hardware.
454  *
455  * The job_lock should be held during this.
456  */
457 void
458 vc4_submit_next_bin_job(struct drm_device *dev)
459 {
460 	struct vc4_dev *vc4 = to_vc4_dev(dev);
461 	struct vc4_exec_info *exec;
462 
463 again:
464 	exec = vc4_first_bin_job(vc4);
465 	if (!exec)
466 		return;
467 
468 	vc4_flush_caches(dev);
469 
470 	/* Only start the perfmon if it was not already started by a previous
471 	 * job.
472 	 */
473 	if (exec->perfmon && vc4->active_perfmon != exec->perfmon)
474 		vc4_perfmon_start(vc4, exec->perfmon);
475 
476 	/* Either put the job in the binner if it uses the binner, or
477 	 * immediately move it to the to-be-rendered queue.
478 	 */
479 	if (exec->ct0ca != exec->ct0ea) {
480 		submit_cl(dev, 0, exec->ct0ca, exec->ct0ea);
481 	} else {
482 		struct vc4_exec_info *next;
483 
484 		vc4_move_job_to_render(dev, exec);
485 		next = vc4_first_bin_job(vc4);
486 
487 		/* We can't start the next bin job if the previous job had a
488 		 * different perfmon instance attached to it. The same goes
489 		 * if one of them had a perfmon attached to it and the other
490 		 * one doesn't.
491 		 */
492 		if (next && next->perfmon == exec->perfmon)
493 			goto again;
494 	}
495 }
496 
497 void
498 vc4_submit_next_render_job(struct drm_device *dev)
499 {
500 	struct vc4_dev *vc4 = to_vc4_dev(dev);
501 	struct vc4_exec_info *exec = vc4_first_render_job(vc4);
502 
503 	if (!exec)
504 		return;
505 
506 	/* A previous RCL may have written to one of our textures, and
507 	 * our full cache flush at bin time may have occurred before
508 	 * that RCL completed.  Flush the texture cache now, but not
509 	 * the instructions or uniforms (since we don't write those
510 	 * from an RCL).
511 	 */
512 	vc4_flush_texture_caches(dev);
513 
514 	submit_cl(dev, 1, exec->ct1ca, exec->ct1ea);
515 }
516 
517 void
518 vc4_move_job_to_render(struct drm_device *dev, struct vc4_exec_info *exec)
519 {
520 	struct vc4_dev *vc4 = to_vc4_dev(dev);
521 	bool was_empty = list_empty(&vc4->render_job_list);
522 
523 	list_move_tail(&exec->head, &vc4->render_job_list);
524 	if (was_empty)
525 		vc4_submit_next_render_job(dev);
526 }
527 
528 static void
529 vc4_update_bo_seqnos(struct vc4_exec_info *exec, uint64_t seqno)
530 {
531 	struct vc4_bo *bo;
532 	unsigned i;
533 
534 	for (i = 0; i < exec->bo_count; i++) {
535 		bo = to_vc4_bo(&exec->bo[i]->base);
536 		bo->seqno = seqno;
537 
538 		reservation_object_add_shared_fence(bo->resv, exec->fence);
539 	}
540 
541 	list_for_each_entry(bo, &exec->unref_list, unref_head) {
542 		bo->seqno = seqno;
543 	}
544 
545 	for (i = 0; i < exec->rcl_write_bo_count; i++) {
546 		bo = to_vc4_bo(&exec->rcl_write_bo[i]->base);
547 		bo->write_seqno = seqno;
548 
549 		reservation_object_add_excl_fence(bo->resv, exec->fence);
550 	}
551 }
552 
553 static void
554 vc4_unlock_bo_reservations(struct drm_device *dev,
555 			   struct vc4_exec_info *exec,
556 			   struct ww_acquire_ctx *acquire_ctx)
557 {
558 	int i;
559 
560 	for (i = 0; i < exec->bo_count; i++) {
561 		struct vc4_bo *bo = to_vc4_bo(&exec->bo[i]->base);
562 
563 		ww_mutex_unlock(&bo->resv->lock);
564 	}
565 
566 	ww_acquire_fini(acquire_ctx);
567 }
568 
569 /* Takes the reservation lock on all the BOs being referenced, so that
570  * at queue submit time we can update the reservations.
571  *
572  * We don't lock the RCL the tile alloc/state BOs, or overflow memory
573  * (all of which are on exec->unref_list).  They're entirely private
574  * to vc4, so we don't attach dma-buf fences to them.
575  */
576 static int
577 vc4_lock_bo_reservations(struct drm_device *dev,
578 			 struct vc4_exec_info *exec,
579 			 struct ww_acquire_ctx *acquire_ctx)
580 {
581 	int contended_lock = -1;
582 	int i, ret;
583 	struct vc4_bo *bo;
584 
585 	ww_acquire_init(acquire_ctx, &reservation_ww_class);
586 
587 retry:
588 	if (contended_lock != -1) {
589 		bo = to_vc4_bo(&exec->bo[contended_lock]->base);
590 		ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock,
591 						       acquire_ctx);
592 		if (ret) {
593 			ww_acquire_done(acquire_ctx);
594 			return ret;
595 		}
596 	}
597 
598 	for (i = 0; i < exec->bo_count; i++) {
599 		if (i == contended_lock)
600 			continue;
601 
602 		bo = to_vc4_bo(&exec->bo[i]->base);
603 
604 		ret = ww_mutex_lock_interruptible(&bo->resv->lock, acquire_ctx);
605 		if (ret) {
606 			int j;
607 
608 			for (j = 0; j < i; j++) {
609 				bo = to_vc4_bo(&exec->bo[j]->base);
610 				ww_mutex_unlock(&bo->resv->lock);
611 			}
612 
613 			if (contended_lock != -1 && contended_lock >= i) {
614 				bo = to_vc4_bo(&exec->bo[contended_lock]->base);
615 
616 				ww_mutex_unlock(&bo->resv->lock);
617 			}
618 
619 			if (ret == -EDEADLK) {
620 				contended_lock = i;
621 				goto retry;
622 			}
623 
624 			ww_acquire_done(acquire_ctx);
625 			return ret;
626 		}
627 	}
628 
629 	ww_acquire_done(acquire_ctx);
630 
631 	/* Reserve space for our shared (read-only) fence references,
632 	 * before we commit the CL to the hardware.
633 	 */
634 	for (i = 0; i < exec->bo_count; i++) {
635 		bo = to_vc4_bo(&exec->bo[i]->base);
636 
637 		ret = reservation_object_reserve_shared(bo->resv);
638 		if (ret) {
639 			vc4_unlock_bo_reservations(dev, exec, acquire_ctx);
640 			return ret;
641 		}
642 	}
643 
644 	return 0;
645 }
646 
647 /* Queues a struct vc4_exec_info for execution.  If no job is
648  * currently executing, then submits it.
649  *
650  * Unlike most GPUs, our hardware only handles one command list at a
651  * time.  To queue multiple jobs at once, we'd need to edit the
652  * previous command list to have a jump to the new one at the end, and
653  * then bump the end address.  That's a change for a later date,
654  * though.
655  */
656 static int
657 vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec,
658 		 struct ww_acquire_ctx *acquire_ctx)
659 {
660 	struct vc4_dev *vc4 = to_vc4_dev(dev);
661 	struct vc4_exec_info *renderjob;
662 	uint64_t seqno;
663 	unsigned long irqflags;
664 	struct vc4_fence *fence;
665 
666 	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
667 	if (!fence)
668 		return -ENOMEM;
669 	fence->dev = dev;
670 
671 	spin_lock_irqsave(&vc4->job_lock, irqflags);
672 
673 	seqno = ++vc4->emit_seqno;
674 	exec->seqno = seqno;
675 
676 	dma_fence_init(&fence->base, &vc4_fence_ops, &vc4->job_lock,
677 		       vc4->dma_fence_context, exec->seqno);
678 	fence->seqno = exec->seqno;
679 	exec->fence = &fence->base;
680 
681 	vc4_update_bo_seqnos(exec, seqno);
682 
683 	vc4_unlock_bo_reservations(dev, exec, acquire_ctx);
684 
685 	list_add_tail(&exec->head, &vc4->bin_job_list);
686 
687 	/* If no bin job was executing and if the render job (if any) has the
688 	 * same perfmon as our job attached to it (or if both jobs don't have
689 	 * perfmon activated), then kick ours off.  Otherwise, it'll get
690 	 * started when the previous job's flush/render done interrupt occurs.
691 	 */
692 	renderjob = vc4_first_render_job(vc4);
693 	if (vc4_first_bin_job(vc4) == exec &&
694 	    (!renderjob || renderjob->perfmon == exec->perfmon)) {
695 		vc4_submit_next_bin_job(dev);
696 		vc4_queue_hangcheck(dev);
697 	}
698 
699 	spin_unlock_irqrestore(&vc4->job_lock, irqflags);
700 
701 	return 0;
702 }
703 
704 /**
705  * vc4_cl_lookup_bos() - Sets up exec->bo[] with the GEM objects
706  * referenced by the job.
707  * @dev: DRM device
708  * @file_priv: DRM file for this fd
709  * @exec: V3D job being set up
710  *
711  * The command validator needs to reference BOs by their index within
712  * the submitted job's BO list.  This does the validation of the job's
713  * BO list and reference counting for the lifetime of the job.
714  */
715 static int
716 vc4_cl_lookup_bos(struct drm_device *dev,
717 		  struct drm_file *file_priv,
718 		  struct vc4_exec_info *exec)
719 {
720 	struct drm_vc4_submit_cl *args = exec->args;
721 	uint32_t *handles;
722 	int ret = 0;
723 	int i;
724 
725 	exec->bo_count = args->bo_handle_count;
726 
727 	if (!exec->bo_count) {
728 		/* See comment on bo_index for why we have to check
729 		 * this.
730 		 */
731 		DRM_DEBUG("Rendering requires BOs to validate\n");
732 		return -EINVAL;
733 	}
734 
735 	exec->bo = kvmalloc_array(exec->bo_count,
736 				    sizeof(struct drm_gem_cma_object *),
737 				    GFP_KERNEL | __GFP_ZERO);
738 	if (!exec->bo) {
739 		DRM_ERROR("Failed to allocate validated BO pointers\n");
740 		return -ENOMEM;
741 	}
742 
743 	handles = kvmalloc_array(exec->bo_count, sizeof(uint32_t), GFP_KERNEL);
744 	if (!handles) {
745 		ret = -ENOMEM;
746 		DRM_ERROR("Failed to allocate incoming GEM handles\n");
747 		goto fail;
748 	}
749 
750 	if (copy_from_user(handles, u64_to_user_ptr(args->bo_handles),
751 			   exec->bo_count * sizeof(uint32_t))) {
752 		ret = -EFAULT;
753 		DRM_ERROR("Failed to copy in GEM handles\n");
754 		goto fail;
755 	}
756 
757 	spin_lock(&file_priv->table_lock);
758 	for (i = 0; i < exec->bo_count; i++) {
759 		struct drm_gem_object *bo = idr_find(&file_priv->object_idr,
760 						     handles[i]);
761 		if (!bo) {
762 			DRM_DEBUG("Failed to look up GEM BO %d: %d\n",
763 				  i, handles[i]);
764 			ret = -EINVAL;
765 			break;
766 		}
767 
768 		drm_gem_object_get(bo);
769 		exec->bo[i] = (struct drm_gem_cma_object *)bo;
770 	}
771 	spin_unlock(&file_priv->table_lock);
772 
773 	if (ret)
774 		goto fail_put_bo;
775 
776 	for (i = 0; i < exec->bo_count; i++) {
777 		ret = vc4_bo_inc_usecnt(to_vc4_bo(&exec->bo[i]->base));
778 		if (ret)
779 			goto fail_dec_usecnt;
780 	}
781 
782 	kvfree(handles);
783 	return 0;
784 
785 fail_dec_usecnt:
786 	/* Decrease usecnt on acquired objects.
787 	 * We cannot rely on  vc4_complete_exec() to release resources here,
788 	 * because vc4_complete_exec() has no information about which BO has
789 	 * had its ->usecnt incremented.
790 	 * To make things easier we just free everything explicitly and set
791 	 * exec->bo to NULL so that vc4_complete_exec() skips the 'BO release'
792 	 * step.
793 	 */
794 	for (i-- ; i >= 0; i--)
795 		vc4_bo_dec_usecnt(to_vc4_bo(&exec->bo[i]->base));
796 
797 fail_put_bo:
798 	/* Release any reference to acquired objects. */
799 	for (i = 0; i < exec->bo_count && exec->bo[i]; i++)
800 		drm_gem_object_put_unlocked(&exec->bo[i]->base);
801 
802 fail:
803 	kvfree(handles);
804 	kvfree(exec->bo);
805 	exec->bo = NULL;
806 	return ret;
807 }
808 
809 static int
810 vc4_get_bcl(struct drm_device *dev, struct vc4_exec_info *exec)
811 {
812 	struct drm_vc4_submit_cl *args = exec->args;
813 	void *temp = NULL;
814 	void *bin;
815 	int ret = 0;
816 	uint32_t bin_offset = 0;
817 	uint32_t shader_rec_offset = roundup(bin_offset + args->bin_cl_size,
818 					     16);
819 	uint32_t uniforms_offset = shader_rec_offset + args->shader_rec_size;
820 	uint32_t exec_size = uniforms_offset + args->uniforms_size;
821 	uint32_t temp_size = exec_size + (sizeof(struct vc4_shader_state) *
822 					  args->shader_rec_count);
823 	struct vc4_bo *bo;
824 
825 	if (shader_rec_offset < args->bin_cl_size ||
826 	    uniforms_offset < shader_rec_offset ||
827 	    exec_size < uniforms_offset ||
828 	    args->shader_rec_count >= (UINT_MAX /
829 					  sizeof(struct vc4_shader_state)) ||
830 	    temp_size < exec_size) {
831 		DRM_DEBUG("overflow in exec arguments\n");
832 		ret = -EINVAL;
833 		goto fail;
834 	}
835 
836 	/* Allocate space where we'll store the copied in user command lists
837 	 * and shader records.
838 	 *
839 	 * We don't just copy directly into the BOs because we need to
840 	 * read the contents back for validation, and I think the
841 	 * bo->vaddr is uncached access.
842 	 */
843 	temp = kvmalloc_array(temp_size, 1, GFP_KERNEL);
844 	if (!temp) {
845 		DRM_ERROR("Failed to allocate storage for copying "
846 			  "in bin/render CLs.\n");
847 		ret = -ENOMEM;
848 		goto fail;
849 	}
850 	bin = temp + bin_offset;
851 	exec->shader_rec_u = temp + shader_rec_offset;
852 	exec->uniforms_u = temp + uniforms_offset;
853 	exec->shader_state = temp + exec_size;
854 	exec->shader_state_size = args->shader_rec_count;
855 
856 	if (copy_from_user(bin,
857 			   u64_to_user_ptr(args->bin_cl),
858 			   args->bin_cl_size)) {
859 		ret = -EFAULT;
860 		goto fail;
861 	}
862 
863 	if (copy_from_user(exec->shader_rec_u,
864 			   u64_to_user_ptr(args->shader_rec),
865 			   args->shader_rec_size)) {
866 		ret = -EFAULT;
867 		goto fail;
868 	}
869 
870 	if (copy_from_user(exec->uniforms_u,
871 			   u64_to_user_ptr(args->uniforms),
872 			   args->uniforms_size)) {
873 		ret = -EFAULT;
874 		goto fail;
875 	}
876 
877 	bo = vc4_bo_create(dev, exec_size, true, VC4_BO_TYPE_BCL);
878 	if (IS_ERR(bo)) {
879 		DRM_ERROR("Couldn't allocate BO for binning\n");
880 		ret = PTR_ERR(bo);
881 		goto fail;
882 	}
883 	exec->exec_bo = &bo->base;
884 
885 	list_add_tail(&to_vc4_bo(&exec->exec_bo->base)->unref_head,
886 		      &exec->unref_list);
887 
888 	exec->ct0ca = exec->exec_bo->paddr + bin_offset;
889 
890 	exec->bin_u = bin;
891 
892 	exec->shader_rec_v = exec->exec_bo->vaddr + shader_rec_offset;
893 	exec->shader_rec_p = exec->exec_bo->paddr + shader_rec_offset;
894 	exec->shader_rec_size = args->shader_rec_size;
895 
896 	exec->uniforms_v = exec->exec_bo->vaddr + uniforms_offset;
897 	exec->uniforms_p = exec->exec_bo->paddr + uniforms_offset;
898 	exec->uniforms_size = args->uniforms_size;
899 
900 	ret = vc4_validate_bin_cl(dev,
901 				  exec->exec_bo->vaddr + bin_offset,
902 				  bin,
903 				  exec);
904 	if (ret)
905 		goto fail;
906 
907 	ret = vc4_validate_shader_recs(dev, exec);
908 	if (ret)
909 		goto fail;
910 
911 	/* Block waiting on any previous rendering into the CS's VBO,
912 	 * IB, or textures, so that pixels are actually written by the
913 	 * time we try to read them.
914 	 */
915 	ret = vc4_wait_for_seqno(dev, exec->bin_dep_seqno, ~0ull, true);
916 
917 fail:
918 	kvfree(temp);
919 	return ret;
920 }
921 
922 static void
923 vc4_complete_exec(struct drm_device *dev, struct vc4_exec_info *exec)
924 {
925 	struct vc4_dev *vc4 = to_vc4_dev(dev);
926 	unsigned long irqflags;
927 	unsigned i;
928 
929 	/* If we got force-completed because of GPU reset rather than
930 	 * through our IRQ handler, signal the fence now.
931 	 */
932 	if (exec->fence) {
933 		dma_fence_signal(exec->fence);
934 		dma_fence_put(exec->fence);
935 	}
936 
937 	if (exec->bo) {
938 		for (i = 0; i < exec->bo_count; i++) {
939 			struct vc4_bo *bo = to_vc4_bo(&exec->bo[i]->base);
940 
941 			vc4_bo_dec_usecnt(bo);
942 			drm_gem_object_put_unlocked(&exec->bo[i]->base);
943 		}
944 		kvfree(exec->bo);
945 	}
946 
947 	while (!list_empty(&exec->unref_list)) {
948 		struct vc4_bo *bo = list_first_entry(&exec->unref_list,
949 						     struct vc4_bo, unref_head);
950 		list_del(&bo->unref_head);
951 		drm_gem_object_put_unlocked(&bo->base.base);
952 	}
953 
954 	/* Free up the allocation of any bin slots we used. */
955 	spin_lock_irqsave(&vc4->job_lock, irqflags);
956 	vc4->bin_alloc_used &= ~exec->bin_slots;
957 	spin_unlock_irqrestore(&vc4->job_lock, irqflags);
958 
959 	/* Release the reference we had on the perf monitor. */
960 	vc4_perfmon_put(exec->perfmon);
961 
962 	mutex_lock(&vc4->power_lock);
963 	if (--vc4->power_refcount == 0) {
964 		pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev);
965 		pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
966 	}
967 	mutex_unlock(&vc4->power_lock);
968 
969 	kfree(exec);
970 }
971 
972 void
973 vc4_job_handle_completed(struct vc4_dev *vc4)
974 {
975 	unsigned long irqflags;
976 	struct vc4_seqno_cb *cb, *cb_temp;
977 
978 	spin_lock_irqsave(&vc4->job_lock, irqflags);
979 	while (!list_empty(&vc4->job_done_list)) {
980 		struct vc4_exec_info *exec =
981 			list_first_entry(&vc4->job_done_list,
982 					 struct vc4_exec_info, head);
983 		list_del(&exec->head);
984 
985 		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
986 		vc4_complete_exec(vc4->dev, exec);
987 		spin_lock_irqsave(&vc4->job_lock, irqflags);
988 	}
989 
990 	list_for_each_entry_safe(cb, cb_temp, &vc4->seqno_cb_list, work.entry) {
991 		if (cb->seqno <= vc4->finished_seqno) {
992 			list_del_init(&cb->work.entry);
993 			schedule_work(&cb->work);
994 		}
995 	}
996 
997 	spin_unlock_irqrestore(&vc4->job_lock, irqflags);
998 }
999 
1000 static void vc4_seqno_cb_work(struct work_struct *work)
1001 {
1002 	struct vc4_seqno_cb *cb = container_of(work, struct vc4_seqno_cb, work);
1003 
1004 	cb->func(cb);
1005 }
1006 
1007 int vc4_queue_seqno_cb(struct drm_device *dev,
1008 		       struct vc4_seqno_cb *cb, uint64_t seqno,
1009 		       void (*func)(struct vc4_seqno_cb *cb))
1010 {
1011 	struct vc4_dev *vc4 = to_vc4_dev(dev);
1012 	int ret = 0;
1013 	unsigned long irqflags;
1014 
1015 	cb->func = func;
1016 	INIT_WORK(&cb->work, vc4_seqno_cb_work);
1017 
1018 	spin_lock_irqsave(&vc4->job_lock, irqflags);
1019 	if (seqno > vc4->finished_seqno) {
1020 		cb->seqno = seqno;
1021 		list_add_tail(&cb->work.entry, &vc4->seqno_cb_list);
1022 	} else {
1023 		schedule_work(&cb->work);
1024 	}
1025 	spin_unlock_irqrestore(&vc4->job_lock, irqflags);
1026 
1027 	return ret;
1028 }
1029 
1030 /* Scheduled when any job has been completed, this walks the list of
1031  * jobs that had completed and unrefs their BOs and frees their exec
1032  * structs.
1033  */
1034 static void
1035 vc4_job_done_work(struct work_struct *work)
1036 {
1037 	struct vc4_dev *vc4 =
1038 		container_of(work, struct vc4_dev, job_done_work);
1039 
1040 	vc4_job_handle_completed(vc4);
1041 }
1042 
1043 static int
1044 vc4_wait_for_seqno_ioctl_helper(struct drm_device *dev,
1045 				uint64_t seqno,
1046 				uint64_t *timeout_ns)
1047 {
1048 	unsigned long start = jiffies;
1049 	int ret = vc4_wait_for_seqno(dev, seqno, *timeout_ns, true);
1050 
1051 	if ((ret == -EINTR || ret == -ERESTARTSYS) && *timeout_ns != ~0ull) {
1052 		uint64_t delta = jiffies_to_nsecs(jiffies - start);
1053 
1054 		if (*timeout_ns >= delta)
1055 			*timeout_ns -= delta;
1056 	}
1057 
1058 	return ret;
1059 }
1060 
1061 int
1062 vc4_wait_seqno_ioctl(struct drm_device *dev, void *data,
1063 		     struct drm_file *file_priv)
1064 {
1065 	struct drm_vc4_wait_seqno *args = data;
1066 
1067 	return vc4_wait_for_seqno_ioctl_helper(dev, args->seqno,
1068 					       &args->timeout_ns);
1069 }
1070 
1071 int
1072 vc4_wait_bo_ioctl(struct drm_device *dev, void *data,
1073 		  struct drm_file *file_priv)
1074 {
1075 	int ret;
1076 	struct drm_vc4_wait_bo *args = data;
1077 	struct drm_gem_object *gem_obj;
1078 	struct vc4_bo *bo;
1079 
1080 	if (args->pad != 0)
1081 		return -EINVAL;
1082 
1083 	gem_obj = drm_gem_object_lookup(file_priv, args->handle);
1084 	if (!gem_obj) {
1085 		DRM_DEBUG("Failed to look up GEM BO %d\n", args->handle);
1086 		return -EINVAL;
1087 	}
1088 	bo = to_vc4_bo(gem_obj);
1089 
1090 	ret = vc4_wait_for_seqno_ioctl_helper(dev, bo->seqno,
1091 					      &args->timeout_ns);
1092 
1093 	drm_gem_object_put_unlocked(gem_obj);
1094 	return ret;
1095 }
1096 
1097 /**
1098  * vc4_submit_cl_ioctl() - Submits a job (frame) to the VC4.
1099  * @dev: DRM device
1100  * @data: ioctl argument
1101  * @file_priv: DRM file for this fd
1102  *
1103  * This is the main entrypoint for userspace to submit a 3D frame to
1104  * the GPU.  Userspace provides the binner command list (if
1105  * applicable), and the kernel sets up the render command list to draw
1106  * to the framebuffer described in the ioctl, using the command lists
1107  * that the 3D engine's binner will produce.
1108  */
1109 int
1110 vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
1111 		    struct drm_file *file_priv)
1112 {
1113 	struct vc4_dev *vc4 = to_vc4_dev(dev);
1114 	struct vc4_file *vc4file = file_priv->driver_priv;
1115 	struct drm_vc4_submit_cl *args = data;
1116 	struct vc4_exec_info *exec;
1117 	struct ww_acquire_ctx acquire_ctx;
1118 	int ret = 0;
1119 
1120 	if ((args->flags & ~(VC4_SUBMIT_CL_USE_CLEAR_COLOR |
1121 			     VC4_SUBMIT_CL_FIXED_RCL_ORDER |
1122 			     VC4_SUBMIT_CL_RCL_ORDER_INCREASING_X |
1123 			     VC4_SUBMIT_CL_RCL_ORDER_INCREASING_Y)) != 0) {
1124 		DRM_DEBUG("Unknown flags: 0x%02x\n", args->flags);
1125 		return -EINVAL;
1126 	}
1127 
1128 	if (args->pad2 != 0) {
1129 		DRM_DEBUG("->pad2 must be set to zero\n");
1130 		return -EINVAL;
1131 	}
1132 
1133 	exec = kcalloc(1, sizeof(*exec), GFP_KERNEL);
1134 	if (!exec) {
1135 		DRM_ERROR("malloc failure on exec struct\n");
1136 		return -ENOMEM;
1137 	}
1138 
1139 	mutex_lock(&vc4->power_lock);
1140 	if (vc4->power_refcount++ == 0) {
1141 		ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev);
1142 		if (ret < 0) {
1143 			mutex_unlock(&vc4->power_lock);
1144 			vc4->power_refcount--;
1145 			kfree(exec);
1146 			return ret;
1147 		}
1148 	}
1149 	mutex_unlock(&vc4->power_lock);
1150 
1151 	exec->args = args;
1152 	INIT_LIST_HEAD(&exec->unref_list);
1153 
1154 	ret = vc4_cl_lookup_bos(dev, file_priv, exec);
1155 	if (ret)
1156 		goto fail;
1157 
1158 	if (args->perfmonid) {
1159 		exec->perfmon = vc4_perfmon_find(vc4file,
1160 						 args->perfmonid);
1161 		if (!exec->perfmon) {
1162 			ret = -ENOENT;
1163 			goto fail;
1164 		}
1165 	}
1166 
1167 	if (exec->args->bin_cl_size != 0) {
1168 		ret = vc4_get_bcl(dev, exec);
1169 		if (ret)
1170 			goto fail;
1171 	} else {
1172 		exec->ct0ca = 0;
1173 		exec->ct0ea = 0;
1174 	}
1175 
1176 	ret = vc4_get_rcl(dev, exec);
1177 	if (ret)
1178 		goto fail;
1179 
1180 	ret = vc4_lock_bo_reservations(dev, exec, &acquire_ctx);
1181 	if (ret)
1182 		goto fail;
1183 
1184 	/* Clear this out of the struct we'll be putting in the queue,
1185 	 * since it's part of our stack.
1186 	 */
1187 	exec->args = NULL;
1188 
1189 	ret = vc4_queue_submit(dev, exec, &acquire_ctx);
1190 	if (ret)
1191 		goto fail;
1192 
1193 	/* Return the seqno for our job. */
1194 	args->seqno = vc4->emit_seqno;
1195 
1196 	return 0;
1197 
1198 fail:
1199 	vc4_complete_exec(vc4->dev, exec);
1200 
1201 	return ret;
1202 }
1203 
1204 void
1205 vc4_gem_init(struct drm_device *dev)
1206 {
1207 	struct vc4_dev *vc4 = to_vc4_dev(dev);
1208 
1209 	vc4->dma_fence_context = dma_fence_context_alloc(1);
1210 
1211 	INIT_LIST_HEAD(&vc4->bin_job_list);
1212 	INIT_LIST_HEAD(&vc4->render_job_list);
1213 	INIT_LIST_HEAD(&vc4->job_done_list);
1214 	INIT_LIST_HEAD(&vc4->seqno_cb_list);
1215 	spin_lock_init(&vc4->job_lock);
1216 
1217 	INIT_WORK(&vc4->hangcheck.reset_work, vc4_reset_work);
1218 	timer_setup(&vc4->hangcheck.timer, vc4_hangcheck_elapsed, 0);
1219 
1220 	INIT_WORK(&vc4->job_done_work, vc4_job_done_work);
1221 
1222 	mutex_init(&vc4->power_lock);
1223 
1224 	INIT_LIST_HEAD(&vc4->purgeable.list);
1225 	mutex_init(&vc4->purgeable.lock);
1226 }
1227 
1228 void
1229 vc4_gem_destroy(struct drm_device *dev)
1230 {
1231 	struct vc4_dev *vc4 = to_vc4_dev(dev);
1232 
1233 	/* Waiting for exec to finish would need to be done before
1234 	 * unregistering V3D.
1235 	 */
1236 	WARN_ON(vc4->emit_seqno != vc4->finished_seqno);
1237 
1238 	/* V3D should already have disabled its interrupt and cleared
1239 	 * the overflow allocation registers.  Now free the object.
1240 	 */
1241 	if (vc4->bin_bo) {
1242 		drm_gem_object_put_unlocked(&vc4->bin_bo->base.base);
1243 		vc4->bin_bo = NULL;
1244 	}
1245 
1246 	if (vc4->hang_state)
1247 		vc4_free_hang_state(dev, vc4->hang_state);
1248 }
1249 
1250 int vc4_gem_madvise_ioctl(struct drm_device *dev, void *data,
1251 			  struct drm_file *file_priv)
1252 {
1253 	struct drm_vc4_gem_madvise *args = data;
1254 	struct drm_gem_object *gem_obj;
1255 	struct vc4_bo *bo;
1256 	int ret;
1257 
1258 	switch (args->madv) {
1259 	case VC4_MADV_DONTNEED:
1260 	case VC4_MADV_WILLNEED:
1261 		break;
1262 	default:
1263 		return -EINVAL;
1264 	}
1265 
1266 	if (args->pad != 0)
1267 		return -EINVAL;
1268 
1269 	gem_obj = drm_gem_object_lookup(file_priv, args->handle);
1270 	if (!gem_obj) {
1271 		DRM_DEBUG("Failed to look up GEM BO %d\n", args->handle);
1272 		return -ENOENT;
1273 	}
1274 
1275 	bo = to_vc4_bo(gem_obj);
1276 
1277 	/* Only BOs exposed to userspace can be purged. */
1278 	if (bo->madv == __VC4_MADV_NOTSUPP) {
1279 		DRM_DEBUG("madvise not supported on this BO\n");
1280 		ret = -EINVAL;
1281 		goto out_put_gem;
1282 	}
1283 
1284 	/* Not sure it's safe to purge imported BOs. Let's just assume it's
1285 	 * not until proven otherwise.
1286 	 */
1287 	if (gem_obj->import_attach) {
1288 		DRM_DEBUG("madvise not supported on imported BOs\n");
1289 		ret = -EINVAL;
1290 		goto out_put_gem;
1291 	}
1292 
1293 	mutex_lock(&bo->madv_lock);
1294 
1295 	if (args->madv == VC4_MADV_DONTNEED && bo->madv == VC4_MADV_WILLNEED &&
1296 	    !refcount_read(&bo->usecnt)) {
1297 		/* If the BO is about to be marked as purgeable, is not used
1298 		 * and is not already purgeable or purged, add it to the
1299 		 * purgeable list.
1300 		 */
1301 		vc4_bo_add_to_purgeable_pool(bo);
1302 	} else if (args->madv == VC4_MADV_WILLNEED &&
1303 		   bo->madv == VC4_MADV_DONTNEED &&
1304 		   !refcount_read(&bo->usecnt)) {
1305 		/* The BO has not been purged yet, just remove it from
1306 		 * the purgeable list.
1307 		 */
1308 		vc4_bo_remove_from_purgeable_pool(bo);
1309 	}
1310 
1311 	/* Save the purged state. */
1312 	args->retained = bo->madv != __VC4_MADV_PURGED;
1313 
1314 	/* Update internal madv state only if the bo was not purged. */
1315 	if (bo->madv != __VC4_MADV_PURGED)
1316 		bo->madv = args->madv;
1317 
1318 	mutex_unlock(&bo->madv_lock);
1319 
1320 	ret = 0;
1321 
1322 out_put_gem:
1323 	drm_gem_object_put_unlocked(gem_obj);
1324 
1325 	return ret;
1326 }
1327