xref: /linux/drivers/gpu/drm/nouveau/dispnv50/crc.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: MIT
2 #include <linux/debugfs.h>
3 #include <linux/string.h>
4 
5 #include <drm/drm_crtc.h>
6 #include <drm/drm_atomic_helper.h>
7 #include <drm/drm_vblank.h>
8 #include <drm/drm_vblank_work.h>
9 
10 #include <nvif/class.h>
11 #include <nvif/cl0002.h>
12 #include <nvif/timer.h>
13 
14 #include <nvhw/class/cl907d.h>
15 
16 #include "nouveau_drv.h"
17 #include "core.h"
18 #include "head.h"
19 #include "wndw.h"
20 #include "handles.h"
21 #include "crc.h"
22 
23 static const char * const nv50_crc_sources[] = {
24 	[NV50_CRC_SOURCE_NONE] = "none",
25 	[NV50_CRC_SOURCE_AUTO] = "auto",
26 	[NV50_CRC_SOURCE_RG] = "rg",
27 	[NV50_CRC_SOURCE_OUTP_ACTIVE] = "outp-active",
28 	[NV50_CRC_SOURCE_OUTP_COMPLETE] = "outp-complete",
29 	[NV50_CRC_SOURCE_OUTP_INACTIVE] = "outp-inactive",
30 };
31 
32 static int nv50_crc_parse_source(const char *buf, enum nv50_crc_source *s)
33 {
34 	int i;
35 
36 	if (!buf) {
37 		*s = NV50_CRC_SOURCE_NONE;
38 		return 0;
39 	}
40 
41 	i = match_string(nv50_crc_sources, ARRAY_SIZE(nv50_crc_sources), buf);
42 	if (i < 0)
43 		return i;
44 
45 	*s = i;
46 	return 0;
47 }
48 
49 int
50 nv50_crc_verify_source(struct drm_crtc *crtc, const char *source_name,
51 		       size_t *values_cnt)
52 {
53 	struct nouveau_drm *drm = nouveau_drm(crtc->dev);
54 	enum nv50_crc_source source;
55 
56 	if (nv50_crc_parse_source(source_name, &source) < 0) {
57 		NV_DEBUG(drm, "unknown source %s\n", source_name);
58 		return -EINVAL;
59 	}
60 
61 	*values_cnt = 1;
62 	return 0;
63 }
64 
65 const char *const *nv50_crc_get_sources(struct drm_crtc *crtc, size_t *count)
66 {
67 	*count = ARRAY_SIZE(nv50_crc_sources);
68 	return nv50_crc_sources;
69 }
70 
71 static void
72 nv50_crc_program_ctx(struct nv50_head *head,
73 		     struct nv50_crc_notifier_ctx *ctx)
74 {
75 	struct nv50_disp *disp = nv50_disp(head->base.base.dev);
76 	struct nv50_core *core = disp->core;
77 	u32 interlock[NV50_DISP_INTERLOCK__SIZE] = { 0 };
78 
79 	core->func->crc->set_ctx(head, ctx);
80 	core->func->update(core, interlock, false);
81 }
82 
83 static void nv50_crc_ctx_flip_work(struct kthread_work *base)
84 {
85 	struct drm_vblank_work *work = to_drm_vblank_work(base);
86 	struct nv50_crc *crc = container_of(work, struct nv50_crc, flip_work);
87 	struct nv50_head *head = container_of(crc, struct nv50_head, crc);
88 	struct drm_crtc *crtc = &head->base.base;
89 	struct drm_device *dev = crtc->dev;
90 	struct nv50_disp *disp = nv50_disp(dev);
91 	const uint64_t start_vbl = drm_crtc_vblank_count(crtc);
92 	uint64_t end_vbl;
93 	u8 new_idx = crc->ctx_idx ^ 1;
94 
95 	/*
96 	 * We don't want to accidentally wait for longer then the vblank, so
97 	 * try again for the next vblank if we don't grab the lock
98 	 */
99 	if (!mutex_trylock(&disp->mutex)) {
100 		drm_dbg_kms(dev, "Lock contended, delaying CRC ctx flip for %s\n", crtc->name);
101 		drm_vblank_work_schedule(work, start_vbl + 1, true);
102 		return;
103 	}
104 
105 	drm_dbg_kms(dev, "Flipping notifier ctx for %s (%d -> %d)\n",
106 		    crtc->name, crc->ctx_idx, new_idx);
107 
108 	nv50_crc_program_ctx(head, NULL);
109 	nv50_crc_program_ctx(head, &crc->ctx[new_idx]);
110 	mutex_unlock(&disp->mutex);
111 
112 	end_vbl = drm_crtc_vblank_count(crtc);
113 	if (unlikely(end_vbl != start_vbl))
114 		NV_ERROR(nouveau_drm(dev),
115 			 "Failed to flip CRC context on %s on time (%llu > %llu)\n",
116 			 crtc->name, end_vbl, start_vbl);
117 
118 	spin_lock_irq(&crc->lock);
119 	crc->ctx_changed = true;
120 	spin_unlock_irq(&crc->lock);
121 }
122 
123 static inline void nv50_crc_reset_ctx(struct nv50_crc_notifier_ctx *ctx)
124 {
125 	memset_io(ctx->mem.object.map.ptr, 0, ctx->mem.object.map.size);
126 }
127 
128 static void
129 nv50_crc_get_entries(struct nv50_head *head,
130 		     const struct nv50_crc_func *func,
131 		     enum nv50_crc_source source)
132 {
133 	struct drm_crtc *crtc = &head->base.base;
134 	struct nv50_crc *crc = &head->crc;
135 	u32 output_crc;
136 
137 	while (crc->entry_idx < func->num_entries) {
138 		/*
139 		 * While Nvidia's documentation says CRCs are written on each
140 		 * subsequent vblank after being enabled, in practice they
141 		 * aren't written immediately.
142 		 */
143 		output_crc = func->get_entry(head, &crc->ctx[crc->ctx_idx],
144 					     source, crc->entry_idx);
145 		if (!output_crc)
146 			return;
147 
148 		drm_crtc_add_crc_entry(crtc, true, crc->frame, &output_crc);
149 		crc->frame++;
150 		crc->entry_idx++;
151 	}
152 }
153 
154 void nv50_crc_handle_vblank(struct nv50_head *head)
155 {
156 	struct drm_crtc *crtc = &head->base.base;
157 	struct nv50_crc *crc = &head->crc;
158 	const struct nv50_crc_func *func =
159 		nv50_disp(head->base.base.dev)->core->func->crc;
160 	struct nv50_crc_notifier_ctx *ctx;
161 	bool need_reschedule = false;
162 
163 	if (!func)
164 		return;
165 
166 	/*
167 	 * We don't lose events if we aren't able to report CRCs until the
168 	 * next vblank, so only report CRCs if the locks we need aren't
169 	 * contended to prevent missing an actual vblank event
170 	 */
171 	if (!spin_trylock(&crc->lock))
172 		return;
173 
174 	if (!crc->src)
175 		goto out;
176 
177 	ctx = &crc->ctx[crc->ctx_idx];
178 	if (crc->ctx_changed && func->ctx_finished(head, ctx)) {
179 		nv50_crc_get_entries(head, func, crc->src);
180 
181 		crc->ctx_idx ^= 1;
182 		crc->entry_idx = 0;
183 		crc->ctx_changed = false;
184 
185 		/*
186 		 * Unfortunately when notifier contexts are changed during CRC
187 		 * capture, we will inevitably lose the CRC entry for the
188 		 * frame where the hardware actually latched onto the first
189 		 * UPDATE. According to Nvidia's hardware engineers, there's
190 		 * no workaround for this.
191 		 *
192 		 * Now, we could try to be smart here and calculate the number
193 		 * of missed CRCs based on audit timestamps, but those were
194 		 * removed starting with volta. Since we always flush our
195 		 * updates back-to-back without waiting, we'll just be
196 		 * optimistic and assume we always miss exactly one frame.
197 		 */
198 		drm_dbg_kms(head->base.base.dev,
199 			    "Notifier ctx flip for head-%d finished, lost CRC for frame %llu\n",
200 			    head->base.index, crc->frame);
201 		crc->frame++;
202 
203 		nv50_crc_reset_ctx(ctx);
204 		need_reschedule = true;
205 	}
206 
207 	nv50_crc_get_entries(head, func, crc->src);
208 
209 	if (need_reschedule)
210 		drm_vblank_work_schedule(&crc->flip_work,
211 					 drm_crtc_vblank_count(crtc)
212 					 + crc->flip_threshold
213 					 - crc->entry_idx,
214 					 true);
215 
216 out:
217 	spin_unlock(&crc->lock);
218 }
219 
220 static void nv50_crc_wait_ctx_finished(struct nv50_head *head,
221 				       const struct nv50_crc_func *func,
222 				       struct nv50_crc_notifier_ctx *ctx)
223 {
224 	struct drm_device *dev = head->base.base.dev;
225 	struct nouveau_drm *drm = nouveau_drm(dev);
226 	s64 ret;
227 
228 	ret = nvif_msec(&drm->client.device, 50,
229 			if (func->ctx_finished(head, ctx)) break;);
230 	if (ret == -ETIMEDOUT)
231 		NV_ERROR(drm,
232 			 "CRC notifier ctx for head %d not finished after 50ms\n",
233 			 head->base.index);
234 	else if (ret)
235 		NV_ATOMIC(drm,
236 			  "CRC notifier ctx for head-%d finished after %lldns\n",
237 			  head->base.index, ret);
238 }
239 
240 void nv50_crc_atomic_stop_reporting(struct drm_atomic_state *state)
241 {
242 	struct drm_crtc_state *crtc_state;
243 	struct drm_crtc *crtc;
244 	int i;
245 
246 	for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
247 		struct nv50_head *head = nv50_head(crtc);
248 		struct nv50_head_atom *asyh = nv50_head_atom(crtc_state);
249 		struct nv50_crc *crc = &head->crc;
250 
251 		if (!asyh->clr.crc)
252 			continue;
253 
254 		spin_lock_irq(&crc->lock);
255 		crc->src = NV50_CRC_SOURCE_NONE;
256 		spin_unlock_irq(&crc->lock);
257 
258 		drm_crtc_vblank_put(crtc);
259 		drm_vblank_work_cancel_sync(&crc->flip_work);
260 
261 		NV_ATOMIC(nouveau_drm(crtc->dev),
262 			  "CRC reporting on vblank for head-%d disabled\n",
263 			  head->base.index);
264 
265 		/* CRC generation is still enabled in hw, we'll just report
266 		 * any remaining CRC entries ourselves after it gets disabled
267 		 * in hardware
268 		 */
269 	}
270 }
271 
272 void nv50_crc_atomic_init_notifier_contexts(struct drm_atomic_state *state)
273 {
274 	struct drm_crtc_state *new_crtc_state;
275 	struct drm_crtc *crtc;
276 	int i;
277 
278 	for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
279 		struct nv50_head *head = nv50_head(crtc);
280 		struct nv50_head_atom *asyh = nv50_head_atom(new_crtc_state);
281 		struct nv50_crc *crc = &head->crc;
282 		int i;
283 
284 		if (!asyh->set.crc)
285 			continue;
286 
287 		crc->entry_idx = 0;
288 		crc->ctx_changed = false;
289 		for (i = 0; i < ARRAY_SIZE(crc->ctx); i++)
290 			nv50_crc_reset_ctx(&crc->ctx[i]);
291 	}
292 }
293 
294 void nv50_crc_atomic_release_notifier_contexts(struct drm_atomic_state *state)
295 {
296 	const struct nv50_crc_func *func =
297 		nv50_disp(state->dev)->core->func->crc;
298 	struct drm_crtc_state *new_crtc_state;
299 	struct drm_crtc *crtc;
300 	int i;
301 
302 	for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
303 		struct nv50_head *head = nv50_head(crtc);
304 		struct nv50_head_atom *asyh = nv50_head_atom(new_crtc_state);
305 		struct nv50_crc *crc = &head->crc;
306 		struct nv50_crc_notifier_ctx *ctx = &crc->ctx[crc->ctx_idx];
307 
308 		if (!asyh->clr.crc)
309 			continue;
310 
311 		if (crc->ctx_changed) {
312 			nv50_crc_wait_ctx_finished(head, func, ctx);
313 			ctx = &crc->ctx[crc->ctx_idx ^ 1];
314 		}
315 		nv50_crc_wait_ctx_finished(head, func, ctx);
316 	}
317 }
318 
319 void nv50_crc_atomic_start_reporting(struct drm_atomic_state *state)
320 {
321 	struct drm_crtc_state *crtc_state;
322 	struct drm_crtc *crtc;
323 	int i;
324 
325 	for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
326 		struct nv50_head *head = nv50_head(crtc);
327 		struct nv50_head_atom *asyh = nv50_head_atom(crtc_state);
328 		struct nv50_crc *crc = &head->crc;
329 		u64 vbl_count;
330 
331 		if (!asyh->set.crc)
332 			continue;
333 
334 		drm_crtc_vblank_get(crtc);
335 
336 		spin_lock_irq(&crc->lock);
337 		vbl_count = drm_crtc_vblank_count(crtc);
338 		crc->frame = vbl_count;
339 		crc->src = asyh->crc.src;
340 		drm_vblank_work_schedule(&crc->flip_work,
341 					 vbl_count + crc->flip_threshold,
342 					 true);
343 		spin_unlock_irq(&crc->lock);
344 
345 		NV_ATOMIC(nouveau_drm(crtc->dev),
346 			  "CRC reporting on vblank for head-%d enabled\n",
347 			  head->base.index);
348 	}
349 }
350 
351 int nv50_crc_atomic_check_head(struct nv50_head *head,
352 			       struct nv50_head_atom *asyh,
353 			       struct nv50_head_atom *armh)
354 {
355 	struct nv50_atom *atom = nv50_atom(asyh->state.state);
356 	bool changed = armh->crc.src != asyh->crc.src;
357 
358 	if (!armh->crc.src && !asyh->crc.src) {
359 		asyh->set.crc = false;
360 		asyh->clr.crc = false;
361 		return 0;
362 	}
363 
364 	if (drm_atomic_crtc_needs_modeset(&asyh->state) || changed) {
365 		asyh->clr.crc = armh->crc.src && armh->state.active;
366 		asyh->set.crc = asyh->crc.src && asyh->state.active;
367 		if (changed)
368 			asyh->set.or |= armh->or.crc_raster !=
369 					asyh->or.crc_raster;
370 
371 		if (asyh->clr.crc && asyh->set.crc)
372 			atom->flush_disable = true;
373 	} else {
374 		asyh->set.crc = false;
375 		asyh->clr.crc = false;
376 	}
377 
378 	return 0;
379 }
380 
381 void nv50_crc_atomic_check_outp(struct nv50_atom *atom)
382 {
383 	struct drm_crtc *crtc;
384 	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
385 	int i;
386 
387 	if (atom->flush_disable)
388 		return;
389 
390 	for_each_oldnew_crtc_in_state(&atom->state, crtc, old_crtc_state,
391 				      new_crtc_state, i) {
392 		struct nv50_head_atom *armh = nv50_head_atom(old_crtc_state);
393 		struct nv50_head_atom *asyh = nv50_head_atom(new_crtc_state);
394 		struct nv50_outp_atom *outp_atom;
395 		struct nouveau_encoder *outp;
396 		struct drm_encoder *encoder, *enc;
397 
398 		enc = nv50_head_atom_get_encoder(armh);
399 		if (!enc)
400 			continue;
401 
402 		outp = nv50_real_outp(enc);
403 		if (!outp)
404 			continue;
405 
406 		encoder = &outp->base.base;
407 
408 		if (!asyh->clr.crc)
409 			continue;
410 
411 		/*
412 		 * Re-programming ORs can't be done in the same flush as
413 		 * disabling CRCs
414 		 */
415 		list_for_each_entry(outp_atom, &atom->outp, head) {
416 			if (outp_atom->encoder == encoder) {
417 				if (outp_atom->set.mask) {
418 					atom->flush_disable = true;
419 					return;
420 				} else {
421 					break;
422 				}
423 			}
424 		}
425 	}
426 }
427 
428 static enum nv50_crc_source_type
429 nv50_crc_source_type(struct nouveau_encoder *outp,
430 		     enum nv50_crc_source source)
431 {
432 	struct dcb_output *dcbe = outp->dcb;
433 
434 	switch (source) {
435 	case NV50_CRC_SOURCE_NONE: return NV50_CRC_SOURCE_TYPE_NONE;
436 	case NV50_CRC_SOURCE_RG:   return NV50_CRC_SOURCE_TYPE_RG;
437 	default:		   break;
438 	}
439 
440 	if (dcbe->location != DCB_LOC_ON_CHIP)
441 		return NV50_CRC_SOURCE_TYPE_PIOR;
442 
443 	switch (dcbe->type) {
444 	case DCB_OUTPUT_DP:	return NV50_CRC_SOURCE_TYPE_SF;
445 	case DCB_OUTPUT_ANALOG:	return NV50_CRC_SOURCE_TYPE_DAC;
446 	default:		return NV50_CRC_SOURCE_TYPE_SOR;
447 	}
448 }
449 
450 void nv50_crc_atomic_set(struct nv50_head *head,
451 			 struct nv50_head_atom *asyh)
452 {
453 	struct drm_crtc *crtc = &head->base.base;
454 	struct drm_device *dev = crtc->dev;
455 	struct nv50_crc *crc = &head->crc;
456 	const struct nv50_crc_func *func = nv50_disp(dev)->core->func->crc;
457 	struct nouveau_encoder *outp;
458 	struct drm_encoder *encoder;
459 
460 	encoder = nv50_head_atom_get_encoder(asyh);
461 	if (!encoder)
462 		return;
463 
464 	outp = nv50_real_outp(encoder);
465 	if (!outp)
466 		return;
467 
468 	func->set_src(head, outp->outp.or.id, nv50_crc_source_type(outp, asyh->crc.src),
469 		      &crc->ctx[crc->ctx_idx]);
470 }
471 
472 void nv50_crc_atomic_clr(struct nv50_head *head)
473 {
474 	const struct nv50_crc_func *func =
475 		nv50_disp(head->base.base.dev)->core->func->crc;
476 
477 	func->set_src(head, 0, NV50_CRC_SOURCE_TYPE_NONE, NULL);
478 }
479 
480 static inline int
481 nv50_crc_raster_type(enum nv50_crc_source source)
482 {
483 	switch (source) {
484 	case NV50_CRC_SOURCE_NONE:
485 	case NV50_CRC_SOURCE_AUTO:
486 	case NV50_CRC_SOURCE_RG:
487 	case NV50_CRC_SOURCE_OUTP_ACTIVE:
488 		return NV907D_HEAD_SET_CONTROL_OUTPUT_RESOURCE_CRC_MODE_ACTIVE_RASTER;
489 	case NV50_CRC_SOURCE_OUTP_COMPLETE:
490 		return NV907D_HEAD_SET_CONTROL_OUTPUT_RESOURCE_CRC_MODE_COMPLETE_RASTER;
491 	case NV50_CRC_SOURCE_OUTP_INACTIVE:
492 		return NV907D_HEAD_SET_CONTROL_OUTPUT_RESOURCE_CRC_MODE_NON_ACTIVE_RASTER;
493 	}
494 
495 	return 0;
496 }
497 
498 /* We handle mapping the memory for CRC notifiers ourselves, since each
499  * notifier needs it's own handle
500  */
501 static inline int
502 nv50_crc_ctx_init(struct nv50_head *head, struct nvif_mmu *mmu,
503 		  struct nv50_crc_notifier_ctx *ctx, size_t len, int idx)
504 {
505 	struct nv50_core *core = nv50_disp(head->base.base.dev)->core;
506 	int ret;
507 
508 	ret = nvif_mem_ctor_map(mmu, "kmsCrcNtfy", NVIF_MEM_VRAM, len, &ctx->mem);
509 	if (ret)
510 		return ret;
511 
512 	ret = nvif_object_ctor(&core->chan.base.user, "kmsCrcNtfyCtxDma",
513 			       NV50_DISP_HANDLE_CRC_CTX(head, idx),
514 			       NV_DMA_IN_MEMORY,
515 			       &(struct nv_dma_v0) {
516 					.target = NV_DMA_V0_TARGET_VRAM,
517 					.access = NV_DMA_V0_ACCESS_RDWR,
518 					.start = ctx->mem.addr,
519 					.limit =  ctx->mem.addr
520 						+ ctx->mem.size - 1,
521 			       }, sizeof(struct nv_dma_v0),
522 			       &ctx->ntfy);
523 	if (ret)
524 		goto fail_fini;
525 
526 	return 0;
527 
528 fail_fini:
529 	nvif_mem_dtor(&ctx->mem);
530 	return ret;
531 }
532 
533 static inline void
534 nv50_crc_ctx_fini(struct nv50_crc_notifier_ctx *ctx)
535 {
536 	nvif_object_dtor(&ctx->ntfy);
537 	nvif_mem_dtor(&ctx->mem);
538 }
539 
540 int nv50_crc_set_source(struct drm_crtc *crtc, const char *source_str)
541 {
542 	struct drm_device *dev = crtc->dev;
543 	struct drm_atomic_state *state;
544 	struct drm_modeset_acquire_ctx ctx;
545 	struct nv50_head *head = nv50_head(crtc);
546 	struct nv50_crc *crc = &head->crc;
547 	const struct nv50_crc_func *func = nv50_disp(dev)->core->func->crc;
548 	struct nvif_mmu *mmu = &nouveau_drm(dev)->client.mmu;
549 	struct nv50_head_atom *asyh;
550 	struct drm_crtc_state *crtc_state;
551 	enum nv50_crc_source source;
552 	int ret = 0, ctx_flags = 0, i;
553 
554 	ret = nv50_crc_parse_source(source_str, &source);
555 	if (ret)
556 		return ret;
557 
558 	/*
559 	 * Since we don't want the user to accidentally interrupt us as we're
560 	 * disabling CRCs
561 	 */
562 	if (source)
563 		ctx_flags |= DRM_MODESET_ACQUIRE_INTERRUPTIBLE;
564 	drm_modeset_acquire_init(&ctx, ctx_flags);
565 
566 	state = drm_atomic_state_alloc(dev);
567 	if (!state) {
568 		ret = -ENOMEM;
569 		goto out_acquire_fini;
570 	}
571 	state->acquire_ctx = &ctx;
572 
573 	if (source) {
574 		for (i = 0; i < ARRAY_SIZE(head->crc.ctx); i++) {
575 			ret = nv50_crc_ctx_init(head, mmu, &crc->ctx[i],
576 						func->notifier_len, i);
577 			if (ret)
578 				goto out_ctx_fini;
579 		}
580 	}
581 
582 retry:
583 	crtc_state = drm_atomic_get_crtc_state(state, &head->base.base);
584 	if (IS_ERR(crtc_state)) {
585 		ret = PTR_ERR(crtc_state);
586 		if (ret == -EDEADLK)
587 			goto deadlock;
588 		else if (ret)
589 			goto out_drop_locks;
590 	}
591 	asyh = nv50_head_atom(crtc_state);
592 	asyh->crc.src = source;
593 	asyh->or.crc_raster = nv50_crc_raster_type(source);
594 
595 	ret = drm_atomic_commit(state);
596 	if (ret == -EDEADLK)
597 		goto deadlock;
598 	else if (ret)
599 		goto out_drop_locks;
600 
601 	if (!source) {
602 		/*
603 		 * If the user specified a custom flip threshold through
604 		 * debugfs, reset it
605 		 */
606 		crc->flip_threshold = func->flip_threshold;
607 	}
608 
609 out_drop_locks:
610 	drm_modeset_drop_locks(&ctx);
611 out_ctx_fini:
612 	if (!source || ret) {
613 		for (i = 0; i < ARRAY_SIZE(crc->ctx); i++)
614 			nv50_crc_ctx_fini(&crc->ctx[i]);
615 	}
616 	drm_atomic_state_put(state);
617 out_acquire_fini:
618 	drm_modeset_acquire_fini(&ctx);
619 	return ret;
620 
621 deadlock:
622 	drm_atomic_state_clear(state);
623 	drm_modeset_backoff(&ctx);
624 	goto retry;
625 }
626 
627 static int
628 nv50_crc_debugfs_flip_threshold_get(struct seq_file *m, void *data)
629 {
630 	struct nv50_head *head = m->private;
631 	struct drm_crtc *crtc = &head->base.base;
632 	struct nv50_crc *crc = &head->crc;
633 	int ret;
634 
635 	ret = drm_modeset_lock_single_interruptible(&crtc->mutex);
636 	if (ret)
637 		return ret;
638 
639 	seq_printf(m, "%d\n", crc->flip_threshold);
640 
641 	drm_modeset_unlock(&crtc->mutex);
642 	return ret;
643 }
644 
645 static int
646 nv50_crc_debugfs_flip_threshold_open(struct inode *inode, struct file *file)
647 {
648 	return single_open(file, nv50_crc_debugfs_flip_threshold_get,
649 			   inode->i_private);
650 }
651 
652 static ssize_t
653 nv50_crc_debugfs_flip_threshold_set(struct file *file,
654 				    const char __user *ubuf, size_t len,
655 				    loff_t *offp)
656 {
657 	struct seq_file *m = file->private_data;
658 	struct nv50_head *head = m->private;
659 	struct nv50_head_atom *armh;
660 	struct drm_crtc *crtc = &head->base.base;
661 	struct nouveau_drm *drm = nouveau_drm(crtc->dev);
662 	struct nv50_crc *crc = &head->crc;
663 	const struct nv50_crc_func *func =
664 		nv50_disp(crtc->dev)->core->func->crc;
665 	int value, ret;
666 
667 	ret = kstrtoint_from_user(ubuf, len, 10, &value);
668 	if (ret)
669 		return ret;
670 
671 	if (value > func->flip_threshold)
672 		return -EINVAL;
673 	else if (value == -1)
674 		value = func->flip_threshold;
675 	else if (value < -1)
676 		return -EINVAL;
677 
678 	ret = drm_modeset_lock_single_interruptible(&crtc->mutex);
679 	if (ret)
680 		return ret;
681 
682 	armh = nv50_head_atom(crtc->state);
683 	if (armh->crc.src) {
684 		ret = -EBUSY;
685 		goto out;
686 	}
687 
688 	NV_DEBUG(drm,
689 		 "Changing CRC flip threshold for next capture on head-%d to %d\n",
690 		 head->base.index, value);
691 	crc->flip_threshold = value;
692 	ret = len;
693 
694 out:
695 	drm_modeset_unlock(&crtc->mutex);
696 	return ret;
697 }
698 
699 static const struct file_operations nv50_crc_flip_threshold_fops = {
700 	.owner = THIS_MODULE,
701 	.open = nv50_crc_debugfs_flip_threshold_open,
702 	.read = seq_read,
703 	.write = nv50_crc_debugfs_flip_threshold_set,
704 	.release = single_release,
705 };
706 
707 int nv50_head_crc_late_register(struct nv50_head *head)
708 {
709 	struct drm_crtc *crtc = &head->base.base;
710 	const struct nv50_crc_func *func =
711 		nv50_disp(crtc->dev)->core->func->crc;
712 	struct dentry *root;
713 
714 	if (!func || !crtc->debugfs_entry)
715 		return 0;
716 
717 	root = debugfs_create_dir("nv_crc", crtc->debugfs_entry);
718 	debugfs_create_file("flip_threshold", 0644, root, head,
719 			    &nv50_crc_flip_threshold_fops);
720 
721 	return 0;
722 }
723 
724 static inline void
725 nv50_crc_init_head(struct nv50_disp *disp, const struct nv50_crc_func *func,
726 		   struct nv50_head *head)
727 {
728 	struct nv50_crc *crc = &head->crc;
729 
730 	crc->flip_threshold = func->flip_threshold;
731 	spin_lock_init(&crc->lock);
732 	drm_vblank_work_init(&crc->flip_work, &head->base.base,
733 			     nv50_crc_ctx_flip_work);
734 }
735 
736 void nv50_crc_init(struct drm_device *dev)
737 {
738 	struct nv50_disp *disp = nv50_disp(dev);
739 	struct drm_crtc *crtc;
740 	const struct nv50_crc_func *func = disp->core->func->crc;
741 
742 	if (!func)
743 		return;
744 
745 	drm_for_each_crtc(crtc, dev)
746 		nv50_crc_init_head(disp, func, nv50_head(crtc));
747 }
748