xref: /openbmc/linux/drivers/gpu/drm/drm_plane_helper.c (revision 93707cbabcc8baf2b2b5f4a99c1f08ee83eb7abd)
1 /*
2  * Copyright (C) 2014 Intel Corporation
3  *
4  * DRM universal plane helper functions
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23  * SOFTWARE.
24  */
25 
26 #include <linux/list.h>
27 #include <drm/drmP.h>
28 #include <drm/drm_plane_helper.h>
29 #include <drm/drm_rect.h>
30 #include <drm/drm_atomic.h>
31 #include <drm/drm_crtc_helper.h>
32 #include <drm/drm_encoder.h>
33 #include <drm/drm_atomic_helper.h>
34 
35 #define SUBPIXEL_MASK 0xffff
36 
37 /**
38  * DOC: overview
39  *
40  * This helper library has two parts. The first part has support to implement
41  * primary plane support on top of the normal CRTC configuration interface.
42  * Since the legacy &drm_mode_config_funcs.set_config interface ties the primary
43  * plane together with the CRTC state this does not allow userspace to disable
44  * the primary plane itself.  To avoid too much duplicated code use
45  * drm_plane_helper_check_update() which can be used to enforce the same
46  * restrictions as primary planes had thus. The default primary plane only
47  * expose XRBG8888 and ARGB8888 as valid pixel formats for the attached
48  * framebuffer.
49  *
50  * Drivers are highly recommended to implement proper support for primary
51  * planes, and newly merged drivers must not rely upon these transitional
52  * helpers.
53  *
54  * The second part also implements transitional helpers which allow drivers to
55  * gradually switch to the atomic helper infrastructure for plane updates. Once
56  * that switch is complete drivers shouldn't use these any longer, instead using
57  * the proper legacy implementations for update and disable plane hooks provided
58  * by the atomic helpers.
59  *
60  * Again drivers are strongly urged to switch to the new interfaces.
61  *
62  * The plane helpers share the function table structures with other helpers,
63  * specifically also the atomic helpers. See &struct drm_plane_helper_funcs for
64  * the details.
65  */
66 
67 /*
68  * Returns the connectors currently associated with a CRTC.  This function
69  * should be called twice:  once with a NULL connector list to retrieve
70  * the list size, and once with the properly allocated list to be filled in.
71  */
72 static int get_connectors_for_crtc(struct drm_crtc *crtc,
73 				   struct drm_connector **connector_list,
74 				   int num_connectors)
75 {
76 	struct drm_device *dev = crtc->dev;
77 	struct drm_connector *connector;
78 	struct drm_connector_list_iter conn_iter;
79 	int count = 0;
80 
81 	/*
82 	 * Note: Once we change the plane hooks to more fine-grained locking we
83 	 * need to grab the connection_mutex here to be able to make these
84 	 * checks.
85 	 */
86 	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
87 
88 	drm_connector_list_iter_begin(dev, &conn_iter);
89 	drm_for_each_connector_iter(connector, &conn_iter) {
90 		if (connector->encoder && connector->encoder->crtc == crtc) {
91 			if (connector_list != NULL && count < num_connectors)
92 				*(connector_list++) = connector;
93 
94 			count++;
95 		}
96 	}
97 	drm_connector_list_iter_end(&conn_iter);
98 
99 	return count;
100 }
101 
102 /**
103  * drm_plane_helper_check_update() - Check plane update for validity
104  * @plane: plane object to update
105  * @crtc: owning CRTC of owning plane
106  * @fb: framebuffer to flip onto plane
107  * @src: source coordinates in 16.16 fixed point
108  * @dst: integer destination coordinates
109  * @clip: integer clipping coordinates
110  * @rotation: plane rotation
111  * @min_scale: minimum @src:@dest scaling factor in 16.16 fixed point
112  * @max_scale: maximum @src:@dest scaling factor in 16.16 fixed point
113  * @can_position: is it legal to position the plane such that it
114  *                doesn't cover the entire crtc?  This will generally
115  *                only be false for primary planes.
116  * @can_update_disabled: can the plane be updated while the crtc
117  *                       is disabled?
118  * @visible: output parameter indicating whether plane is still visible after
119  *           clipping
120  *
121  * Checks that a desired plane update is valid.  Drivers that provide
122  * their own plane handling rather than helper-provided implementations may
123  * still wish to call this function to avoid duplication of error checking
124  * code.
125  *
126  * RETURNS:
127  * Zero if update appears valid, error code on failure
128  */
129 int drm_plane_helper_check_update(struct drm_plane *plane,
130 				  struct drm_crtc *crtc,
131 				  struct drm_framebuffer *fb,
132 				  struct drm_rect *src,
133 				  struct drm_rect *dst,
134 				  const struct drm_rect *clip,
135 				  unsigned int rotation,
136 				  int min_scale,
137 				  int max_scale,
138 				  bool can_position,
139 				  bool can_update_disabled,
140 				  bool *visible)
141 {
142 	struct drm_plane_state plane_state = {
143 		.plane = plane,
144 		.crtc = crtc,
145 		.fb = fb,
146 		.src_x = src->x1,
147 		.src_y = src->y1,
148 		.src_w = drm_rect_width(src),
149 		.src_h = drm_rect_height(src),
150 		.crtc_x = dst->x1,
151 		.crtc_y = dst->y1,
152 		.crtc_w = drm_rect_width(dst),
153 		.crtc_h = drm_rect_height(dst),
154 		.rotation = rotation,
155 		.visible = *visible,
156 	};
157 	struct drm_crtc_state crtc_state = {
158 		.crtc = crtc,
159 		.enable = crtc->enabled,
160 	};
161 	int ret;
162 
163 	ret = drm_atomic_helper_check_plane_state(&plane_state, &crtc_state,
164 						  clip, min_scale, max_scale,
165 						  can_position,
166 						  can_update_disabled);
167 	if (ret)
168 		return ret;
169 
170 	*src = plane_state.src;
171 	*dst = plane_state.dst;
172 	*visible = plane_state.visible;
173 
174 	return 0;
175 }
176 EXPORT_SYMBOL(drm_plane_helper_check_update);
177 
178 /**
179  * drm_primary_helper_update() - Helper for primary plane update
180  * @plane: plane object to update
181  * @crtc: owning CRTC of owning plane
182  * @fb: framebuffer to flip onto plane
183  * @crtc_x: x offset of primary plane on crtc
184  * @crtc_y: y offset of primary plane on crtc
185  * @crtc_w: width of primary plane rectangle on crtc
186  * @crtc_h: height of primary plane rectangle on crtc
187  * @src_x: x offset of @fb for panning
188  * @src_y: y offset of @fb for panning
189  * @src_w: width of source rectangle in @fb
190  * @src_h: height of source rectangle in @fb
191  * @ctx: lock acquire context, not used here
192  *
193  * Provides a default plane update handler for primary planes.  This is handler
194  * is called in response to a userspace SetPlane operation on the plane with a
195  * non-NULL framebuffer.  We call the driver's modeset handler to update the
196  * framebuffer.
197  *
198  * SetPlane() on a primary plane of a disabled CRTC is not supported, and will
199  * return an error.
200  *
201  * Note that we make some assumptions about hardware limitations that may not be
202  * true for all hardware --
203  *
204  * 1. Primary plane cannot be repositioned.
205  * 2. Primary plane cannot be scaled.
206  * 3. Primary plane must cover the entire CRTC.
207  * 4. Subpixel positioning is not supported.
208  *
209  * Drivers for hardware that don't have these restrictions can provide their
210  * own implementation rather than using this helper.
211  *
212  * RETURNS:
213  * Zero on success, error code on failure
214  */
215 int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
216 			      struct drm_framebuffer *fb,
217 			      int crtc_x, int crtc_y,
218 			      unsigned int crtc_w, unsigned int crtc_h,
219 			      uint32_t src_x, uint32_t src_y,
220 			      uint32_t src_w, uint32_t src_h,
221 			      struct drm_modeset_acquire_ctx *ctx)
222 {
223 	struct drm_mode_set set = {
224 		.crtc = crtc,
225 		.fb = fb,
226 		.mode = &crtc->mode,
227 		.x = src_x >> 16,
228 		.y = src_y >> 16,
229 	};
230 	struct drm_rect src = {
231 		.x1 = src_x,
232 		.y1 = src_y,
233 		.x2 = src_x + src_w,
234 		.y2 = src_y + src_h,
235 	};
236 	struct drm_rect dest = {
237 		.x1 = crtc_x,
238 		.y1 = crtc_y,
239 		.x2 = crtc_x + crtc_w,
240 		.y2 = crtc_y + crtc_h,
241 	};
242 	const struct drm_rect clip = {
243 		.x2 = crtc->mode.hdisplay,
244 		.y2 = crtc->mode.vdisplay,
245 	};
246 	struct drm_connector **connector_list;
247 	int num_connectors, ret;
248 	bool visible;
249 
250 	ret = drm_plane_helper_check_update(plane, crtc, fb,
251 					    &src, &dest, &clip,
252 					    DRM_MODE_ROTATE_0,
253 					    DRM_PLANE_HELPER_NO_SCALING,
254 					    DRM_PLANE_HELPER_NO_SCALING,
255 					    false, false, &visible);
256 	if (ret)
257 		return ret;
258 
259 	if (!visible)
260 		/*
261 		 * Primary plane isn't visible.  Note that unless a driver
262 		 * provides their own disable function, this will just
263 		 * wind up returning -EINVAL to userspace.
264 		 */
265 		return plane->funcs->disable_plane(plane, ctx);
266 
267 	/* Find current connectors for CRTC */
268 	num_connectors = get_connectors_for_crtc(crtc, NULL, 0);
269 	BUG_ON(num_connectors == 0);
270 	connector_list = kcalloc(num_connectors, sizeof(*connector_list),
271 				 GFP_KERNEL);
272 	if (!connector_list)
273 		return -ENOMEM;
274 	get_connectors_for_crtc(crtc, connector_list, num_connectors);
275 
276 	set.connectors = connector_list;
277 	set.num_connectors = num_connectors;
278 
279 	/*
280 	 * We call set_config() directly here rather than using
281 	 * drm_mode_set_config_internal.  We're reprogramming the same
282 	 * connectors that were already in use, so we shouldn't need the extra
283 	 * cross-CRTC fb refcounting to accomodate stealing connectors.
284 	 * drm_mode_setplane() already handles the basic refcounting for the
285 	 * framebuffers involved in this operation.
286 	 */
287 	ret = crtc->funcs->set_config(&set, ctx);
288 
289 	kfree(connector_list);
290 	return ret;
291 }
292 EXPORT_SYMBOL(drm_primary_helper_update);
293 
294 /**
295  * drm_primary_helper_disable() - Helper for primary plane disable
296  * @plane: plane to disable
297  * @ctx: lock acquire context, not used here
298  *
299  * Provides a default plane disable handler for primary planes.  This is handler
300  * is called in response to a userspace SetPlane operation on the plane with a
301  * NULL framebuffer parameter.  It unconditionally fails the disable call with
302  * -EINVAL the only way to disable the primary plane without driver support is
303  * to disable the entire CRTC. Which does not match the plane
304  * &drm_plane_funcs.disable_plane hook.
305  *
306  * Note that some hardware may be able to disable the primary plane without
307  * disabling the whole CRTC.  Drivers for such hardware should provide their
308  * own disable handler that disables just the primary plane (and they'll likely
309  * need to provide their own update handler as well to properly re-enable a
310  * disabled primary plane).
311  *
312  * RETURNS:
313  * Unconditionally returns -EINVAL.
314  */
315 int drm_primary_helper_disable(struct drm_plane *plane,
316 			       struct drm_modeset_acquire_ctx *ctx)
317 {
318 	return -EINVAL;
319 }
320 EXPORT_SYMBOL(drm_primary_helper_disable);
321 
322 /**
323  * drm_primary_helper_destroy() - Helper for primary plane destruction
324  * @plane: plane to destroy
325  *
326  * Provides a default plane destroy handler for primary planes.  This handler
327  * is called during CRTC destruction.  We disable the primary plane, remove
328  * it from the DRM plane list, and deallocate the plane structure.
329  */
330 void drm_primary_helper_destroy(struct drm_plane *plane)
331 {
332 	drm_plane_cleanup(plane);
333 	kfree(plane);
334 }
335 EXPORT_SYMBOL(drm_primary_helper_destroy);
336 
337 const struct drm_plane_funcs drm_primary_helper_funcs = {
338 	.update_plane = drm_primary_helper_update,
339 	.disable_plane = drm_primary_helper_disable,
340 	.destroy = drm_primary_helper_destroy,
341 };
342 EXPORT_SYMBOL(drm_primary_helper_funcs);
343 
344 int drm_plane_helper_commit(struct drm_plane *plane,
345 			    struct drm_plane_state *plane_state,
346 			    struct drm_framebuffer *old_fb)
347 {
348 	const struct drm_plane_helper_funcs *plane_funcs;
349 	struct drm_crtc *crtc[2];
350 	const struct drm_crtc_helper_funcs *crtc_funcs[2];
351 	int i, ret = 0;
352 
353 	plane_funcs = plane->helper_private;
354 
355 	/* Since this is a transitional helper we can't assume that plane->state
356 	 * is always valid. Hence we need to use plane->crtc instead of
357 	 * plane->state->crtc as the old crtc. */
358 	crtc[0] = plane->crtc;
359 	crtc[1] = crtc[0] != plane_state->crtc ? plane_state->crtc : NULL;
360 
361 	for (i = 0; i < 2; i++)
362 		crtc_funcs[i] = crtc[i] ? crtc[i]->helper_private : NULL;
363 
364 	if (plane_funcs->atomic_check) {
365 		ret = plane_funcs->atomic_check(plane, plane_state);
366 		if (ret)
367 			goto out;
368 	}
369 
370 	if (plane_funcs->prepare_fb && plane_state->fb != old_fb) {
371 		ret = plane_funcs->prepare_fb(plane,
372 					      plane_state);
373 		if (ret)
374 			goto out;
375 	}
376 
377 	/* Point of no return, commit sw state. */
378 	swap(plane->state, plane_state);
379 
380 	for (i = 0; i < 2; i++) {
381 		if (crtc_funcs[i] && crtc_funcs[i]->atomic_begin)
382 			crtc_funcs[i]->atomic_begin(crtc[i], crtc[i]->state);
383 	}
384 
385 	/*
386 	 * Drivers may optionally implement the ->atomic_disable callback, so
387 	 * special-case that here.
388 	 */
389 	if (drm_atomic_plane_disabling(plane_state, plane->state) &&
390 	    plane_funcs->atomic_disable)
391 		plane_funcs->atomic_disable(plane, plane_state);
392 	else
393 		plane_funcs->atomic_update(plane, plane_state);
394 
395 	for (i = 0; i < 2; i++) {
396 		if (crtc_funcs[i] && crtc_funcs[i]->atomic_flush)
397 			crtc_funcs[i]->atomic_flush(crtc[i], crtc[i]->state);
398 	}
399 
400 	/*
401 	 * If we only moved the plane and didn't change fb's, there's no need to
402 	 * wait for vblank.
403 	 */
404 	if (plane->state->fb == old_fb)
405 		goto out;
406 
407 	for (i = 0; i < 2; i++) {
408 		if (!crtc[i])
409 			continue;
410 
411 		if (crtc[i]->cursor == plane)
412 			continue;
413 
414 		/* There's no other way to figure out whether the crtc is running. */
415 		ret = drm_crtc_vblank_get(crtc[i]);
416 		if (ret == 0) {
417 			drm_crtc_wait_one_vblank(crtc[i]);
418 			drm_crtc_vblank_put(crtc[i]);
419 		}
420 
421 		ret = 0;
422 	}
423 
424 	if (plane_funcs->cleanup_fb)
425 		plane_funcs->cleanup_fb(plane, plane_state);
426 out:
427 	if (plane->funcs->atomic_destroy_state)
428 		plane->funcs->atomic_destroy_state(plane, plane_state);
429 	else
430 		drm_atomic_helper_plane_destroy_state(plane, plane_state);
431 
432 	return ret;
433 }
434 
435 /**
436  * drm_plane_helper_update() - Transitional helper for plane update
437  * @plane: plane object to update
438  * @crtc: owning CRTC of owning plane
439  * @fb: framebuffer to flip onto plane
440  * @crtc_x: x offset of primary plane on crtc
441  * @crtc_y: y offset of primary plane on crtc
442  * @crtc_w: width of primary plane rectangle on crtc
443  * @crtc_h: height of primary plane rectangle on crtc
444  * @src_x: x offset of @fb for panning
445  * @src_y: y offset of @fb for panning
446  * @src_w: width of source rectangle in @fb
447  * @src_h: height of source rectangle in @fb
448  *
449  * Provides a default plane update handler using the atomic plane update
450  * functions. It is fully left to the driver to check plane constraints and
451  * handle corner-cases like a fully occluded or otherwise invisible plane.
452  *
453  * This is useful for piecewise transitioning of a driver to the atomic helpers.
454  *
455  * RETURNS:
456  * Zero on success, error code on failure
457  */
458 int drm_plane_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
459 			    struct drm_framebuffer *fb,
460 			    int crtc_x, int crtc_y,
461 			    unsigned int crtc_w, unsigned int crtc_h,
462 			    uint32_t src_x, uint32_t src_y,
463 			    uint32_t src_w, uint32_t src_h)
464 {
465 	struct drm_plane_state *plane_state;
466 
467 	if (plane->funcs->atomic_duplicate_state)
468 		plane_state = plane->funcs->atomic_duplicate_state(plane);
469 	else {
470 		if (!plane->state)
471 			drm_atomic_helper_plane_reset(plane);
472 
473 		plane_state = drm_atomic_helper_plane_duplicate_state(plane);
474 	}
475 	if (!plane_state)
476 		return -ENOMEM;
477 	plane_state->plane = plane;
478 
479 	plane_state->crtc = crtc;
480 	drm_atomic_set_fb_for_plane(plane_state, fb);
481 	plane_state->crtc_x = crtc_x;
482 	plane_state->crtc_y = crtc_y;
483 	plane_state->crtc_h = crtc_h;
484 	plane_state->crtc_w = crtc_w;
485 	plane_state->src_x = src_x;
486 	plane_state->src_y = src_y;
487 	plane_state->src_h = src_h;
488 	plane_state->src_w = src_w;
489 
490 	return drm_plane_helper_commit(plane, plane_state, plane->fb);
491 }
492 EXPORT_SYMBOL(drm_plane_helper_update);
493 
494 /**
495  * drm_plane_helper_disable() - Transitional helper for plane disable
496  * @plane: plane to disable
497  *
498  * Provides a default plane disable handler using the atomic plane update
499  * functions. It is fully left to the driver to check plane constraints and
500  * handle corner-cases like a fully occluded or otherwise invisible plane.
501  *
502  * This is useful for piecewise transitioning of a driver to the atomic helpers.
503  *
504  * RETURNS:
505  * Zero on success, error code on failure
506  */
507 int drm_plane_helper_disable(struct drm_plane *plane)
508 {
509 	struct drm_plane_state *plane_state;
510 
511 	/* crtc helpers love to call disable functions for already disabled hw
512 	 * functions. So cope with that. */
513 	if (!plane->crtc)
514 		return 0;
515 
516 	if (plane->funcs->atomic_duplicate_state)
517 		plane_state = plane->funcs->atomic_duplicate_state(plane);
518 	else {
519 		if (!plane->state)
520 			drm_atomic_helper_plane_reset(plane);
521 
522 		plane_state = drm_atomic_helper_plane_duplicate_state(plane);
523 	}
524 	if (!plane_state)
525 		return -ENOMEM;
526 	plane_state->plane = plane;
527 
528 	plane_state->crtc = NULL;
529 	drm_atomic_set_fb_for_plane(plane_state, NULL);
530 
531 	return drm_plane_helper_commit(plane, plane_state, plane->fb);
532 }
533 EXPORT_SYMBOL(drm_plane_helper_disable);
534