xref: /linux/drivers/gpu/drm/drm_blend.c (revision 13c072b8e91a5ccb5855ca1ba6fe3ea467dbf94d)
1 /*
2  * Copyright (C) 2016 Samsung Electronics Co.Ltd
3  * Authors:
4  *	Marek Szyprowski <m.szyprowski@samsung.com>
5  *
6  * DRM core plane blending related functions
7  *
8  * Permission to use, copy, modify, distribute, and sell this software and its
9  * documentation for any purpose is hereby granted without fee, provided that
10  * the above copyright notice appear in all copies and that both that copyright
11  * notice and this permission notice appear in supporting documentation, and
12  * that the name of the copyright holders not be used in advertising or
13  * publicity pertaining to distribution of the software without specific,
14  * written prior permission.  The copyright holders make no representations
15  * about the suitability of this software for any purpose.  It is provided "as
16  * is" without express or implied warranty.
17  *
18  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
20  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
21  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
22  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
23  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
24  * OF THIS SOFTWARE.
25  */
26 
27 #include <linux/export.h>
28 #include <linux/slab.h>
29 #include <linux/sort.h>
30 
31 #include <drm/drm_atomic.h>
32 #include <drm/drm_blend.h>
33 #include <drm/drm_device.h>
34 #include <drm/drm_print.h>
35 
36 #include "drm_crtc_internal.h"
37 
38 /**
39  * DOC: overview
40  *
41  * The basic plane composition model supported by standard plane properties only
42  * has a source rectangle (in logical pixels within the &drm_framebuffer), with
43  * sub-pixel accuracy, which is scaled up to a pixel-aligned destination
44  * rectangle in the visible area of a &drm_crtc. The visible area of a CRTC is
45  * defined by the horizontal and vertical visible pixels (stored in @hdisplay
46  * and @vdisplay) of the requested mode (stored in &drm_crtc_state.mode). These
47  * two rectangles are both stored in the &drm_plane_state.
48  *
49  * For the atomic ioctl the following standard (atomic) properties on the plane object
50  * encode the basic plane composition model:
51  *
52  * SRC_X:
53  * 	X coordinate offset for the source rectangle within the
54  * 	&drm_framebuffer, in 16.16 fixed point. Must be positive.
55  * SRC_Y:
56  * 	Y coordinate offset for the source rectangle within the
57  * 	&drm_framebuffer, in 16.16 fixed point. Must be positive.
58  * SRC_W:
59  * 	Width for the source rectangle within the &drm_framebuffer, in 16.16
60  * 	fixed point. SRC_X plus SRC_W must be within the width of the source
61  * 	framebuffer. Must be positive.
62  * SRC_H:
63  * 	Height for the source rectangle within the &drm_framebuffer, in 16.16
64  * 	fixed point. SRC_Y plus SRC_H must be within the height of the source
65  * 	framebuffer. Must be positive.
66  * CRTC_X:
67  * 	X coordinate offset for the destination rectangle. Can be negative.
68  * CRTC_Y:
69  * 	Y coordinate offset for the destination rectangle. Can be negative.
70  * CRTC_W:
71  * 	Width for the destination rectangle. CRTC_X plus CRTC_W can extend past
72  * 	the currently visible horizontal area of the &drm_crtc.
73  * CRTC_H:
74  * 	Height for the destination rectangle. CRTC_Y plus CRTC_H can extend past
75  * 	the currently visible vertical area of the &drm_crtc.
76  * FB_ID:
77  * 	Mode object ID of the &drm_framebuffer this plane should scan out.
78  *
79  *	When a KMS client is performing front-buffer rendering, it should set
80  *	FB_ID to the same front-buffer FB on each atomic commit. This implies
81  *	to the driver that it needs to re-read the same FB again. Otherwise
82  *	drivers which do not employ continuously repeated scanout cycles might
83  *	not update the screen.
84  * CRTC_ID:
85  * 	Mode object ID of the &drm_crtc this plane should be connected to.
86  *
87  * Note that the source rectangle must fully lie within the bounds of the
88  * &drm_framebuffer. The destination rectangle can lie outside of the visible
89  * area of the current mode of the CRTC. It must be appropriately clipped by the
90  * driver, which can be done by calling drm_plane_helper_check_update(). Drivers
91  * are also allowed to round the subpixel sampling positions appropriately, but
92  * only to the next full pixel. No pixel outside of the source rectangle may
93  * ever be sampled, which is important when applying more sophisticated
94  * filtering than just a bilinear one when scaling. The filtering mode when
95  * scaling is unspecified.
96  *
97  * On top of this basic transformation additional properties can be exposed by
98  * the driver:
99  *
100  * alpha:
101  * 	Alpha is setup with drm_plane_create_alpha_property(). It controls the
102  * 	plane-wide opacity, from transparent (0) to opaque (0xffff). It can be
103  * 	combined with pixel alpha.
104  *	The pixel values in the framebuffers are expected to not be
105  *	pre-multiplied by the global alpha associated to the plane.
106  *
107  * rotation:
108  *	Rotation is set up with drm_plane_create_rotation_property(). It adds a
109  *	rotation and reflection step between the source and destination rectangles.
110  *	Without this property the rectangle is only scaled, but not rotated or
111  *	reflected.
112  *
113  *	Possbile values:
114  *
115  *	"rotate-<degrees>":
116  *		Signals that a drm plane is rotated <degrees> degrees in counter
117  *		clockwise direction.
118  *
119  *	"reflect-<axis>":
120  *		Signals that the contents of a drm plane is reflected along the
121  *		<axis> axis, in the same way as mirroring.
122  *
123  *	reflect-x::
124  *
125  *			|o |    | o|
126  *			|  | -> |  |
127  *			| v|    |v |
128  *
129  *	reflect-y::
130  *
131  *			|o |    | ^|
132  *			|  | -> |  |
133  *			| v|    |o |
134  *
135  * zpos:
136  *	Z position is set up with drm_plane_create_zpos_immutable_property() and
137  *	drm_plane_create_zpos_property(). It controls the visibility of overlapping
138  *	planes. Without this property the primary plane is always below the cursor
139  *	plane, and ordering between all other planes is undefined. The positive
140  *	Z axis points towards the user, i.e. planes with lower Z position values
141  *	are underneath planes with higher Z position values. Two planes with the
142  *	same Z position value have undefined ordering. Note that the Z position
143  *	value can also be immutable, to inform userspace about the hard-coded
144  *	stacking of planes, see drm_plane_create_zpos_immutable_property(). If
145  *	any plane has a zpos property (either mutable or immutable), then all
146  *	planes shall have a zpos property.
147  *
148  * pixel blend mode:
149  *	Pixel blend mode is set up with drm_plane_create_blend_mode_property().
150  *	It adds a blend mode for alpha blending equation selection, describing
151  *	how the pixels from the current plane are composited with the
152  *	background.
153  *
154  *	 Three alpha blending equations are defined:
155  *
156  *	 "None":
157  *		 Blend formula that ignores the pixel alpha::
158  *
159  *			 out.rgb = plane_alpha * fg.rgb +
160  *				 (1 - plane_alpha) * bg.rgb
161  *
162  *	 "Pre-multiplied":
163  *		 Blend formula that assumes the pixel color values
164  *		 have been already pre-multiplied with the alpha
165  *		 channel values::
166  *
167  *			 out.rgb = plane_alpha * fg.rgb +
168  *				 (1 - (plane_alpha * fg.alpha)) * bg.rgb
169  *
170  *	 "Coverage":
171  *		 Blend formula that assumes the pixel color values have not
172  *		 been pre-multiplied and will do so when blending them to the
173  *		 background color values::
174  *
175  *			 out.rgb = plane_alpha * fg.alpha * fg.rgb +
176  *				 (1 - (plane_alpha * fg.alpha)) * bg.rgb
177  *
178  *	 Using the following symbols:
179  *
180  *	 "fg.rgb":
181  *		 Each of the RGB component values from the plane's pixel
182  *	 "fg.alpha":
183  *		 Alpha component value from the plane's pixel. If the plane's
184  *		 pixel format has no alpha component, then this is assumed to be
185  *		 1.0. In these cases, this property has no effect, as all three
186  *		 equations become equivalent.
187  *	 "bg.rgb":
188  *		 Each of the RGB component values from the background
189  *	 "plane_alpha":
190  *		 Plane alpha value set by the plane "alpha" property. If the
191  *		 plane does not expose the "alpha" property, then this is
192  *		 assumed to be 1.0
193  *
194  * SCALING_FILTER:
195  *     Indicates scaling filter to be used for plane scaler
196  *
197  *     The value of this property can be one of the following:
198  *
199  *     Default:
200  *             Driver's default scaling filter
201  *     Nearest Neighbor:
202  *             Nearest Neighbor scaling filter
203  *
204  * Drivers can set up this property for a plane by calling
205  * drm_plane_create_scaling_filter_property
206  *
207  * The property extensions described above all apply to the plane.  Drivers
208  * may also expose the following crtc property extension:
209  *
210  * BACKGROUND_COLOR:
211  *	Background color is set up with drm_crtc_attach_background_color_property(),
212  *	and expects a 64-bit ARGB value following DRM_FORMAT_ARGB16161616, as
213  *	generated by the DRM_ARGB64_PREP*() helpers. It controls the color of a
214  *	full-screen layer that exists below all planes. This color will be used
215  *	for pixels not covered by any plane and may also be blended with plane
216  *	contents as allowed by a plane's alpha values.
217  *	The background color defaults to black, and is assumed to be black for
218  *	drivers that do not expose this property. Although background color
219  *	isn't a plane, it is assumed that the color provided here undergoes the
220  *	CRTC degamma/CSC/gamma transformations applied after the planes blending.
221  *	Note that the color value includes an alpha channel, hence non-opaque
222  *	background color values are allowed, but since physically transparent
223  *	monitors do not (yet) exists, the final alpha value may not reach the
224  *	video sink or it may simply ignore it.
225  */
226 
227 /**
228  * drm_plane_create_alpha_property - create a new alpha property
229  * @plane: drm plane
230  *
231  * This function creates a generic, mutable, alpha property and enables support
232  * for it in the DRM core. It is attached to @plane.
233  *
234  * The alpha property will be allowed to be within the bounds of 0
235  * (transparent) to 0xffff (opaque).
236  *
237  * Returns:
238  * 0 on success, negative error code on failure.
239  */
240 int drm_plane_create_alpha_property(struct drm_plane *plane)
241 {
242 	struct drm_property *prop;
243 
244 	prop = drm_property_create_range(plane->dev, 0, "alpha",
245 					 0, DRM_BLEND_ALPHA_OPAQUE);
246 	if (!prop)
247 		return -ENOMEM;
248 
249 	drm_object_attach_property(&plane->base, prop, DRM_BLEND_ALPHA_OPAQUE);
250 	plane->alpha_property = prop;
251 
252 	if (plane->state)
253 		plane->state->alpha = DRM_BLEND_ALPHA_OPAQUE;
254 
255 	return 0;
256 }
257 EXPORT_SYMBOL(drm_plane_create_alpha_property);
258 
259 /**
260  * drm_plane_create_rotation_property - create a new rotation property
261  * @plane: drm plane
262  * @rotation: initial value of the rotation property
263  * @supported_rotations: bitmask of supported rotations and reflections
264  *
265  * This creates a new property with the selected support for transformations.
266  *
267  * Since a rotation by 180° degress is the same as reflecting both along the x
268  * and the y axis the rotation property is somewhat redundant. Drivers can use
269  * drm_rotation_simplify() to normalize values of this property.
270  *
271  * The property exposed to userspace is a bitmask property (see
272  * drm_property_create_bitmask()) called "rotation" and has the following
273  * bitmask enumaration values:
274  *
275  * DRM_MODE_ROTATE_0:
276  * 	"rotate-0"
277  * DRM_MODE_ROTATE_90:
278  * 	"rotate-90"
279  * DRM_MODE_ROTATE_180:
280  * 	"rotate-180"
281  * DRM_MODE_ROTATE_270:
282  * 	"rotate-270"
283  * DRM_MODE_REFLECT_X:
284  * 	"reflect-x"
285  * DRM_MODE_REFLECT_Y:
286  * 	"reflect-y"
287  *
288  * Rotation is the specified amount in degrees in counter clockwise direction,
289  * the X and Y axis are within the source rectangle, i.e.  the X/Y axis before
290  * rotation. After reflection, the rotation is applied to the image sampled from
291  * the source rectangle, before scaling it to fit the destination rectangle.
292  */
293 int drm_plane_create_rotation_property(struct drm_plane *plane,
294 				       unsigned int rotation,
295 				       unsigned int supported_rotations)
296 {
297 	static const struct drm_prop_enum_list props[] = {
298 		{ __builtin_ffs(DRM_MODE_ROTATE_0) - 1,   "rotate-0" },
299 		{ __builtin_ffs(DRM_MODE_ROTATE_90) - 1,  "rotate-90" },
300 		{ __builtin_ffs(DRM_MODE_ROTATE_180) - 1, "rotate-180" },
301 		{ __builtin_ffs(DRM_MODE_ROTATE_270) - 1, "rotate-270" },
302 		{ __builtin_ffs(DRM_MODE_REFLECT_X) - 1,  "reflect-x" },
303 		{ __builtin_ffs(DRM_MODE_REFLECT_Y) - 1,  "reflect-y" },
304 	};
305 	struct drm_property *prop;
306 
307 	WARN_ON((supported_rotations & DRM_MODE_ROTATE_MASK) == 0);
308 	WARN_ON(!is_power_of_2(rotation & DRM_MODE_ROTATE_MASK));
309 	WARN_ON(rotation & ~supported_rotations);
310 
311 	prop = drm_property_create_bitmask(plane->dev, 0, "rotation",
312 					   props, ARRAY_SIZE(props),
313 					   supported_rotations);
314 	if (!prop)
315 		return -ENOMEM;
316 
317 	drm_object_attach_property(&plane->base, prop, rotation);
318 
319 	if (plane->state)
320 		plane->state->rotation = rotation;
321 
322 	plane->rotation_property = prop;
323 
324 	return 0;
325 }
326 EXPORT_SYMBOL(drm_plane_create_rotation_property);
327 
328 /**
329  * drm_rotation_simplify() - Try to simplify the rotation
330  * @rotation: Rotation to be simplified
331  * @supported_rotations: Supported rotations
332  *
333  * Attempt to simplify the rotation to a form that is supported.
334  * Eg. if the hardware supports everything except DRM_MODE_REFLECT_X
335  * one could call this function like this:
336  *
337  * drm_rotation_simplify(rotation, DRM_MODE_ROTATE_0 |
338  *                       DRM_MODE_ROTATE_90 | DRM_MODE_ROTATE_180 |
339  *                       DRM_MODE_ROTATE_270 | DRM_MODE_REFLECT_Y);
340  *
341  * to eliminate the DRM_MODE_REFLECT_X flag. Depending on what kind of
342  * transforms the hardware supports, this function may not
343  * be able to produce a supported transform, so the caller should
344  * check the result afterwards.
345  */
346 unsigned int drm_rotation_simplify(unsigned int rotation,
347 				   unsigned int supported_rotations)
348 {
349 	if (rotation & ~supported_rotations) {
350 		rotation ^= DRM_MODE_REFLECT_X | DRM_MODE_REFLECT_Y;
351 		rotation = (rotation & DRM_MODE_REFLECT_MASK) |
352 			    BIT((ffs(rotation & DRM_MODE_ROTATE_MASK) + 1)
353 			    % 4);
354 	}
355 
356 	return rotation;
357 }
358 EXPORT_SYMBOL(drm_rotation_simplify);
359 
360 /**
361  * drm_plane_create_zpos_property - create mutable zpos property
362  * @plane: drm plane
363  * @zpos: initial value of zpos property
364  * @min: minimal possible value of zpos property
365  * @max: maximal possible value of zpos property
366  *
367  * This function initializes generic mutable zpos property and enables support
368  * for it in drm core. Drivers can then attach this property to planes to enable
369  * support for configurable planes arrangement during blending operation.
370  * Drivers that attach a mutable zpos property to any plane should call the
371  * drm_atomic_normalize_zpos() helper during their implementation of
372  * &drm_mode_config_funcs.atomic_check(), which will update the normalized zpos
373  * values and store them in &drm_plane_state.normalized_zpos. Usually min
374  * should be set to 0 and max to maximal number of planes for given crtc - 1.
375  *
376  * If zpos of some planes cannot be changed (like fixed background or
377  * cursor/topmost planes), drivers shall adjust the min/max values and assign
378  * those planes immutable zpos properties with lower or higher values (for more
379  * information, see drm_plane_create_zpos_immutable_property() function). In such
380  * case drivers shall also assign proper initial zpos values for all planes in
381  * its plane_reset() callback, so the planes will be always sorted properly.
382  *
383  * See also drm_atomic_normalize_zpos().
384  *
385  * The property exposed to userspace is called "zpos".
386  *
387  * Returns:
388  * Zero on success, negative errno on failure.
389  */
390 int drm_plane_create_zpos_property(struct drm_plane *plane,
391 				   unsigned int zpos,
392 				   unsigned int min, unsigned int max)
393 {
394 	struct drm_property *prop;
395 
396 	prop = drm_property_create_range(plane->dev, 0, "zpos", min, max);
397 	if (!prop)
398 		return -ENOMEM;
399 
400 	drm_object_attach_property(&plane->base, prop, zpos);
401 
402 	plane->zpos_property = prop;
403 
404 	if (plane->state) {
405 		plane->state->zpos = zpos;
406 		plane->state->normalized_zpos = zpos;
407 	}
408 
409 	return 0;
410 }
411 EXPORT_SYMBOL(drm_plane_create_zpos_property);
412 
413 /**
414  * drm_plane_create_zpos_immutable_property - create immuttable zpos property
415  * @plane: drm plane
416  * @zpos: value of zpos property
417  *
418  * This function initializes generic immutable zpos property and enables
419  * support for it in drm core. Using this property driver lets userspace
420  * to get the arrangement of the planes for blending operation and notifies
421  * it that the hardware (or driver) doesn't support changing of the planes'
422  * order. For mutable zpos see drm_plane_create_zpos_property().
423  *
424  * The property exposed to userspace is called "zpos".
425  *
426  * Returns:
427  * Zero on success, negative errno on failure.
428  */
429 int drm_plane_create_zpos_immutable_property(struct drm_plane *plane,
430 					     unsigned int zpos)
431 {
432 	struct drm_property *prop;
433 
434 	prop = drm_property_create_range(plane->dev, DRM_MODE_PROP_IMMUTABLE,
435 					 "zpos", zpos, zpos);
436 	if (!prop)
437 		return -ENOMEM;
438 
439 	drm_object_attach_property(&plane->base, prop, zpos);
440 
441 	plane->zpos_property = prop;
442 
443 	if (plane->state) {
444 		plane->state->zpos = zpos;
445 		plane->state->normalized_zpos = zpos;
446 	}
447 
448 	return 0;
449 }
450 EXPORT_SYMBOL(drm_plane_create_zpos_immutable_property);
451 
452 static int drm_atomic_state_zpos_cmp(const void *a, const void *b)
453 {
454 	const struct drm_plane_state *sa = *(struct drm_plane_state **)a;
455 	const struct drm_plane_state *sb = *(struct drm_plane_state **)b;
456 
457 	if (sa->zpos != sb->zpos)
458 		return sa->zpos - sb->zpos;
459 	else
460 		return sa->plane->base.id - sb->plane->base.id;
461 }
462 
463 static int drm_atomic_helper_crtc_normalize_zpos(struct drm_crtc *crtc,
464 					  struct drm_crtc_state *crtc_state)
465 {
466 	struct drm_atomic_state *state = crtc_state->state;
467 	struct drm_device *dev = crtc->dev;
468 	int total_planes = dev->mode_config.num_total_plane;
469 	struct drm_plane_state **states;
470 	struct drm_plane *plane;
471 	int i, n = 0;
472 	int ret = 0;
473 
474 	drm_dbg_atomic(dev, "[CRTC:%d:%s] calculating normalized zpos values\n",
475 		       crtc->base.id, crtc->name);
476 
477 	states = kmalloc_objs(*states, total_planes);
478 	if (!states)
479 		return -ENOMEM;
480 
481 	/*
482 	 * Normalization process might create new states for planes which
483 	 * normalized_zpos has to be recalculated.
484 	 */
485 	drm_for_each_plane_mask(plane, dev, crtc_state->plane_mask) {
486 		struct drm_plane_state *plane_state =
487 			drm_atomic_get_plane_state(state, plane);
488 		if (IS_ERR(plane_state)) {
489 			ret = PTR_ERR(plane_state);
490 			goto done;
491 		}
492 		states[n++] = plane_state;
493 		drm_dbg_atomic(dev, "[PLANE:%d:%s] processing zpos value %d\n",
494 			       plane->base.id, plane->name, plane_state->zpos);
495 	}
496 
497 	sort(states, n, sizeof(*states), drm_atomic_state_zpos_cmp, NULL);
498 
499 	for (i = 0; i < n; i++) {
500 		plane = states[i]->plane;
501 
502 		states[i]->normalized_zpos = i;
503 		drm_dbg_atomic(dev, "[PLANE:%d:%s] normalized zpos value %d\n",
504 			       plane->base.id, plane->name, i);
505 	}
506 	crtc_state->zpos_changed = true;
507 
508 done:
509 	kfree(states);
510 	return ret;
511 }
512 
513 /**
514  * drm_atomic_normalize_zpos - calculate normalized zpos values for all crtcs
515  * @dev: DRM device
516  * @state: atomic state of DRM device
517  *
518  * This function calculates normalized zpos value for all modified planes in
519  * the provided atomic state of DRM device.
520  *
521  * For every CRTC this function checks new states of all planes assigned to
522  * it and calculates normalized zpos value for these planes. Planes are compared
523  * first by their zpos values, then by plane id (if zpos is equal). The plane
524  * with lowest zpos value is at the bottom. The &drm_plane_state.normalized_zpos
525  * is then filled with unique values from 0 to number of active planes in crtc
526  * minus one.
527  *
528  * RETURNS
529  * Zero for success or -errno
530  */
531 int drm_atomic_normalize_zpos(struct drm_device *dev,
532 			      struct drm_atomic_state *state)
533 {
534 	struct drm_crtc *crtc;
535 	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
536 	struct drm_plane *plane;
537 	struct drm_plane_state *old_plane_state, *new_plane_state;
538 	int i, ret = 0;
539 
540 	for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
541 		crtc = new_plane_state->crtc;
542 		if (!crtc)
543 			continue;
544 		if (old_plane_state->zpos != new_plane_state->zpos) {
545 			new_crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
546 			new_crtc_state->zpos_changed = true;
547 		}
548 	}
549 
550 	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
551 		if (old_crtc_state->plane_mask != new_crtc_state->plane_mask ||
552 		    new_crtc_state->zpos_changed) {
553 			ret = drm_atomic_helper_crtc_normalize_zpos(crtc,
554 								    new_crtc_state);
555 			if (ret)
556 				return ret;
557 		}
558 	}
559 	return 0;
560 }
561 EXPORT_SYMBOL(drm_atomic_normalize_zpos);
562 
563 /**
564  * drm_plane_create_blend_mode_property - create a new blend mode property
565  * @plane: drm plane
566  * @supported_modes: bitmask of supported modes, must include
567  *		     BIT(DRM_MODE_BLEND_PREMULTI). Current DRM assumption is
568  *		     that alpha is premultiplied, and old userspace can break if
569  *		     the property defaults to anything else.
570  *
571  * This creates a new property describing the blend mode.
572  *
573  * The property exposed to userspace is an enumeration property (see
574  * drm_property_create_enum()) called "pixel blend mode" and has the
575  * following enumeration values:
576  *
577  * "None":
578  *	Blend formula that ignores the pixel alpha.
579  *
580  * "Pre-multiplied":
581  *	Blend formula that assumes the pixel color values have been already
582  *	pre-multiplied with the alpha channel values.
583  *
584  * "Coverage":
585  *	Blend formula that assumes the pixel color values have not been
586  *	pre-multiplied and will do so when blending them to the background color
587  *	values.
588  *
589  * RETURNS:
590  * Zero for success or -errno
591  */
592 int drm_plane_create_blend_mode_property(struct drm_plane *plane,
593 					 unsigned int supported_modes)
594 {
595 	struct drm_device *dev = plane->dev;
596 	struct drm_property *prop;
597 	static const struct drm_prop_enum_list props[] = {
598 		{ DRM_MODE_BLEND_PIXEL_NONE, "None" },
599 		{ DRM_MODE_BLEND_PREMULTI, "Pre-multiplied" },
600 		{ DRM_MODE_BLEND_COVERAGE, "Coverage" },
601 	};
602 	unsigned int valid_mode_mask = BIT(DRM_MODE_BLEND_PIXEL_NONE) |
603 				       BIT(DRM_MODE_BLEND_PREMULTI)   |
604 				       BIT(DRM_MODE_BLEND_COVERAGE);
605 	int i;
606 
607 	if (WARN_ON((supported_modes & ~valid_mode_mask) ||
608 		    ((supported_modes & BIT(DRM_MODE_BLEND_PREMULTI)) == 0)))
609 		return -EINVAL;
610 
611 	prop = drm_property_create(dev, DRM_MODE_PROP_ENUM,
612 				   "pixel blend mode",
613 				   hweight32(supported_modes));
614 	if (!prop)
615 		return -ENOMEM;
616 
617 	for (i = 0; i < ARRAY_SIZE(props); i++) {
618 		int ret;
619 
620 		if (!(BIT(props[i].type) & supported_modes))
621 			continue;
622 
623 		ret = drm_property_add_enum(prop, props[i].type,
624 					    props[i].name);
625 
626 		if (ret) {
627 			drm_property_destroy(dev, prop);
628 
629 			return ret;
630 		}
631 	}
632 
633 	drm_object_attach_property(&plane->base, prop, DRM_MODE_BLEND_PREMULTI);
634 	plane->blend_mode_property = prop;
635 
636 	return 0;
637 }
638 EXPORT_SYMBOL(drm_plane_create_blend_mode_property);
639 
640 /**
641  * drm_crtc_attach_background_color_property - attach background color property
642  * @crtc: drm crtc
643  *
644  * Attaches the background color property to @crtc.  The property defaults to
645  * solid black and will accept 64-bit ARGB values in the format generated by
646  * DRM_ARGB64_PREP*() helpers.
647  */
648 void drm_crtc_attach_background_color_property(struct drm_crtc *crtc)
649 {
650 	drm_object_attach_property(&crtc->base,
651 				   crtc->dev->mode_config.background_color_property,
652 				   DRM_ARGB64_PREP(0xffff, 0, 0, 0));
653 }
654 EXPORT_SYMBOL(drm_crtc_attach_background_color_property);
655