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_atomic_uapi.h>
32 #include <drm/drm_crtc_helper.h>
33 #include <drm/drm_encoder.h>
34 #include <drm/drm_atomic_helper.h>
35 
36 #define SUBPIXEL_MASK 0xffff
37 
38 /**
39  * DOC: overview
40  *
41  * This helper library has two parts. The first part has support to implement
42  * primary plane support on top of the normal CRTC configuration interface.
43  * Since the legacy &drm_mode_config_funcs.set_config interface ties the primary
44  * plane together with the CRTC state this does not allow userspace to disable
45  * the primary plane itself.  To avoid too much duplicated code use
46  * drm_plane_helper_check_update() which can be used to enforce the same
47  * restrictions as primary planes had thus. The default primary plane only
48  * expose XRBG8888 and ARGB8888 as valid pixel formats for the attached
49  * framebuffer.
50  *
51  * Drivers are highly recommended to implement proper support for primary
52  * planes, and newly merged drivers must not rely upon these transitional
53  * helpers.
54  *
55  * The second part also implements transitional helpers which allow drivers to
56  * gradually switch to the atomic helper infrastructure for plane updates. Once
57  * that switch is complete drivers shouldn't use these any longer, instead using
58  * the proper legacy implementations for update and disable plane hooks provided
59  * by the atomic helpers.
60  *
61  * Again drivers are strongly urged to switch to the new interfaces.
62  *
63  * The plane helpers share the function table structures with other helpers,
64  * specifically also the atomic helpers. See &struct drm_plane_helper_funcs for
65  * the details.
66  */
67 
68 /*
69  * Returns the connectors currently associated with a CRTC.  This function
70  * should be called twice:  once with a NULL connector list to retrieve
71  * the list size, and once with the properly allocated list to be filled in.
72  */
73 static int get_connectors_for_crtc(struct drm_crtc *crtc,
74 				   struct drm_connector **connector_list,
75 				   int num_connectors)
76 {
77 	struct drm_device *dev = crtc->dev;
78 	struct drm_connector *connector;
79 	struct drm_connector_list_iter conn_iter;
80 	int count = 0;
81 
82 	/*
83 	 * Note: Once we change the plane hooks to more fine-grained locking we
84 	 * need to grab the connection_mutex here to be able to make these
85 	 * checks.
86 	 */
87 	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
88 
89 	drm_connector_list_iter_begin(dev, &conn_iter);
90 	drm_for_each_connector_iter(connector, &conn_iter) {
91 		if (connector->encoder && connector->encoder->crtc == crtc) {
92 			if (connector_list != NULL && count < num_connectors)
93 				*(connector_list++) = connector;
94 
95 			count++;
96 		}
97 	}
98 	drm_connector_list_iter_end(&conn_iter);
99 
100 	return count;
101 }
102 
103 /**
104  * drm_plane_helper_check_update() - Check plane update for validity
105  * @plane: plane object to update
106  * @crtc: owning CRTC of owning plane
107  * @fb: framebuffer to flip onto plane
108  * @src: source coordinates in 16.16 fixed point
109  * @dst: integer destination 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 				  unsigned int rotation,
135 				  int min_scale,
136 				  int max_scale,
137 				  bool can_position,
138 				  bool can_update_disabled,
139 				  bool *visible)
140 {
141 	struct drm_plane_state plane_state = {
142 		.plane = plane,
143 		.crtc = crtc,
144 		.fb = fb,
145 		.src_x = src->x1,
146 		.src_y = src->y1,
147 		.src_w = drm_rect_width(src),
148 		.src_h = drm_rect_height(src),
149 		.crtc_x = dst->x1,
150 		.crtc_y = dst->y1,
151 		.crtc_w = drm_rect_width(dst),
152 		.crtc_h = drm_rect_height(dst),
153 		.rotation = rotation,
154 		.visible = *visible,
155 	};
156 	struct drm_crtc_state crtc_state = {
157 		.crtc = crtc,
158 		.enable = crtc->enabled,
159 		.mode = crtc->mode,
160 	};
161 	int ret;
162 
163 	ret = drm_atomic_helper_check_plane_state(&plane_state, &crtc_state,
164 						  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 	struct drm_connector **connector_list;
243 	int num_connectors, ret;
244 	bool visible;
245 
246 	ret = drm_plane_helper_check_update(plane, crtc, fb,
247 					    &src, &dest,
248 					    DRM_MODE_ROTATE_0,
249 					    DRM_PLANE_HELPER_NO_SCALING,
250 					    DRM_PLANE_HELPER_NO_SCALING,
251 					    false, false, &visible);
252 	if (ret)
253 		return ret;
254 
255 	if (!visible)
256 		/*
257 		 * Primary plane isn't visible.  Note that unless a driver
258 		 * provides their own disable function, this will just
259 		 * wind up returning -EINVAL to userspace.
260 		 */
261 		return plane->funcs->disable_plane(plane, ctx);
262 
263 	/* Find current connectors for CRTC */
264 	num_connectors = get_connectors_for_crtc(crtc, NULL, 0);
265 	BUG_ON(num_connectors == 0);
266 	connector_list = kcalloc(num_connectors, sizeof(*connector_list),
267 				 GFP_KERNEL);
268 	if (!connector_list)
269 		return -ENOMEM;
270 	get_connectors_for_crtc(crtc, connector_list, num_connectors);
271 
272 	set.connectors = connector_list;
273 	set.num_connectors = num_connectors;
274 
275 	/*
276 	 * We call set_config() directly here rather than using
277 	 * drm_mode_set_config_internal.  We're reprogramming the same
278 	 * connectors that were already in use, so we shouldn't need the extra
279 	 * cross-CRTC fb refcounting to accomodate stealing connectors.
280 	 * drm_mode_setplane() already handles the basic refcounting for the
281 	 * framebuffers involved in this operation.
282 	 */
283 	ret = crtc->funcs->set_config(&set, ctx);
284 
285 	kfree(connector_list);
286 	return ret;
287 }
288 EXPORT_SYMBOL(drm_primary_helper_update);
289 
290 /**
291  * drm_primary_helper_disable() - Helper for primary plane disable
292  * @plane: plane to disable
293  * @ctx: lock acquire context, not used here
294  *
295  * Provides a default plane disable handler for primary planes.  This is handler
296  * is called in response to a userspace SetPlane operation on the plane with a
297  * NULL framebuffer parameter.  It unconditionally fails the disable call with
298  * -EINVAL the only way to disable the primary plane without driver support is
299  * to disable the entire CRTC. Which does not match the plane
300  * &drm_plane_funcs.disable_plane hook.
301  *
302  * Note that some hardware may be able to disable the primary plane without
303  * disabling the whole CRTC.  Drivers for such hardware should provide their
304  * own disable handler that disables just the primary plane (and they'll likely
305  * need to provide their own update handler as well to properly re-enable a
306  * disabled primary plane).
307  *
308  * RETURNS:
309  * Unconditionally returns -EINVAL.
310  */
311 int drm_primary_helper_disable(struct drm_plane *plane,
312 			       struct drm_modeset_acquire_ctx *ctx)
313 {
314 	return -EINVAL;
315 }
316 EXPORT_SYMBOL(drm_primary_helper_disable);
317 
318 /**
319  * drm_primary_helper_destroy() - Helper for primary plane destruction
320  * @plane: plane to destroy
321  *
322  * Provides a default plane destroy handler for primary planes.  This handler
323  * is called during CRTC destruction.  We disable the primary plane, remove
324  * it from the DRM plane list, and deallocate the plane structure.
325  */
326 void drm_primary_helper_destroy(struct drm_plane *plane)
327 {
328 	drm_plane_cleanup(plane);
329 	kfree(plane);
330 }
331 EXPORT_SYMBOL(drm_primary_helper_destroy);
332 
333 const struct drm_plane_funcs drm_primary_helper_funcs = {
334 	.update_plane = drm_primary_helper_update,
335 	.disable_plane = drm_primary_helper_disable,
336 	.destroy = drm_primary_helper_destroy,
337 };
338 EXPORT_SYMBOL(drm_primary_helper_funcs);
339 
340 int drm_plane_helper_commit(struct drm_plane *plane,
341 			    struct drm_plane_state *plane_state,
342 			    struct drm_framebuffer *old_fb)
343 {
344 	const struct drm_plane_helper_funcs *plane_funcs;
345 	struct drm_crtc *crtc[2];
346 	const struct drm_crtc_helper_funcs *crtc_funcs[2];
347 	int i, ret = 0;
348 
349 	plane_funcs = plane->helper_private;
350 
351 	/* Since this is a transitional helper we can't assume that plane->state
352 	 * is always valid. Hence we need to use plane->crtc instead of
353 	 * plane->state->crtc as the old crtc. */
354 	crtc[0] = plane->crtc;
355 	crtc[1] = crtc[0] != plane_state->crtc ? plane_state->crtc : NULL;
356 
357 	for (i = 0; i < 2; i++)
358 		crtc_funcs[i] = crtc[i] ? crtc[i]->helper_private : NULL;
359 
360 	if (plane_funcs->atomic_check) {
361 		ret = plane_funcs->atomic_check(plane, plane_state);
362 		if (ret)
363 			goto out;
364 	}
365 
366 	if (plane_funcs->prepare_fb && plane_state->fb != old_fb) {
367 		ret = plane_funcs->prepare_fb(plane,
368 					      plane_state);
369 		if (ret)
370 			goto out;
371 	}
372 
373 	/* Point of no return, commit sw state. */
374 	swap(plane->state, plane_state);
375 
376 	for (i = 0; i < 2; i++) {
377 		if (crtc_funcs[i] && crtc_funcs[i]->atomic_begin)
378 			crtc_funcs[i]->atomic_begin(crtc[i], crtc[i]->state);
379 	}
380 
381 	/*
382 	 * Drivers may optionally implement the ->atomic_disable callback, so
383 	 * special-case that here.
384 	 */
385 	if (drm_atomic_plane_disabling(plane_state, plane->state) &&
386 	    plane_funcs->atomic_disable)
387 		plane_funcs->atomic_disable(plane, plane_state);
388 	else
389 		plane_funcs->atomic_update(plane, plane_state);
390 
391 	for (i = 0; i < 2; i++) {
392 		if (crtc_funcs[i] && crtc_funcs[i]->atomic_flush)
393 			crtc_funcs[i]->atomic_flush(crtc[i], crtc[i]->state);
394 	}
395 
396 	/*
397 	 * If we only moved the plane and didn't change fb's, there's no need to
398 	 * wait for vblank.
399 	 */
400 	if (plane->state->fb == old_fb)
401 		goto out;
402 
403 	for (i = 0; i < 2; i++) {
404 		if (!crtc[i])
405 			continue;
406 
407 		if (crtc[i]->cursor == plane)
408 			continue;
409 
410 		/* There's no other way to figure out whether the crtc is running. */
411 		ret = drm_crtc_vblank_get(crtc[i]);
412 		if (ret == 0) {
413 			drm_crtc_wait_one_vblank(crtc[i]);
414 			drm_crtc_vblank_put(crtc[i]);
415 		}
416 
417 		ret = 0;
418 	}
419 
420 	if (plane_funcs->cleanup_fb)
421 		plane_funcs->cleanup_fb(plane, plane_state);
422 out:
423 	if (plane->funcs->atomic_destroy_state)
424 		plane->funcs->atomic_destroy_state(plane, plane_state);
425 	else
426 		drm_atomic_helper_plane_destroy_state(plane, plane_state);
427 
428 	return ret;
429 }
430 
431 /**
432  * drm_plane_helper_update() - Transitional helper for plane update
433  * @plane: plane object to update
434  * @crtc: owning CRTC of owning plane
435  * @fb: framebuffer to flip onto plane
436  * @crtc_x: x offset of primary plane on crtc
437  * @crtc_y: y offset of primary plane on crtc
438  * @crtc_w: width of primary plane rectangle on crtc
439  * @crtc_h: height of primary plane rectangle on crtc
440  * @src_x: x offset of @fb for panning
441  * @src_y: y offset of @fb for panning
442  * @src_w: width of source rectangle in @fb
443  * @src_h: height of source rectangle in @fb
444  * @ctx: lock acquire context, not used here
445  *
446  * Provides a default plane update handler using the atomic plane update
447  * functions. It is fully left to the driver to check plane constraints and
448  * handle corner-cases like a fully occluded or otherwise invisible plane.
449  *
450  * This is useful for piecewise transitioning of a driver to the atomic helpers.
451  *
452  * RETURNS:
453  * Zero on success, error code on failure
454  */
455 int drm_plane_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
456 			    struct drm_framebuffer *fb,
457 			    int crtc_x, int crtc_y,
458 			    unsigned int crtc_w, unsigned int crtc_h,
459 			    uint32_t src_x, uint32_t src_y,
460 			    uint32_t src_w, uint32_t src_h,
461 			    struct drm_modeset_acquire_ctx *ctx)
462 {
463 	struct drm_plane_state *plane_state;
464 
465 	if (plane->funcs->atomic_duplicate_state)
466 		plane_state = plane->funcs->atomic_duplicate_state(plane);
467 	else {
468 		if (!plane->state)
469 			drm_atomic_helper_plane_reset(plane);
470 
471 		plane_state = drm_atomic_helper_plane_duplicate_state(plane);
472 	}
473 	if (!plane_state)
474 		return -ENOMEM;
475 	plane_state->plane = plane;
476 
477 	plane_state->crtc = crtc;
478 	drm_atomic_set_fb_for_plane(plane_state, fb);
479 	plane_state->crtc_x = crtc_x;
480 	plane_state->crtc_y = crtc_y;
481 	plane_state->crtc_h = crtc_h;
482 	plane_state->crtc_w = crtc_w;
483 	plane_state->src_x = src_x;
484 	plane_state->src_y = src_y;
485 	plane_state->src_h = src_h;
486 	plane_state->src_w = src_w;
487 
488 	return drm_plane_helper_commit(plane, plane_state, plane->fb);
489 }
490 EXPORT_SYMBOL(drm_plane_helper_update);
491 
492 /**
493  * drm_plane_helper_disable() - Transitional helper for plane disable
494  * @plane: plane to disable
495  * @ctx: lock acquire context, not used here
496  *
497  * Provides a default plane disable handler using the atomic plane update
498  * functions. It is fully left to the driver to check plane constraints and
499  * handle corner-cases like a fully occluded or otherwise invisible plane.
500  *
501  * This is useful for piecewise transitioning of a driver to the atomic helpers.
502  *
503  * RETURNS:
504  * Zero on success, error code on failure
505  */
506 int drm_plane_helper_disable(struct drm_plane *plane,
507 			     struct drm_modeset_acquire_ctx *ctx)
508 {
509 	struct drm_plane_state *plane_state;
510 	struct drm_framebuffer *old_fb;
511 
512 	/* crtc helpers love to call disable functions for already disabled hw
513 	 * functions. So cope with that. */
514 	if (!plane->crtc)
515 		return 0;
516 
517 	if (plane->funcs->atomic_duplicate_state)
518 		plane_state = plane->funcs->atomic_duplicate_state(plane);
519 	else {
520 		if (!plane->state)
521 			drm_atomic_helper_plane_reset(plane);
522 
523 		plane_state = drm_atomic_helper_plane_duplicate_state(plane);
524 	}
525 	if (!plane_state)
526 		return -ENOMEM;
527 	plane_state->plane = plane;
528 
529 	plane_state->crtc = NULL;
530 	old_fb = plane_state->fb;
531 	drm_atomic_set_fb_for_plane(plane_state, NULL);
532 
533 	return drm_plane_helper_commit(plane, plane_state, old_fb);
534 }
535 EXPORT_SYMBOL(drm_plane_helper_disable);
536