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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * drm gem framebuffer helper functions
4 *
5 * Copyright (C) 2017 Noralf Trønnes
6 */
7
8#include <linux/dma-buf.h>
9#include <linux/dma-fence.h>
10#include <linux/dma-resv.h>
11#include <linux/slab.h>
12
13#include <drm/drm_atomic.h>
14#include <drm/drm_atomic_uapi.h>
15#include <drm/drm_damage_helper.h>
16#include <drm/drm_fb_helper.h>
17#include <drm/drm_fourcc.h>
18#include <drm/drm_framebuffer.h>
19#include <drm/drm_gem.h>
20#include <drm/drm_gem_framebuffer_helper.h>
21#include <drm/drm_modeset_helper.h>
22#include <drm/drm_simple_kms_helper.h>
23
24#define AFBC_HEADER_SIZE 16
25#define AFBC_TH_LAYOUT_ALIGNMENT 8
26#define AFBC_HDR_ALIGN 64
27#define AFBC_SUPERBLOCK_PIXELS 256
28#define AFBC_SUPERBLOCK_ALIGNMENT 128
29#define AFBC_TH_BODY_START_ALIGNMENT 4096
30
31/**
32 * DOC: overview
33 *
34 * This library provides helpers for drivers that don't subclass
35 * &drm_framebuffer and use &drm_gem_object for their backing storage.
36 *
37 * Drivers without additional needs to validate framebuffers can simply use
38 * drm_gem_fb_create() and everything is wired up automatically. Other drivers
39 * can use all parts independently.
40 */
41
42/**
43 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer
44 * @fb: Framebuffer
45 * @plane: Plane index
46 *
47 * No additional reference is taken beyond the one that the &drm_frambuffer
48 * already holds.
49 *
50 * Returns:
51 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL
52 * if it does not exist.
53 */
54struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
55 unsigned int plane)
56{
57 if (plane >= 4)
58 return NULL;
59
60 return fb->obj[plane];
61}
62EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);
63
64static int
65drm_gem_fb_init(struct drm_device *dev,
66 struct drm_framebuffer *fb,
67 const struct drm_mode_fb_cmd2 *mode_cmd,
68 struct drm_gem_object **obj, unsigned int num_planes,
69 const struct drm_framebuffer_funcs *funcs)
70{
71 int ret, i;
72
73 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
74
75 for (i = 0; i < num_planes; i++)
76 fb->obj[i] = obj[i];
77
78 ret = drm_framebuffer_init(dev, fb, funcs);
79 if (ret)
80 drm_err(dev, "Failed to init framebuffer: %d\n", ret);
81
82 return ret;
83}
84
85/**
86 * drm_gem_fb_destroy - Free GEM backed framebuffer
87 * @fb: Framebuffer
88 *
89 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure
90 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy
91 * callback.
92 */
93void drm_gem_fb_destroy(struct drm_framebuffer *fb)
94{
95 int i;
96
97 for (i = 0; i < 4; i++)
98 drm_gem_object_put(fb->obj[i]);
99
100 drm_framebuffer_cleanup(fb);
101 kfree(fb);
102}
103EXPORT_SYMBOL(drm_gem_fb_destroy);
104
105/**
106 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer
107 * @fb: Framebuffer
108 * @file: DRM file to register the handle for
109 * @handle: Pointer to return the created handle
110 *
111 * This function creates a handle for the GEM object backing the framebuffer.
112 * Drivers can use this as their &drm_framebuffer_funcs->create_handle
113 * callback. The GETFB IOCTL calls into this callback.
114 *
115 * Returns:
116 * 0 on success or a negative error code on failure.
117 */
118int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
119 unsigned int *handle)
120{
121 return drm_gem_handle_create(file, fb->obj[0], handle);
122}
123EXPORT_SYMBOL(drm_gem_fb_create_handle);
124
125/**
126 * drm_gem_fb_init_with_funcs() - Helper function for implementing
127 * &drm_mode_config_funcs.fb_create
128 * callback in cases when the driver
129 * allocates a subclass of
130 * struct drm_framebuffer
131 * @dev: DRM device
132 * @fb: framebuffer object
133 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
134 * @mode_cmd: Metadata from the userspace framebuffer creation request
135 * @funcs: vtable to be used for the new framebuffer object
136 *
137 * This function can be used to set &drm_framebuffer_funcs for drivers that need
138 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to
139 * change &drm_framebuffer_funcs. The function does buffer size validation.
140 * The buffer size validation is for a general case, though, so users should
141 * pay attention to the checks being appropriate for them or, at least,
142 * non-conflicting.
143 *
144 * Returns:
145 * Zero or a negative error code.
146 */
147int drm_gem_fb_init_with_funcs(struct drm_device *dev,
148 struct drm_framebuffer *fb,
149 struct drm_file *file,
150 const struct drm_mode_fb_cmd2 *mode_cmd,
151 const struct drm_framebuffer_funcs *funcs)
152{
153 const struct drm_format_info *info;
154 struct drm_gem_object *objs[4];
155 int ret, i;
156
157 info = drm_get_format_info(dev, mode_cmd);
158 if (!info)
159 return -EINVAL;
160
161 for (i = 0; i < info->num_planes; i++) {
162 unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
163 unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
164 unsigned int min_size;
165
166 objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
167 if (!objs[i]) {
168 drm_dbg_kms(dev, "Failed to lookup GEM object\n");
169 ret = -ENOENT;
170 goto err_gem_object_put;
171 }
172
173 min_size = (height - 1) * mode_cmd->pitches[i]
174 + drm_format_info_min_pitch(info, i, width)
175 + mode_cmd->offsets[i];
176
177 if (objs[i]->size < min_size) {
178 drm_gem_object_put(objs[i]);
179 ret = -EINVAL;
180 goto err_gem_object_put;
181 }
182 }
183
184 ret = drm_gem_fb_init(dev, fb, mode_cmd, objs, i, funcs);
185 if (ret)
186 goto err_gem_object_put;
187
188 return 0;
189
190err_gem_object_put:
191 for (i--; i >= 0; i--)
192 drm_gem_object_put(objs[i]);
193
194 return ret;
195}
196EXPORT_SYMBOL_GPL(drm_gem_fb_init_with_funcs);
197
198/**
199 * drm_gem_fb_create_with_funcs() - Helper function for the
200 * &drm_mode_config_funcs.fb_create
201 * callback
202 * @dev: DRM device
203 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
204 * @mode_cmd: Metadata from the userspace framebuffer creation request
205 * @funcs: vtable to be used for the new framebuffer object
206 *
207 * This function can be used to set &drm_framebuffer_funcs for drivers that need
208 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to
209 * change &drm_framebuffer_funcs. The function does buffer size validation.
210 *
211 * Returns:
212 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
213 */
214struct drm_framebuffer *
215drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
216 const struct drm_mode_fb_cmd2 *mode_cmd,
217 const struct drm_framebuffer_funcs *funcs)
218{
219 struct drm_framebuffer *fb;
220 int ret;
221
222 fb = kzalloc(sizeof(*fb), GFP_KERNEL);
223 if (!fb)
224 return ERR_PTR(-ENOMEM);
225
226 ret = drm_gem_fb_init_with_funcs(dev, fb, file, mode_cmd, funcs);
227 if (ret) {
228 kfree(fb);
229 return ERR_PTR(ret);
230 }
231
232 return fb;
233}
234EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);
235
236static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
237 .destroy = drm_gem_fb_destroy,
238 .create_handle = drm_gem_fb_create_handle,
239};
240
241/**
242 * drm_gem_fb_create() - Helper function for the
243 * &drm_mode_config_funcs.fb_create callback
244 * @dev: DRM device
245 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
246 * @mode_cmd: Metadata from the userspace framebuffer creation request
247 *
248 * This function creates a new framebuffer object described by
249 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
250 * backing the framebuffer.
251 *
252 * If your hardware has special alignment or pitch requirements these should be
253 * checked before calling this function. The function does buffer size
254 * validation. Use drm_gem_fb_create_with_dirty() if you need framebuffer
255 * flushing.
256 *
257 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
258 * The ADDFB2 IOCTL calls into this callback.
259 *
260 * Returns:
261 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
262 */
263struct drm_framebuffer *
264drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
265 const struct drm_mode_fb_cmd2 *mode_cmd)
266{
267 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
268 &drm_gem_fb_funcs);
269}
270EXPORT_SYMBOL_GPL(drm_gem_fb_create);
271
272static const struct drm_framebuffer_funcs drm_gem_fb_funcs_dirtyfb = {
273 .destroy = drm_gem_fb_destroy,
274 .create_handle = drm_gem_fb_create_handle,
275 .dirty = drm_atomic_helper_dirtyfb,
276};
277
278/**
279 * drm_gem_fb_create_with_dirty() - Helper function for the
280 * &drm_mode_config_funcs.fb_create callback
281 * @dev: DRM device
282 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
283 * @mode_cmd: Metadata from the userspace framebuffer creation request
284 *
285 * This function creates a new framebuffer object described by
286 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
287 * backing the framebuffer. drm_atomic_helper_dirtyfb() is used for the dirty
288 * callback giving framebuffer flushing through the atomic machinery. Use
289 * drm_gem_fb_create() if you don't need the dirty callback.
290 * The function does buffer size validation.
291 *
292 * Drivers should also call drm_plane_enable_fb_damage_clips() on all planes
293 * to enable userspace to use damage clips also with the ATOMIC IOCTL.
294 *
295 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
296 * The ADDFB2 IOCTL calls into this callback.
297 *
298 * Returns:
299 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
300 */
301struct drm_framebuffer *
302drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
303 const struct drm_mode_fb_cmd2 *mode_cmd)
304{
305 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
306 &drm_gem_fb_funcs_dirtyfb);
307}
308EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty);
309
310static __u32 drm_gem_afbc_get_bpp(struct drm_device *dev,
311 const struct drm_mode_fb_cmd2 *mode_cmd)
312{
313 const struct drm_format_info *info;
314
315 info = drm_get_format_info(dev, mode_cmd);
316
317 /* use whatever a driver has set */
318 if (info->cpp[0])
319 return info->cpp[0] * 8;
320
321 /* guess otherwise */
322 switch (info->format) {
323 case DRM_FORMAT_YUV420_8BIT:
324 return 12;
325 case DRM_FORMAT_YUV420_10BIT:
326 return 15;
327 case DRM_FORMAT_VUY101010:
328 return 30;
329 default:
330 break;
331 }
332
333 /* all attempts failed */
334 return 0;
335}
336
337static int drm_gem_afbc_min_size(struct drm_device *dev,
338 const struct drm_mode_fb_cmd2 *mode_cmd,
339 struct drm_afbc_framebuffer *afbc_fb)
340{
341 __u32 n_blocks, w_alignment, h_alignment, hdr_alignment;
342 /* remove bpp when all users properly encode cpp in drm_format_info */
343 __u32 bpp;
344
345 switch (mode_cmd->modifier[0] & AFBC_FORMAT_MOD_BLOCK_SIZE_MASK) {
346 case AFBC_FORMAT_MOD_BLOCK_SIZE_16x16:
347 afbc_fb->block_width = 16;
348 afbc_fb->block_height = 16;
349 break;
350 case AFBC_FORMAT_MOD_BLOCK_SIZE_32x8:
351 afbc_fb->block_width = 32;
352 afbc_fb->block_height = 8;
353 break;
354 /* no user exists yet - fall through */
355 case AFBC_FORMAT_MOD_BLOCK_SIZE_64x4:
356 case AFBC_FORMAT_MOD_BLOCK_SIZE_32x8_64x4:
357 default:
358 drm_dbg_kms(dev, "Invalid AFBC_FORMAT_MOD_BLOCK_SIZE: %lld.\n",
359 mode_cmd->modifier[0]
360 & AFBC_FORMAT_MOD_BLOCK_SIZE_MASK);
361 return -EINVAL;
362 }
363
364 /* tiled header afbc */
365 w_alignment = afbc_fb->block_width;
366 h_alignment = afbc_fb->block_height;
367 hdr_alignment = AFBC_HDR_ALIGN;
368 if (mode_cmd->modifier[0] & AFBC_FORMAT_MOD_TILED) {
369 w_alignment *= AFBC_TH_LAYOUT_ALIGNMENT;
370 h_alignment *= AFBC_TH_LAYOUT_ALIGNMENT;
371 hdr_alignment = AFBC_TH_BODY_START_ALIGNMENT;
372 }
373
374 afbc_fb->aligned_width = ALIGN(mode_cmd->width, w_alignment);
375 afbc_fb->aligned_height = ALIGN(mode_cmd->height, h_alignment);
376 afbc_fb->offset = mode_cmd->offsets[0];
377
378 bpp = drm_gem_afbc_get_bpp(dev, mode_cmd);
379 if (!bpp) {
380 drm_dbg_kms(dev, "Invalid AFBC bpp value: %d\n", bpp);
381 return -EINVAL;
382 }
383
384 n_blocks = (afbc_fb->aligned_width * afbc_fb->aligned_height)
385 / AFBC_SUPERBLOCK_PIXELS;
386 afbc_fb->afbc_size = ALIGN(n_blocks * AFBC_HEADER_SIZE, hdr_alignment);
387 afbc_fb->afbc_size += n_blocks * ALIGN(bpp * AFBC_SUPERBLOCK_PIXELS / 8,
388 AFBC_SUPERBLOCK_ALIGNMENT);
389
390 return 0;
391}
392
393/**
394 * drm_gem_fb_afbc_init() - Helper function for drivers using afbc to
395 * fill and validate all the afbc-specific
396 * struct drm_afbc_framebuffer members
397 *
398 * @dev: DRM device
399 * @afbc_fb: afbc-specific framebuffer
400 * @mode_cmd: Metadata from the userspace framebuffer creation request
401 * @afbc_fb: afbc framebuffer
402 *
403 * This function can be used by drivers which support afbc to complete
404 * the preparation of struct drm_afbc_framebuffer. It must be called after
405 * allocating the said struct and calling drm_gem_fb_init_with_funcs().
406 * It is caller's responsibility to put afbc_fb->base.obj objects in case
407 * the call is unsuccessful.
408 *
409 * Returns:
410 * Zero on success or a negative error value on failure.
411 */
412int drm_gem_fb_afbc_init(struct drm_device *dev,
413 const struct drm_mode_fb_cmd2 *mode_cmd,
414 struct drm_afbc_framebuffer *afbc_fb)
415{
416 const struct drm_format_info *info;
417 struct drm_gem_object **objs;
418 int ret;
419
420 objs = afbc_fb->base.obj;
421 info = drm_get_format_info(dev, mode_cmd);
422 if (!info)
423 return -EINVAL;
424
425 ret = drm_gem_afbc_min_size(dev, mode_cmd, afbc_fb);
426 if (ret < 0)
427 return ret;
428
429 if (objs[0]->size < afbc_fb->afbc_size)
430 return -EINVAL;
431
432 return 0;
433}
434EXPORT_SYMBOL_GPL(drm_gem_fb_afbc_init);
435
436/**
437 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer
438 * @plane: Plane
439 * @state: Plane state the fence will be attached to
440 *
441 * This function extracts the exclusive fence from &drm_gem_object.resv and
442 * attaches it to plane state for the atomic helper to wait on. This is
443 * necessary to correctly implement implicit synchronization for any buffers
444 * shared as a struct &dma_buf. This function can be used as the
445 * &drm_plane_helper_funcs.prepare_fb callback.
446 *
447 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple
448 * gem based framebuffer drivers which have their buffers always pinned in
449 * memory.
450 *
451 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and
452 * explicit fencing in atomic modeset updates.
453 */
454int drm_gem_fb_prepare_fb(struct drm_plane *plane,
455 struct drm_plane_state *state)
456{
457 struct drm_gem_object *obj;
458 struct dma_fence *fence;
459
460 if (!state->fb)
461 return 0;
462
463 obj = drm_gem_fb_get_obj(state->fb, 0);
464 fence = dma_resv_get_excl_rcu(obj->resv);
465 drm_atomic_set_fence_for_plane(state, fence);
466
467 return 0;
468}
469EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);
470
471/**
472 * drm_gem_fb_simple_display_pipe_prepare_fb - prepare_fb helper for
473 * &drm_simple_display_pipe
474 * @pipe: Simple display pipe
475 * @plane_state: Plane state
476 *
477 * This function uses drm_gem_fb_prepare_fb() to extract the exclusive fence
478 * from &drm_gem_object.resv and attaches it to plane state for the atomic
479 * helper to wait on. This is necessary to correctly implement implicit
480 * synchronization for any buffers shared as a struct &dma_buf. Drivers can use
481 * this as their &drm_simple_display_pipe_funcs.prepare_fb callback.
482 *
483 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and
484 * explicit fencing in atomic modeset updates.
485 */
486int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe,
487 struct drm_plane_state *plane_state)
488{
489 return drm_gem_fb_prepare_fb(&pipe->plane, plane_state);
490}
491EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb);