drm_gem_framebuffer_helper.c 15 KB

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