1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * drm gem framebuffer helper functions
5 * Copyright (C) 2017 Noralf Trønnes
8 #include <linux/dma-buf.h>
9 #include <linux/dma-fence.h>
10 #include <linux/dma-resv.h>
11 #include <linux/slab.h>
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>
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
34 * This library provides helpers for drivers that don't subclass
35 * &drm_framebuffer and use &drm_gem_object for their backing storage.
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.
43 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer
47 * No additional reference is taken beyond the one that the &drm_frambuffer
51 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL
52 * if it does not exist.
54 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
60 return fb->obj[plane];
62 EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);
65 drm_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)
73 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
75 for (i = 0; i < num_planes; i++)
78 ret = drm_framebuffer_init(dev, fb, funcs);
80 drm_err(dev, "Failed to init framebuffer: %d\n", ret);
88 * drm_gem_fb_destroy - Free GEM backed framebuffer
91 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure
92 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy
95 void drm_gem_fb_destroy(struct drm_framebuffer *fb)
99 for (i = 0; i < 4; i++)
100 drm_gem_object_put_unlocked(fb->obj[i]);
102 drm_framebuffer_cleanup(fb);
105 EXPORT_SYMBOL(drm_gem_fb_destroy);
108 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer
110 * @file: DRM file to register the handle for
111 * @handle: Pointer to return the created handle
113 * This function creates a handle for the GEM object backing the framebuffer.
114 * Drivers can use this as their &drm_framebuffer_funcs->create_handle
115 * callback. The GETFB IOCTL calls into this callback.
118 * 0 on success or a negative error code on failure.
120 int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
121 unsigned int *handle)
123 return drm_gem_handle_create(file, fb->obj[0], handle);
125 EXPORT_SYMBOL(drm_gem_fb_create_handle);
128 * drm_gem_fb_init_with_funcs() - Helper function for implementing
129 * &drm_mode_config_funcs.fb_create
130 * callback in cases when the driver
131 * allocates a subclass of
132 * struct drm_framebuffer
134 * @fb: framebuffer object
135 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
136 * @mode_cmd: Metadata from the userspace framebuffer creation request
137 * @funcs: vtable to be used for the new framebuffer object
139 * This function can be used to set &drm_framebuffer_funcs for drivers that need
140 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to
141 * change &drm_framebuffer_funcs. The function does buffer size validation.
142 * The buffer size validation is for a general case, though, so users should
143 * pay attention to the checks being appropriate for them or, at least,
147 * Zero or a negative error code.
149 int drm_gem_fb_init_with_funcs(struct drm_device *dev,
150 struct drm_framebuffer *fb,
151 struct drm_file *file,
152 const struct drm_mode_fb_cmd2 *mode_cmd,
153 const struct drm_framebuffer_funcs *funcs)
155 const struct drm_format_info *info;
156 struct drm_gem_object *objs[4];
159 info = drm_get_format_info(dev, mode_cmd);
163 for (i = 0; i < info->num_planes; i++) {
164 unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
165 unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
166 unsigned int min_size;
168 objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
170 drm_dbg_kms(dev, "Failed to lookup GEM object\n");
172 goto err_gem_object_put;
175 min_size = (height - 1) * mode_cmd->pitches[i]
176 + drm_format_info_min_pitch(info, i, width)
177 + mode_cmd->offsets[i];
179 if (objs[i]->size < min_size) {
180 drm_gem_object_put_unlocked(objs[i]);
182 goto err_gem_object_put;
186 ret = drm_gem_fb_init(dev, fb, mode_cmd, objs, i, funcs);
188 goto err_gem_object_put;
193 for (i--; i >= 0; i--)
194 drm_gem_object_put_unlocked(objs[i]);
198 EXPORT_SYMBOL_GPL(drm_gem_fb_init_with_funcs);
201 * drm_gem_fb_create_with_funcs() - Helper function for the
202 * &drm_mode_config_funcs.fb_create
205 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
206 * @mode_cmd: Metadata from the userspace framebuffer creation request
207 * @funcs: vtable to be used for the new framebuffer object
209 * This function can be used to set &drm_framebuffer_funcs for drivers that need
210 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to
211 * change &drm_framebuffer_funcs. The function does buffer size validation.
214 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
216 struct drm_framebuffer *
217 drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
218 const struct drm_mode_fb_cmd2 *mode_cmd,
219 const struct drm_framebuffer_funcs *funcs)
221 struct drm_framebuffer *fb;
224 fb = kzalloc(sizeof(*fb), GFP_KERNEL);
226 return ERR_PTR(-ENOMEM);
228 ret = drm_gem_fb_init_with_funcs(dev, fb, file, mode_cmd, funcs);
236 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);
238 static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
239 .destroy = drm_gem_fb_destroy,
240 .create_handle = drm_gem_fb_create_handle,
244 * drm_gem_fb_create() - Helper function for the
245 * &drm_mode_config_funcs.fb_create callback
247 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
248 * @mode_cmd: Metadata from the userspace framebuffer creation request
250 * This function creates a new framebuffer object described by
251 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
252 * backing the framebuffer.
254 * If your hardware has special alignment or pitch requirements these should be
255 * checked before calling this function. The function does buffer size
256 * validation. Use drm_gem_fb_create_with_dirty() if you need framebuffer
259 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
260 * The ADDFB2 IOCTL calls into this callback.
263 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
265 struct drm_framebuffer *
266 drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
267 const struct drm_mode_fb_cmd2 *mode_cmd)
269 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
272 EXPORT_SYMBOL_GPL(drm_gem_fb_create);
274 static const struct drm_framebuffer_funcs drm_gem_fb_funcs_dirtyfb = {
275 .destroy = drm_gem_fb_destroy,
276 .create_handle = drm_gem_fb_create_handle,
277 .dirty = drm_atomic_helper_dirtyfb,
281 * drm_gem_fb_create_with_dirty() - Helper function for the
282 * &drm_mode_config_funcs.fb_create callback
284 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
285 * @mode_cmd: Metadata from the userspace framebuffer creation request
287 * This function creates a new framebuffer object described by
288 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
289 * backing the framebuffer. drm_atomic_helper_dirtyfb() is used for the dirty
290 * callback giving framebuffer flushing through the atomic machinery. Use
291 * drm_gem_fb_create() if you don't need the dirty callback.
292 * The function does buffer size validation.
294 * Drivers should also call drm_plane_enable_fb_damage_clips() on all planes
295 * to enable userspace to use damage clips also with the ATOMIC IOCTL.
297 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
298 * The ADDFB2 IOCTL calls into this callback.
301 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
303 struct drm_framebuffer *
304 drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
305 const struct drm_mode_fb_cmd2 *mode_cmd)
307 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
308 &drm_gem_fb_funcs_dirtyfb);
310 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty);
312 static __u32 drm_gem_afbc_get_bpp(struct drm_device *dev,
313 const struct drm_mode_fb_cmd2 *mode_cmd)
315 const struct drm_format_info *info;
317 info = drm_get_format_info(dev, mode_cmd);
319 /* use whatever a driver has set */
321 return info->cpp[0] * 8;
323 /* guess otherwise */
324 switch (info->format) {
325 case DRM_FORMAT_YUV420_8BIT:
327 case DRM_FORMAT_YUV420_10BIT:
329 case DRM_FORMAT_VUY101010:
335 /* all attempts failed */
339 static int drm_gem_afbc_min_size(struct drm_device *dev,
340 const struct drm_mode_fb_cmd2 *mode_cmd,
341 struct drm_afbc_framebuffer *afbc_fb)
343 __u32 n_blocks, w_alignment, h_alignment, hdr_alignment;
344 /* remove bpp when all users properly encode cpp in drm_format_info */
347 switch (mode_cmd->modifier[0] & AFBC_FORMAT_MOD_BLOCK_SIZE_MASK) {
348 case AFBC_FORMAT_MOD_BLOCK_SIZE_16x16:
349 afbc_fb->block_width = 16;
350 afbc_fb->block_height = 16;
352 case AFBC_FORMAT_MOD_BLOCK_SIZE_32x8:
353 afbc_fb->block_width = 32;
354 afbc_fb->block_height = 8;
356 /* no user exists yet - fall through */
357 case AFBC_FORMAT_MOD_BLOCK_SIZE_64x4:
358 case AFBC_FORMAT_MOD_BLOCK_SIZE_32x8_64x4:
360 drm_dbg_kms(dev, "Invalid AFBC_FORMAT_MOD_BLOCK_SIZE: %lld.\n",
361 mode_cmd->modifier[0]
362 & AFBC_FORMAT_MOD_BLOCK_SIZE_MASK);
366 /* tiled header afbc */
367 w_alignment = afbc_fb->block_width;
368 h_alignment = afbc_fb->block_height;
369 hdr_alignment = AFBC_HDR_ALIGN;
370 if (mode_cmd->modifier[0] & AFBC_FORMAT_MOD_TILED) {
371 w_alignment *= AFBC_TH_LAYOUT_ALIGNMENT;
372 h_alignment *= AFBC_TH_LAYOUT_ALIGNMENT;
373 hdr_alignment = AFBC_TH_BODY_START_ALIGNMENT;
376 afbc_fb->aligned_width = ALIGN(mode_cmd->width, w_alignment);
377 afbc_fb->aligned_height = ALIGN(mode_cmd->height, h_alignment);
378 afbc_fb->offset = mode_cmd->offsets[0];
380 bpp = drm_gem_afbc_get_bpp(dev, mode_cmd);
382 drm_dbg_kms(dev, "Invalid AFBC bpp value: %d\n", bpp);
386 n_blocks = (afbc_fb->aligned_width * afbc_fb->aligned_height)
387 / AFBC_SUPERBLOCK_PIXELS;
388 afbc_fb->afbc_size = ALIGN(n_blocks * AFBC_HEADER_SIZE, hdr_alignment);
389 afbc_fb->afbc_size += n_blocks * ALIGN(bpp * AFBC_SUPERBLOCK_PIXELS / 8,
390 AFBC_SUPERBLOCK_ALIGNMENT);
396 * drm_gem_fb_afbc_init() - Helper function for drivers using afbc to
397 * fill and validate all the afbc-specific
398 * struct drm_afbc_framebuffer members
401 * @afbc_fb: afbc-specific framebuffer
402 * @mode_cmd: Metadata from the userspace framebuffer creation request
403 * @afbc_fb: afbc framebuffer
405 * This function can be used by drivers which support afbc to complete
406 * the preparation of struct drm_afbc_framebuffer. It must be called after
407 * allocating the said struct and calling drm_gem_fb_init_with_funcs().
408 * It is caller's responsibility to put afbc_fb->base.obj objects in case
409 * the call is unsuccessful.
412 * Zero on success or a negative error value on failure.
414 int drm_gem_fb_afbc_init(struct drm_device *dev,
415 const struct drm_mode_fb_cmd2 *mode_cmd,
416 struct drm_afbc_framebuffer *afbc_fb)
418 const struct drm_format_info *info;
419 struct drm_gem_object **objs;
422 objs = afbc_fb->base.obj;
423 info = drm_get_format_info(dev, mode_cmd);
427 ret = drm_gem_afbc_min_size(dev, mode_cmd, afbc_fb);
431 if (objs[0]->size < afbc_fb->afbc_size)
436 EXPORT_SYMBOL_GPL(drm_gem_fb_afbc_init);
439 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer
441 * @state: Plane state the fence will be attached to
443 * This function extracts the exclusive fence from &drm_gem_object.resv and
444 * attaches it to plane state for the atomic helper to wait on. This is
445 * necessary to correctly implement implicit synchronization for any buffers
446 * shared as a struct &dma_buf. This function can be used as the
447 * &drm_plane_helper_funcs.prepare_fb callback.
449 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple
450 * gem based framebuffer drivers which have their buffers always pinned in
453 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and
454 * explicit fencing in atomic modeset updates.
456 int drm_gem_fb_prepare_fb(struct drm_plane *plane,
457 struct drm_plane_state *state)
459 struct drm_gem_object *obj;
460 struct dma_fence *fence;
465 obj = drm_gem_fb_get_obj(state->fb, 0);
466 fence = dma_resv_get_excl_rcu(obj->resv);
467 drm_atomic_set_fence_for_plane(state, fence);
471 EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);
474 * drm_gem_fb_simple_display_pipe_prepare_fb - prepare_fb helper for
475 * &drm_simple_display_pipe
476 * @pipe: Simple display pipe
477 * @plane_state: Plane state
479 * This function uses drm_gem_fb_prepare_fb() to extract the exclusive fence
480 * from &drm_gem_object.resv and attaches it to plane state for the atomic
481 * helper to wait on. This is necessary to correctly implement implicit
482 * synchronization for any buffers shared as a struct &dma_buf. Drivers can use
483 * this as their &drm_simple_display_pipe_funcs.prepare_fb callback.
485 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and
486 * explicit fencing in atomic modeset updates.
488 int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe,
489 struct drm_plane_state *plane_state)
491 return drm_gem_fb_prepare_fb(&pipe->plane, plane_state);
493 EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb);