2 * drm gem framebuffer helper functions
4 * Copyright (C) 2017 Noralf Trønnes
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
12 #include <linux/dma-buf.h>
13 #include <linux/dma-fence.h>
14 #include <linux/reservation.h>
15 #include <linux/slab.h>
18 #include <drm/drm_atomic.h>
19 #include <drm/drm_fb_helper.h>
20 #include <drm/drm_fourcc.h>
21 #include <drm/drm_framebuffer.h>
22 #include <drm/drm_gem.h>
23 #include <drm/drm_gem_framebuffer_helper.h>
24 #include <drm/drm_modeset_helper.h>
29 * This library provides helpers for drivers that don't subclass
30 * &drm_framebuffer and and use &drm_gem_object for their backing storage.
32 * Drivers without additional needs to validate framebuffers can simply use
33 * drm_gem_fb_create() and everything is wired up automatically. But all
34 * parts can be used individually.
38 * drm_gem_fb_get_obj() - Get GEM object for framebuffer
39 * @fb: The framebuffer
42 * Returns the GEM object for given framebuffer.
44 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
50 return fb->obj[plane];
52 EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);
54 static struct drm_framebuffer *
55 drm_gem_fb_alloc(struct drm_device *dev,
56 const struct drm_mode_fb_cmd2 *mode_cmd,
57 struct drm_gem_object **obj, unsigned int num_planes,
58 const struct drm_framebuffer_funcs *funcs)
60 struct drm_framebuffer *fb;
63 fb = kzalloc(sizeof(*fb), GFP_KERNEL);
65 return ERR_PTR(-ENOMEM);
67 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
69 for (i = 0; i < num_planes; i++)
72 ret = drm_framebuffer_init(dev, fb, funcs);
74 DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n",
84 * drm_gem_fb_destroy - Free GEM backed framebuffer
85 * @fb: DRM framebuffer
87 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure
88 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy
91 void drm_gem_fb_destroy(struct drm_framebuffer *fb)
95 for (i = 0; i < 4; i++)
96 drm_gem_object_put_unlocked(fb->obj[i]);
98 drm_framebuffer_cleanup(fb);
101 EXPORT_SYMBOL(drm_gem_fb_destroy);
104 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer
105 * @fb: DRM framebuffer
107 * @handle: handle created
109 * Drivers can use this as their &drm_framebuffer_funcs->create_handle
113 * 0 on success or a negative error code on failure.
115 int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
116 unsigned int *handle)
118 return drm_gem_handle_create(file, fb->obj[0], handle);
120 EXPORT_SYMBOL(drm_gem_fb_create_handle);
123 * drm_gem_fb_create_with_funcs() - helper function for the
124 * &drm_mode_config_funcs.fb_create
127 * @file: drm file for the ioctl call
128 * @mode_cmd: metadata from the userspace fb creation request
129 * @funcs: vtable to be used for the new framebuffer object
131 * This can be used to set &drm_framebuffer_funcs for drivers that need the
132 * &drm_framebuffer_funcs.dirty callback. Use drm_gem_fb_create() if you don't
133 * need to change &drm_framebuffer_funcs.
134 * The function does buffer size validation.
136 struct drm_framebuffer *
137 drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
138 const struct drm_mode_fb_cmd2 *mode_cmd,
139 const struct drm_framebuffer_funcs *funcs)
141 const struct drm_format_info *info;
142 struct drm_gem_object *objs[4];
143 struct drm_framebuffer *fb;
146 info = drm_get_format_info(dev, mode_cmd);
148 return ERR_PTR(-EINVAL);
150 for (i = 0; i < info->num_planes; i++) {
151 unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
152 unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
153 unsigned int min_size;
155 objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
157 DRM_DEV_ERROR(dev->dev, "Failed to lookup GEM\n");
159 goto err_gem_object_put;
162 min_size = (height - 1) * mode_cmd->pitches[i]
163 + width * info->cpp[i]
164 + mode_cmd->offsets[i];
166 if (objs[i]->size < min_size) {
167 drm_gem_object_put_unlocked(objs[i]);
169 goto err_gem_object_put;
173 fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs);
176 goto err_gem_object_put;
182 for (i--; i >= 0; i--)
183 drm_gem_object_put_unlocked(objs[i]);
187 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);
189 static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
190 .destroy = drm_gem_fb_destroy,
191 .create_handle = drm_gem_fb_create_handle,
195 * drm_gem_fb_create() - &drm_mode_config_funcs.fb_create callback function
197 * @file: drm file for the ioctl call
198 * @mode_cmd: metadata from the userspace fb creation request
200 * If your hardware has special alignment or pitch requirements these should be
201 * checked before calling this function. The function does buffer size
202 * validation. Use drm_gem_fb_create_with_funcs() if you need to set
203 * &drm_framebuffer_funcs.dirty.
205 struct drm_framebuffer *
206 drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
207 const struct drm_mode_fb_cmd2 *mode_cmd)
209 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
212 EXPORT_SYMBOL_GPL(drm_gem_fb_create);
215 * drm_gem_fb_prepare_fb() - Prepare gem framebuffer
216 * @plane: Which plane
217 * @state: Plane state attach fence to
219 * This can be used as the &drm_plane_helper_funcs.prepare_fb hook.
221 * This function checks if the plane FB has an dma-buf attached, extracts
222 * the exclusive fence and attaches it to plane state for the atomic helper
225 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple
226 * gem based framebuffer drivers which have their buffers always pinned in
229 int drm_gem_fb_prepare_fb(struct drm_plane *plane,
230 struct drm_plane_state *state)
232 struct dma_buf *dma_buf;
233 struct dma_fence *fence;
235 if ((plane->state->fb == state->fb) || !state->fb)
238 dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf;
240 fence = reservation_object_get_excl_rcu(dma_buf->resv);
241 drm_atomic_set_fence_for_plane(state, fence);
246 EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);
249 * drm_gem_fbdev_fb_create - Create a drm_framebuffer for fbdev emulation
251 * @sizes: fbdev size description
252 * @pitch_align: optional pitch alignment
253 * @obj: GEM object backing the framebuffer
254 * @funcs: vtable to be used for the new framebuffer object
256 * This function creates a framebuffer for use with fbdev emulation.
259 * Pointer to a drm_framebuffer on success or an error pointer on failure.
261 struct drm_framebuffer *
262 drm_gem_fbdev_fb_create(struct drm_device *dev,
263 struct drm_fb_helper_surface_size *sizes,
264 unsigned int pitch_align, struct drm_gem_object *obj,
265 const struct drm_framebuffer_funcs *funcs)
267 struct drm_mode_fb_cmd2 mode_cmd = { 0 };
269 mode_cmd.width = sizes->surface_width;
270 mode_cmd.height = sizes->surface_height;
271 mode_cmd.pitches[0] = sizes->surface_width *
272 DIV_ROUND_UP(sizes->surface_bpp, 8);
274 mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0],
276 mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
277 sizes->surface_depth);
278 if (obj->size < mode_cmd.pitches[0] * mode_cmd.height)
279 return ERR_PTR(-EINVAL);
281 return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs);
283 EXPORT_SYMBOL(drm_gem_fbdev_fb_create);