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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/**
25 * DOC: overview
26 *
27 * This library provides helpers for drivers that don't subclass
28 * &drm_framebuffer and use &drm_gem_object for their backing storage.
29 *
30 * Drivers without additional needs to validate framebuffers can simply use
31 * drm_gem_fb_create() and everything is wired up automatically. Other drivers
32 * can use all parts independently.
33 */
34
35/**
36 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer
37 * @fb: Framebuffer
38 * @plane: Plane index
39 *
40 * No additional reference is taken beyond the one that the &drm_frambuffer
41 * already holds.
42 *
43 * Returns:
44 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL
45 * if it does not exist.
46 */
47struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
48 unsigned int plane)
49{
50 if (plane >= 4)
51 return NULL;
52
53 return fb->obj[plane];
54}
55EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);
56
57static struct drm_framebuffer *
58drm_gem_fb_alloc(struct drm_device *dev,
59 const struct drm_mode_fb_cmd2 *mode_cmd,
60 struct drm_gem_object **obj, unsigned int num_planes,
61 const struct drm_framebuffer_funcs *funcs)
62{
63 struct drm_framebuffer *fb;
64 int ret, i;
65
66 fb = kzalloc(sizeof(*fb), GFP_KERNEL);
67 if (!fb)
68 return ERR_PTR(-ENOMEM);
69
70 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
71
72 for (i = 0; i < num_planes; i++)
73 fb->obj[i] = obj[i];
74
75 ret = drm_framebuffer_init(dev, fb, funcs);
76 if (ret) {
77 DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n",
78 ret);
79 kfree(fb);
80 return ERR_PTR(ret);
81 }
82
83 return fb;
84}
85
86/**
87 * drm_gem_fb_destroy - Free GEM backed framebuffer
88 * @fb: Framebuffer
89 *
90 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure
91 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy
92 * callback.
93 */
94void drm_gem_fb_destroy(struct drm_framebuffer *fb)
95{
96 int i;
97
98 for (i = 0; i < 4; i++)
99 drm_gem_object_put_unlocked(fb->obj[i]);
100
101 drm_framebuffer_cleanup(fb);
102 kfree(fb);
103}
104EXPORT_SYMBOL(drm_gem_fb_destroy);
105
106/**
107 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer
108 * @fb: Framebuffer
109 * @file: DRM file to register the handle for
110 * @handle: Pointer to return the created handle
111 *
112 * This function creates a handle for the GEM object backing the framebuffer.
113 * Drivers can use this as their &drm_framebuffer_funcs->create_handle
114 * callback. The GETFB IOCTL calls into this callback.
115 *
116 * Returns:
117 * 0 on success or a negative error code on failure.
118 */
119int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
120 unsigned int *handle)
121{
122 return drm_gem_handle_create(file, fb->obj[0], handle);
123}
124EXPORT_SYMBOL(drm_gem_fb_create_handle);
125
126/**
127 * drm_gem_fb_create_with_funcs() - Helper function for the
128 * &drm_mode_config_funcs.fb_create
129 * callback
130 * @dev: DRM device
131 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
132 * @mode_cmd: Metadata from the userspace framebuffer creation request
133 * @funcs: vtable to be used for the new framebuffer object
134 *
135 * This function can be used to set &drm_framebuffer_funcs for drivers that need
136 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to
137 * change &drm_framebuffer_funcs. The function does buffer size validation.
138 *
139 * Returns:
140 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
141 */
142struct drm_framebuffer *
143drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
144 const struct drm_mode_fb_cmd2 *mode_cmd,
145 const struct drm_framebuffer_funcs *funcs)
146{
147 const struct drm_format_info *info;
148 struct drm_gem_object *objs[4];
149 struct drm_framebuffer *fb;
150 int ret, i;
151
152 info = drm_get_format_info(dev, mode_cmd);
153 if (!info)
154 return ERR_PTR(-EINVAL);
155
156 for (i = 0; i < info->num_planes; i++) {
157 unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
158 unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
159 unsigned int min_size;
160
161 objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
162 if (!objs[i]) {
163 DRM_DEBUG_KMS("Failed to lookup GEM object\n");
164 ret = -ENOENT;
165 goto err_gem_object_put;
166 }
167
168 min_size = (height - 1) * mode_cmd->pitches[i]
169 + drm_format_info_min_pitch(info, i, width)
170 + mode_cmd->offsets[i];
171
172 if (objs[i]->size < min_size) {
173 drm_gem_object_put_unlocked(objs[i]);
174 ret = -EINVAL;
175 goto err_gem_object_put;
176 }
177 }
178
179 fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs);
180 if (IS_ERR(fb)) {
181 ret = PTR_ERR(fb);
182 goto err_gem_object_put;
183 }
184
185 return fb;
186
187err_gem_object_put:
188 for (i--; i >= 0; i--)
189 drm_gem_object_put_unlocked(objs[i]);
190
191 return ERR_PTR(ret);
192}
193EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);
194
195static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
196 .destroy = drm_gem_fb_destroy,
197 .create_handle = drm_gem_fb_create_handle,
198};
199
200/**
201 * drm_gem_fb_create() - Helper function for the
202 * &drm_mode_config_funcs.fb_create callback
203 * @dev: DRM device
204 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
205 * @mode_cmd: Metadata from the userspace framebuffer creation request
206 *
207 * This function creates a new framebuffer object described by
208 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
209 * backing the framebuffer.
210 *
211 * If your hardware has special alignment or pitch requirements these should be
212 * checked before calling this function. The function does buffer size
213 * validation. Use drm_gem_fb_create_with_dirty() if you need framebuffer
214 * flushing.
215 *
216 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
217 * The ADDFB2 IOCTL calls into this callback.
218 *
219 * Returns:
220 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
221 */
222struct drm_framebuffer *
223drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
224 const struct drm_mode_fb_cmd2 *mode_cmd)
225{
226 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
227 &drm_gem_fb_funcs);
228}
229EXPORT_SYMBOL_GPL(drm_gem_fb_create);
230
231static const struct drm_framebuffer_funcs drm_gem_fb_funcs_dirtyfb = {
232 .destroy = drm_gem_fb_destroy,
233 .create_handle = drm_gem_fb_create_handle,
234 .dirty = drm_atomic_helper_dirtyfb,
235};
236
237/**
238 * drm_gem_fb_create_with_dirty() - Helper function for the
239 * &drm_mode_config_funcs.fb_create callback
240 * @dev: DRM device
241 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
242 * @mode_cmd: Metadata from the userspace framebuffer creation request
243 *
244 * This function creates a new framebuffer object described by
245 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
246 * backing the framebuffer. drm_atomic_helper_dirtyfb() is used for the dirty
247 * callback giving framebuffer flushing through the atomic machinery. Use
248 * drm_gem_fb_create() if you don't need the dirty callback.
249 * The function does buffer size validation.
250 *
251 * Drivers should also call drm_plane_enable_fb_damage_clips() on all planes
252 * to enable userspace to use damage clips also with the ATOMIC IOCTL.
253 *
254 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
255 * The ADDFB2 IOCTL calls into this callback.
256 *
257 * Returns:
258 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
259 */
260struct drm_framebuffer *
261drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
262 const struct drm_mode_fb_cmd2 *mode_cmd)
263{
264 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
265 &drm_gem_fb_funcs_dirtyfb);
266}
267EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty);
268
269/**
270 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer
271 * @plane: Plane
272 * @state: Plane state the fence will be attached to
273 *
274 * This function extracts the exclusive fence from &drm_gem_object.resv and
275 * attaches it to plane state for the atomic helper to wait on. This is
276 * necessary to correctly implement implicit synchronization for any buffers
277 * shared as a struct &dma_buf. This function can be used as the
278 * &drm_plane_helper_funcs.prepare_fb callback.
279 *
280 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple
281 * gem based framebuffer drivers which have their buffers always pinned in
282 * memory.
283 *
284 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and
285 * explicit fencing in atomic modeset updates.
286 */
287int drm_gem_fb_prepare_fb(struct drm_plane *plane,
288 struct drm_plane_state *state)
289{
290 struct drm_gem_object *obj;
291 struct dma_fence *fence;
292
293 if (!state->fb)
294 return 0;
295
296 obj = drm_gem_fb_get_obj(state->fb, 0);
297 fence = dma_resv_get_excl_rcu(obj->resv);
298 drm_atomic_set_fence_for_plane(state, fence);
299
300 return 0;
301}
302EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);
303
304/**
305 * drm_gem_fb_simple_display_pipe_prepare_fb - prepare_fb helper for
306 * &drm_simple_display_pipe
307 * @pipe: Simple display pipe
308 * @plane_state: Plane state
309 *
310 * This function uses drm_gem_fb_prepare_fb() to extract the exclusive fence
311 * from &drm_gem_object.resv and attaches it to plane state for the atomic
312 * helper to wait on. This is necessary to correctly implement implicit
313 * synchronization for any buffers shared as a struct &dma_buf. Drivers can use
314 * this as their &drm_simple_display_pipe_funcs.prepare_fb callback.
315 *
316 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and
317 * explicit fencing in atomic modeset updates.
318 */
319int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe,
320 struct drm_plane_state *plane_state)
321{
322 return drm_gem_fb_prepare_fb(&pipe->plane, plane_state);
323}
324EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb);
1/*
2 * drm gem framebuffer helper functions
3 *
4 * Copyright (C) 2017 Noralf Trønnes
5 *
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.
10 */
11
12#include <linux/dma-buf.h>
13#include <linux/dma-fence.h>
14#include <linux/reservation.h>
15#include <linux/slab.h>
16
17#include <drm/drmP.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>
25
26/**
27 * DOC: overview
28 *
29 * This library provides helpers for drivers that don't subclass
30 * &drm_framebuffer and use &drm_gem_object for their backing storage.
31 *
32 * Drivers without additional needs to validate framebuffers can simply use
33 * drm_gem_fb_create() and everything is wired up automatically. Other drivers
34 * can use all parts independently.
35 */
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 */
49struct 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
55 return fb->obj[plane];
56}
57EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);
58
59static struct drm_framebuffer *
60drm_gem_fb_alloc(struct drm_device *dev,
61 const struct drm_mode_fb_cmd2 *mode_cmd,
62 struct drm_gem_object **obj, unsigned int num_planes,
63 const struct drm_framebuffer_funcs *funcs)
64{
65 struct drm_framebuffer *fb;
66 int ret, i;
67
68 fb = kzalloc(sizeof(*fb), GFP_KERNEL);
69 if (!fb)
70 return ERR_PTR(-ENOMEM);
71
72 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
73
74 for (i = 0; i < num_planes; i++)
75 fb->obj[i] = obj[i];
76
77 ret = drm_framebuffer_init(dev, fb, funcs);
78 if (ret) {
79 DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n",
80 ret);
81 kfree(fb);
82 return ERR_PTR(ret);
83 }
84
85 return fb;
86}
87
88/**
89 * drm_gem_fb_destroy - Free GEM backed framebuffer
90 * @fb: Framebuffer
91 *
92 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure
93 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy
94 * callback.
95 */
96void drm_gem_fb_destroy(struct drm_framebuffer *fb)
97{
98 int i;
99
100 for (i = 0; i < 4; i++)
101 drm_gem_object_put_unlocked(fb->obj[i]);
102
103 drm_framebuffer_cleanup(fb);
104 kfree(fb);
105}
106EXPORT_SYMBOL(drm_gem_fb_destroy);
107
108/**
109 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer
110 * @fb: Framebuffer
111 * @file: DRM file to register the handle for
112 * @handle: Pointer to return the created handle
113 *
114 * This function creates a handle for the GEM object backing the framebuffer.
115 * Drivers can use this as their &drm_framebuffer_funcs->create_handle
116 * callback. The GETFB IOCTL calls into this callback.
117 *
118 * Returns:
119 * 0 on success or a negative error code on failure.
120 */
121int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
122 unsigned int *handle)
123{
124 return drm_gem_handle_create(file, fb->obj[0], handle);
125}
126EXPORT_SYMBOL(drm_gem_fb_create_handle);
127
128/**
129 * drm_gem_fb_create_with_funcs() - Helper function for the
130 * &drm_mode_config_funcs.fb_create
131 * callback
132 * @dev: DRM device
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 can be used to set &drm_framebuffer_funcs for drivers that need the
138 * &drm_framebuffer_funcs.dirty callback. Use drm_gem_fb_create() if you don't
139 * need to change &drm_framebuffer_funcs.
140 * The function does buffer size validation.
141 *
142 * Returns:
143 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
144 */
145struct drm_framebuffer *
146drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
147 const struct drm_mode_fb_cmd2 *mode_cmd,
148 const struct drm_framebuffer_funcs *funcs)
149{
150 const struct drm_format_info *info;
151 struct drm_gem_object *objs[4];
152 struct drm_framebuffer *fb;
153 int ret, i;
154
155 info = drm_get_format_info(dev, mode_cmd);
156 if (!info)
157 return ERR_PTR(-EINVAL);
158
159 for (i = 0; i < info->num_planes; i++) {
160 unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
161 unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
162 unsigned int min_size;
163
164 objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
165 if (!objs[i]) {
166 DRM_DEBUG_KMS("Failed to lookup GEM object\n");
167 ret = -ENOENT;
168 goto err_gem_object_put;
169 }
170
171 min_size = (height - 1) * mode_cmd->pitches[i]
172 + width * info->cpp[i]
173 + mode_cmd->offsets[i];
174
175 if (objs[i]->size < min_size) {
176 drm_gem_object_put_unlocked(objs[i]);
177 ret = -EINVAL;
178 goto err_gem_object_put;
179 }
180 }
181
182 fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs);
183 if (IS_ERR(fb)) {
184 ret = PTR_ERR(fb);
185 goto err_gem_object_put;
186 }
187
188 return fb;
189
190err_gem_object_put:
191 for (i--; i >= 0; i--)
192 drm_gem_object_put_unlocked(objs[i]);
193
194 return ERR_PTR(ret);
195}
196EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);
197
198static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
199 .destroy = drm_gem_fb_destroy,
200 .create_handle = drm_gem_fb_create_handle,
201};
202
203/**
204 * drm_gem_fb_create() - Helper function for the
205 * &drm_mode_config_funcs.fb_create callback
206 * @dev: DRM device
207 * @file: DRM file that holds the GEM handle(s) backing the framebuffer
208 * @mode_cmd: Metadata from the userspace framebuffer creation request
209 *
210 * This function creates a new framebuffer object described by
211 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
212 * backing the framebuffer.
213 *
214 * If your hardware has special alignment or pitch requirements these should be
215 * checked before calling this function. The function does buffer size
216 * validation. Use drm_gem_fb_create_with_funcs() if you need to set
217 * &drm_framebuffer_funcs.dirty.
218 *
219 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
220 * The ADDFB2 IOCTL calls into this callback.
221 *
222 * Returns:
223 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
224 */
225struct drm_framebuffer *
226drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
227 const struct drm_mode_fb_cmd2 *mode_cmd)
228{
229 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
230 &drm_gem_fb_funcs);
231}
232EXPORT_SYMBOL_GPL(drm_gem_fb_create);
233
234/**
235 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer
236 * @plane: Plane
237 * @state: Plane state the fence will be attached to
238 *
239 * This function prepares a GEM backed framebuffer for scanout by checking if
240 * the plane framebuffer has a DMA-BUF attached. If it does, it extracts the
241 * exclusive fence and attaches it to the plane state for the atomic helper to
242 * wait on. This function can be used as the &drm_plane_helper_funcs.prepare_fb
243 * callback.
244 *
245 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple
246 * gem based framebuffer drivers which have their buffers always pinned in
247 * memory.
248 */
249int drm_gem_fb_prepare_fb(struct drm_plane *plane,
250 struct drm_plane_state *state)
251{
252 struct dma_buf *dma_buf;
253 struct dma_fence *fence;
254
255 if (plane->state->fb == state->fb || !state->fb)
256 return 0;
257
258 dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf;
259 if (dma_buf) {
260 fence = reservation_object_get_excl_rcu(dma_buf->resv);
261 drm_atomic_set_fence_for_plane(state, fence);
262 }
263
264 return 0;
265}
266EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);
267
268/**
269 * drm_gem_fbdev_fb_create - Create a GEM backed &drm_framebuffer for fbdev
270 * emulation
271 * @dev: DRM device
272 * @sizes: fbdev size description
273 * @pitch_align: Optional pitch alignment
274 * @obj: GEM object backing the framebuffer
275 * @funcs: Optional vtable to be used for the new framebuffer object when the
276 * dirty callback is needed.
277 *
278 * This function creates a framebuffer from a &drm_fb_helper_surface_size
279 * description for use in the &drm_fb_helper_funcs.fb_probe callback.
280 *
281 * Returns:
282 * Pointer to a &drm_framebuffer on success or an error pointer on failure.
283 */
284struct drm_framebuffer *
285drm_gem_fbdev_fb_create(struct drm_device *dev,
286 struct drm_fb_helper_surface_size *sizes,
287 unsigned int pitch_align, struct drm_gem_object *obj,
288 const struct drm_framebuffer_funcs *funcs)
289{
290 struct drm_mode_fb_cmd2 mode_cmd = { 0 };
291
292 mode_cmd.width = sizes->surface_width;
293 mode_cmd.height = sizes->surface_height;
294 mode_cmd.pitches[0] = sizes->surface_width *
295 DIV_ROUND_UP(sizes->surface_bpp, 8);
296 if (pitch_align)
297 mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0],
298 pitch_align);
299 mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
300 sizes->surface_depth);
301 if (obj->size < mode_cmd.pitches[0] * mode_cmd.height)
302 return ERR_PTR(-EINVAL);
303
304 if (!funcs)
305 funcs = &drm_gem_fb_funcs;
306
307 return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs);
308}
309EXPORT_SYMBOL(drm_gem_fbdev_fb_create);