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 */ 47 struct 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 } 55 EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj); 56 57 static struct drm_framebuffer * 58 drm_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 */ 94 void 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 } 104 EXPORT_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 */ 119 int 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 } 124 EXPORT_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 */ 142 struct drm_framebuffer * 143 drm_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; 186 187 err_gem_object_put: 188 for (i--; i >= 0; i--) 189 drm_gem_object_put_unlocked(objs[i]); 190 191 return ERR_PTR(ret); 192 } 193 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs); 194 195 static 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 */ 222 struct drm_framebuffer * 223 drm_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 } 229 EXPORT_SYMBOL_GPL(drm_gem_fb_create); 230 231 static 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 */ 260 struct drm_framebuffer * 261 drm_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 } 267 EXPORT_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 */ 287 int 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 } 302 EXPORT_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 */ 319 int 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 } 324 EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb); 325