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/reservation.h> 11 #include <linux/slab.h> 12 13 #include <drm/drmP.h> 14 #include <drm/drm_atomic.h> 15 #include <drm/drm_atomic_uapi.h> 16 #include <drm/drm_damage_helper.h> 17 #include <drm/drm_fb_helper.h> 18 #include <drm/drm_fourcc.h> 19 #include <drm/drm_framebuffer.h> 20 #include <drm/drm_gem.h> 21 #include <drm/drm_gem_framebuffer_helper.h> 22 #include <drm/drm_modeset_helper.h> 23 #include <drm/drm_simple_kms_helper.h> 24 25 /** 26 * DOC: overview 27 * 28 * This library provides helpers for drivers that don't subclass 29 * &drm_framebuffer and use &drm_gem_object for their backing storage. 30 * 31 * Drivers without additional needs to validate framebuffers can simply use 32 * drm_gem_fb_create() and everything is wired up automatically. Other drivers 33 * can use all parts independently. 34 */ 35 36 /** 37 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer 38 * @fb: Framebuffer 39 * @plane: Plane index 40 * 41 * No additional reference is taken beyond the one that the &drm_frambuffer 42 * already holds. 43 * 44 * Returns: 45 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL 46 * if it does not exist. 47 */ 48 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb, 49 unsigned int plane) 50 { 51 if (plane >= 4) 52 return NULL; 53 54 return fb->obj[plane]; 55 } 56 EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj); 57 58 static struct drm_framebuffer * 59 drm_gem_fb_alloc(struct drm_device *dev, 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 struct drm_framebuffer *fb; 65 int ret, i; 66 67 fb = kzalloc(sizeof(*fb), GFP_KERNEL); 68 if (!fb) 69 return ERR_PTR(-ENOMEM); 70 71 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd); 72 73 for (i = 0; i < num_planes; i++) 74 fb->obj[i] = obj[i]; 75 76 ret = drm_framebuffer_init(dev, fb, funcs); 77 if (ret) { 78 DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n", 79 ret); 80 kfree(fb); 81 return ERR_PTR(ret); 82 } 83 84 return fb; 85 } 86 87 /** 88 * drm_gem_fb_destroy - Free GEM backed framebuffer 89 * @fb: Framebuffer 90 * 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 93 * callback. 94 */ 95 void drm_gem_fb_destroy(struct drm_framebuffer *fb) 96 { 97 int i; 98 99 for (i = 0; i < 4; i++) 100 drm_gem_object_put_unlocked(fb->obj[i]); 101 102 drm_framebuffer_cleanup(fb); 103 kfree(fb); 104 } 105 EXPORT_SYMBOL(drm_gem_fb_destroy); 106 107 /** 108 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer 109 * @fb: Framebuffer 110 * @file: DRM file to register the handle for 111 * @handle: Pointer to return the created handle 112 * 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. 116 * 117 * Returns: 118 * 0 on success or a negative error code on failure. 119 */ 120 int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file, 121 unsigned int *handle) 122 { 123 return drm_gem_handle_create(file, fb->obj[0], handle); 124 } 125 EXPORT_SYMBOL(drm_gem_fb_create_handle); 126 127 /** 128 * drm_gem_fb_create_with_funcs() - Helper function for the 129 * &drm_mode_config_funcs.fb_create 130 * callback 131 * @dev: DRM device 132 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 133 * @mode_cmd: Metadata from the userspace framebuffer creation request 134 * @funcs: vtable to be used for the new framebuffer object 135 * 136 * This function can be used to set &drm_framebuffer_funcs for drivers that need 137 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to 138 * change &drm_framebuffer_funcs. The function does buffer size validation. 139 * 140 * Returns: 141 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 142 */ 143 struct drm_framebuffer * 144 drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file, 145 const struct drm_mode_fb_cmd2 *mode_cmd, 146 const struct drm_framebuffer_funcs *funcs) 147 { 148 const struct drm_format_info *info; 149 struct drm_gem_object *objs[4]; 150 struct drm_framebuffer *fb; 151 int ret, i; 152 153 info = drm_get_format_info(dev, mode_cmd); 154 if (!info) 155 return ERR_PTR(-EINVAL); 156 157 for (i = 0; i < info->num_planes; i++) { 158 unsigned int width = mode_cmd->width / (i ? info->hsub : 1); 159 unsigned int height = mode_cmd->height / (i ? info->vsub : 1); 160 unsigned int min_size; 161 162 objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]); 163 if (!objs[i]) { 164 DRM_DEBUG_KMS("Failed to lookup GEM object\n"); 165 ret = -ENOENT; 166 goto err_gem_object_put; 167 } 168 169 min_size = (height - 1) * mode_cmd->pitches[i] 170 + drm_format_info_min_pitch(info, i, width) 171 + mode_cmd->offsets[i]; 172 173 if (objs[i]->size < min_size) { 174 drm_gem_object_put_unlocked(objs[i]); 175 ret = -EINVAL; 176 goto err_gem_object_put; 177 } 178 } 179 180 fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs); 181 if (IS_ERR(fb)) { 182 ret = PTR_ERR(fb); 183 goto err_gem_object_put; 184 } 185 186 return fb; 187 188 err_gem_object_put: 189 for (i--; i >= 0; i--) 190 drm_gem_object_put_unlocked(objs[i]); 191 192 return ERR_PTR(ret); 193 } 194 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs); 195 196 static const struct drm_framebuffer_funcs drm_gem_fb_funcs = { 197 .destroy = drm_gem_fb_destroy, 198 .create_handle = drm_gem_fb_create_handle, 199 }; 200 201 /** 202 * drm_gem_fb_create() - Helper function for the 203 * &drm_mode_config_funcs.fb_create callback 204 * @dev: DRM device 205 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 206 * @mode_cmd: Metadata from the userspace framebuffer creation request 207 * 208 * This function creates a new framebuffer object described by 209 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s) 210 * backing the framebuffer. 211 * 212 * If your hardware has special alignment or pitch requirements these should be 213 * checked before calling this function. The function does buffer size 214 * validation. Use drm_gem_fb_create_with_dirty() if you need framebuffer 215 * flushing. 216 * 217 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback. 218 * The ADDFB2 IOCTL calls into this callback. 219 * 220 * Returns: 221 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 222 */ 223 struct drm_framebuffer * 224 drm_gem_fb_create(struct drm_device *dev, struct drm_file *file, 225 const struct drm_mode_fb_cmd2 *mode_cmd) 226 { 227 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd, 228 &drm_gem_fb_funcs); 229 } 230 EXPORT_SYMBOL_GPL(drm_gem_fb_create); 231 232 static const struct drm_framebuffer_funcs drm_gem_fb_funcs_dirtyfb = { 233 .destroy = drm_gem_fb_destroy, 234 .create_handle = drm_gem_fb_create_handle, 235 .dirty = drm_atomic_helper_dirtyfb, 236 }; 237 238 /** 239 * drm_gem_fb_create_with_dirty() - Helper function for the 240 * &drm_mode_config_funcs.fb_create callback 241 * @dev: DRM device 242 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 243 * @mode_cmd: Metadata from the userspace framebuffer creation request 244 * 245 * This function creates a new framebuffer object described by 246 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s) 247 * backing the framebuffer. drm_atomic_helper_dirtyfb() is used for the dirty 248 * callback giving framebuffer flushing through the atomic machinery. Use 249 * drm_gem_fb_create() if you don't need the dirty callback. 250 * The function does buffer size validation. 251 * 252 * Drivers should also call drm_plane_enable_fb_damage_clips() on all planes 253 * to enable userspace to use damage clips also with the ATOMIC IOCTL. 254 * 255 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback. 256 * The ADDFB2 IOCTL calls into this callback. 257 * 258 * Returns: 259 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 260 */ 261 struct drm_framebuffer * 262 drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file, 263 const struct drm_mode_fb_cmd2 *mode_cmd) 264 { 265 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd, 266 &drm_gem_fb_funcs_dirtyfb); 267 } 268 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty); 269 270 /** 271 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer 272 * @plane: Plane 273 * @state: Plane state the fence will be attached to 274 * 275 * This function prepares a GEM backed framebuffer for scanout by checking if 276 * the plane framebuffer has a DMA-BUF attached. If it does, it extracts the 277 * exclusive fence and attaches it to the plane state for the atomic helper to 278 * wait on. This function can be used as the &drm_plane_helper_funcs.prepare_fb 279 * callback. 280 * 281 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple 282 * gem based framebuffer drivers which have their buffers always pinned in 283 * memory. 284 */ 285 int drm_gem_fb_prepare_fb(struct drm_plane *plane, 286 struct drm_plane_state *state) 287 { 288 struct dma_buf *dma_buf; 289 struct dma_fence *fence; 290 291 if (!state->fb) 292 return 0; 293 294 dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf; 295 if (dma_buf) { 296 fence = reservation_object_get_excl_rcu(dma_buf->resv); 297 drm_atomic_set_fence_for_plane(state, fence); 298 } 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 check if the plane FB has a 311 * &dma_buf attached, extracts the exclusive fence and attaches it to plane 312 * state for the atomic helper to wait on. Drivers can use this as their 313 * &drm_simple_display_pipe_funcs.prepare_fb callback. 314 */ 315 int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe, 316 struct drm_plane_state *plane_state) 317 { 318 return drm_gem_fb_prepare_fb(&pipe->plane, plane_state); 319 } 320 EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb); 321 322 /** 323 * drm_gem_fbdev_fb_create - Create a GEM backed &drm_framebuffer for fbdev 324 * emulation 325 * @dev: DRM device 326 * @sizes: fbdev size description 327 * @pitch_align: Optional pitch alignment 328 * @obj: GEM object backing the framebuffer 329 * @funcs: Optional vtable to be used for the new framebuffer object when the 330 * dirty callback is needed. 331 * 332 * This function creates a framebuffer from a &drm_fb_helper_surface_size 333 * description for use in the &drm_fb_helper_funcs.fb_probe callback. 334 * 335 * Returns: 336 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 337 */ 338 struct drm_framebuffer * 339 drm_gem_fbdev_fb_create(struct drm_device *dev, 340 struct drm_fb_helper_surface_size *sizes, 341 unsigned int pitch_align, struct drm_gem_object *obj, 342 const struct drm_framebuffer_funcs *funcs) 343 { 344 struct drm_mode_fb_cmd2 mode_cmd = { 0 }; 345 346 mode_cmd.width = sizes->surface_width; 347 mode_cmd.height = sizes->surface_height; 348 mode_cmd.pitches[0] = sizes->surface_width * 349 DIV_ROUND_UP(sizes->surface_bpp, 8); 350 if (pitch_align) 351 mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0], 352 pitch_align); 353 mode_cmd.pixel_format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp, 354 sizes->surface_depth); 355 if (obj->size < mode_cmd.pitches[0] * mode_cmd.height) 356 return ERR_PTR(-EINVAL); 357 358 if (!funcs) 359 funcs = &drm_gem_fb_funcs; 360 361 return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs); 362 } 363 EXPORT_SYMBOL(drm_gem_fbdev_fb_create); 364