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_atomic_uapi.h> 20 #include <drm/drm_damage_helper.h> 21 #include <drm/drm_fb_helper.h> 22 #include <drm/drm_fourcc.h> 23 #include <drm/drm_framebuffer.h> 24 #include <drm/drm_gem.h> 25 #include <drm/drm_gem_framebuffer_helper.h> 26 #include <drm/drm_modeset_helper.h> 27 #include <drm/drm_simple_kms_helper.h> 28 29 /** 30 * DOC: overview 31 * 32 * This library provides helpers for drivers that don't subclass 33 * &drm_framebuffer and use &drm_gem_object for their backing storage. 34 * 35 * Drivers without additional needs to validate framebuffers can simply use 36 * drm_gem_fb_create() and everything is wired up automatically. Other drivers 37 * can use all parts independently. 38 */ 39 40 /** 41 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer 42 * @fb: Framebuffer 43 * @plane: Plane index 44 * 45 * No additional reference is taken beyond the one that the &drm_frambuffer 46 * already holds. 47 * 48 * Returns: 49 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL 50 * if it does not exist. 51 */ 52 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb, 53 unsigned int plane) 54 { 55 if (plane >= 4) 56 return NULL; 57 58 return fb->obj[plane]; 59 } 60 EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj); 61 62 static struct drm_framebuffer * 63 drm_gem_fb_alloc(struct drm_device *dev, 64 const struct drm_mode_fb_cmd2 *mode_cmd, 65 struct drm_gem_object **obj, unsigned int num_planes, 66 const struct drm_framebuffer_funcs *funcs) 67 { 68 struct drm_framebuffer *fb; 69 int ret, i; 70 71 fb = kzalloc(sizeof(*fb), GFP_KERNEL); 72 if (!fb) 73 return ERR_PTR(-ENOMEM); 74 75 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd); 76 77 for (i = 0; i < num_planes; i++) 78 fb->obj[i] = obj[i]; 79 80 ret = drm_framebuffer_init(dev, fb, funcs); 81 if (ret) { 82 DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n", 83 ret); 84 kfree(fb); 85 return ERR_PTR(ret); 86 } 87 88 return fb; 89 } 90 91 /** 92 * drm_gem_fb_destroy - Free GEM backed framebuffer 93 * @fb: Framebuffer 94 * 95 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure 96 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy 97 * callback. 98 */ 99 void drm_gem_fb_destroy(struct drm_framebuffer *fb) 100 { 101 int i; 102 103 for (i = 0; i < 4; i++) 104 drm_gem_object_put_unlocked(fb->obj[i]); 105 106 drm_framebuffer_cleanup(fb); 107 kfree(fb); 108 } 109 EXPORT_SYMBOL(drm_gem_fb_destroy); 110 111 /** 112 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer 113 * @fb: Framebuffer 114 * @file: DRM file to register the handle for 115 * @handle: Pointer to return the created handle 116 * 117 * This function creates a handle for the GEM object backing the framebuffer. 118 * Drivers can use this as their &drm_framebuffer_funcs->create_handle 119 * callback. The GETFB IOCTL calls into this callback. 120 * 121 * Returns: 122 * 0 on success or a negative error code on failure. 123 */ 124 int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file, 125 unsigned int *handle) 126 { 127 return drm_gem_handle_create(file, fb->obj[0], handle); 128 } 129 EXPORT_SYMBOL(drm_gem_fb_create_handle); 130 131 /** 132 * drm_gem_fb_create_with_funcs() - Helper function for the 133 * &drm_mode_config_funcs.fb_create 134 * callback 135 * @dev: DRM device 136 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 137 * @mode_cmd: Metadata from the userspace framebuffer creation request 138 * @funcs: vtable to be used for the new framebuffer object 139 * 140 * This function can be used to set &drm_framebuffer_funcs for drivers that need 141 * custom framebuffer callbacks. Use drm_gem_fb_create() if you don't need to 142 * change &drm_framebuffer_funcs. The function does buffer size validation. 143 * 144 * Returns: 145 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 146 */ 147 struct drm_framebuffer * 148 drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file, 149 const struct drm_mode_fb_cmd2 *mode_cmd, 150 const struct drm_framebuffer_funcs *funcs) 151 { 152 const struct drm_format_info *info; 153 struct drm_gem_object *objs[4]; 154 struct drm_framebuffer *fb; 155 int ret, i; 156 157 info = drm_get_format_info(dev, mode_cmd); 158 if (!info) 159 return ERR_PTR(-EINVAL); 160 161 for (i = 0; i < info->num_planes; i++) { 162 unsigned int width = mode_cmd->width / (i ? info->hsub : 1); 163 unsigned int height = mode_cmd->height / (i ? info->vsub : 1); 164 unsigned int min_size; 165 166 objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]); 167 if (!objs[i]) { 168 DRM_DEBUG_KMS("Failed to lookup GEM object\n"); 169 ret = -ENOENT; 170 goto err_gem_object_put; 171 } 172 173 min_size = (height - 1) * mode_cmd->pitches[i] 174 + drm_format_info_min_pitch(info, i, width) 175 + mode_cmd->offsets[i]; 176 177 if (objs[i]->size < min_size) { 178 drm_gem_object_put_unlocked(objs[i]); 179 ret = -EINVAL; 180 goto err_gem_object_put; 181 } 182 } 183 184 fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs); 185 if (IS_ERR(fb)) { 186 ret = PTR_ERR(fb); 187 goto err_gem_object_put; 188 } 189 190 return fb; 191 192 err_gem_object_put: 193 for (i--; i >= 0; i--) 194 drm_gem_object_put_unlocked(objs[i]); 195 196 return ERR_PTR(ret); 197 } 198 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs); 199 200 static const struct drm_framebuffer_funcs drm_gem_fb_funcs = { 201 .destroy = drm_gem_fb_destroy, 202 .create_handle = drm_gem_fb_create_handle, 203 }; 204 205 /** 206 * drm_gem_fb_create() - Helper function for the 207 * &drm_mode_config_funcs.fb_create callback 208 * @dev: DRM device 209 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 210 * @mode_cmd: Metadata from the userspace framebuffer creation request 211 * 212 * This function creates a new framebuffer object described by 213 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s) 214 * backing the framebuffer. 215 * 216 * If your hardware has special alignment or pitch requirements these should be 217 * checked before calling this function. The function does buffer size 218 * validation. Use drm_gem_fb_create_with_dirty() if you need framebuffer 219 * flushing. 220 * 221 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback. 222 * The ADDFB2 IOCTL calls into this callback. 223 * 224 * Returns: 225 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 226 */ 227 struct drm_framebuffer * 228 drm_gem_fb_create(struct drm_device *dev, struct drm_file *file, 229 const struct drm_mode_fb_cmd2 *mode_cmd) 230 { 231 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd, 232 &drm_gem_fb_funcs); 233 } 234 EXPORT_SYMBOL_GPL(drm_gem_fb_create); 235 236 static const struct drm_framebuffer_funcs drm_gem_fb_funcs_dirtyfb = { 237 .destroy = drm_gem_fb_destroy, 238 .create_handle = drm_gem_fb_create_handle, 239 .dirty = drm_atomic_helper_dirtyfb, 240 }; 241 242 /** 243 * drm_gem_fb_create_with_dirty() - Helper function for the 244 * &drm_mode_config_funcs.fb_create callback 245 * @dev: DRM device 246 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 247 * @mode_cmd: Metadata from the userspace framebuffer creation request 248 * 249 * This function creates a new framebuffer object described by 250 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s) 251 * backing the framebuffer. drm_atomic_helper_dirtyfb() is used for the dirty 252 * callback giving framebuffer flushing through the atomic machinery. Use 253 * drm_gem_fb_create() if you don't need the dirty callback. 254 * The function does buffer size validation. 255 * 256 * Drivers should also call drm_plane_enable_fb_damage_clips() on all planes 257 * to enable userspace to use damage clips also with the ATOMIC IOCTL. 258 * 259 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback. 260 * The ADDFB2 IOCTL calls into this callback. 261 * 262 * Returns: 263 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 264 */ 265 struct drm_framebuffer * 266 drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file, 267 const struct drm_mode_fb_cmd2 *mode_cmd) 268 { 269 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd, 270 &drm_gem_fb_funcs_dirtyfb); 271 } 272 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty); 273 274 /** 275 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer 276 * @plane: Plane 277 * @state: Plane state the fence will be attached to 278 * 279 * This function prepares a GEM backed framebuffer for scanout by checking if 280 * the plane framebuffer has a DMA-BUF attached. If it does, it extracts the 281 * exclusive fence and attaches it to the plane state for the atomic helper to 282 * wait on. This function can be used as the &drm_plane_helper_funcs.prepare_fb 283 * callback. 284 * 285 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple 286 * gem based framebuffer drivers which have their buffers always pinned in 287 * memory. 288 */ 289 int drm_gem_fb_prepare_fb(struct drm_plane *plane, 290 struct drm_plane_state *state) 291 { 292 struct dma_buf *dma_buf; 293 struct dma_fence *fence; 294 295 if (!state->fb) 296 return 0; 297 298 dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf; 299 if (dma_buf) { 300 fence = reservation_object_get_excl_rcu(dma_buf->resv); 301 drm_atomic_set_fence_for_plane(state, fence); 302 } 303 304 return 0; 305 } 306 EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb); 307 308 /** 309 * drm_gem_fb_simple_display_pipe_prepare_fb - prepare_fb helper for 310 * &drm_simple_display_pipe 311 * @pipe: Simple display pipe 312 * @plane_state: Plane state 313 * 314 * This function uses drm_gem_fb_prepare_fb() to check if the plane FB has a 315 * &dma_buf attached, extracts the exclusive fence and attaches it to plane 316 * state for the atomic helper to wait on. Drivers can use this as their 317 * &drm_simple_display_pipe_funcs.prepare_fb callback. 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); 325 326 /** 327 * drm_gem_fbdev_fb_create - Create a GEM backed &drm_framebuffer for fbdev 328 * emulation 329 * @dev: DRM device 330 * @sizes: fbdev size description 331 * @pitch_align: Optional pitch alignment 332 * @obj: GEM object backing the framebuffer 333 * @funcs: Optional vtable to be used for the new framebuffer object when the 334 * dirty callback is needed. 335 * 336 * This function creates a framebuffer from a &drm_fb_helper_surface_size 337 * description for use in the &drm_fb_helper_funcs.fb_probe callback. 338 * 339 * Returns: 340 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 341 */ 342 struct drm_framebuffer * 343 drm_gem_fbdev_fb_create(struct drm_device *dev, 344 struct drm_fb_helper_surface_size *sizes, 345 unsigned int pitch_align, struct drm_gem_object *obj, 346 const struct drm_framebuffer_funcs *funcs) 347 { 348 struct drm_mode_fb_cmd2 mode_cmd = { 0 }; 349 350 mode_cmd.width = sizes->surface_width; 351 mode_cmd.height = sizes->surface_height; 352 mode_cmd.pitches[0] = sizes->surface_width * 353 DIV_ROUND_UP(sizes->surface_bpp, 8); 354 if (pitch_align) 355 mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0], 356 pitch_align); 357 mode_cmd.pixel_format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp, 358 sizes->surface_depth); 359 if (obj->size < mode_cmd.pitches[0] * mode_cmd.height) 360 return ERR_PTR(-EINVAL); 361 362 if (!funcs) 363 funcs = &drm_gem_fb_funcs; 364 365 return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs); 366 } 367 EXPORT_SYMBOL(drm_gem_fbdev_fb_create); 368