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_fb_helper.h> 21 #include <drm/drm_fourcc.h> 22 #include <drm/drm_framebuffer.h> 23 #include <drm/drm_gem.h> 24 #include <drm/drm_gem_framebuffer_helper.h> 25 #include <drm/drm_modeset_helper.h> 26 #include <drm/drm_simple_kms_helper.h> 27 28 /** 29 * DOC: overview 30 * 31 * This library provides helpers for drivers that don't subclass 32 * &drm_framebuffer and use &drm_gem_object for their backing storage. 33 * 34 * Drivers without additional needs to validate framebuffers can simply use 35 * drm_gem_fb_create() and everything is wired up automatically. Other drivers 36 * can use all parts independently. 37 */ 38 39 /** 40 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer 41 * @fb: Framebuffer 42 * @plane: Plane index 43 * 44 * No additional reference is taken beyond the one that the &drm_frambuffer 45 * already holds. 46 * 47 * Returns: 48 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL 49 * if it does not exist. 50 */ 51 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb, 52 unsigned int plane) 53 { 54 if (plane >= 4) 55 return NULL; 56 57 return fb->obj[plane]; 58 } 59 EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj); 60 61 static struct drm_framebuffer * 62 drm_gem_fb_alloc(struct drm_device *dev, 63 const struct drm_mode_fb_cmd2 *mode_cmd, 64 struct drm_gem_object **obj, unsigned int num_planes, 65 const struct drm_framebuffer_funcs *funcs) 66 { 67 struct drm_framebuffer *fb; 68 int ret, i; 69 70 fb = kzalloc(sizeof(*fb), GFP_KERNEL); 71 if (!fb) 72 return ERR_PTR(-ENOMEM); 73 74 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd); 75 76 for (i = 0; i < num_planes; i++) 77 fb->obj[i] = obj[i]; 78 79 ret = drm_framebuffer_init(dev, fb, funcs); 80 if (ret) { 81 DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n", 82 ret); 83 kfree(fb); 84 return ERR_PTR(ret); 85 } 86 87 return fb; 88 } 89 90 /** 91 * drm_gem_fb_destroy - Free GEM backed framebuffer 92 * @fb: Framebuffer 93 * 94 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure 95 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy 96 * callback. 97 */ 98 void drm_gem_fb_destroy(struct drm_framebuffer *fb) 99 { 100 int i; 101 102 for (i = 0; i < 4; i++) 103 drm_gem_object_put_unlocked(fb->obj[i]); 104 105 drm_framebuffer_cleanup(fb); 106 kfree(fb); 107 } 108 EXPORT_SYMBOL(drm_gem_fb_destroy); 109 110 /** 111 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer 112 * @fb: Framebuffer 113 * @file: DRM file to register the handle for 114 * @handle: Pointer to return the created handle 115 * 116 * This function creates a handle for the GEM object backing the framebuffer. 117 * Drivers can use this as their &drm_framebuffer_funcs->create_handle 118 * callback. The GETFB IOCTL calls into this callback. 119 * 120 * Returns: 121 * 0 on success or a negative error code on failure. 122 */ 123 int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file, 124 unsigned int *handle) 125 { 126 return drm_gem_handle_create(file, fb->obj[0], handle); 127 } 128 EXPORT_SYMBOL(drm_gem_fb_create_handle); 129 130 /** 131 * drm_gem_fb_create_with_funcs() - Helper function for the 132 * &drm_mode_config_funcs.fb_create 133 * callback 134 * @dev: DRM device 135 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 136 * @mode_cmd: Metadata from the userspace framebuffer creation request 137 * @funcs: vtable to be used for the new framebuffer object 138 * 139 * This can be used to set &drm_framebuffer_funcs for drivers that need the 140 * &drm_framebuffer_funcs.dirty callback. Use drm_gem_fb_create() if you don't 141 * need to change &drm_framebuffer_funcs. 142 * 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 + width * info->cpp[i] 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_funcs() if you need to set 219 * &drm_framebuffer_funcs.dirty. 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 /** 237 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer 238 * @plane: Plane 239 * @state: Plane state the fence will be attached to 240 * 241 * This function prepares a GEM backed framebuffer for scanout by checking if 242 * the plane framebuffer has a DMA-BUF attached. If it does, it extracts the 243 * exclusive fence and attaches it to the plane state for the atomic helper to 244 * wait on. This function can be used as the &drm_plane_helper_funcs.prepare_fb 245 * callback. 246 * 247 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple 248 * gem based framebuffer drivers which have their buffers always pinned in 249 * memory. 250 */ 251 int drm_gem_fb_prepare_fb(struct drm_plane *plane, 252 struct drm_plane_state *state) 253 { 254 struct dma_buf *dma_buf; 255 struct dma_fence *fence; 256 257 if (!state->fb) 258 return 0; 259 260 dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf; 261 if (dma_buf) { 262 fence = reservation_object_get_excl_rcu(dma_buf->resv); 263 drm_atomic_set_fence_for_plane(state, fence); 264 } 265 266 return 0; 267 } 268 EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb); 269 270 /** 271 * drm_gem_fb_simple_display_pipe_prepare_fb - prepare_fb helper for 272 * &drm_simple_display_pipe 273 * @pipe: Simple display pipe 274 * @plane_state: Plane state 275 * 276 * This function uses drm_gem_fb_prepare_fb() to check if the plane FB has a 277 * &dma_buf attached, extracts the exclusive fence and attaches it to plane 278 * state for the atomic helper to wait on. Drivers can use this as their 279 * &drm_simple_display_pipe_funcs.prepare_fb callback. 280 */ 281 int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe, 282 struct drm_plane_state *plane_state) 283 { 284 return drm_gem_fb_prepare_fb(&pipe->plane, plane_state); 285 } 286 EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb); 287 288 /** 289 * drm_gem_fbdev_fb_create - Create a GEM backed &drm_framebuffer for fbdev 290 * emulation 291 * @dev: DRM device 292 * @sizes: fbdev size description 293 * @pitch_align: Optional pitch alignment 294 * @obj: GEM object backing the framebuffer 295 * @funcs: Optional vtable to be used for the new framebuffer object when the 296 * dirty callback is needed. 297 * 298 * This function creates a framebuffer from a &drm_fb_helper_surface_size 299 * description for use in the &drm_fb_helper_funcs.fb_probe callback. 300 * 301 * Returns: 302 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 303 */ 304 struct drm_framebuffer * 305 drm_gem_fbdev_fb_create(struct drm_device *dev, 306 struct drm_fb_helper_surface_size *sizes, 307 unsigned int pitch_align, struct drm_gem_object *obj, 308 const struct drm_framebuffer_funcs *funcs) 309 { 310 struct drm_mode_fb_cmd2 mode_cmd = { 0 }; 311 312 mode_cmd.width = sizes->surface_width; 313 mode_cmd.height = sizes->surface_height; 314 mode_cmd.pitches[0] = sizes->surface_width * 315 DIV_ROUND_UP(sizes->surface_bpp, 8); 316 if (pitch_align) 317 mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0], 318 pitch_align); 319 mode_cmd.pixel_format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp, 320 sizes->surface_depth); 321 if (obj->size < mode_cmd.pitches[0] * mode_cmd.height) 322 return ERR_PTR(-EINVAL); 323 324 if (!funcs) 325 funcs = &drm_gem_fb_funcs; 326 327 return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs); 328 } 329 EXPORT_SYMBOL(drm_gem_fbdev_fb_create); 330