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 #include <drm/drm_simple_kms_helper.h> 26 27 /** 28 * DOC: overview 29 * 30 * This library provides helpers for drivers that don't subclass 31 * &drm_framebuffer and use &drm_gem_object for their backing storage. 32 * 33 * Drivers without additional needs to validate framebuffers can simply use 34 * drm_gem_fb_create() and everything is wired up automatically. Other drivers 35 * can use all parts independently. 36 */ 37 38 /** 39 * drm_gem_fb_get_obj() - Get GEM object backing the framebuffer 40 * @fb: Framebuffer 41 * @plane: Plane index 42 * 43 * No additional reference is taken beyond the one that the &drm_frambuffer 44 * already holds. 45 * 46 * Returns: 47 * Pointer to &drm_gem_object for the given framebuffer and plane index or NULL 48 * if it does not exist. 49 */ 50 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb, 51 unsigned int plane) 52 { 53 if (plane >= 4) 54 return NULL; 55 56 return fb->obj[plane]; 57 } 58 EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj); 59 60 static struct drm_framebuffer * 61 drm_gem_fb_alloc(struct drm_device *dev, 62 const struct drm_mode_fb_cmd2 *mode_cmd, 63 struct drm_gem_object **obj, unsigned int num_planes, 64 const struct drm_framebuffer_funcs *funcs) 65 { 66 struct drm_framebuffer *fb; 67 int ret, i; 68 69 fb = kzalloc(sizeof(*fb), GFP_KERNEL); 70 if (!fb) 71 return ERR_PTR(-ENOMEM); 72 73 drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd); 74 75 for (i = 0; i < num_planes; i++) 76 fb->obj[i] = obj[i]; 77 78 ret = drm_framebuffer_init(dev, fb, funcs); 79 if (ret) { 80 DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n", 81 ret); 82 kfree(fb); 83 return ERR_PTR(ret); 84 } 85 86 return fb; 87 } 88 89 /** 90 * drm_gem_fb_destroy - Free GEM backed framebuffer 91 * @fb: Framebuffer 92 * 93 * Frees a GEM backed framebuffer with its backing buffer(s) and the structure 94 * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy 95 * callback. 96 */ 97 void drm_gem_fb_destroy(struct drm_framebuffer *fb) 98 { 99 int i; 100 101 for (i = 0; i < 4; i++) 102 drm_gem_object_put_unlocked(fb->obj[i]); 103 104 drm_framebuffer_cleanup(fb); 105 kfree(fb); 106 } 107 EXPORT_SYMBOL(drm_gem_fb_destroy); 108 109 /** 110 * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer 111 * @fb: Framebuffer 112 * @file: DRM file to register the handle for 113 * @handle: Pointer to return the created handle 114 * 115 * This function creates a handle for the GEM object backing the framebuffer. 116 * Drivers can use this as their &drm_framebuffer_funcs->create_handle 117 * callback. The GETFB IOCTL calls into this callback. 118 * 119 * Returns: 120 * 0 on success or a negative error code on failure. 121 */ 122 int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file, 123 unsigned int *handle) 124 { 125 return drm_gem_handle_create(file, fb->obj[0], handle); 126 } 127 EXPORT_SYMBOL(drm_gem_fb_create_handle); 128 129 /** 130 * drm_gem_fb_create_with_funcs() - Helper function for the 131 * &drm_mode_config_funcs.fb_create 132 * callback 133 * @dev: DRM device 134 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 135 * @mode_cmd: Metadata from the userspace framebuffer creation request 136 * @funcs: vtable to be used for the new framebuffer object 137 * 138 * This can be used to set &drm_framebuffer_funcs for drivers that need the 139 * &drm_framebuffer_funcs.dirty callback. Use drm_gem_fb_create() if you don't 140 * need to change &drm_framebuffer_funcs. 141 * The function does buffer size validation. 142 * 143 * Returns: 144 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 145 */ 146 struct drm_framebuffer * 147 drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file, 148 const struct drm_mode_fb_cmd2 *mode_cmd, 149 const struct drm_framebuffer_funcs *funcs) 150 { 151 const struct drm_format_info *info; 152 struct drm_gem_object *objs[4]; 153 struct drm_framebuffer *fb; 154 int ret, i; 155 156 info = drm_get_format_info(dev, mode_cmd); 157 if (!info) 158 return ERR_PTR(-EINVAL); 159 160 for (i = 0; i < info->num_planes; i++) { 161 unsigned int width = mode_cmd->width / (i ? info->hsub : 1); 162 unsigned int height = mode_cmd->height / (i ? info->vsub : 1); 163 unsigned int min_size; 164 165 objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]); 166 if (!objs[i]) { 167 DRM_DEBUG_KMS("Failed to lookup GEM object\n"); 168 ret = -ENOENT; 169 goto err_gem_object_put; 170 } 171 172 min_size = (height - 1) * mode_cmd->pitches[i] 173 + width * info->cpp[i] 174 + mode_cmd->offsets[i]; 175 176 if (objs[i]->size < min_size) { 177 drm_gem_object_put_unlocked(objs[i]); 178 ret = -EINVAL; 179 goto err_gem_object_put; 180 } 181 } 182 183 fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs); 184 if (IS_ERR(fb)) { 185 ret = PTR_ERR(fb); 186 goto err_gem_object_put; 187 } 188 189 return fb; 190 191 err_gem_object_put: 192 for (i--; i >= 0; i--) 193 drm_gem_object_put_unlocked(objs[i]); 194 195 return ERR_PTR(ret); 196 } 197 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs); 198 199 static const struct drm_framebuffer_funcs drm_gem_fb_funcs = { 200 .destroy = drm_gem_fb_destroy, 201 .create_handle = drm_gem_fb_create_handle, 202 }; 203 204 /** 205 * drm_gem_fb_create() - Helper function for the 206 * &drm_mode_config_funcs.fb_create callback 207 * @dev: DRM device 208 * @file: DRM file that holds the GEM handle(s) backing the framebuffer 209 * @mode_cmd: Metadata from the userspace framebuffer creation request 210 * 211 * This function creates a new framebuffer object described by 212 * &drm_mode_fb_cmd2. This description includes handles for the buffer(s) 213 * backing the framebuffer. 214 * 215 * If your hardware has special alignment or pitch requirements these should be 216 * checked before calling this function. The function does buffer size 217 * validation. Use drm_gem_fb_create_with_funcs() if you need to set 218 * &drm_framebuffer_funcs.dirty. 219 * 220 * Drivers can use this as their &drm_mode_config_funcs.fb_create callback. 221 * The ADDFB2 IOCTL calls into this callback. 222 * 223 * Returns: 224 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 225 */ 226 struct drm_framebuffer * 227 drm_gem_fb_create(struct drm_device *dev, struct drm_file *file, 228 const struct drm_mode_fb_cmd2 *mode_cmd) 229 { 230 return drm_gem_fb_create_with_funcs(dev, file, mode_cmd, 231 &drm_gem_fb_funcs); 232 } 233 EXPORT_SYMBOL_GPL(drm_gem_fb_create); 234 235 /** 236 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer 237 * @plane: Plane 238 * @state: Plane state the fence will be attached to 239 * 240 * This function prepares a GEM backed framebuffer for scanout by checking if 241 * the plane framebuffer has a DMA-BUF attached. If it does, it extracts the 242 * exclusive fence and attaches it to the plane state for the atomic helper to 243 * wait on. This function can be used as the &drm_plane_helper_funcs.prepare_fb 244 * callback. 245 * 246 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple 247 * gem based framebuffer drivers which have their buffers always pinned in 248 * memory. 249 */ 250 int drm_gem_fb_prepare_fb(struct drm_plane *plane, 251 struct drm_plane_state *state) 252 { 253 struct dma_buf *dma_buf; 254 struct dma_fence *fence; 255 256 if (!state->fb) 257 return 0; 258 259 dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf; 260 if (dma_buf) { 261 fence = reservation_object_get_excl_rcu(dma_buf->resv); 262 drm_atomic_set_fence_for_plane(state, fence); 263 } 264 265 return 0; 266 } 267 EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb); 268 269 /** 270 * drm_gem_fb_simple_display_pipe_prepare_fb - prepare_fb helper for 271 * &drm_simple_display_pipe 272 * @pipe: Simple display pipe 273 * @plane_state: Plane state 274 * 275 * This function uses drm_gem_fb_prepare_fb() to check if the plane FB has a 276 * &dma_buf attached, extracts the exclusive fence and attaches it to plane 277 * state for the atomic helper to wait on. Drivers can use this as their 278 * &drm_simple_display_pipe_funcs.prepare_fb callback. 279 */ 280 int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe, 281 struct drm_plane_state *plane_state) 282 { 283 return drm_gem_fb_prepare_fb(&pipe->plane, plane_state); 284 } 285 EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb); 286 287 /** 288 * drm_gem_fbdev_fb_create - Create a GEM backed &drm_framebuffer for fbdev 289 * emulation 290 * @dev: DRM device 291 * @sizes: fbdev size description 292 * @pitch_align: Optional pitch alignment 293 * @obj: GEM object backing the framebuffer 294 * @funcs: Optional vtable to be used for the new framebuffer object when the 295 * dirty callback is needed. 296 * 297 * This function creates a framebuffer from a &drm_fb_helper_surface_size 298 * description for use in the &drm_fb_helper_funcs.fb_probe callback. 299 * 300 * Returns: 301 * Pointer to a &drm_framebuffer on success or an error pointer on failure. 302 */ 303 struct drm_framebuffer * 304 drm_gem_fbdev_fb_create(struct drm_device *dev, 305 struct drm_fb_helper_surface_size *sizes, 306 unsigned int pitch_align, struct drm_gem_object *obj, 307 const struct drm_framebuffer_funcs *funcs) 308 { 309 struct drm_mode_fb_cmd2 mode_cmd = { 0 }; 310 311 mode_cmd.width = sizes->surface_width; 312 mode_cmd.height = sizes->surface_height; 313 mode_cmd.pitches[0] = sizes->surface_width * 314 DIV_ROUND_UP(sizes->surface_bpp, 8); 315 if (pitch_align) 316 mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0], 317 pitch_align); 318 mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp, 319 sizes->surface_depth); 320 if (obj->size < mode_cmd.pitches[0] * mode_cmd.height) 321 return ERR_PTR(-EINVAL); 322 323 if (!funcs) 324 funcs = &drm_gem_fb_funcs; 325 326 return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs); 327 } 328 EXPORT_SYMBOL(drm_gem_fbdev_fb_create); 329