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