drivers/gpu/drm/drm_gem_framebuffer_helper.c

   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);