drivers/gpu/drm/drm_prime.c

   1 /*
   2  * Copyright © 2012 Red Hat
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *      Dave Airlie <airlied@redhat.com>
  25  *      Rob Clark <rob.clark@linaro.org>
  26  *
  27  */
  28
  29 #include <linux/export.h>
  30 #include <linux/dma-buf.h>
  31 #include <drm/drmP.h>
  32
  33 /*
  34  * DMA-BUF/GEM Object references and lifetime overview:
  35  *
  36  * On the export the dma_buf holds a reference to the exporting GEM
  37  * object. It takes this reference in handle_to_fd_ioctl, when it
  38  * first calls .prime_export and stores the exporting GEM object in
  39  * the dma_buf priv. This reference is released when the dma_buf
  40  * object goes away in the driver .release function.
  41  *
  42  * On the import the importing GEM object holds a reference to the
  43  * dma_buf (which in turn holds a ref to the exporting GEM object).
  44  * It takes that reference in the fd_to_handle ioctl.
  45  * It calls dma_buf_get, creates an attachment to it and stores the
  46  * attachment in the GEM object. When this attachment is destroyed
  47  * when the imported object is destroyed, we remove the attachment
  48  * and drop the reference to the dma_buf.
  49  *
  50  * Thus the chain of references always flows in one direction
  51  * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
  52  *
  53  * Self-importing: if userspace is using PRIME as a replacement for flink
  54  * then it will get a fd->handle request for a GEM object that it created.
  55  * Drivers should detect this situation and return back the gem object
  56  * from the dma-buf private.  Prime will do this automatically for drivers that
  57  * use the drm_gem_prime_{import,export} helpers.
  58  */
  59
  60 struct drm_prime_member {
  61         struct list_head entry;
  62         struct dma_buf *dma_buf;
  63         uint32_t handle;
  64 };
  65 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle);
  66
  67 static int drm_gem_map_attach(struct dma_buf *dma_buf,
  68                               struct device *target_dev,
  69                               struct dma_buf_attachment *attach)
  70 {
  71         struct drm_gem_object *obj = dma_buf->priv;
  72         struct drm_device *dev = obj->dev;
  73
  74         if (!dev->driver->gem_prime_pin)
  75                 return 0;
  76
  77         return dev->driver->gem_prime_pin(obj);
  78 }
  79
  80 static void drm_gem_map_detach(struct dma_buf *dma_buf,
  81                                struct dma_buf_attachment *attach)
  82 {
  83         struct drm_gem_object *obj = dma_buf->priv;
  84         struct drm_device *dev = obj->dev;
  85
  86         if (dev->driver->gem_prime_unpin)
  87                 dev->driver->gem_prime_unpin(obj);
  88 }
  89
  90 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
  91                 enum dma_data_direction dir)
  92 {
  93         struct drm_gem_object *obj = attach->dmabuf->priv;
  94         struct sg_table *sgt;
  95
  96         mutex_lock(&obj->dev->struct_mutex);
  97
  98         sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
  99
 100         if (!IS_ERR_OR_NULL(sgt))
 101                 dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
 102
 103         mutex_unlock(&obj->dev->struct_mutex);
 104         return sgt;
 105 }
 106
 107 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 108                 struct sg_table *sgt, enum dma_data_direction dir)
 109 {
 110         dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
 111         sg_free_table(sgt);
 112         kfree(sgt);
 113 }
 114
 115 static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
 116 {
 117         struct drm_gem_object *obj = dma_buf->priv;
 118
 119         if (obj->export_dma_buf == dma_buf) {
 120                 /* drop the reference on the export fd holds */
 121                 obj->export_dma_buf = NULL;
 122                 drm_gem_object_unreference_unlocked(obj);
 123         }
 124 }
 125
 126 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 127 {
 128         struct drm_gem_object *obj = dma_buf->priv;
 129         struct drm_device *dev = obj->dev;
 130
 131         return dev->driver->gem_prime_vmap(obj);
 132 }
 133
 134 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 135 {
 136         struct drm_gem_object *obj = dma_buf->priv;
 137         struct drm_device *dev = obj->dev;
 138
 139         dev->driver->gem_prime_vunmap(obj, vaddr);
 140 }
 141
 142 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
 143                 unsigned long page_num)
 144 {
 145         return NULL;
 146 }
 147
 148 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
 149                 unsigned long page_num, void *addr)
 150 {
 151
 152 }
 153 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
 154                 unsigned long page_num)
 155 {
 156         return NULL;
 157 }
 158
 159 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
 160                 unsigned long page_num, void *addr)
 161 {
 162
 163 }
 164
 165 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
 166                 struct vm_area_struct *vma)
 167 {
 168         return -EINVAL;
 169 }
 170
 171 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 172         .attach = drm_gem_map_attach,
 173         .detach = drm_gem_map_detach,
 174         .map_dma_buf = drm_gem_map_dma_buf,
 175         .unmap_dma_buf = drm_gem_unmap_dma_buf,
 176         .release = drm_gem_dmabuf_release,
 177         .kmap = drm_gem_dmabuf_kmap,
 178         .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
 179         .kunmap = drm_gem_dmabuf_kunmap,
 180         .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 181         .mmap = drm_gem_dmabuf_mmap,
 182         .vmap = drm_gem_dmabuf_vmap,
 183         .vunmap = drm_gem_dmabuf_vunmap,
 184 };
 185
 186 /**
 187  * DOC: PRIME Helpers
 188  *
 189  * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
 190  * simpler APIs by using the helper functions @drm_gem_prime_export and
 191  * @drm_gem_prime_import.  These functions implement dma-buf support in terms of
 192  * five lower-level driver callbacks:
 193  *
 194  * Export callbacks:
 195  *
 196  *  - @gem_prime_pin (optional): prepare a GEM object for exporting
 197  *
 198  *  - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
 199  *
 200  *  - @gem_prime_vmap: vmap a buffer exported by your driver
 201  *
 202  *  - @gem_prime_vunmap: vunmap a buffer exported by your driver
 203  *
 204  * Import callback:
 205  *
 206  *  - @gem_prime_import_sg_table (import): produce a GEM object from another
 207  *    driver's scatter/gather table
 208  */
 209
 210 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 211                                      struct drm_gem_object *obj, int flags)
 212 {
 213         return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
 214 }
 215 EXPORT_SYMBOL(drm_gem_prime_export);
 216
 217 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 218                 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
 219                 int *prime_fd)
 220 {
 221         struct drm_gem_object *obj;
 222         void *buf;
 223         int ret = 0;
 224         struct dma_buf *dmabuf;
 225
 226         obj = drm_gem_object_lookup(dev, file_priv, handle);
 227         if (!obj)
 228                 return -ENOENT;
 229
 230         mutex_lock(&file_priv->prime.lock);
 231         /* re-export the original imported object */
 232         if (obj->import_attach) {
 233                 dmabuf = obj->import_attach->dmabuf;
 234                 goto out_have_obj;
 235         }
 236
 237         if (obj->export_dma_buf) {
 238                 dmabuf = obj->export_dma_buf;
 239                 goto out_have_obj;
 240         }
 241
 242         buf = dev->driver->gem_prime_export(dev, obj, flags);
 243         if (IS_ERR(buf)) {
 244                 /* normally the created dma-buf takes ownership of the ref,
 245                  * but if that fails then drop the ref
 246                  */
 247                 ret = PTR_ERR(buf);
 248                 goto out;
 249         }
 250         obj->export_dma_buf = buf;
 251
 252         /* if we've exported this buffer the cheat and add it to the import list
 253          * so we get the correct handle back
 254          */
 255         ret = drm_prime_add_buf_handle(&file_priv->prime,
 256                                        obj->export_dma_buf, handle);
 257         if (ret)
 258                 goto out;
 259
 260         *prime_fd = dma_buf_fd(buf, flags);
 261         mutex_unlock(&file_priv->prime.lock);
 262         return 0;
 263
 264 out_have_obj:
 265         get_dma_buf(dmabuf);
 266         *prime_fd = dma_buf_fd(dmabuf, flags);
 267 out:
 268         drm_gem_object_unreference_unlocked(obj);
 269         mutex_unlock(&file_priv->prime.lock);
 270         return ret;
 271 }
 272 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 273
 274 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 275                                             struct dma_buf *dma_buf)
 276 {
 277         struct dma_buf_attachment *attach;
 278         struct sg_table *sgt;
 279         struct drm_gem_object *obj;
 280         int ret;
 281
 282         if (!dev->driver->gem_prime_import_sg_table)
 283                 return ERR_PTR(-EINVAL);
 284
 285         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 286                 obj = dma_buf->priv;
 287                 if (obj->dev == dev) {
 288                         /*
 289                          * Importing dmabuf exported from out own gem increases
 290                          * refcount on gem itself instead of f_count of dmabuf.
 291                          */
 292                         drm_gem_object_reference(obj);
 293                         return obj;
 294                 }
 295         }
 296
 297         attach = dma_buf_attach(dma_buf, dev->dev);
 298         if (IS_ERR(attach))
 299                 return ERR_CAST(attach);
 300
 301         get_dma_buf(dma_buf);
 302
 303         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 304         if (IS_ERR_OR_NULL(sgt)) {
 305                 ret = PTR_ERR(sgt);
 306                 goto fail_detach;
 307         }
 308
 309         obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
 310         if (IS_ERR(obj)) {
 311                 ret = PTR_ERR(obj);
 312                 goto fail_unmap;
 313         }
 314
 315         obj->import_attach = attach;
 316
 317         return obj;
 318
 319 fail_unmap:
 320         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 321 fail_detach:
 322         dma_buf_detach(dma_buf, attach);
 323         dma_buf_put(dma_buf);
 324
 325         return ERR_PTR(ret);
 326 }
 327 EXPORT_SYMBOL(drm_gem_prime_import);
 328
 329 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 330                 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
 331 {
 332         struct dma_buf *dma_buf;
 333         struct drm_gem_object *obj;
 334         int ret;
 335
 336         dma_buf = dma_buf_get(prime_fd);
 337         if (IS_ERR(dma_buf))
 338                 return PTR_ERR(dma_buf);
 339
 340         mutex_lock(&file_priv->prime.lock);
 341
 342         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 343                         dma_buf, handle);
 344         if (!ret) {
 345                 ret = 0;
 346                 goto out_put;
 347         }
 348
 349         /* never seen this one, need to import */
 350         obj = dev->driver->gem_prime_import(dev, dma_buf);
 351         if (IS_ERR(obj)) {
 352                 ret = PTR_ERR(obj);
 353                 goto out_put;
 354         }
 355
 356         ret = drm_gem_handle_create(file_priv, obj, handle);
 357         drm_gem_object_unreference_unlocked(obj);
 358         if (ret)
 359                 goto out_put;
 360
 361         ret = drm_prime_add_buf_handle(&file_priv->prime,
 362                         dma_buf, *handle);
 363         if (ret)
 364                 goto fail;
 365
 366         mutex_unlock(&file_priv->prime.lock);
 367
 368         dma_buf_put(dma_buf);
 369
 370         return 0;
 371
 372 fail:
 373         /* hmm, if driver attached, we are relying on the free-object path
 374          * to detach.. which seems ok..
 375          */
 376         drm_gem_object_handle_unreference_unlocked(obj);
 377 out_put:
 378         dma_buf_put(dma_buf);
 379         mutex_unlock(&file_priv->prime.lock);
 380         return ret;
 381 }
 382 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 383
 384 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 385                                  struct drm_file *file_priv)
 386 {
 387         struct drm_prime_handle *args = data;
 388         uint32_t flags;
 389
 390         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 391                 return -EINVAL;
 392
 393         if (!dev->driver->prime_handle_to_fd)
 394                 return -ENOSYS;
 395
 396         /* check flags are valid */
 397         if (args->flags & ~DRM_CLOEXEC)
 398                 return -EINVAL;
 399
 400         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 401         flags = args->flags & DRM_CLOEXEC;
 402
 403         return dev->driver->prime_handle_to_fd(dev, file_priv,
 404                         args->handle, flags, &args->fd);
 405 }
 406
 407 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 408                                  struct drm_file *file_priv)
 409 {
 410         struct drm_prime_handle *args = data;
 411
 412         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 413                 return -EINVAL;
 414
 415         if (!dev->driver->prime_fd_to_handle)
 416                 return -ENOSYS;
 417
 418         return dev->driver->prime_fd_to_handle(dev, file_priv,
 419                         args->fd, &args->handle);
 420 }
 421
 422 /*
 423  * drm_prime_pages_to_sg
 424  *
 425  * this helper creates an sg table object from a set of pages
 426  * the driver is responsible for mapping the pages into the
 427  * importers address space
 428  */
 429 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 430 {
 431         struct sg_table *sg = NULL;
 432         int ret;
 433
 434         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 435         if (!sg)
 436                 goto out;
 437
 438         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 439                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 440         if (ret)
 441                 goto out;
 442
 443         return sg;
 444 out:
 445         kfree(sg);
 446         return NULL;
 447 }
 448 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 449
 450 /* export an sg table into an array of pages and addresses
 451    this is currently required by the TTM driver in order to do correct fault
 452    handling */
 453 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 454                                      dma_addr_t *addrs, int max_pages)
 455 {
 456         unsigned count;
 457         struct scatterlist *sg;
 458         struct page *page;
 459         u32 len, offset;
 460         int pg_index;
 461         dma_addr_t addr;
 462
 463         pg_index = 0;
 464         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 465                 len = sg->length;
 466                 offset = sg->offset;
 467                 page = sg_page(sg);
 468                 addr = sg_dma_address(sg);
 469
 470                 while (len > 0) {
 471                         if (WARN_ON(pg_index >= max_pages))
 472                                 return -1;
 473                         pages[pg_index] = page;
 474                         if (addrs)
 475                                 addrs[pg_index] = addr;
 476
 477                         page++;
 478                         addr += PAGE_SIZE;
 479                         len -= PAGE_SIZE;
 480                         pg_index++;
 481                 }
 482         }
 483         return 0;
 484 }
 485 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 486 /* helper function to cleanup a GEM/prime object */
 487 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 488 {
 489         struct dma_buf_attachment *attach;
 490         struct dma_buf *dma_buf;
 491         attach = obj->import_attach;
 492         if (sg)
 493                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 494         dma_buf = attach->dmabuf;
 495         dma_buf_detach(attach->dmabuf, attach);
 496         /* remove the reference */
 497         dma_buf_put(dma_buf);
 498 }
 499 EXPORT_SYMBOL(drm_prime_gem_destroy);
 500
 501 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 502 {
 503         INIT_LIST_HEAD(&prime_fpriv->head);
 504         mutex_init(&prime_fpriv->lock);
 505 }
 506 EXPORT_SYMBOL(drm_prime_init_file_private);
 507
 508 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 509 {
 510         /* by now drm_gem_release should've made sure the list is empty */
 511         WARN_ON(!list_empty(&prime_fpriv->head));
 512 }
 513 EXPORT_SYMBOL(drm_prime_destroy_file_private);
 514
 515 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
 516 {
 517         struct drm_prime_member *member;
 518
 519         member = kmalloc(sizeof(*member), GFP_KERNEL);
 520         if (!member)
 521                 return -ENOMEM;
 522
 523         get_dma_buf(dma_buf);
 524         member->dma_buf = dma_buf;
 525         member->handle = handle;
 526         list_add(&member->entry, &prime_fpriv->head);
 527         return 0;
 528 }
 529
 530 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
 531 {
 532         struct drm_prime_member *member;
 533
 534         list_for_each_entry(member, &prime_fpriv->head, entry) {
 535                 if (member->dma_buf == dma_buf) {
 536                         *handle = member->handle;
 537                         return 0;
 538                 }
 539         }
 540         return -ENOENT;
 541 }
 542 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
 543
 544 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
 545 {
 546         struct drm_prime_member *member, *safe;
 547
 548         mutex_lock(&prime_fpriv->lock);
 549         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 550                 if (member->dma_buf == dma_buf) {
 551                         dma_buf_put(dma_buf);
 552                         list_del(&member->entry);
 553                         kfree(member);
 554                 }
 555         }
 556         mutex_unlock(&prime_fpriv->lock);
 557 }
 558 EXPORT_SYMBOL(drm_prime_remove_buf_handle);