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
  66 struct drm_prime_attachment {
  67         struct sg_table *sgt;
  68         enum dma_data_direction dir;
  69 };
  70
  71 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle);
  72
  73 static int drm_gem_map_attach(struct dma_buf *dma_buf,
  74                               struct device *target_dev,
  75                               struct dma_buf_attachment *attach)
  76 {
  77         struct drm_prime_attachment *prime_attach;
  78         struct drm_gem_object *obj = dma_buf->priv;
  79         struct drm_device *dev = obj->dev;
  80
  81         prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
  82         if (!prime_attach)
  83                 return -ENOMEM;
  84
  85         prime_attach->dir = DMA_NONE;
  86         attach->priv = prime_attach;
  87
  88         if (!dev->driver->gem_prime_pin)
  89                 return 0;
  90
  91         return dev->driver->gem_prime_pin(obj);
  92 }
  93
  94 static void drm_gem_map_detach(struct dma_buf *dma_buf,
  95                                struct dma_buf_attachment *attach)
  96 {
  97         struct drm_prime_attachment *prime_attach = attach->priv;
  98         struct drm_gem_object *obj = dma_buf->priv;
  99         struct drm_device *dev = obj->dev;
 100         struct sg_table *sgt;
 101
 102         if (dev->driver->gem_prime_unpin)
 103                 dev->driver->gem_prime_unpin(obj);
 104
 105         if (!prime_attach)
 106                 return;
 107
 108         sgt = prime_attach->sgt;
 109
 110         if (prime_attach->dir != DMA_NONE)
 111                 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
 112                                 prime_attach->dir);
 113
 114         sg_free_table(sgt);
 115         kfree(sgt);
 116         kfree(prime_attach);
 117         attach->priv = NULL;
 118 }
 119
 120 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
 121                 enum dma_data_direction dir)
 122 {
 123         struct drm_prime_attachment *prime_attach = attach->priv;
 124         struct drm_gem_object *obj = attach->dmabuf->priv;
 125         struct sg_table *sgt;
 126
 127         if (WARN_ON(dir == DMA_NONE || !prime_attach))
 128                 return ERR_PTR(-EINVAL);
 129
 130         /* return the cached mapping when possible */
 131         if (prime_attach->dir == dir)
 132                 return prime_attach->sgt;
 133
 134         /*
 135          * two mappings with different directions for the same attachment are
 136          * not allowed
 137          */
 138         if (WARN_ON(prime_attach->dir != DMA_NONE))
 139                 return ERR_PTR(-EBUSY);
 140
 141         mutex_lock(&obj->dev->struct_mutex);
 142
 143         sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
 144
 145         if (!IS_ERR(sgt)) {
 146                 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
 147                         sg_free_table(sgt);
 148                         kfree(sgt);
 149                         sgt = ERR_PTR(-ENOMEM);
 150                 } else {
 151                         prime_attach->sgt = sgt;
 152                         prime_attach->dir = dir;
 153                 }
 154         }
 155
 156         mutex_unlock(&obj->dev->struct_mutex);
 157         return sgt;
 158 }
 159
 160 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 161                 struct sg_table *sgt, enum dma_data_direction dir)
 162 {
 163         /* nothing to be done here */
 164 }
 165
 166 static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
 167 {
 168         struct drm_gem_object *obj = dma_buf->priv;
 169
 170         if (obj->export_dma_buf == dma_buf) {
 171                 /* drop the reference on the export fd holds */
 172                 obj->export_dma_buf = NULL;
 173                 drm_gem_object_unreference_unlocked(obj);
 174         }
 175 }
 176
 177 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 178 {
 179         struct drm_gem_object *obj = dma_buf->priv;
 180         struct drm_device *dev = obj->dev;
 181
 182         return dev->driver->gem_prime_vmap(obj);
 183 }
 184
 185 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 186 {
 187         struct drm_gem_object *obj = dma_buf->priv;
 188         struct drm_device *dev = obj->dev;
 189
 190         dev->driver->gem_prime_vunmap(obj, vaddr);
 191 }
 192
 193 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
 194                 unsigned long page_num)
 195 {
 196         return NULL;
 197 }
 198
 199 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
 200                 unsigned long page_num, void *addr)
 201 {
 202
 203 }
 204 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
 205                 unsigned long page_num)
 206 {
 207         return NULL;
 208 }
 209
 210 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
 211                 unsigned long page_num, void *addr)
 212 {
 213
 214 }
 215
 216 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
 217                 struct vm_area_struct *vma)
 218 {
 219         return -EINVAL;
 220 }
 221
 222 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 223         .attach = drm_gem_map_attach,
 224         .detach = drm_gem_map_detach,
 225         .map_dma_buf = drm_gem_map_dma_buf,
 226         .unmap_dma_buf = drm_gem_unmap_dma_buf,
 227         .release = drm_gem_dmabuf_release,
 228         .kmap = drm_gem_dmabuf_kmap,
 229         .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
 230         .kunmap = drm_gem_dmabuf_kunmap,
 231         .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 232         .mmap = drm_gem_dmabuf_mmap,
 233         .vmap = drm_gem_dmabuf_vmap,
 234         .vunmap = drm_gem_dmabuf_vunmap,
 235 };
 236
 237 /**
 238  * DOC: PRIME Helpers
 239  *
 240  * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
 241  * simpler APIs by using the helper functions @drm_gem_prime_export and
 242  * @drm_gem_prime_import.  These functions implement dma-buf support in terms of
 243  * five lower-level driver callbacks:
 244  *
 245  * Export callbacks:
 246  *
 247  *  - @gem_prime_pin (optional): prepare a GEM object for exporting
 248  *
 249  *  - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
 250  *
 251  *  - @gem_prime_vmap: vmap a buffer exported by your driver
 252  *
 253  *  - @gem_prime_vunmap: vunmap a buffer exported by your driver
 254  *
 255  * Import callback:
 256  *
 257  *  - @gem_prime_import_sg_table (import): produce a GEM object from another
 258  *    driver's scatter/gather table
 259  */
 260
 261 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 262                                      struct drm_gem_object *obj, int flags)
 263 {
 264         return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
 265 }
 266 EXPORT_SYMBOL(drm_gem_prime_export);
 267
 268 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 269                 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
 270                 int *prime_fd)
 271 {
 272         struct drm_gem_object *obj;
 273         void *buf;
 274         int ret = 0;
 275         struct dma_buf *dmabuf;
 276
 277         obj = drm_gem_object_lookup(dev, file_priv, handle);
 278         if (!obj)
 279                 return -ENOENT;
 280
 281         mutex_lock(&file_priv->prime.lock);
 282         /* re-export the original imported object */
 283         if (obj->import_attach) {
 284                 dmabuf = obj->import_attach->dmabuf;
 285                 goto out_have_obj;
 286         }
 287
 288         if (obj->export_dma_buf) {
 289                 dmabuf = obj->export_dma_buf;
 290                 goto out_have_obj;
 291         }
 292
 293         buf = dev->driver->gem_prime_export(dev, obj, flags);
 294         if (IS_ERR(buf)) {
 295                 /* normally the created dma-buf takes ownership of the ref,
 296                  * but if that fails then drop the ref
 297                  */
 298                 ret = PTR_ERR(buf);
 299                 goto out;
 300         }
 301         obj->export_dma_buf = buf;
 302
 303         /* if we've exported this buffer the cheat and add it to the import list
 304          * so we get the correct handle back
 305          */
 306         ret = drm_prime_add_buf_handle(&file_priv->prime,
 307                                        obj->export_dma_buf, handle);
 308         if (ret)
 309                 goto out;
 310
 311         *prime_fd = dma_buf_fd(buf, flags);
 312         mutex_unlock(&file_priv->prime.lock);
 313         return 0;
 314
 315 out_have_obj:
 316         get_dma_buf(dmabuf);
 317         *prime_fd = dma_buf_fd(dmabuf, flags);
 318 out:
 319         drm_gem_object_unreference_unlocked(obj);
 320         mutex_unlock(&file_priv->prime.lock);
 321         return ret;
 322 }
 323 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 324
 325 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 326                                             struct dma_buf *dma_buf)
 327 {
 328         struct dma_buf_attachment *attach;
 329         struct sg_table *sgt;
 330         struct drm_gem_object *obj;
 331         int ret;
 332
 333         if (!dev->driver->gem_prime_import_sg_table)
 334                 return ERR_PTR(-EINVAL);
 335
 336         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 337                 obj = dma_buf->priv;
 338                 if (obj->dev == dev) {
 339                         /*
 340                          * Importing dmabuf exported from out own gem increases
 341                          * refcount on gem itself instead of f_count of dmabuf.
 342                          */
 343                         drm_gem_object_reference(obj);
 344                         return obj;
 345                 }
 346         }
 347
 348         attach = dma_buf_attach(dma_buf, dev->dev);
 349         if (IS_ERR(attach))
 350                 return ERR_CAST(attach);
 351
 352         get_dma_buf(dma_buf);
 353
 354         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 355         if (IS_ERR_OR_NULL(sgt)) {
 356                 ret = PTR_ERR(sgt);
 357                 goto fail_detach;
 358         }
 359
 360         obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
 361         if (IS_ERR(obj)) {
 362                 ret = PTR_ERR(obj);
 363                 goto fail_unmap;
 364         }
 365
 366         obj->import_attach = attach;
 367
 368         return obj;
 369
 370 fail_unmap:
 371         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 372 fail_detach:
 373         dma_buf_detach(dma_buf, attach);
 374         dma_buf_put(dma_buf);
 375
 376         return ERR_PTR(ret);
 377 }
 378 EXPORT_SYMBOL(drm_gem_prime_import);
 379
 380 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 381                 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
 382 {
 383         struct dma_buf *dma_buf;
 384         struct drm_gem_object *obj;
 385         int ret;
 386
 387         dma_buf = dma_buf_get(prime_fd);
 388         if (IS_ERR(dma_buf))
 389                 return PTR_ERR(dma_buf);
 390
 391         mutex_lock(&file_priv->prime.lock);
 392
 393         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 394                         dma_buf, handle);
 395         if (!ret) {
 396                 ret = 0;
 397                 goto out_put;
 398         }
 399
 400         /* never seen this one, need to import */
 401         obj = dev->driver->gem_prime_import(dev, dma_buf);
 402         if (IS_ERR(obj)) {
 403                 ret = PTR_ERR(obj);
 404                 goto out_put;
 405         }
 406
 407         ret = drm_gem_handle_create(file_priv, obj, handle);
 408         drm_gem_object_unreference_unlocked(obj);
 409         if (ret)
 410                 goto out_put;
 411
 412         ret = drm_prime_add_buf_handle(&file_priv->prime,
 413                         dma_buf, *handle);
 414         if (ret)
 415                 goto fail;
 416
 417         mutex_unlock(&file_priv->prime.lock);
 418
 419         dma_buf_put(dma_buf);
 420
 421         return 0;
 422
 423 fail:
 424         /* hmm, if driver attached, we are relying on the free-object path
 425          * to detach.. which seems ok..
 426          */
 427         drm_gem_object_handle_unreference_unlocked(obj);
 428 out_put:
 429         dma_buf_put(dma_buf);
 430         mutex_unlock(&file_priv->prime.lock);
 431         return ret;
 432 }
 433 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 434
 435 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 436                                  struct drm_file *file_priv)
 437 {
 438         struct drm_prime_handle *args = data;
 439         uint32_t flags;
 440
 441         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 442                 return -EINVAL;
 443
 444         if (!dev->driver->prime_handle_to_fd)
 445                 return -ENOSYS;
 446
 447         /* check flags are valid */
 448         if (args->flags & ~DRM_CLOEXEC)
 449                 return -EINVAL;
 450
 451         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 452         flags = args->flags & DRM_CLOEXEC;
 453
 454         return dev->driver->prime_handle_to_fd(dev, file_priv,
 455                         args->handle, flags, &args->fd);
 456 }
 457
 458 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 459                                  struct drm_file *file_priv)
 460 {
 461         struct drm_prime_handle *args = data;
 462
 463         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 464                 return -EINVAL;
 465
 466         if (!dev->driver->prime_fd_to_handle)
 467                 return -ENOSYS;
 468
 469         return dev->driver->prime_fd_to_handle(dev, file_priv,
 470                         args->fd, &args->handle);
 471 }
 472
 473 /*
 474  * drm_prime_pages_to_sg
 475  *
 476  * this helper creates an sg table object from a set of pages
 477  * the driver is responsible for mapping the pages into the
 478  * importers address space
 479  */
 480 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 481 {
 482         struct sg_table *sg = NULL;
 483         int ret;
 484
 485         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 486         if (!sg) {
 487                 ret = -ENOMEM;
 488                 goto out;
 489         }
 490
 491         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 492                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 493         if (ret)
 494                 goto out;
 495
 496         return sg;
 497 out:
 498         kfree(sg);
 499         return ERR_PTR(ret);
 500 }
 501 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 502
 503 /* export an sg table into an array of pages and addresses
 504    this is currently required by the TTM driver in order to do correct fault
 505    handling */
 506 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 507                                      dma_addr_t *addrs, int max_pages)
 508 {
 509         unsigned count;
 510         struct scatterlist *sg;
 511         struct page *page;
 512         u32 len, offset;
 513         int pg_index;
 514         dma_addr_t addr;
 515
 516         pg_index = 0;
 517         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 518                 len = sg->length;
 519                 offset = sg->offset;
 520                 page = sg_page(sg);
 521                 addr = sg_dma_address(sg);
 522
 523                 while (len > 0) {
 524                         if (WARN_ON(pg_index >= max_pages))
 525                                 return -1;
 526                         pages[pg_index] = page;
 527                         if (addrs)
 528                                 addrs[pg_index] = addr;
 529
 530                         page++;
 531                         addr += PAGE_SIZE;
 532                         len -= PAGE_SIZE;
 533                         pg_index++;
 534                 }
 535         }
 536         return 0;
 537 }
 538 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 539 /* helper function to cleanup a GEM/prime object */
 540 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 541 {
 542         struct dma_buf_attachment *attach;
 543         struct dma_buf *dma_buf;
 544         attach = obj->import_attach;
 545         if (sg)
 546                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 547         dma_buf = attach->dmabuf;
 548         dma_buf_detach(attach->dmabuf, attach);
 549         /* remove the reference */
 550         dma_buf_put(dma_buf);
 551 }
 552 EXPORT_SYMBOL(drm_prime_gem_destroy);
 553
 554 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 555 {
 556         INIT_LIST_HEAD(&prime_fpriv->head);
 557         mutex_init(&prime_fpriv->lock);
 558 }
 559 EXPORT_SYMBOL(drm_prime_init_file_private);
 560
 561 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 562 {
 563         /* by now drm_gem_release should've made sure the list is empty */
 564         WARN_ON(!list_empty(&prime_fpriv->head));
 565 }
 566 EXPORT_SYMBOL(drm_prime_destroy_file_private);
 567
 568 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
 569 {
 570         struct drm_prime_member *member;
 571
 572         member = kmalloc(sizeof(*member), GFP_KERNEL);
 573         if (!member)
 574                 return -ENOMEM;
 575
 576         get_dma_buf(dma_buf);
 577         member->dma_buf = dma_buf;
 578         member->handle = handle;
 579         list_add(&member->entry, &prime_fpriv->head);
 580         return 0;
 581 }
 582
 583 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
 584 {
 585         struct drm_prime_member *member;
 586
 587         list_for_each_entry(member, &prime_fpriv->head, entry) {
 588                 if (member->dma_buf == dma_buf) {
 589                         *handle = member->handle;
 590                         return 0;
 591                 }
 592         }
 593         return -ENOENT;
 594 }
 595 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
 596
 597 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
 598 {
 599         struct drm_prime_member *member, *safe;
 600
 601         mutex_lock(&prime_fpriv->lock);
 602         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 603                 if (member->dma_buf == dma_buf) {
 604                         dma_buf_put(dma_buf);
 605                         list_del(&member->entry);
 606                         kfree(member);
 607                 }
 608         }
 609         mutex_unlock(&prime_fpriv->lock);
 610 }
 611 EXPORT_SYMBOL(drm_prime_remove_buf_handle);