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         struct drm_prime_member *member;
  74
  75         member = kmalloc(sizeof(*member), GFP_KERNEL);
  76         if (!member)
  77                 return -ENOMEM;
  78
  79         get_dma_buf(dma_buf);
  80         member->dma_buf = dma_buf;
  81         member->handle = handle;
  82         list_add(&member->entry, &prime_fpriv->head);
  83         return 0;
  84 }
  85
  86 static int drm_gem_map_attach(struct dma_buf *dma_buf,
  87                               struct device *target_dev,
  88                               struct dma_buf_attachment *attach)
  89 {
  90         struct drm_prime_attachment *prime_attach;
  91         struct drm_gem_object *obj = dma_buf->priv;
  92         struct drm_device *dev = obj->dev;
  93
  94         prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
  95         if (!prime_attach)
  96                 return -ENOMEM;
  97
  98         prime_attach->dir = DMA_NONE;
  99         attach->priv = prime_attach;
 100
 101         if (!dev->driver->gem_prime_pin)
 102                 return 0;
 103
 104         return dev->driver->gem_prime_pin(obj);
 105 }
 106
 107 static void drm_gem_map_detach(struct dma_buf *dma_buf,
 108                                struct dma_buf_attachment *attach)
 109 {
 110         struct drm_prime_attachment *prime_attach = attach->priv;
 111         struct drm_gem_object *obj = dma_buf->priv;
 112         struct drm_device *dev = obj->dev;
 113         struct sg_table *sgt;
 114
 115         if (dev->driver->gem_prime_unpin)
 116                 dev->driver->gem_prime_unpin(obj);
 117
 118         if (!prime_attach)
 119                 return;
 120
 121         sgt = prime_attach->sgt;
 122
 123         if (prime_attach->dir != DMA_NONE)
 124                 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
 125                                 prime_attach->dir);
 126
 127         sg_free_table(sgt);
 128         kfree(sgt);
 129         kfree(prime_attach);
 130         attach->priv = NULL;
 131 }
 132
 133 static void drm_prime_remove_buf_handle_locked(
 134                 struct drm_prime_file_private *prime_fpriv,
 135                 struct dma_buf *dma_buf)
 136 {
 137         struct drm_prime_member *member, *safe;
 138
 139         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 140                 if (member->dma_buf == dma_buf) {
 141                         dma_buf_put(dma_buf);
 142                         list_del(&member->entry);
 143                         kfree(member);
 144                 }
 145         }
 146 }
 147
 148 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
 149                 enum dma_data_direction dir)
 150 {
 151         struct drm_prime_attachment *prime_attach = attach->priv;
 152         struct drm_gem_object *obj = attach->dmabuf->priv;
 153         struct sg_table *sgt;
 154
 155         if (WARN_ON(dir == DMA_NONE || !prime_attach))
 156                 return ERR_PTR(-EINVAL);
 157
 158         /* return the cached mapping when possible */
 159         if (prime_attach->dir == dir)
 160                 return prime_attach->sgt;
 161
 162         /*
 163          * two mappings with different directions for the same attachment are
 164          * not allowed
 165          */
 166         if (WARN_ON(prime_attach->dir != DMA_NONE))
 167                 return ERR_PTR(-EBUSY);
 168
 169         mutex_lock(&obj->dev->struct_mutex);
 170
 171         sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
 172
 173         if (!IS_ERR(sgt)) {
 174                 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
 175                         sg_free_table(sgt);
 176                         kfree(sgt);
 177                         sgt = ERR_PTR(-ENOMEM);
 178                 } else {
 179                         prime_attach->sgt = sgt;
 180                         prime_attach->dir = dir;
 181                 }
 182         }
 183
 184         mutex_unlock(&obj->dev->struct_mutex);
 185         return sgt;
 186 }
 187
 188 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 189                 struct sg_table *sgt, enum dma_data_direction dir)
 190 {
 191         /* nothing to be done here */
 192 }
 193
 194 static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
 195 {
 196         struct drm_gem_object *obj = dma_buf->priv;
 197
 198         if (obj->export_dma_buf == dma_buf) {
 199                 /* drop the reference on the export fd holds */
 200                 obj->export_dma_buf = NULL;
 201                 drm_gem_object_unreference_unlocked(obj);
 202         }
 203 }
 204
 205 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 206 {
 207         struct drm_gem_object *obj = dma_buf->priv;
 208         struct drm_device *dev = obj->dev;
 209
 210         return dev->driver->gem_prime_vmap(obj);
 211 }
 212
 213 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 214 {
 215         struct drm_gem_object *obj = dma_buf->priv;
 216         struct drm_device *dev = obj->dev;
 217
 218         dev->driver->gem_prime_vunmap(obj, vaddr);
 219 }
 220
 221 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
 222                 unsigned long page_num)
 223 {
 224         return NULL;
 225 }
 226
 227 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
 228                 unsigned long page_num, void *addr)
 229 {
 230
 231 }
 232 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
 233                 unsigned long page_num)
 234 {
 235         return NULL;
 236 }
 237
 238 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
 239                 unsigned long page_num, void *addr)
 240 {
 241
 242 }
 243
 244 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
 245                 struct vm_area_struct *vma)
 246 {
 247         return -EINVAL;
 248 }
 249
 250 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 251         .attach = drm_gem_map_attach,
 252         .detach = drm_gem_map_detach,
 253         .map_dma_buf = drm_gem_map_dma_buf,
 254         .unmap_dma_buf = drm_gem_unmap_dma_buf,
 255         .release = drm_gem_dmabuf_release,
 256         .kmap = drm_gem_dmabuf_kmap,
 257         .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
 258         .kunmap = drm_gem_dmabuf_kunmap,
 259         .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 260         .mmap = drm_gem_dmabuf_mmap,
 261         .vmap = drm_gem_dmabuf_vmap,
 262         .vunmap = drm_gem_dmabuf_vunmap,
 263 };
 264
 265 /**
 266  * DOC: PRIME Helpers
 267  *
 268  * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
 269  * simpler APIs by using the helper functions @drm_gem_prime_export and
 270  * @drm_gem_prime_import.  These functions implement dma-buf support in terms of
 271  * five lower-level driver callbacks:
 272  *
 273  * Export callbacks:
 274  *
 275  *  - @gem_prime_pin (optional): prepare a GEM object for exporting
 276  *
 277  *  - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
 278  *
 279  *  - @gem_prime_vmap: vmap a buffer exported by your driver
 280  *
 281  *  - @gem_prime_vunmap: vunmap a buffer exported by your driver
 282  *
 283  * Import callback:
 284  *
 285  *  - @gem_prime_import_sg_table (import): produce a GEM object from another
 286  *    driver's scatter/gather table
 287  */
 288
 289 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 290                                      struct drm_gem_object *obj, int flags)
 291 {
 292         return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
 293 }
 294 EXPORT_SYMBOL(drm_gem_prime_export);
 295
 296 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 297                 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
 298                 int *prime_fd)
 299 {
 300         struct drm_gem_object *obj;
 301         void *buf;
 302         int ret = 0;
 303         struct dma_buf *dmabuf;
 304
 305         obj = drm_gem_object_lookup(dev, file_priv, handle);
 306         if (!obj)
 307                 return -ENOENT;
 308
 309         mutex_lock(&file_priv->prime.lock);
 310         /* re-export the original imported object */
 311         if (obj->import_attach) {
 312                 dmabuf = obj->import_attach->dmabuf;
 313                 goto out_have_obj;
 314         }
 315
 316         if (obj->export_dma_buf) {
 317                 dmabuf = obj->export_dma_buf;
 318                 goto out_have_obj;
 319         }
 320
 321         buf = dev->driver->gem_prime_export(dev, obj, flags);
 322         if (IS_ERR(buf)) {
 323                 /* normally the created dma-buf takes ownership of the ref,
 324                  * but if that fails then drop the ref
 325                  */
 326                 ret = PTR_ERR(buf);
 327                 goto out;
 328         }
 329         obj->export_dma_buf = buf;
 330
 331         /* if we've exported this buffer the cheat and add it to the import list
 332          * so we get the correct handle back
 333          */
 334         ret = drm_prime_add_buf_handle(&file_priv->prime,
 335                                        obj->export_dma_buf, handle);
 336         if (ret)
 337                 goto fail_put_dmabuf;
 338
 339         ret = dma_buf_fd(buf, flags);
 340         if (ret < 0)
 341                 goto fail_rm_handle;
 342
 343         *prime_fd = ret;
 344         mutex_unlock(&file_priv->prime.lock);
 345         return 0;
 346
 347 out_have_obj:
 348         get_dma_buf(dmabuf);
 349         ret = dma_buf_fd(dmabuf, flags);
 350         if (ret < 0)
 351                 dma_buf_put(dmabuf);
 352         else
 353                 *prime_fd = ret;
 354         goto out;
 355
 356 fail_rm_handle:
 357         drm_prime_remove_buf_handle_locked(&file_priv->prime, buf);
 358 fail_put_dmabuf:
 359         /* clear NOT to be checked when releasing dma_buf */
 360         obj->export_dma_buf = NULL;
 361         dma_buf_put(buf);
 362 out:
 363         drm_gem_object_unreference_unlocked(obj);
 364         mutex_unlock(&file_priv->prime.lock);
 365         return ret;
 366 }
 367 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 368
 369 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 370                                             struct dma_buf *dma_buf)
 371 {
 372         struct dma_buf_attachment *attach;
 373         struct sg_table *sgt;
 374         struct drm_gem_object *obj;
 375         int ret;
 376
 377         if (!dev->driver->gem_prime_import_sg_table)
 378                 return ERR_PTR(-EINVAL);
 379
 380         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 381                 obj = dma_buf->priv;
 382                 if (obj->dev == dev) {
 383                         /*
 384                          * Importing dmabuf exported from out own gem increases
 385                          * refcount on gem itself instead of f_count of dmabuf.
 386                          */
 387                         drm_gem_object_reference(obj);
 388                         return obj;
 389                 }
 390         }
 391
 392         attach = dma_buf_attach(dma_buf, dev->dev);
 393         if (IS_ERR(attach))
 394                 return ERR_CAST(attach);
 395
 396         get_dma_buf(dma_buf);
 397
 398         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 399         if (IS_ERR_OR_NULL(sgt)) {
 400                 ret = PTR_ERR(sgt);
 401                 goto fail_detach;
 402         }
 403
 404         obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
 405         if (IS_ERR(obj)) {
 406                 ret = PTR_ERR(obj);
 407                 goto fail_unmap;
 408         }
 409
 410         obj->import_attach = attach;
 411
 412         return obj;
 413
 414 fail_unmap:
 415         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 416 fail_detach:
 417         dma_buf_detach(dma_buf, attach);
 418         dma_buf_put(dma_buf);
 419
 420         return ERR_PTR(ret);
 421 }
 422 EXPORT_SYMBOL(drm_gem_prime_import);
 423
 424 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 425                 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
 426 {
 427         struct dma_buf *dma_buf;
 428         struct drm_gem_object *obj;
 429         int ret;
 430
 431         dma_buf = dma_buf_get(prime_fd);
 432         if (IS_ERR(dma_buf))
 433                 return PTR_ERR(dma_buf);
 434
 435         mutex_lock(&file_priv->prime.lock);
 436
 437         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 438                         dma_buf, handle);
 439         if (!ret) {
 440                 ret = 0;
 441                 goto out_put;
 442         }
 443
 444         /* never seen this one, need to import */
 445         obj = dev->driver->gem_prime_import(dev, dma_buf);
 446         if (IS_ERR(obj)) {
 447                 ret = PTR_ERR(obj);
 448                 goto out_put;
 449         }
 450
 451         ret = drm_gem_handle_create(file_priv, obj, handle);
 452         drm_gem_object_unreference_unlocked(obj);
 453         if (ret)
 454                 goto out_put;
 455
 456         ret = drm_prime_add_buf_handle(&file_priv->prime,
 457                         dma_buf, *handle);
 458         if (ret)
 459                 goto fail;
 460
 461         mutex_unlock(&file_priv->prime.lock);
 462
 463         dma_buf_put(dma_buf);
 464
 465         return 0;
 466
 467 fail:
 468         /* hmm, if driver attached, we are relying on the free-object path
 469          * to detach.. which seems ok..
 470          */
 471         drm_gem_object_handle_unreference_unlocked(obj);
 472 out_put:
 473         dma_buf_put(dma_buf);
 474         mutex_unlock(&file_priv->prime.lock);
 475         return ret;
 476 }
 477 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 478
 479 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 480                                  struct drm_file *file_priv)
 481 {
 482         struct drm_prime_handle *args = data;
 483         uint32_t flags;
 484
 485         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 486                 return -EINVAL;
 487
 488         if (!dev->driver->prime_handle_to_fd)
 489                 return -ENOSYS;
 490
 491         /* check flags are valid */
 492         if (args->flags & ~DRM_CLOEXEC)
 493                 return -EINVAL;
 494
 495         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 496         flags = args->flags & DRM_CLOEXEC;
 497
 498         return dev->driver->prime_handle_to_fd(dev, file_priv,
 499                         args->handle, flags, &args->fd);
 500 }
 501
 502 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 503                                  struct drm_file *file_priv)
 504 {
 505         struct drm_prime_handle *args = data;
 506
 507         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 508                 return -EINVAL;
 509
 510         if (!dev->driver->prime_fd_to_handle)
 511                 return -ENOSYS;
 512
 513         return dev->driver->prime_fd_to_handle(dev, file_priv,
 514                         args->fd, &args->handle);
 515 }
 516
 517 /*
 518  * drm_prime_pages_to_sg
 519  *
 520  * this helper creates an sg table object from a set of pages
 521  * the driver is responsible for mapping the pages into the
 522  * importers address space
 523  */
 524 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 525 {
 526         struct sg_table *sg = NULL;
 527         int ret;
 528
 529         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 530         if (!sg) {
 531                 ret = -ENOMEM;
 532                 goto out;
 533         }
 534
 535         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 536                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 537         if (ret)
 538                 goto out;
 539
 540         return sg;
 541 out:
 542         kfree(sg);
 543         return ERR_PTR(ret);
 544 }
 545 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 546
 547 /* export an sg table into an array of pages and addresses
 548    this is currently required by the TTM driver in order to do correct fault
 549    handling */
 550 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 551                                      dma_addr_t *addrs, int max_pages)
 552 {
 553         unsigned count;
 554         struct scatterlist *sg;
 555         struct page *page;
 556         u32 len, offset;
 557         int pg_index;
 558         dma_addr_t addr;
 559
 560         pg_index = 0;
 561         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 562                 len = sg->length;
 563                 offset = sg->offset;
 564                 page = sg_page(sg);
 565                 addr = sg_dma_address(sg);
 566
 567                 while (len > 0) {
 568                         if (WARN_ON(pg_index >= max_pages))
 569                                 return -1;
 570                         pages[pg_index] = page;
 571                         if (addrs)
 572                                 addrs[pg_index] = addr;
 573
 574                         page++;
 575                         addr += PAGE_SIZE;
 576                         len -= PAGE_SIZE;
 577                         pg_index++;
 578                 }
 579         }
 580         return 0;
 581 }
 582 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 583 /* helper function to cleanup a GEM/prime object */
 584 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 585 {
 586         struct dma_buf_attachment *attach;
 587         struct dma_buf *dma_buf;
 588         attach = obj->import_attach;
 589         if (sg)
 590                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 591         dma_buf = attach->dmabuf;
 592         dma_buf_detach(attach->dmabuf, attach);
 593         /* remove the reference */
 594         dma_buf_put(dma_buf);
 595 }
 596 EXPORT_SYMBOL(drm_prime_gem_destroy);
 597
 598 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 599 {
 600         INIT_LIST_HEAD(&prime_fpriv->head);
 601         mutex_init(&prime_fpriv->lock);
 602 }
 603 EXPORT_SYMBOL(drm_prime_init_file_private);
 604
 605 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 606 {
 607         /* by now drm_gem_release should've made sure the list is empty */
 608         WARN_ON(!list_empty(&prime_fpriv->head));
 609 }
 610 EXPORT_SYMBOL(drm_prime_destroy_file_private);
 611
 612 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
 613 {
 614         struct drm_prime_member *member;
 615
 616         list_for_each_entry(member, &prime_fpriv->head, entry) {
 617                 if (member->dma_buf == dma_buf) {
 618                         *handle = member->handle;
 619                         return 0;
 620                 }
 621         }
 622         return -ENOENT;
 623 }
 624 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
 625
 626 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
 627 {
 628         mutex_lock(&prime_fpriv->lock);
 629         drm_prime_remove_buf_handle_locked(prime_fpriv, dma_buf);
 630         mutex_unlock(&prime_fpriv->lock);
 631 }
 632 EXPORT_SYMBOL(drm_prime_remove_buf_handle);