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,
 214                              0600);
 215 }
 216 EXPORT_SYMBOL(drm_gem_prime_export);
 217
 218 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 219                 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
 220                 int *prime_fd)
 221 {
 222         struct drm_gem_object *obj;
 223         void *buf;
 224         int ret = 0;
 225         struct dma_buf *dmabuf;
 226
 227         obj = drm_gem_object_lookup(dev, file_priv, handle);
 228         if (!obj)
 229                 return -ENOENT;
 230
 231         mutex_lock(&file_priv->prime.lock);
 232         /* re-export the original imported object */
 233         if (obj->import_attach) {
 234                 dmabuf = obj->import_attach->dmabuf;
 235                 goto out_have_obj;
 236         }
 237
 238         if (obj->export_dma_buf) {
 239                 dmabuf = obj->export_dma_buf;
 240                 goto out_have_obj;
 241         }
 242
 243         buf = dev->driver->gem_prime_export(dev, obj, flags);
 244         if (IS_ERR(buf)) {
 245                 /* normally the created dma-buf takes ownership of the ref,
 246                  * but if that fails then drop the ref
 247                  */
 248                 ret = PTR_ERR(buf);
 249                 goto out;
 250         }
 251         obj->export_dma_buf = buf;
 252
 253         /* if we've exported this buffer the cheat and add it to the import list
 254          * so we get the correct handle back
 255          */
 256         ret = drm_prime_add_buf_handle(&file_priv->prime,
 257                                        obj->export_dma_buf, handle);
 258         if (ret)
 259                 goto out;
 260
 261         *prime_fd = dma_buf_fd(buf, flags);
 262         mutex_unlock(&file_priv->prime.lock);
 263         return 0;
 264
 265 out_have_obj:
 266         get_dma_buf(dmabuf);
 267         *prime_fd = dma_buf_fd(dmabuf, flags);
 268 out:
 269         drm_gem_object_unreference_unlocked(obj);
 270         mutex_unlock(&file_priv->prime.lock);
 271         return ret;
 272 }
 273 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 274
 275 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 276                                             struct dma_buf *dma_buf)
 277 {
 278         struct dma_buf_attachment *attach;
 279         struct sg_table *sgt;
 280         struct drm_gem_object *obj;
 281         int ret;
 282
 283         if (!dev->driver->gem_prime_import_sg_table)
 284                 return ERR_PTR(-EINVAL);
 285
 286         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 287                 obj = dma_buf->priv;
 288                 if (obj->dev == dev) {
 289                         /*
 290                          * Importing dmabuf exported from out own gem increases
 291                          * refcount on gem itself instead of f_count of dmabuf.
 292                          */
 293                         drm_gem_object_reference(obj);
 294                         return obj;
 295                 }
 296         }
 297
 298         attach = dma_buf_attach(dma_buf, dev->dev);
 299         if (IS_ERR(attach))
 300                 return ERR_CAST(attach);
 301
 302         get_dma_buf(dma_buf);
 303
 304         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 305         if (IS_ERR_OR_NULL(sgt)) {
 306                 ret = PTR_ERR(sgt);
 307                 goto fail_detach;
 308         }
 309
 310         obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
 311         if (IS_ERR(obj)) {
 312                 ret = PTR_ERR(obj);
 313                 goto fail_unmap;
 314         }
 315
 316         obj->import_attach = attach;
 317
 318         return obj;
 319
 320 fail_unmap:
 321         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 322 fail_detach:
 323         dma_buf_detach(dma_buf, attach);
 324         dma_buf_put(dma_buf);
 325
 326         return ERR_PTR(ret);
 327 }
 328 EXPORT_SYMBOL(drm_gem_prime_import);
 329
 330 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 331                 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
 332 {
 333         struct dma_buf *dma_buf;
 334         struct drm_gem_object *obj;
 335         int ret;
 336
 337         dma_buf = dma_buf_get(prime_fd);
 338         if (IS_ERR(dma_buf))
 339                 return PTR_ERR(dma_buf);
 340
 341         mutex_lock(&file_priv->prime.lock);
 342
 343         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 344                         dma_buf, handle);
 345         if (!ret) {
 346                 ret = 0;
 347                 goto out_put;
 348         }
 349
 350         /* never seen this one, need to import */
 351         obj = dev->driver->gem_prime_import(dev, dma_buf);
 352         if (IS_ERR(obj)) {
 353                 ret = PTR_ERR(obj);
 354                 goto out_put;
 355         }
 356
 357         ret = drm_gem_handle_create(file_priv, obj, handle);
 358         drm_gem_object_unreference_unlocked(obj);
 359         if (ret)
 360                 goto out_put;
 361
 362         ret = drm_prime_add_buf_handle(&file_priv->prime,
 363                         dma_buf, *handle);
 364         if (ret)
 365                 goto fail;
 366
 367         mutex_unlock(&file_priv->prime.lock);
 368
 369         dma_buf_put(dma_buf);
 370
 371         return 0;
 372
 373 fail:
 374         /* hmm, if driver attached, we are relying on the free-object path
 375          * to detach.. which seems ok..
 376          */
 377         drm_gem_object_handle_unreference_unlocked(obj);
 378 out_put:
 379         dma_buf_put(dma_buf);
 380         mutex_unlock(&file_priv->prime.lock);
 381         return ret;
 382 }
 383 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 384
 385 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 386                                  struct drm_file *file_priv)
 387 {
 388         struct drm_prime_handle *args = data;
 389         uint32_t flags;
 390
 391         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 392                 return -EINVAL;
 393
 394         if (!dev->driver->prime_handle_to_fd)
 395                 return -ENOSYS;
 396
 397         /* check flags are valid */
 398         if (args->flags & ~DRM_CLOEXEC)
 399                 return -EINVAL;
 400
 401         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 402         flags = args->flags & DRM_CLOEXEC;
 403
 404         return dev->driver->prime_handle_to_fd(dev, file_priv,
 405                         args->handle, flags, &args->fd);
 406 }
 407
 408 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 409                                  struct drm_file *file_priv)
 410 {
 411         struct drm_prime_handle *args = data;
 412
 413         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 414                 return -EINVAL;
 415
 416         if (!dev->driver->prime_fd_to_handle)
 417                 return -ENOSYS;
 418
 419         return dev->driver->prime_fd_to_handle(dev, file_priv,
 420                         args->fd, &args->handle);
 421 }
 422
 423 /*
 424  * drm_prime_pages_to_sg
 425  *
 426  * this helper creates an sg table object from a set of pages
 427  * the driver is responsible for mapping the pages into the
 428  * importers address space
 429  */
 430 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 431 {
 432         struct sg_table *sg = NULL;
 433         int ret;
 434
 435         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 436         if (!sg)
 437                 goto out;
 438
 439         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 440                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 441         if (ret)
 442                 goto out;
 443
 444         return sg;
 445 out:
 446         kfree(sg);
 447         return NULL;
 448 }
 449 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 450
 451 /* export an sg table into an array of pages and addresses
 452    this is currently required by the TTM driver in order to do correct fault
 453    handling */
 454 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 455                                      dma_addr_t *addrs, int max_pages)
 456 {
 457         unsigned count;
 458         struct scatterlist *sg;
 459         struct page *page;
 460         u32 len, offset;
 461         int pg_index;
 462         dma_addr_t addr;
 463
 464         pg_index = 0;
 465         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 466                 len = sg->length;
 467                 offset = sg->offset;
 468                 page = sg_page(sg);
 469                 addr = sg_dma_address(sg);
 470
 471                 while (len > 0) {
 472                         if (WARN_ON(pg_index >= max_pages))
 473                                 return -1;
 474                         pages[pg_index] = page;
 475                         if (addrs)
 476                                 addrs[pg_index] = addr;
 477
 478                         page++;
 479                         addr += PAGE_SIZE;
 480                         len -= PAGE_SIZE;
 481                         pg_index++;
 482                 }
 483         }
 484         return 0;
 485 }
 486 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 487 /* helper function to cleanup a GEM/prime object */
 488 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 489 {
 490         struct dma_buf_attachment *attach;
 491         struct dma_buf *dma_buf;
 492         attach = obj->import_attach;
 493         if (sg)
 494                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 495         dma_buf = attach->dmabuf;
 496         dma_buf_detach(attach->dmabuf, attach);
 497         /* remove the reference */
 498         dma_buf_put(dma_buf);
 499 }
 500 EXPORT_SYMBOL(drm_prime_gem_destroy);
 501
 502 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 503 {
 504         INIT_LIST_HEAD(&prime_fpriv->head);
 505         mutex_init(&prime_fpriv->lock);
 506 }
 507 EXPORT_SYMBOL(drm_prime_init_file_private);
 508
 509 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 510 {
 511         /* by now drm_gem_release should've made sure the list is empty */
 512         WARN_ON(!list_empty(&prime_fpriv->head));
 513 }
 514 EXPORT_SYMBOL(drm_prime_destroy_file_private);
 515
 516 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
 517 {
 518         struct drm_prime_member *member;
 519
 520         member = kmalloc(sizeof(*member), GFP_KERNEL);
 521         if (!member)
 522                 return -ENOMEM;
 523
 524         get_dma_buf(dma_buf);
 525         member->dma_buf = dma_buf;
 526         member->handle = handle;
 527         list_add(&member->entry, &prime_fpriv->head);
 528         return 0;
 529 }
 530
 531 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
 532 {
 533         struct drm_prime_member *member;
 534
 535         list_for_each_entry(member, &prime_fpriv->head, entry) {
 536                 if (member->dma_buf == dma_buf) {
 537                         *handle = member->handle;
 538                         return 0;
 539                 }
 540         }
 541         return -ENOENT;
 542 }
 543 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
 544
 545 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
 546 {
 547         struct drm_prime_member *member, *safe;
 548
 549         mutex_lock(&prime_fpriv->lock);
 550         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 551                 if (member->dma_buf == dma_buf) {
 552                         dma_buf_put(dma_buf);
 553                         list_del(&member->entry);
 554                         kfree(member);
 555                 }
 556         }
 557         mutex_unlock(&prime_fpriv->lock);
 558 }
 559 EXPORT_SYMBOL(drm_prime_remove_buf_handle);