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 struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
  68                 enum dma_data_direction dir)
  69 {
  70         struct drm_gem_object *obj = attach->dmabuf->priv;
  71         struct sg_table *sgt;
  72
  73         mutex_lock(&obj->dev->struct_mutex);
  74
  75         sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
  76
  77         if (!IS_ERR_OR_NULL(sgt))
  78                 dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
  79
  80         mutex_unlock(&obj->dev->struct_mutex);
  81         return sgt;
  82 }
  83
  84 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
  85                 struct sg_table *sgt, enum dma_data_direction dir)
  86 {
  87         dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
  88         sg_free_table(sgt);
  89         kfree(sgt);
  90 }
  91
  92 static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
  93 {
  94         struct drm_gem_object *obj = dma_buf->priv;
  95
  96         if (obj->export_dma_buf == dma_buf) {
  97                 /* drop the reference on the export fd holds */
  98                 obj->export_dma_buf = NULL;
  99                 drm_gem_object_unreference_unlocked(obj);
 100         }
 101 }
 102
 103 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 104 {
 105         struct drm_gem_object *obj = dma_buf->priv;
 106         struct drm_device *dev = obj->dev;
 107
 108         return dev->driver->gem_prime_vmap(obj);
 109 }
 110
 111 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 112 {
 113         struct drm_gem_object *obj = dma_buf->priv;
 114         struct drm_device *dev = obj->dev;
 115
 116         dev->driver->gem_prime_vunmap(obj, vaddr);
 117 }
 118
 119 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
 120                 unsigned long page_num)
 121 {
 122         return NULL;
 123 }
 124
 125 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
 126                 unsigned long page_num, void *addr)
 127 {
 128
 129 }
 130 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
 131                 unsigned long page_num)
 132 {
 133         return NULL;
 134 }
 135
 136 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
 137                 unsigned long page_num, void *addr)
 138 {
 139
 140 }
 141
 142 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
 143                 struct vm_area_struct *vma)
 144 {
 145         return -EINVAL;
 146 }
 147
 148 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 149         .map_dma_buf = drm_gem_map_dma_buf,
 150         .unmap_dma_buf = drm_gem_unmap_dma_buf,
 151         .release = drm_gem_dmabuf_release,
 152         .kmap = drm_gem_dmabuf_kmap,
 153         .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
 154         .kunmap = drm_gem_dmabuf_kunmap,
 155         .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 156         .mmap = drm_gem_dmabuf_mmap,
 157         .vmap = drm_gem_dmabuf_vmap,
 158         .vunmap = drm_gem_dmabuf_vunmap,
 159 };
 160
 161 /**
 162  * DOC: PRIME Helpers
 163  *
 164  * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
 165  * simpler APIs by using the helper functions @drm_gem_prime_export and
 166  * @drm_gem_prime_import.  These functions implement dma-buf support in terms of
 167  * five lower-level driver callbacks:
 168  *
 169  * Export callbacks:
 170  *
 171  *  - @gem_prime_pin (optional): prepare a GEM object for exporting
 172  *
 173  *  - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
 174  *
 175  *  - @gem_prime_vmap: vmap a buffer exported by your driver
 176  *
 177  *  - @gem_prime_vunmap: vunmap a buffer exported by your driver
 178  *
 179  * Import callback:
 180  *
 181  *  - @gem_prime_import_sg_table (import): produce a GEM object from another
 182  *    driver's scatter/gather table
 183  */
 184
 185 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 186                                      struct drm_gem_object *obj, int flags)
 187 {
 188         if (dev->driver->gem_prime_pin) {
 189                 int ret = dev->driver->gem_prime_pin(obj);
 190                 if (ret)
 191                         return ERR_PTR(ret);
 192         }
 193         return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,
 194                               0600);
 195 }
 196 EXPORT_SYMBOL(drm_gem_prime_export);
 197
 198 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 199                 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
 200                 int *prime_fd)
 201 {
 202         struct drm_gem_object *obj;
 203         void *buf;
 204         int ret = 0;
 205         struct dma_buf *dmabuf;
 206
 207         obj = drm_gem_object_lookup(dev, file_priv, handle);
 208         if (!obj)
 209                 return -ENOENT;
 210
 211         mutex_lock(&file_priv->prime.lock);
 212         /* re-export the original imported object */
 213         if (obj->import_attach) {
 214                 dmabuf = obj->import_attach->dmabuf;
 215                 goto out_have_obj;
 216         }
 217
 218         if (obj->export_dma_buf) {
 219                 dmabuf = obj->export_dma_buf;
 220                 goto out_have_obj;
 221         }
 222
 223         buf = dev->driver->gem_prime_export(dev, obj, flags);
 224         if (IS_ERR(buf)) {
 225                 /* normally the created dma-buf takes ownership of the ref,
 226                  * but if that fails then drop the ref
 227                  */
 228                 ret = PTR_ERR(buf);
 229                 goto out;
 230         }
 231         obj->export_dma_buf = buf;
 232
 233         /* if we've exported this buffer the cheat and add it to the import list
 234          * so we get the correct handle back
 235          */
 236         ret = drm_prime_add_buf_handle(&file_priv->prime,
 237                                        obj->export_dma_buf, handle);
 238         if (ret)
 239                 goto out;
 240
 241         *prime_fd = dma_buf_fd(buf, flags);
 242         mutex_unlock(&file_priv->prime.lock);
 243         return 0;
 244
 245 out_have_obj:
 246         get_dma_buf(dmabuf);
 247         *prime_fd = dma_buf_fd(dmabuf, flags);
 248 out:
 249         drm_gem_object_unreference_unlocked(obj);
 250         mutex_unlock(&file_priv->prime.lock);
 251         return ret;
 252 }
 253 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 254
 255 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 256                                             struct dma_buf *dma_buf)
 257 {
 258         struct dma_buf_attachment *attach;
 259         struct sg_table *sgt;
 260         struct drm_gem_object *obj;
 261         int ret;
 262
 263         if (!dev->driver->gem_prime_import_sg_table)
 264                 return ERR_PTR(-EINVAL);
 265
 266         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 267                 obj = dma_buf->priv;
 268                 if (obj->dev == dev) {
 269                         /*
 270                          * Importing dmabuf exported from out own gem increases
 271                          * refcount on gem itself instead of f_count of dmabuf.
 272                          */
 273                         drm_gem_object_reference(obj);
 274                         return obj;
 275                 }
 276         }
 277
 278         attach = dma_buf_attach(dma_buf, dev->dev);
 279         if (IS_ERR(attach))
 280                 return ERR_PTR(PTR_ERR(attach));
 281
 282         get_dma_buf(dma_buf);
 283
 284         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 285         if (IS_ERR_OR_NULL(sgt)) {
 286                 ret = PTR_ERR(sgt);
 287                 goto fail_detach;
 288         }
 289
 290         obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
 291         if (IS_ERR(obj)) {
 292                 ret = PTR_ERR(obj);
 293                 goto fail_unmap;
 294         }
 295
 296         obj->import_attach = attach;
 297
 298         return obj;
 299
 300 fail_unmap:
 301         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 302 fail_detach:
 303         dma_buf_detach(dma_buf, attach);
 304         dma_buf_put(dma_buf);
 305
 306         return ERR_PTR(ret);
 307 }
 308 EXPORT_SYMBOL(drm_gem_prime_import);
 309
 310 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 311                 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
 312 {
 313         struct dma_buf *dma_buf;
 314         struct drm_gem_object *obj;
 315         int ret;
 316
 317         dma_buf = dma_buf_get(prime_fd);
 318         if (IS_ERR(dma_buf))
 319                 return PTR_ERR(dma_buf);
 320
 321         mutex_lock(&file_priv->prime.lock);
 322
 323         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 324                         dma_buf, handle);
 325         if (!ret) {
 326                 ret = 0;
 327                 goto out_put;
 328         }
 329
 330         /* never seen this one, need to import */
 331         obj = dev->driver->gem_prime_import(dev, dma_buf);
 332         if (IS_ERR(obj)) {
 333                 ret = PTR_ERR(obj);
 334                 goto out_put;
 335         }
 336
 337         ret = drm_gem_handle_create(file_priv, obj, handle);
 338         drm_gem_object_unreference_unlocked(obj);
 339         if (ret)
 340                 goto out_put;
 341
 342         ret = drm_prime_add_buf_handle(&file_priv->prime,
 343                         dma_buf, *handle);
 344         if (ret)
 345                 goto fail;
 346
 347         mutex_unlock(&file_priv->prime.lock);
 348
 349         dma_buf_put(dma_buf);
 350
 351         return 0;
 352
 353 fail:
 354         /* hmm, if driver attached, we are relying on the free-object path
 355          * to detach.. which seems ok..
 356          */
 357         drm_gem_object_handle_unreference_unlocked(obj);
 358 out_put:
 359         dma_buf_put(dma_buf);
 360         mutex_unlock(&file_priv->prime.lock);
 361         return ret;
 362 }
 363 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 364
 365 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 366                                  struct drm_file *file_priv)
 367 {
 368         struct drm_prime_handle *args = data;
 369         uint32_t flags;
 370
 371         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 372                 return -EINVAL;
 373
 374         if (!dev->driver->prime_handle_to_fd)
 375                 return -ENOSYS;
 376
 377         /* check flags are valid */
 378         if (args->flags & ~DRM_CLOEXEC)
 379                 return -EINVAL;
 380
 381         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 382         flags = args->flags & DRM_CLOEXEC;
 383
 384         return dev->driver->prime_handle_to_fd(dev, file_priv,
 385                         args->handle, flags, &args->fd);
 386 }
 387
 388 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 389                                  struct drm_file *file_priv)
 390 {
 391         struct drm_prime_handle *args = data;
 392
 393         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 394                 return -EINVAL;
 395
 396         if (!dev->driver->prime_fd_to_handle)
 397                 return -ENOSYS;
 398
 399         return dev->driver->prime_fd_to_handle(dev, file_priv,
 400                         args->fd, &args->handle);
 401 }
 402
 403 /*
 404  * drm_prime_pages_to_sg
 405  *
 406  * this helper creates an sg table object from a set of pages
 407  * the driver is responsible for mapping the pages into the
 408  * importers address space
 409  */
 410 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 411 {
 412         struct sg_table *sg = NULL;
 413         int ret;
 414
 415         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 416         if (!sg)
 417                 goto out;
 418
 419         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 420                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 421         if (ret)
 422                 goto out;
 423
 424         return sg;
 425 out:
 426         kfree(sg);
 427         return NULL;
 428 }
 429 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 430
 431 /* export an sg table into an array of pages and addresses
 432    this is currently required by the TTM driver in order to do correct fault
 433    handling */
 434 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 435                                      dma_addr_t *addrs, int max_pages)
 436 {
 437         unsigned count;
 438         struct scatterlist *sg;
 439         struct page *page;
 440         u32 len, offset;
 441         int pg_index;
 442         dma_addr_t addr;
 443
 444         pg_index = 0;
 445         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 446                 len = sg->length;
 447                 offset = sg->offset;
 448                 page = sg_page(sg);
 449                 addr = sg_dma_address(sg);
 450
 451                 while (len > 0) {
 452                         if (WARN_ON(pg_index >= max_pages))
 453                                 return -1;
 454                         pages[pg_index] = page;
 455                         if (addrs)
 456                                 addrs[pg_index] = addr;
 457
 458                         page++;
 459                         addr += PAGE_SIZE;
 460                         len -= PAGE_SIZE;
 461                         pg_index++;
 462                 }
 463         }
 464         return 0;
 465 }
 466 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 467 /* helper function to cleanup a GEM/prime object */
 468 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 469 {
 470         struct dma_buf_attachment *attach;
 471         struct dma_buf *dma_buf;
 472         attach = obj->import_attach;
 473         if (sg)
 474                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 475         dma_buf = attach->dmabuf;
 476         dma_buf_detach(attach->dmabuf, attach);
 477         /* remove the reference */
 478         dma_buf_put(dma_buf);
 479 }
 480 EXPORT_SYMBOL(drm_prime_gem_destroy);
 481
 482 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 483 {
 484         INIT_LIST_HEAD(&prime_fpriv->head);
 485         mutex_init(&prime_fpriv->lock);
 486 }
 487 EXPORT_SYMBOL(drm_prime_init_file_private);
 488
 489 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 490 {
 491         /* by now drm_gem_release should've made sure the list is empty */
 492         WARN_ON(!list_empty(&prime_fpriv->head));
 493 }
 494 EXPORT_SYMBOL(drm_prime_destroy_file_private);
 495
 496 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
 497 {
 498         struct drm_prime_member *member;
 499
 500         member = kmalloc(sizeof(*member), GFP_KERNEL);
 501         if (!member)
 502                 return -ENOMEM;
 503
 504         get_dma_buf(dma_buf);
 505         member->dma_buf = dma_buf;
 506         member->handle = handle;
 507         list_add(&member->entry, &prime_fpriv->head);
 508         return 0;
 509 }
 510
 511 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
 512 {
 513         struct drm_prime_member *member;
 514
 515         list_for_each_entry(member, &prime_fpriv->head, entry) {
 516                 if (member->dma_buf == dma_buf) {
 517                         *handle = member->handle;
 518                         return 0;
 519                 }
 520         }
 521         return -ENOENT;
 522 }
 523 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
 524
 525 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
 526 {
 527         struct drm_prime_member *member, *safe;
 528
 529         mutex_lock(&prime_fpriv->lock);
 530         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 531                 if (member->dma_buf == dma_buf) {
 532                         dma_buf_put(dma_buf);
 533                         list_del(&member->entry);
 534                         kfree(member);
 535                 }
 536         }
 537         mutex_unlock(&prime_fpriv->lock);
 538 }
 539 EXPORT_SYMBOL(drm_prime_remove_buf_handle);