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