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, flags);
 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 = 0;
 204         struct dma_buf *dmabuf;
 205
 206         obj = drm_gem_object_lookup(dev, file_priv, handle);
 207         if (!obj)
 208                 return -ENOENT;
 209
 210         mutex_lock(&file_priv->prime.lock);
 211         /* re-export the original imported object */
 212         if (obj->import_attach) {
 213                 dmabuf = obj->import_attach->dmabuf;
 214                 goto out_have_obj;
 215         }
 216
 217         if (obj->export_dma_buf) {
 218                 dmabuf = obj->export_dma_buf;
 219                 goto out_have_obj;
 220         }
 221
 222         buf = dev->driver->gem_prime_export(dev, obj, flags);
 223         if (IS_ERR(buf)) {
 224                 /* normally the created dma-buf takes ownership of the ref,
 225                  * but if that fails then drop the ref
 226                  */
 227                 ret = PTR_ERR(buf);
 228                 goto out;
 229         }
 230         obj->export_dma_buf = buf;
 231
 232         /* if we've exported this buffer the cheat and add it to the import list
 233          * so we get the correct handle back
 234          */
 235         ret = drm_prime_add_buf_handle(&file_priv->prime,
 236                                        obj->export_dma_buf, handle);
 237         if (ret)
 238                 goto out;
 239
 240         *prime_fd = dma_buf_fd(buf, flags);
 241         mutex_unlock(&file_priv->prime.lock);
 242         return 0;
 243
 244 out_have_obj:
 245         get_dma_buf(dmabuf);
 246         *prime_fd = dma_buf_fd(dmabuf, flags);
 247 out:
 248         drm_gem_object_unreference_unlocked(obj);
 249         mutex_unlock(&file_priv->prime.lock);
 250         return ret;
 251 }
 252 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 253
 254 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 255                                             struct dma_buf *dma_buf)
 256 {
 257         struct dma_buf_attachment *attach;
 258         struct sg_table *sgt;
 259         struct drm_gem_object *obj;
 260         int ret;
 261
 262         if (!dev->driver->gem_prime_import_sg_table)
 263                 return ERR_PTR(-EINVAL);
 264
 265         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 266                 obj = dma_buf->priv;
 267                 if (obj->dev == dev) {
 268                         /*
 269                          * Importing dmabuf exported from out own gem increases
 270                          * refcount on gem itself instead of f_count of dmabuf.
 271                          */
 272                         drm_gem_object_reference(obj);
 273                         return obj;
 274                 }
 275         }
 276
 277         attach = dma_buf_attach(dma_buf, dev->dev);
 278         if (IS_ERR(attach))
 279                 return ERR_PTR(PTR_ERR(attach));
 280
 281         get_dma_buf(dma_buf);
 282
 283         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 284         if (IS_ERR_OR_NULL(sgt)) {
 285                 ret = PTR_ERR(sgt);
 286                 goto fail_detach;
 287         }
 288
 289         obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
 290         if (IS_ERR(obj)) {
 291                 ret = PTR_ERR(obj);
 292                 goto fail_unmap;
 293         }
 294
 295         obj->import_attach = attach;
 296
 297         return obj;
 298
 299 fail_unmap:
 300         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 301 fail_detach:
 302         dma_buf_detach(dma_buf, attach);
 303         dma_buf_put(dma_buf);
 304
 305         return ERR_PTR(ret);
 306 }
 307 EXPORT_SYMBOL(drm_gem_prime_import);
 308
 309 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 310                 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
 311 {
 312         struct dma_buf *dma_buf;
 313         struct drm_gem_object *obj;
 314         int ret;
 315
 316         dma_buf = dma_buf_get(prime_fd);
 317         if (IS_ERR(dma_buf))
 318                 return PTR_ERR(dma_buf);
 319
 320         mutex_lock(&file_priv->prime.lock);
 321
 322         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 323                         dma_buf, handle);
 324         if (!ret) {
 325                 ret = 0;
 326                 goto out_put;
 327         }
 328
 329         /* never seen this one, need to import */
 330         obj = dev->driver->gem_prime_import(dev, dma_buf);
 331         if (IS_ERR(obj)) {
 332                 ret = PTR_ERR(obj);
 333                 goto out_put;
 334         }
 335
 336         ret = drm_gem_handle_create(file_priv, obj, handle);
 337         drm_gem_object_unreference_unlocked(obj);
 338         if (ret)
 339                 goto out_put;
 340
 341         ret = drm_prime_add_buf_handle(&file_priv->prime,
 342                         dma_buf, *handle);
 343         if (ret)
 344                 goto fail;
 345
 346         mutex_unlock(&file_priv->prime.lock);
 347
 348         dma_buf_put(dma_buf);
 349
 350         return 0;
 351
 352 fail:
 353         /* hmm, if driver attached, we are relying on the free-object path
 354          * to detach.. which seems ok..
 355          */
 356         drm_gem_object_handle_unreference_unlocked(obj);
 357 out_put:
 358         dma_buf_put(dma_buf);
 359         mutex_unlock(&file_priv->prime.lock);
 360         return ret;
 361 }
 362 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 363
 364 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 365                                  struct drm_file *file_priv)
 366 {
 367         struct drm_prime_handle *args = data;
 368         uint32_t flags;
 369
 370         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 371                 return -EINVAL;
 372
 373         if (!dev->driver->prime_handle_to_fd)
 374                 return -ENOSYS;
 375
 376         /* check flags are valid */
 377         if (args->flags & ~DRM_CLOEXEC)
 378                 return -EINVAL;
 379
 380         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 381         flags = args->flags & DRM_CLOEXEC;
 382
 383         return dev->driver->prime_handle_to_fd(dev, file_priv,
 384                         args->handle, flags, &args->fd);
 385 }
 386
 387 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 388                                  struct drm_file *file_priv)
 389 {
 390         struct drm_prime_handle *args = data;
 391
 392         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 393                 return -EINVAL;
 394
 395         if (!dev->driver->prime_fd_to_handle)
 396                 return -ENOSYS;
 397
 398         return dev->driver->prime_fd_to_handle(dev, file_priv,
 399                         args->fd, &args->handle);
 400 }
 401
 402 /*
 403  * drm_prime_pages_to_sg
 404  *
 405  * this helper creates an sg table object from a set of pages
 406  * the driver is responsible for mapping the pages into the
 407  * importers address space
 408  */
 409 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 410 {
 411         struct sg_table *sg = NULL;
 412         int ret;
 413
 414         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 415         if (!sg)
 416                 goto out;
 417
 418         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 419                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 420         if (ret)
 421                 goto out;
 422
 423         return sg;
 424 out:
 425         kfree(sg);
 426         return NULL;
 427 }
 428 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 429
 430 /* export an sg table into an array of pages and addresses
 431    this is currently required by the TTM driver in order to do correct fault
 432    handling */
 433 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 434                                      dma_addr_t *addrs, int max_pages)
 435 {
 436         unsigned count;
 437         struct scatterlist *sg;
 438         struct page *page;
 439         u32 len, offset;
 440         int pg_index;
 441         dma_addr_t addr;
 442
 443         pg_index = 0;
 444         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 445                 len = sg->length;
 446                 offset = sg->offset;
 447                 page = sg_page(sg);
 448                 addr = sg_dma_address(sg);
 449
 450                 while (len > 0) {
 451                         if (WARN_ON(pg_index >= max_pages))
 452                                 return -1;
 453                         pages[pg_index] = page;
 454                         if (addrs)
 455                                 addrs[pg_index] = addr;
 456
 457                         page++;
 458                         addr += PAGE_SIZE;
 459                         len -= PAGE_SIZE;
 460                         pg_index++;
 461                 }
 462         }
 463         return 0;
 464 }
 465 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 466 /* helper function to cleanup a GEM/prime object */
 467 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 468 {
 469         struct dma_buf_attachment *attach;
 470         struct dma_buf *dma_buf;
 471         attach = obj->import_attach;
 472         if (sg)
 473                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 474         dma_buf = attach->dmabuf;
 475         dma_buf_detach(attach->dmabuf, attach);
 476         /* remove the reference */
 477         dma_buf_put(dma_buf);
 478 }
 479 EXPORT_SYMBOL(drm_prime_gem_destroy);
 480
 481 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 482 {
 483         INIT_LIST_HEAD(&prime_fpriv->head);
 484         mutex_init(&prime_fpriv->lock);
 485 }
 486 EXPORT_SYMBOL(drm_prime_init_file_private);
 487
 488 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 489 {
 490         /* by now drm_gem_release should've made sure the list is empty */
 491         WARN_ON(!list_empty(&prime_fpriv->head));
 492 }
 493 EXPORT_SYMBOL(drm_prime_destroy_file_private);
 494
 495 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
 496 {
 497         struct drm_prime_member *member;
 498
 499         member = kmalloc(sizeof(*member), GFP_KERNEL);
 500         if (!member)
 501                 return -ENOMEM;
 502
 503         get_dma_buf(dma_buf);
 504         member->dma_buf = dma_buf;
 505         member->handle = handle;
 506         list_add(&member->entry, &prime_fpriv->head);
 507         return 0;
 508 }
 509
 510 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
 511 {
 512         struct drm_prime_member *member;
 513
 514         list_for_each_entry(member, &prime_fpriv->head, entry) {
 515                 if (member->dma_buf == dma_buf) {
 516                         *handle = member->handle;
 517                         return 0;
 518                 }
 519         }
 520         return -ENOENT;
 521 }
 522 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
 523
 524 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
 525 {
 526         struct drm_prime_member *member, *safe;
 527
 528         mutex_lock(&prime_fpriv->lock);
 529         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 530                 if (member->dma_buf == dma_buf) {
 531                         dma_buf_put(dma_buf);
 532                         list_del(&member->entry);
 533                         kfree(member);
 534                 }
 535         }
 536         mutex_unlock(&prime_fpriv->lock);
 537 }
 538 EXPORT_SYMBOL(drm_prime_remove_buf_handle);