drivers/media/common/videobuf2/videobuf2-dma-sg.c

   1 /*
   2  * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  *
   6  * Author: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/mm.h>
  15 #include <linux/refcount.h>
  16 #include <linux/scatterlist.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19 #include <linux/vmalloc.h>
  20
  21 #include <media/videobuf2-v4l2.h>
  22 #include <media/videobuf2-memops.h>
  23 #include <media/videobuf2-dma-sg.h>
  24
  25 static int debug;
  26 module_param(debug, int, 0644);
  27
  28 #define dprintk(level, fmt, arg...)                                     \
  29         do {                                                            \
  30                 if (debug >= level)                                     \
  31                         printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg);  \
  32         } while (0)
  33
  34 struct vb2_dma_sg_buf {
  35         struct device                   *dev;
  36         void                            *vaddr;
  37         struct page                     **pages;
  38         struct frame_vector             *vec;
  39         int                             offset;
  40         enum dma_data_direction         dma_dir;
  41         struct sg_table                 sg_table;
  42         /*
  43          * This will point to sg_table when used with the MMAP or USERPTR
  44          * memory model, and to the dma_buf sglist when used with the
  45          * DMABUF memory model.
  46          */
  47         struct sg_table                 *dma_sgt;
  48         size_t                          size;
  49         unsigned int                    num_pages;
  50         refcount_t                      refcount;
  51         struct vb2_vmarea_handler       handler;
  52
  53         struct dma_buf_attachment       *db_attach;
  54 };
  55
  56 static void vb2_dma_sg_put(void *buf_priv);
  57
  58 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
  59                 gfp_t gfp_flags)
  60 {
  61         unsigned int last_page = 0;
  62         unsigned long size = buf->size;
  63
  64         while (size > 0) {
  65                 struct page *pages;
  66                 int order;
  67                 int i;
  68
  69                 order = get_order(size);
  70                 /* Don't over allocate*/
  71                 if ((PAGE_SIZE << order) > size)
  72                         order--;
  73
  74                 pages = NULL;
  75                 while (!pages) {
  76                         pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
  77                                         __GFP_NOWARN | gfp_flags, order);
  78                         if (pages)
  79                                 break;
  80
  81                         if (order == 0) {
  82                                 while (last_page--)
  83                                         __free_page(buf->pages[last_page]);
  84                                 return -ENOMEM;
  85                         }
  86                         order--;
  87                 }
  88
  89                 split_page(pages, order);
  90                 for (i = 0; i < (1 << order); i++)
  91                         buf->pages[last_page++] = &pages[i];
  92
  93                 size -= PAGE_SIZE << order;
  94         }
  95
  96         return 0;
  97 }
  98
  99 static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
 100                               unsigned long size, enum dma_data_direction dma_dir,
 101                               gfp_t gfp_flags)
 102 {
 103         struct vb2_dma_sg_buf *buf;
 104         struct sg_table *sgt;
 105         int ret;
 106         int num_pages;
 107
 108         if (WARN_ON(!dev))
 109                 return ERR_PTR(-EINVAL);
 110
 111         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 112         if (!buf)
 113                 return ERR_PTR(-ENOMEM);
 114
 115         buf->vaddr = NULL;
 116         buf->dma_dir = dma_dir;
 117         buf->offset = 0;
 118         buf->size = size;
 119         /* size is already page aligned */
 120         buf->num_pages = size >> PAGE_SHIFT;
 121         buf->dma_sgt = &buf->sg_table;
 122
 123         /*
 124          * NOTE: dma-sg allocates memory using the page allocator directly, so
 125          * there is no memory consistency guarantee, hence dma-sg ignores DMA
 126          * attributes passed from the upper layer.
 127          */
 128         buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *),
 129                                     GFP_KERNEL | __GFP_ZERO);
 130         if (!buf->pages)
 131                 goto fail_pages_array_alloc;
 132
 133         ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
 134         if (ret)
 135                 goto fail_pages_alloc;
 136
 137         ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 138                         buf->num_pages, 0, size, GFP_KERNEL);
 139         if (ret)
 140                 goto fail_table_alloc;
 141
 142         /* Prevent the device from being released while the buffer is used */
 143         buf->dev = get_device(dev);
 144
 145         sgt = &buf->sg_table;
 146         /*
 147          * No need to sync to the device, this will happen later when the
 148          * prepare() memop is called.
 149          */
 150         if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
 151                             DMA_ATTR_SKIP_CPU_SYNC))
 152                 goto fail_map;
 153
 154         buf->handler.refcount = &buf->refcount;
 155         buf->handler.put = vb2_dma_sg_put;
 156         buf->handler.arg = buf;
 157
 158         refcount_set(&buf->refcount, 1);
 159
 160         dprintk(1, "%s: Allocated buffer of %d pages\n",
 161                 __func__, buf->num_pages);
 162         return buf;
 163
 164 fail_map:
 165         put_device(buf->dev);
 166         sg_free_table(buf->dma_sgt);
 167 fail_table_alloc:
 168         num_pages = buf->num_pages;
 169         while (num_pages--)
 170                 __free_page(buf->pages[num_pages]);
 171 fail_pages_alloc:
 172         kvfree(buf->pages);
 173 fail_pages_array_alloc:
 174         kfree(buf);
 175         return ERR_PTR(-ENOMEM);
 176 }
 177
 178 static void vb2_dma_sg_put(void *buf_priv)
 179 {
 180         struct vb2_dma_sg_buf *buf = buf_priv;
 181         struct sg_table *sgt = &buf->sg_table;
 182         int i = buf->num_pages;
 183
 184         if (refcount_dec_and_test(&buf->refcount)) {
 185                 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
 186                         buf->num_pages);
 187                 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,
 188                                   DMA_ATTR_SKIP_CPU_SYNC);
 189                 if (buf->vaddr)
 190                         vm_unmap_ram(buf->vaddr, buf->num_pages);
 191                 sg_free_table(buf->dma_sgt);
 192                 while (--i >= 0)
 193                         __free_page(buf->pages[i]);
 194                 kvfree(buf->pages);
 195                 put_device(buf->dev);
 196                 kfree(buf);
 197         }
 198 }
 199
 200 static void vb2_dma_sg_prepare(void *buf_priv)
 201 {
 202         struct vb2_dma_sg_buf *buf = buf_priv;
 203         struct sg_table *sgt = buf->dma_sgt;
 204
 205         dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
 206 }
 207
 208 static void vb2_dma_sg_finish(void *buf_priv)
 209 {
 210         struct vb2_dma_sg_buf *buf = buf_priv;
 211         struct sg_table *sgt = buf->dma_sgt;
 212
 213         dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
 214 }
 215
 216 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
 217                                     unsigned long size,
 218                                     enum dma_data_direction dma_dir)
 219 {
 220         struct vb2_dma_sg_buf *buf;
 221         struct sg_table *sgt;
 222         struct frame_vector *vec;
 223
 224         if (WARN_ON(!dev))
 225                 return ERR_PTR(-EINVAL);
 226
 227         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 228         if (!buf)
 229                 return ERR_PTR(-ENOMEM);
 230
 231         buf->vaddr = NULL;
 232         buf->dev = dev;
 233         buf->dma_dir = dma_dir;
 234         buf->offset = vaddr & ~PAGE_MASK;
 235         buf->size = size;
 236         buf->dma_sgt = &buf->sg_table;
 237         vec = vb2_create_framevec(vaddr, size);
 238         if (IS_ERR(vec))
 239                 goto userptr_fail_pfnvec;
 240         buf->vec = vec;
 241
 242         buf->pages = frame_vector_pages(vec);
 243         if (IS_ERR(buf->pages))
 244                 goto userptr_fail_sgtable;
 245         buf->num_pages = frame_vector_count(vec);
 246
 247         if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 248                         buf->num_pages, buf->offset, size, 0))
 249                 goto userptr_fail_sgtable;
 250
 251         sgt = &buf->sg_table;
 252         /*
 253          * No need to sync to the device, this will happen later when the
 254          * prepare() memop is called.
 255          */
 256         if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
 257                             DMA_ATTR_SKIP_CPU_SYNC))
 258                 goto userptr_fail_map;
 259
 260         return buf;
 261
 262 userptr_fail_map:
 263         sg_free_table(&buf->sg_table);
 264 userptr_fail_sgtable:
 265         vb2_destroy_framevec(vec);
 266 userptr_fail_pfnvec:
 267         kfree(buf);
 268         return ERR_PTR(-ENOMEM);
 269 }
 270
 271 /*
 272  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
 273  *               be used
 274  */
 275 static void vb2_dma_sg_put_userptr(void *buf_priv)
 276 {
 277         struct vb2_dma_sg_buf *buf = buf_priv;
 278         struct sg_table *sgt = &buf->sg_table;
 279         int i = buf->num_pages;
 280
 281         dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
 282                __func__, buf->num_pages);
 283         dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 284         if (buf->vaddr)
 285                 vm_unmap_ram(buf->vaddr, buf->num_pages);
 286         sg_free_table(buf->dma_sgt);
 287         if (buf->dma_dir == DMA_FROM_DEVICE ||
 288             buf->dma_dir == DMA_BIDIRECTIONAL)
 289                 while (--i >= 0)
 290                         set_page_dirty_lock(buf->pages[i]);
 291         vb2_destroy_framevec(buf->vec);
 292         kfree(buf);
 293 }
 294
 295 static void *vb2_dma_sg_vaddr(void *buf_priv)
 296 {
 297         struct vb2_dma_sg_buf *buf = buf_priv;
 298         struct dma_buf_map map;
 299         int ret;
 300
 301         BUG_ON(!buf);
 302
 303         if (!buf->vaddr) {
 304                 if (buf->db_attach) {
 305                         ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
 306                         buf->vaddr = ret ? NULL : map.vaddr;
 307                 } else {
 308                         buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1);
 309                 }
 310         }
 311
 312         /* add offset in case userptr is not page-aligned */
 313         return buf->vaddr ? buf->vaddr + buf->offset : NULL;
 314 }
 315
 316 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
 317 {
 318         struct vb2_dma_sg_buf *buf = buf_priv;
 319
 320         return refcount_read(&buf->refcount);
 321 }
 322
 323 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
 324 {
 325         struct vb2_dma_sg_buf *buf = buf_priv;
 326         int err;
 327
 328         if (!buf) {
 329                 printk(KERN_ERR "No memory to map\n");
 330                 return -EINVAL;
 331         }
 332
 333         err = vm_map_pages(vma, buf->pages, buf->num_pages);
 334         if (err) {
 335                 printk(KERN_ERR "Remapping memory, error: %d\n", err);
 336                 return err;
 337         }
 338
 339         /*
 340          * Use common vm_area operations to track buffer refcount.
 341          */
 342         vma->vm_private_data    = &buf->handler;
 343         vma->vm_ops             = &vb2_common_vm_ops;
 344
 345         vma->vm_ops->open(vma);
 346
 347         return 0;
 348 }
 349
 350 /*********************************************/
 351 /*         DMABUF ops for exporters          */
 352 /*********************************************/
 353
 354 struct vb2_dma_sg_attachment {
 355         struct sg_table sgt;
 356         enum dma_data_direction dma_dir;
 357 };
 358
 359 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf,
 360         struct dma_buf_attachment *dbuf_attach)
 361 {
 362         struct vb2_dma_sg_attachment *attach;
 363         unsigned int i;
 364         struct scatterlist *rd, *wr;
 365         struct sg_table *sgt;
 366         struct vb2_dma_sg_buf *buf = dbuf->priv;
 367         int ret;
 368
 369         attach = kzalloc(sizeof(*attach), GFP_KERNEL);
 370         if (!attach)
 371                 return -ENOMEM;
 372
 373         sgt = &attach->sgt;
 374         /* Copy the buf->base_sgt scatter list to the attachment, as we can't
 375          * map the same scatter list to multiple attachments at the same time.
 376          */
 377         ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
 378         if (ret) {
 379                 kfree(attach);
 380                 return -ENOMEM;
 381         }
 382
 383         rd = buf->dma_sgt->sgl;
 384         wr = sgt->sgl;
 385         for (i = 0; i < sgt->orig_nents; ++i) {
 386                 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
 387                 rd = sg_next(rd);
 388                 wr = sg_next(wr);
 389         }
 390
 391         attach->dma_dir = DMA_NONE;
 392         dbuf_attach->priv = attach;
 393
 394         return 0;
 395 }
 396
 397 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
 398         struct dma_buf_attachment *db_attach)
 399 {
 400         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 401         struct sg_table *sgt;
 402
 403         if (!attach)
 404                 return;
 405
 406         sgt = &attach->sgt;
 407
 408         /* release the scatterlist cache */
 409         if (attach->dma_dir != DMA_NONE)
 410                 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
 411         sg_free_table(sgt);
 412         kfree(attach);
 413         db_attach->priv = NULL;
 414 }
 415
 416 static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
 417         struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
 418 {
 419         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 420         /* stealing dmabuf mutex to serialize map/unmap operations */
 421         struct mutex *lock = &db_attach->dmabuf->lock;
 422         struct sg_table *sgt;
 423
 424         mutex_lock(lock);
 425
 426         sgt = &attach->sgt;
 427         /* return previously mapped sg table */
 428         if (attach->dma_dir == dma_dir) {
 429                 mutex_unlock(lock);
 430                 return sgt;
 431         }
 432
 433         /* release any previous cache */
 434         if (attach->dma_dir != DMA_NONE) {
 435                 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
 436                 attach->dma_dir = DMA_NONE;
 437         }
 438
 439         /* mapping to the client with new direction */
 440         if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
 441                 pr_err("failed to map scatterlist\n");
 442                 mutex_unlock(lock);
 443                 return ERR_PTR(-EIO);
 444         }
 445
 446         attach->dma_dir = dma_dir;
 447
 448         mutex_unlock(lock);
 449
 450         return sgt;
 451 }
 452
 453 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 454         struct sg_table *sgt, enum dma_data_direction dma_dir)
 455 {
 456         /* nothing to be done here */
 457 }
 458
 459 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
 460 {
 461         /* drop reference obtained in vb2_dma_sg_get_dmabuf */
 462         vb2_dma_sg_put(dbuf->priv);
 463 }
 464
 465 static int
 466 vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
 467                                        enum dma_data_direction direction)
 468 {
 469         struct vb2_dma_sg_buf *buf = dbuf->priv;
 470         struct sg_table *sgt = buf->dma_sgt;
 471
 472         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 473         return 0;
 474 }
 475
 476 static int
 477 vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
 478                                      enum dma_data_direction direction)
 479 {
 480         struct vb2_dma_sg_buf *buf = dbuf->priv;
 481         struct sg_table *sgt = buf->dma_sgt;
 482
 483         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 484         return 0;
 485 }
 486
 487 static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
 488 {
 489         struct vb2_dma_sg_buf *buf = dbuf->priv;
 490
 491         dma_buf_map_set_vaddr(map, buf->vaddr);
 492
 493         return 0;
 494 }
 495
 496 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
 497         struct vm_area_struct *vma)
 498 {
 499         return vb2_dma_sg_mmap(dbuf->priv, vma);
 500 }
 501
 502 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
 503         .attach = vb2_dma_sg_dmabuf_ops_attach,
 504         .detach = vb2_dma_sg_dmabuf_ops_detach,
 505         .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
 506         .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
 507         .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access,
 508         .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access,
 509         .vmap = vb2_dma_sg_dmabuf_ops_vmap,
 510         .mmap = vb2_dma_sg_dmabuf_ops_mmap,
 511         .release = vb2_dma_sg_dmabuf_ops_release,
 512 };
 513
 514 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
 515 {
 516         struct vb2_dma_sg_buf *buf = buf_priv;
 517         struct dma_buf *dbuf;
 518         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 519
 520         exp_info.ops = &vb2_dma_sg_dmabuf_ops;
 521         exp_info.size = buf->size;
 522         exp_info.flags = flags;
 523         exp_info.priv = buf;
 524
 525         if (WARN_ON(!buf->dma_sgt))
 526                 return NULL;
 527
 528         dbuf = dma_buf_export(&exp_info);
 529         if (IS_ERR(dbuf))
 530                 return NULL;
 531
 532         /* dmabuf keeps reference to vb2 buffer */
 533         refcount_inc(&buf->refcount);
 534
 535         return dbuf;
 536 }
 537
 538 /*********************************************/
 539 /*       callbacks for DMABUF buffers        */
 540 /*********************************************/
 541
 542 static int vb2_dma_sg_map_dmabuf(void *mem_priv)
 543 {
 544         struct vb2_dma_sg_buf *buf = mem_priv;
 545         struct sg_table *sgt;
 546
 547         if (WARN_ON(!buf->db_attach)) {
 548                 pr_err("trying to pin a non attached buffer\n");
 549                 return -EINVAL;
 550         }
 551
 552         if (WARN_ON(buf->dma_sgt)) {
 553                 pr_err("dmabuf buffer is already pinned\n");
 554                 return 0;
 555         }
 556
 557         /* get the associated scatterlist for this buffer */
 558         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 559         if (IS_ERR(sgt)) {
 560                 pr_err("Error getting dmabuf scatterlist\n");
 561                 return -EINVAL;
 562         }
 563
 564         buf->dma_sgt = sgt;
 565         buf->vaddr = NULL;
 566
 567         return 0;
 568 }
 569
 570 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
 571 {
 572         struct vb2_dma_sg_buf *buf = mem_priv;
 573         struct sg_table *sgt = buf->dma_sgt;
 574         struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(buf->vaddr);
 575
 576         if (WARN_ON(!buf->db_attach)) {
 577                 pr_err("trying to unpin a not attached buffer\n");
 578                 return;
 579         }
 580
 581         if (WARN_ON(!sgt)) {
 582                 pr_err("dmabuf buffer is already unpinned\n");
 583                 return;
 584         }
 585
 586         if (buf->vaddr) {
 587                 dma_buf_vunmap(buf->db_attach->dmabuf, &map);
 588                 buf->vaddr = NULL;
 589         }
 590         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 591
 592         buf->dma_sgt = NULL;
 593 }
 594
 595 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
 596 {
 597         struct vb2_dma_sg_buf *buf = mem_priv;
 598
 599         /* if vb2 works correctly you should never detach mapped buffer */
 600         if (WARN_ON(buf->dma_sgt))
 601                 vb2_dma_sg_unmap_dmabuf(buf);
 602
 603         /* detach this attachment */
 604         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 605         kfree(buf);
 606 }
 607
 608 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
 609         unsigned long size, enum dma_data_direction dma_dir)
 610 {
 611         struct vb2_dma_sg_buf *buf;
 612         struct dma_buf_attachment *dba;
 613
 614         if (WARN_ON(!dev))
 615                 return ERR_PTR(-EINVAL);
 616
 617         if (dbuf->size < size)
 618                 return ERR_PTR(-EFAULT);
 619
 620         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 621         if (!buf)
 622                 return ERR_PTR(-ENOMEM);
 623
 624         buf->dev = dev;
 625         /* create attachment for the dmabuf with the user device */
 626         dba = dma_buf_attach(dbuf, buf->dev);
 627         if (IS_ERR(dba)) {
 628                 pr_err("failed to attach dmabuf\n");
 629                 kfree(buf);
 630                 return dba;
 631         }
 632
 633         buf->dma_dir = dma_dir;
 634         buf->size = size;
 635         buf->db_attach = dba;
 636
 637         return buf;
 638 }
 639
 640 static void *vb2_dma_sg_cookie(void *buf_priv)
 641 {
 642         struct vb2_dma_sg_buf *buf = buf_priv;
 643
 644         return buf->dma_sgt;
 645 }
 646
 647 const struct vb2_mem_ops vb2_dma_sg_memops = {
 648         .alloc          = vb2_dma_sg_alloc,
 649         .put            = vb2_dma_sg_put,
 650         .get_userptr    = vb2_dma_sg_get_userptr,
 651         .put_userptr    = vb2_dma_sg_put_userptr,
 652         .prepare        = vb2_dma_sg_prepare,
 653         .finish         = vb2_dma_sg_finish,
 654         .vaddr          = vb2_dma_sg_vaddr,
 655         .mmap           = vb2_dma_sg_mmap,
 656         .num_users      = vb2_dma_sg_num_users,
 657         .get_dmabuf     = vb2_dma_sg_get_dmabuf,
 658         .map_dmabuf     = vb2_dma_sg_map_dmabuf,
 659         .unmap_dmabuf   = vb2_dma_sg_unmap_dmabuf,
 660         .attach_dmabuf  = vb2_dma_sg_attach_dmabuf,
 661         .detach_dmabuf  = vb2_dma_sg_detach_dmabuf,
 662         .cookie         = vb2_dma_sg_cookie,
 663 };
 664 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
 665
 666 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
 667 MODULE_AUTHOR("Andrzej Pietrasiewicz");
 668 MODULE_LICENSE("GPL");