drivers/media/v4l2-core/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 <andrzej.p@samsung.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/scatterlist.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/vmalloc.h>
  19
  20 #include <media/videobuf2-v4l2.h>
  21 #include <media/videobuf2-memops.h>
  22 #include <media/videobuf2-dma-sg.h>
  23
  24 static int debug;
  25 module_param(debug, int, 0644);
  26
  27 #define dprintk(level, fmt, arg...)                                     \
  28         do {                                                            \
  29                 if (debug >= level)                                     \
  30                         printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg);  \
  31         } while (0)
  32
  33 struct vb2_dma_sg_buf {
  34         struct device                   *dev;
  35         void                            *vaddr;
  36         struct page                     **pages;
  37         struct frame_vector             *vec;
  38         int                             offset;
  39         enum dma_data_direction         dma_dir;
  40         struct sg_table                 sg_table;
  41         /*
  42          * This will point to sg_table when used with the MMAP or USERPTR
  43          * memory model, and to the dma_buf sglist when used with the
  44          * DMABUF memory model.
  45          */
  46         struct sg_table                 *dma_sgt;
  47         size_t                          size;
  48         unsigned int                    num_pages;
  49         atomic_t                        refcount;
  50         struct vb2_vmarea_handler       handler;
  51
  52         struct dma_buf_attachment       *db_attach;
  53 };
  54
  55 static void vb2_dma_sg_put(void *buf_priv);
  56
  57 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
  58                 gfp_t gfp_flags)
  59 {
  60         unsigned int last_page = 0;
  61         int size = buf->size;
  62
  63         while (size > 0) {
  64                 struct page *pages;
  65                 int order;
  66                 int i;
  67
  68                 order = get_order(size);
  69                 /* Dont over allocate*/
  70                 if ((PAGE_SIZE << order) > size)
  71                         order--;
  72
  73                 pages = NULL;
  74                 while (!pages) {
  75                         pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
  76                                         __GFP_NOWARN | gfp_flags, order);
  77                         if (pages)
  78                                 break;
  79
  80                         if (order == 0) {
  81                                 while (last_page--)
  82                                         __free_page(buf->pages[last_page]);
  83                                 return -ENOMEM;
  84                         }
  85                         order--;
  86                 }
  87
  88                 split_page(pages, order);
  89                 for (i = 0; i < (1 << order); i++)
  90                         buf->pages[last_page++] = &pages[i];
  91
  92                 size -= PAGE_SIZE << order;
  93         }
  94
  95         return 0;
  96 }
  97
  98 static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
  99                               unsigned long size, enum dma_data_direction dma_dir,
 100                               gfp_t gfp_flags)
 101 {
 102         struct vb2_dma_sg_buf *buf;
 103         struct sg_table *sgt;
 104         int ret;
 105         int num_pages;
 106
 107         if (WARN_ON(!dev))
 108                 return ERR_PTR(-EINVAL);
 109
 110         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 111         if (!buf)
 112                 return ERR_PTR(-ENOMEM);
 113
 114         buf->vaddr = NULL;
 115         buf->dma_dir = dma_dir;
 116         buf->offset = 0;
 117         buf->size = size;
 118         /* size is already page aligned */
 119         buf->num_pages = size >> PAGE_SHIFT;
 120         buf->dma_sgt = &buf->sg_table;
 121
 122         buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
 123                              GFP_KERNEL);
 124         if (!buf->pages)
 125                 goto fail_pages_array_alloc;
 126
 127         ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
 128         if (ret)
 129                 goto fail_pages_alloc;
 130
 131         ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 132                         buf->num_pages, 0, size, GFP_KERNEL);
 133         if (ret)
 134                 goto fail_table_alloc;
 135
 136         /* Prevent the device from being released while the buffer is used */
 137         buf->dev = get_device(dev);
 138
 139         sgt = &buf->sg_table;
 140         /*
 141          * No need to sync to the device, this will happen later when the
 142          * prepare() memop is called.
 143          */
 144         sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 145                                       buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 146         if (!sgt->nents)
 147                 goto fail_map;
 148
 149         buf->handler.refcount = &buf->refcount;
 150         buf->handler.put = vb2_dma_sg_put;
 151         buf->handler.arg = buf;
 152
 153         atomic_inc(&buf->refcount);
 154
 155         dprintk(1, "%s: Allocated buffer of %d pages\n",
 156                 __func__, buf->num_pages);
 157         return buf;
 158
 159 fail_map:
 160         put_device(buf->dev);
 161         sg_free_table(buf->dma_sgt);
 162 fail_table_alloc:
 163         num_pages = buf->num_pages;
 164         while (num_pages--)
 165                 __free_page(buf->pages[num_pages]);
 166 fail_pages_alloc:
 167         kfree(buf->pages);
 168 fail_pages_array_alloc:
 169         kfree(buf);
 170         return ERR_PTR(-ENOMEM);
 171 }
 172
 173 static void vb2_dma_sg_put(void *buf_priv)
 174 {
 175         struct vb2_dma_sg_buf *buf = buf_priv;
 176         struct sg_table *sgt = &buf->sg_table;
 177         int i = buf->num_pages;
 178
 179         if (atomic_dec_and_test(&buf->refcount)) {
 180                 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
 181                         buf->num_pages);
 182                 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 183                                    buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 184                 if (buf->vaddr)
 185                         vm_unmap_ram(buf->vaddr, buf->num_pages);
 186                 sg_free_table(buf->dma_sgt);
 187                 while (--i >= 0)
 188                         __free_page(buf->pages[i]);
 189                 kfree(buf->pages);
 190                 put_device(buf->dev);
 191                 kfree(buf);
 192         }
 193 }
 194
 195 static void vb2_dma_sg_prepare(void *buf_priv)
 196 {
 197         struct vb2_dma_sg_buf *buf = buf_priv;
 198         struct sg_table *sgt = buf->dma_sgt;
 199
 200         /* DMABUF exporter will flush the cache for us */
 201         if (buf->db_attach)
 202                 return;
 203
 204         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
 205                                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         /* DMABUF exporter will flush the cache for us */
 214         if (buf->db_attach)
 215                 return;
 216
 217         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 218 }
 219
 220 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
 221                                     unsigned long size,
 222                                     enum dma_data_direction dma_dir)
 223 {
 224         struct vb2_dma_sg_buf *buf;
 225         struct sg_table *sgt;
 226         struct frame_vector *vec;
 227
 228         if (WARN_ON(!dev))
 229                 return ERR_PTR(-EINVAL);
 230
 231         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 232         if (!buf)
 233                 return ERR_PTR(-ENOMEM);
 234
 235         buf->vaddr = NULL;
 236         buf->dev = dev;
 237         buf->dma_dir = dma_dir;
 238         buf->offset = vaddr & ~PAGE_MASK;
 239         buf->size = size;
 240         buf->dma_sgt = &buf->sg_table;
 241         vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE);
 242         if (IS_ERR(vec))
 243                 goto userptr_fail_pfnvec;
 244         buf->vec = vec;
 245
 246         buf->pages = frame_vector_pages(vec);
 247         if (IS_ERR(buf->pages))
 248                 goto userptr_fail_sgtable;
 249         buf->num_pages = frame_vector_count(vec);
 250
 251         if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 252                         buf->num_pages, buf->offset, size, 0))
 253                 goto userptr_fail_sgtable;
 254
 255         sgt = &buf->sg_table;
 256         /*
 257          * No need to sync to the device, this will happen later when the
 258          * prepare() memop is called.
 259          */
 260         sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 261                                       buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 262         if (!sgt->nents)
 263                 goto userptr_fail_map;
 264
 265         return buf;
 266
 267 userptr_fail_map:
 268         sg_free_table(&buf->sg_table);
 269 userptr_fail_sgtable:
 270         vb2_destroy_framevec(vec);
 271 userptr_fail_pfnvec:
 272         kfree(buf);
 273         return ERR_PTR(-ENOMEM);
 274 }
 275
 276 /*
 277  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
 278  *               be used
 279  */
 280 static void vb2_dma_sg_put_userptr(void *buf_priv)
 281 {
 282         struct vb2_dma_sg_buf *buf = buf_priv;
 283         struct sg_table *sgt = &buf->sg_table;
 284         int i = buf->num_pages;
 285
 286         dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
 287                __func__, buf->num_pages);
 288         dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
 289                            DMA_ATTR_SKIP_CPU_SYNC);
 290         if (buf->vaddr)
 291                 vm_unmap_ram(buf->vaddr, buf->num_pages);
 292         sg_free_table(buf->dma_sgt);
 293         while (--i >= 0) {
 294                 if (buf->dma_dir == DMA_FROM_DEVICE)
 295                         set_page_dirty_lock(buf->pages[i]);
 296         }
 297         vb2_destroy_framevec(buf->vec);
 298         kfree(buf);
 299 }
 300
 301 static void *vb2_dma_sg_vaddr(void *buf_priv)
 302 {
 303         struct vb2_dma_sg_buf *buf = buf_priv;
 304
 305         BUG_ON(!buf);
 306
 307         if (!buf->vaddr) {
 308                 if (buf->db_attach)
 309                         buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
 310                 else
 311                         buf->vaddr = vm_map_ram(buf->pages,
 312                                         buf->num_pages, -1, PAGE_KERNEL);
 313         }
 314
 315         /* add offset in case userptr is not page-aligned */
 316         return buf->vaddr ? buf->vaddr + buf->offset : NULL;
 317 }
 318
 319 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
 320 {
 321         struct vb2_dma_sg_buf *buf = buf_priv;
 322
 323         return atomic_read(&buf->refcount);
 324 }
 325
 326 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
 327 {
 328         struct vb2_dma_sg_buf *buf = buf_priv;
 329         unsigned long uaddr = vma->vm_start;
 330         unsigned long usize = vma->vm_end - vma->vm_start;
 331         int i = 0;
 332
 333         if (!buf) {
 334                 printk(KERN_ERR "No memory to map\n");
 335                 return -EINVAL;
 336         }
 337
 338         do {
 339                 int ret;
 340
 341                 ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
 342                 if (ret) {
 343                         printk(KERN_ERR "Remapping memory, error: %d\n", ret);
 344                         return ret;
 345                 }
 346
 347                 uaddr += PAGE_SIZE;
 348                 usize -= PAGE_SIZE;
 349         } while (usize > 0);
 350
 351
 352         /*
 353          * Use common vm_area operations to track buffer refcount.
 354          */
 355         vma->vm_private_data    = &buf->handler;
 356         vma->vm_ops             = &vb2_common_vm_ops;
 357
 358         vma->vm_ops->open(vma);
 359
 360         return 0;
 361 }
 362
 363 /*********************************************/
 364 /*         DMABUF ops for exporters          */
 365 /*********************************************/
 366
 367 struct vb2_dma_sg_attachment {
 368         struct sg_table sgt;
 369         enum dma_data_direction dma_dir;
 370 };
 371
 372 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
 373         struct dma_buf_attachment *dbuf_attach)
 374 {
 375         struct vb2_dma_sg_attachment *attach;
 376         unsigned int i;
 377         struct scatterlist *rd, *wr;
 378         struct sg_table *sgt;
 379         struct vb2_dma_sg_buf *buf = dbuf->priv;
 380         int ret;
 381
 382         attach = kzalloc(sizeof(*attach), GFP_KERNEL);
 383         if (!attach)
 384                 return -ENOMEM;
 385
 386         sgt = &attach->sgt;
 387         /* Copy the buf->base_sgt scatter list to the attachment, as we can't
 388          * map the same scatter list to multiple attachments at the same time.
 389          */
 390         ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
 391         if (ret) {
 392                 kfree(attach);
 393                 return -ENOMEM;
 394         }
 395
 396         rd = buf->dma_sgt->sgl;
 397         wr = sgt->sgl;
 398         for (i = 0; i < sgt->orig_nents; ++i) {
 399                 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
 400                 rd = sg_next(rd);
 401                 wr = sg_next(wr);
 402         }
 403
 404         attach->dma_dir = DMA_NONE;
 405         dbuf_attach->priv = attach;
 406
 407         return 0;
 408 }
 409
 410 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
 411         struct dma_buf_attachment *db_attach)
 412 {
 413         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 414         struct sg_table *sgt;
 415
 416         if (!attach)
 417                 return;
 418
 419         sgt = &attach->sgt;
 420
 421         /* release the scatterlist cache */
 422         if (attach->dma_dir != DMA_NONE)
 423                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 424                         attach->dma_dir);
 425         sg_free_table(sgt);
 426         kfree(attach);
 427         db_attach->priv = NULL;
 428 }
 429
 430 static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
 431         struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
 432 {
 433         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 434         /* stealing dmabuf mutex to serialize map/unmap operations */
 435         struct mutex *lock = &db_attach->dmabuf->lock;
 436         struct sg_table *sgt;
 437
 438         mutex_lock(lock);
 439
 440         sgt = &attach->sgt;
 441         /* return previously mapped sg table */
 442         if (attach->dma_dir == dma_dir) {
 443                 mutex_unlock(lock);
 444                 return sgt;
 445         }
 446
 447         /* release any previous cache */
 448         if (attach->dma_dir != DMA_NONE) {
 449                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 450                         attach->dma_dir);
 451                 attach->dma_dir = DMA_NONE;
 452         }
 453
 454         /* mapping to the client with new direction */
 455         sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 456                                 dma_dir);
 457         if (!sgt->nents) {
 458                 pr_err("failed to map scatterlist\n");
 459                 mutex_unlock(lock);
 460                 return ERR_PTR(-EIO);
 461         }
 462
 463         attach->dma_dir = dma_dir;
 464
 465         mutex_unlock(lock);
 466
 467         return sgt;
 468 }
 469
 470 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 471         struct sg_table *sgt, enum dma_data_direction dma_dir)
 472 {
 473         /* nothing to be done here */
 474 }
 475
 476 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
 477 {
 478         /* drop reference obtained in vb2_dma_sg_get_dmabuf */
 479         vb2_dma_sg_put(dbuf->priv);
 480 }
 481
 482 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
 483 {
 484         struct vb2_dma_sg_buf *buf = dbuf->priv;
 485
 486         return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
 487 }
 488
 489 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
 490 {
 491         struct vb2_dma_sg_buf *buf = dbuf->priv;
 492
 493         return vb2_dma_sg_vaddr(buf);
 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 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         .kmap = vb2_dma_sg_dmabuf_ops_kmap,
 508         .kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
 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         atomic_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
 575         if (WARN_ON(!buf->db_attach)) {
 576                 pr_err("trying to unpin a not attached buffer\n");
 577                 return;
 578         }
 579
 580         if (WARN_ON(!sgt)) {
 581                 pr_err("dmabuf buffer is already unpinned\n");
 582                 return;
 583         }
 584
 585         if (buf->vaddr) {
 586                 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
 587                 buf->vaddr = NULL;
 588         }
 589         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 590
 591         buf->dma_sgt = NULL;
 592 }
 593
 594 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
 595 {
 596         struct vb2_dma_sg_buf *buf = mem_priv;
 597
 598         /* if vb2 works correctly you should never detach mapped buffer */
 599         if (WARN_ON(buf->dma_sgt))
 600                 vb2_dma_sg_unmap_dmabuf(buf);
 601
 602         /* detach this attachment */
 603         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 604         kfree(buf);
 605 }
 606
 607 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
 608         unsigned long size, enum dma_data_direction dma_dir)
 609 {
 610         struct vb2_dma_sg_buf *buf;
 611         struct dma_buf_attachment *dba;
 612
 613         if (WARN_ON(!dev))
 614                 return ERR_PTR(-EINVAL);
 615
 616         if (dbuf->size < size)
 617                 return ERR_PTR(-EFAULT);
 618
 619         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 620         if (!buf)
 621                 return ERR_PTR(-ENOMEM);
 622
 623         buf->dev = dev;
 624         /* create attachment for the dmabuf with the user device */
 625         dba = dma_buf_attach(dbuf, buf->dev);
 626         if (IS_ERR(dba)) {
 627                 pr_err("failed to attach dmabuf\n");
 628                 kfree(buf);
 629                 return dba;
 630         }
 631
 632         buf->dma_dir = dma_dir;
 633         buf->size = size;
 634         buf->db_attach = dba;
 635
 636         return buf;
 637 }
 638
 639 static void *vb2_dma_sg_cookie(void *buf_priv)
 640 {
 641         struct vb2_dma_sg_buf *buf = buf_priv;
 642
 643         return buf->dma_sgt;
 644 }
 645
 646 const struct vb2_mem_ops vb2_dma_sg_memops = {
 647         .alloc          = vb2_dma_sg_alloc,
 648         .put            = vb2_dma_sg_put,
 649         .get_userptr    = vb2_dma_sg_get_userptr,
 650         .put_userptr    = vb2_dma_sg_put_userptr,
 651         .prepare        = vb2_dma_sg_prepare,
 652         .finish         = vb2_dma_sg_finish,
 653         .vaddr          = vb2_dma_sg_vaddr,
 654         .mmap           = vb2_dma_sg_mmap,
 655         .num_users      = vb2_dma_sg_num_users,
 656         .get_dmabuf     = vb2_dma_sg_get_dmabuf,
 657         .map_dmabuf     = vb2_dma_sg_map_dmabuf,
 658         .unmap_dmabuf   = vb2_dma_sg_unmap_dmabuf,
 659         .attach_dmabuf  = vb2_dma_sg_attach_dmabuf,
 660         .detach_dmabuf  = vb2_dma_sg_detach_dmabuf,
 661         .cookie         = vb2_dma_sg_cookie,
 662 };
 663 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
 664
 665 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
 666 MODULE_AUTHOR("Andrzej Pietrasiewicz");
 667 MODULE_LICENSE("GPL");