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, const struct dma_attrs *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         DEFINE_DMA_ATTRS(attrs);
 107
 108         dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 109
 110         if (WARN_ON(dev == NULL))
 111                 return NULL;
 112         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 113         if (!buf)
 114                 return NULL;
 115
 116         buf->vaddr = NULL;
 117         buf->dma_dir = dma_dir;
 118         buf->offset = 0;
 119         buf->size = size;
 120         /* size is already page aligned */
 121         buf->num_pages = size >> PAGE_SHIFT;
 122         buf->dma_sgt = &buf->sg_table;
 123
 124         buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
 125                              GFP_KERNEL);
 126         if (!buf->pages)
 127                 goto fail_pages_array_alloc;
 128
 129         ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
 130         if (ret)
 131                 goto fail_pages_alloc;
 132
 133         ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 134                         buf->num_pages, 0, size, GFP_KERNEL);
 135         if (ret)
 136                 goto fail_table_alloc;
 137
 138         /* Prevent the device from being released while the buffer is used */
 139         buf->dev = get_device(dev);
 140
 141         sgt = &buf->sg_table;
 142         /*
 143          * No need to sync to the device, this will happen later when the
 144          * prepare() memop is called.
 145          */
 146         sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 147                                       buf->dma_dir, &attrs);
 148         if (!sgt->nents)
 149                 goto fail_map;
 150
 151         buf->handler.refcount = &buf->refcount;
 152         buf->handler.put = vb2_dma_sg_put;
 153         buf->handler.arg = buf;
 154
 155         atomic_inc(&buf->refcount);
 156
 157         dprintk(1, "%s: Allocated buffer of %d pages\n",
 158                 __func__, buf->num_pages);
 159         return buf;
 160
 161 fail_map:
 162         put_device(buf->dev);
 163         sg_free_table(buf->dma_sgt);
 164 fail_table_alloc:
 165         num_pages = buf->num_pages;
 166         while (num_pages--)
 167                 __free_page(buf->pages[num_pages]);
 168 fail_pages_alloc:
 169         kfree(buf->pages);
 170 fail_pages_array_alloc:
 171         kfree(buf);
 172         return NULL;
 173 }
 174
 175 static void vb2_dma_sg_put(void *buf_priv)
 176 {
 177         struct vb2_dma_sg_buf *buf = buf_priv;
 178         struct sg_table *sgt = &buf->sg_table;
 179         int i = buf->num_pages;
 180
 181         if (atomic_dec_and_test(&buf->refcount)) {
 182                 DEFINE_DMA_ATTRS(attrs);
 183
 184                 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 185                 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
 186                         buf->num_pages);
 187                 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 188                                    buf->dma_dir, &attrs);
 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                 kfree(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         /* DMABUF exporter will flush the cache for us */
 206         if (buf->db_attach)
 207                 return;
 208
 209         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
 210                                buf->dma_dir);
 211 }
 212
 213 static void vb2_dma_sg_finish(void *buf_priv)
 214 {
 215         struct vb2_dma_sg_buf *buf = buf_priv;
 216         struct sg_table *sgt = buf->dma_sgt;
 217
 218         /* DMABUF exporter will flush the cache for us */
 219         if (buf->db_attach)
 220                 return;
 221
 222         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 223 }
 224
 225 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
 226                                     unsigned long size,
 227                                     enum dma_data_direction dma_dir)
 228 {
 229         struct vb2_dma_sg_buf *buf;
 230         struct sg_table *sgt;
 231         DEFINE_DMA_ATTRS(attrs);
 232         struct frame_vector *vec;
 233
 234         dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 235         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 236         if (!buf)
 237                 return NULL;
 238
 239         buf->vaddr = NULL;
 240         buf->dev = dev;
 241         buf->dma_dir = dma_dir;
 242         buf->offset = vaddr & ~PAGE_MASK;
 243         buf->size = size;
 244         buf->dma_sgt = &buf->sg_table;
 245         vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE);
 246         if (IS_ERR(vec))
 247                 goto userptr_fail_pfnvec;
 248         buf->vec = vec;
 249
 250         buf->pages = frame_vector_pages(vec);
 251         if (IS_ERR(buf->pages))
 252                 goto userptr_fail_sgtable;
 253         buf->num_pages = frame_vector_count(vec);
 254
 255         if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 256                         buf->num_pages, buf->offset, size, 0))
 257                 goto userptr_fail_sgtable;
 258
 259         sgt = &buf->sg_table;
 260         /*
 261          * No need to sync to the device, this will happen later when the
 262          * prepare() memop is called.
 263          */
 264         sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 265                                       buf->dma_dir, &attrs);
 266         if (!sgt->nents)
 267                 goto userptr_fail_map;
 268
 269         return buf;
 270
 271 userptr_fail_map:
 272         sg_free_table(&buf->sg_table);
 273 userptr_fail_sgtable:
 274         vb2_destroy_framevec(vec);
 275 userptr_fail_pfnvec:
 276         kfree(buf);
 277         return NULL;
 278 }
 279
 280 /*
 281  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
 282  *               be used
 283  */
 284 static void vb2_dma_sg_put_userptr(void *buf_priv)
 285 {
 286         struct vb2_dma_sg_buf *buf = buf_priv;
 287         struct sg_table *sgt = &buf->sg_table;
 288         int i = buf->num_pages;
 289         DEFINE_DMA_ATTRS(attrs);
 290
 291         dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 292
 293         dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
 294                __func__, buf->num_pages);
 295         dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
 296                            &attrs);
 297         if (buf->vaddr)
 298                 vm_unmap_ram(buf->vaddr, buf->num_pages);
 299         sg_free_table(buf->dma_sgt);
 300         while (--i >= 0) {
 301                 if (buf->dma_dir == DMA_FROM_DEVICE)
 302                         set_page_dirty_lock(buf->pages[i]);
 303         }
 304         vb2_destroy_framevec(buf->vec);
 305         kfree(buf);
 306 }
 307
 308 static void *vb2_dma_sg_vaddr(void *buf_priv)
 309 {
 310         struct vb2_dma_sg_buf *buf = buf_priv;
 311
 312         BUG_ON(!buf);
 313
 314         if (!buf->vaddr) {
 315                 if (buf->db_attach)
 316                         buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
 317                 else
 318                         buf->vaddr = vm_map_ram(buf->pages,
 319                                         buf->num_pages, -1, PAGE_KERNEL);
 320         }
 321
 322         /* add offset in case userptr is not page-aligned */
 323         return buf->vaddr ? buf->vaddr + buf->offset : NULL;
 324 }
 325
 326 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
 327 {
 328         struct vb2_dma_sg_buf *buf = buf_priv;
 329
 330         return atomic_read(&buf->refcount);
 331 }
 332
 333 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
 334 {
 335         struct vb2_dma_sg_buf *buf = buf_priv;
 336         unsigned long uaddr = vma->vm_start;
 337         unsigned long usize = vma->vm_end - vma->vm_start;
 338         int i = 0;
 339
 340         if (!buf) {
 341                 printk(KERN_ERR "No memory to map\n");
 342                 return -EINVAL;
 343         }
 344
 345         do {
 346                 int ret;
 347
 348                 ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
 349                 if (ret) {
 350                         printk(KERN_ERR "Remapping memory, error: %d\n", ret);
 351                         return ret;
 352                 }
 353
 354                 uaddr += PAGE_SIZE;
 355                 usize -= PAGE_SIZE;
 356         } while (usize > 0);
 357
 358
 359         /*
 360          * Use common vm_area operations to track buffer refcount.
 361          */
 362         vma->vm_private_data    = &buf->handler;
 363         vma->vm_ops             = &vb2_common_vm_ops;
 364
 365         vma->vm_ops->open(vma);
 366
 367         return 0;
 368 }
 369
 370 /*********************************************/
 371 /*         DMABUF ops for exporters          */
 372 /*********************************************/
 373
 374 struct vb2_dma_sg_attachment {
 375         struct sg_table sgt;
 376         enum dma_data_direction dma_dir;
 377 };
 378
 379 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
 380         struct dma_buf_attachment *dbuf_attach)
 381 {
 382         struct vb2_dma_sg_attachment *attach;
 383         unsigned int i;
 384         struct scatterlist *rd, *wr;
 385         struct sg_table *sgt;
 386         struct vb2_dma_sg_buf *buf = dbuf->priv;
 387         int ret;
 388
 389         attach = kzalloc(sizeof(*attach), GFP_KERNEL);
 390         if (!attach)
 391                 return -ENOMEM;
 392
 393         sgt = &attach->sgt;
 394         /* Copy the buf->base_sgt scatter list to the attachment, as we can't
 395          * map the same scatter list to multiple attachments at the same time.
 396          */
 397         ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
 398         if (ret) {
 399                 kfree(attach);
 400                 return -ENOMEM;
 401         }
 402
 403         rd = buf->dma_sgt->sgl;
 404         wr = sgt->sgl;
 405         for (i = 0; i < sgt->orig_nents; ++i) {
 406                 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
 407                 rd = sg_next(rd);
 408                 wr = sg_next(wr);
 409         }
 410
 411         attach->dma_dir = DMA_NONE;
 412         dbuf_attach->priv = attach;
 413
 414         return 0;
 415 }
 416
 417 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
 418         struct dma_buf_attachment *db_attach)
 419 {
 420         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 421         struct sg_table *sgt;
 422
 423         if (!attach)
 424                 return;
 425
 426         sgt = &attach->sgt;
 427
 428         /* release the scatterlist cache */
 429         if (attach->dma_dir != DMA_NONE)
 430                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 431                         attach->dma_dir);
 432         sg_free_table(sgt);
 433         kfree(attach);
 434         db_attach->priv = NULL;
 435 }
 436
 437 static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
 438         struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
 439 {
 440         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 441         /* stealing dmabuf mutex to serialize map/unmap operations */
 442         struct mutex *lock = &db_attach->dmabuf->lock;
 443         struct sg_table *sgt;
 444
 445         mutex_lock(lock);
 446
 447         sgt = &attach->sgt;
 448         /* return previously mapped sg table */
 449         if (attach->dma_dir == dma_dir) {
 450                 mutex_unlock(lock);
 451                 return sgt;
 452         }
 453
 454         /* release any previous cache */
 455         if (attach->dma_dir != DMA_NONE) {
 456                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 457                         attach->dma_dir);
 458                 attach->dma_dir = DMA_NONE;
 459         }
 460
 461         /* mapping to the client with new direction */
 462         sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 463                                 dma_dir);
 464         if (!sgt->nents) {
 465                 pr_err("failed to map scatterlist\n");
 466                 mutex_unlock(lock);
 467                 return ERR_PTR(-EIO);
 468         }
 469
 470         attach->dma_dir = dma_dir;
 471
 472         mutex_unlock(lock);
 473
 474         return sgt;
 475 }
 476
 477 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 478         struct sg_table *sgt, enum dma_data_direction dma_dir)
 479 {
 480         /* nothing to be done here */
 481 }
 482
 483 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
 484 {
 485         /* drop reference obtained in vb2_dma_sg_get_dmabuf */
 486         vb2_dma_sg_put(dbuf->priv);
 487 }
 488
 489 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
 490 {
 491         struct vb2_dma_sg_buf *buf = dbuf->priv;
 492
 493         return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
 494 }
 495
 496 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
 497 {
 498         struct vb2_dma_sg_buf *buf = dbuf->priv;
 499
 500         return vb2_dma_sg_vaddr(buf);
 501 }
 502
 503 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
 504         struct vm_area_struct *vma)
 505 {
 506         return vb2_dma_sg_mmap(dbuf->priv, vma);
 507 }
 508
 509 static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
 510         .attach = vb2_dma_sg_dmabuf_ops_attach,
 511         .detach = vb2_dma_sg_dmabuf_ops_detach,
 512         .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
 513         .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
 514         .kmap = vb2_dma_sg_dmabuf_ops_kmap,
 515         .kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
 516         .vmap = vb2_dma_sg_dmabuf_ops_vmap,
 517         .mmap = vb2_dma_sg_dmabuf_ops_mmap,
 518         .release = vb2_dma_sg_dmabuf_ops_release,
 519 };
 520
 521 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
 522 {
 523         struct vb2_dma_sg_buf *buf = buf_priv;
 524         struct dma_buf *dbuf;
 525         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 526
 527         exp_info.ops = &vb2_dma_sg_dmabuf_ops;
 528         exp_info.size = buf->size;
 529         exp_info.flags = flags;
 530         exp_info.priv = buf;
 531
 532         if (WARN_ON(!buf->dma_sgt))
 533                 return NULL;
 534
 535         dbuf = dma_buf_export(&exp_info);
 536         if (IS_ERR(dbuf))
 537                 return NULL;
 538
 539         /* dmabuf keeps reference to vb2 buffer */
 540         atomic_inc(&buf->refcount);
 541
 542         return dbuf;
 543 }
 544
 545 /*********************************************/
 546 /*       callbacks for DMABUF buffers        */
 547 /*********************************************/
 548
 549 static int vb2_dma_sg_map_dmabuf(void *mem_priv)
 550 {
 551         struct vb2_dma_sg_buf *buf = mem_priv;
 552         struct sg_table *sgt;
 553
 554         if (WARN_ON(!buf->db_attach)) {
 555                 pr_err("trying to pin a non attached buffer\n");
 556                 return -EINVAL;
 557         }
 558
 559         if (WARN_ON(buf->dma_sgt)) {
 560                 pr_err("dmabuf buffer is already pinned\n");
 561                 return 0;
 562         }
 563
 564         /* get the associated scatterlist for this buffer */
 565         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 566         if (IS_ERR(sgt)) {
 567                 pr_err("Error getting dmabuf scatterlist\n");
 568                 return -EINVAL;
 569         }
 570
 571         buf->dma_sgt = sgt;
 572         buf->vaddr = NULL;
 573
 574         return 0;
 575 }
 576
 577 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
 578 {
 579         struct vb2_dma_sg_buf *buf = mem_priv;
 580         struct sg_table *sgt = buf->dma_sgt;
 581
 582         if (WARN_ON(!buf->db_attach)) {
 583                 pr_err("trying to unpin a not attached buffer\n");
 584                 return;
 585         }
 586
 587         if (WARN_ON(!sgt)) {
 588                 pr_err("dmabuf buffer is already unpinned\n");
 589                 return;
 590         }
 591
 592         if (buf->vaddr) {
 593                 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
 594                 buf->vaddr = NULL;
 595         }
 596         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 597
 598         buf->dma_sgt = NULL;
 599 }
 600
 601 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
 602 {
 603         struct vb2_dma_sg_buf *buf = mem_priv;
 604
 605         /* if vb2 works correctly you should never detach mapped buffer */
 606         if (WARN_ON(buf->dma_sgt))
 607                 vb2_dma_sg_unmap_dmabuf(buf);
 608
 609         /* detach this attachment */
 610         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 611         kfree(buf);
 612 }
 613
 614 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
 615         unsigned long size, enum dma_data_direction dma_dir)
 616 {
 617         struct vb2_dma_sg_buf *buf;
 618         struct dma_buf_attachment *dba;
 619
 620         if (dbuf->size < size)
 621                 return ERR_PTR(-EFAULT);
 622
 623         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 624         if (!buf)
 625                 return ERR_PTR(-ENOMEM);
 626
 627         buf->dev = dev;
 628         /* create attachment for the dmabuf with the user device */
 629         dba = dma_buf_attach(dbuf, buf->dev);
 630         if (IS_ERR(dba)) {
 631                 pr_err("failed to attach dmabuf\n");
 632                 kfree(buf);
 633                 return dba;
 634         }
 635
 636         buf->dma_dir = dma_dir;
 637         buf->size = size;
 638         buf->db_attach = dba;
 639
 640         return buf;
 641 }
 642
 643 static void *vb2_dma_sg_cookie(void *buf_priv)
 644 {
 645         struct vb2_dma_sg_buf *buf = buf_priv;
 646
 647         return buf->dma_sgt;
 648 }
 649
 650 const struct vb2_mem_ops vb2_dma_sg_memops = {
 651         .alloc          = vb2_dma_sg_alloc,
 652         .put            = vb2_dma_sg_put,
 653         .get_userptr    = vb2_dma_sg_get_userptr,
 654         .put_userptr    = vb2_dma_sg_put_userptr,
 655         .prepare        = vb2_dma_sg_prepare,
 656         .finish         = vb2_dma_sg_finish,
 657         .vaddr          = vb2_dma_sg_vaddr,
 658         .mmap           = vb2_dma_sg_mmap,
 659         .num_users      = vb2_dma_sg_num_users,
 660         .get_dmabuf     = vb2_dma_sg_get_dmabuf,
 661         .map_dmabuf     = vb2_dma_sg_map_dmabuf,
 662         .unmap_dmabuf   = vb2_dma_sg_unmap_dmabuf,
 663         .attach_dmabuf  = vb2_dma_sg_attach_dmabuf,
 664         .detach_dmabuf  = vb2_dma_sg_detach_dmabuf,
 665         .cookie         = vb2_dma_sg_cookie,
 666 };
 667 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
 668
 669 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
 670 MODULE_AUTHOR("Andrzej Pietrasiewicz");
 671 MODULE_LICENSE("GPL");