drivers/media/v4l2-core/videobuf2-dma-contig.c

   1 /*
   2  * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  *
   6  * Author: Pawel Osciak <pawel@osciak.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/dma-buf.h>
  14 #include <linux/module.h>
  15 #include <linux/scatterlist.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/dma-mapping.h>
  19
  20 #include <media/videobuf2-v4l2.h>
  21 #include <media/videobuf2-dma-contig.h>
  22 #include <media/videobuf2-memops.h>
  23
  24 struct vb2_dc_conf {
  25         struct device           *dev;
  26 };
  27
  28 struct vb2_dc_buf {
  29         struct device                   *dev;
  30         void                            *vaddr;
  31         unsigned long                   size;
  32         dma_addr_t                      dma_addr;
  33         enum dma_data_direction         dma_dir;
  34         struct sg_table                 *dma_sgt;
  35         struct frame_vector             *vec;
  36
  37         /* MMAP related */
  38         struct vb2_vmarea_handler       handler;
  39         atomic_t                        refcount;
  40         struct sg_table                 *sgt_base;
  41
  42         /* DMABUF related */
  43         struct dma_buf_attachment       *db_attach;
  44 };
  45
  46 /*********************************************/
  47 /*        scatterlist table functions        */
  48 /*********************************************/
  49
  50 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
  51 {
  52         struct scatterlist *s;
  53         dma_addr_t expected = sg_dma_address(sgt->sgl);
  54         unsigned int i;
  55         unsigned long size = 0;
  56
  57         for_each_sg(sgt->sgl, s, sgt->nents, i) {
  58                 if (sg_dma_address(s) != expected)
  59                         break;
  60                 expected = sg_dma_address(s) + sg_dma_len(s);
  61                 size += sg_dma_len(s);
  62         }
  63         return size;
  64 }
  65
  66 /*********************************************/
  67 /*         callbacks for all buffers         */
  68 /*********************************************/
  69
  70 static void *vb2_dc_cookie(void *buf_priv)
  71 {
  72         struct vb2_dc_buf *buf = buf_priv;
  73
  74         return &buf->dma_addr;
  75 }
  76
  77 static void *vb2_dc_vaddr(void *buf_priv)
  78 {
  79         struct vb2_dc_buf *buf = buf_priv;
  80
  81         if (!buf->vaddr && buf->db_attach)
  82                 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
  83
  84         return buf->vaddr;
  85 }
  86
  87 static unsigned int vb2_dc_num_users(void *buf_priv)
  88 {
  89         struct vb2_dc_buf *buf = buf_priv;
  90
  91         return atomic_read(&buf->refcount);
  92 }
  93
  94 static void vb2_dc_prepare(void *buf_priv)
  95 {
  96         struct vb2_dc_buf *buf = buf_priv;
  97         struct sg_table *sgt = buf->dma_sgt;
  98
  99         /* DMABUF exporter will flush the cache for us */
 100         if (!sgt || buf->db_attach)
 101                 return;
 102
 103         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
 104                                buf->dma_dir);
 105 }
 106
 107 static void vb2_dc_finish(void *buf_priv)
 108 {
 109         struct vb2_dc_buf *buf = buf_priv;
 110         struct sg_table *sgt = buf->dma_sgt;
 111
 112         /* DMABUF exporter will flush the cache for us */
 113         if (!sgt || buf->db_attach)
 114                 return;
 115
 116         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 117 }
 118
 119 /*********************************************/
 120 /*        callbacks for MMAP buffers         */
 121 /*********************************************/
 122
 123 static void vb2_dc_put(void *buf_priv)
 124 {
 125         struct vb2_dc_buf *buf = buf_priv;
 126
 127         if (!atomic_dec_and_test(&buf->refcount))
 128                 return;
 129
 130         if (buf->sgt_base) {
 131                 sg_free_table(buf->sgt_base);
 132                 kfree(buf->sgt_base);
 133         }
 134         dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
 135         put_device(buf->dev);
 136         kfree(buf);
 137 }
 138
 139 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size,
 140                           enum dma_data_direction dma_dir, gfp_t gfp_flags)
 141 {
 142         struct vb2_dc_conf *conf = alloc_ctx;
 143         struct device *dev = conf->dev;
 144         struct vb2_dc_buf *buf;
 145
 146         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 147         if (!buf)
 148                 return ERR_PTR(-ENOMEM);
 149
 150         buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr,
 151                                                 GFP_KERNEL | gfp_flags);
 152         if (!buf->vaddr) {
 153                 dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
 154                 kfree(buf);
 155                 return ERR_PTR(-ENOMEM);
 156         }
 157
 158         /* Prevent the device from being released while the buffer is used */
 159         buf->dev = get_device(dev);
 160         buf->size = size;
 161         buf->dma_dir = dma_dir;
 162
 163         buf->handler.refcount = &buf->refcount;
 164         buf->handler.put = vb2_dc_put;
 165         buf->handler.arg = buf;
 166
 167         atomic_inc(&buf->refcount);
 168
 169         return buf;
 170 }
 171
 172 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 173 {
 174         struct vb2_dc_buf *buf = buf_priv;
 175         int ret;
 176
 177         if (!buf) {
 178                 printk(KERN_ERR "No buffer to map\n");
 179                 return -EINVAL;
 180         }
 181
 182         /*
 183          * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
 184          * map whole buffer
 185          */
 186         vma->vm_pgoff = 0;
 187
 188         ret = dma_mmap_coherent(buf->dev, vma, buf->vaddr,
 189                 buf->dma_addr, buf->size);
 190
 191         if (ret) {
 192                 pr_err("Remapping memory failed, error: %d\n", ret);
 193                 return ret;
 194         }
 195
 196         vma->vm_flags           |= VM_DONTEXPAND | VM_DONTDUMP;
 197         vma->vm_private_data    = &buf->handler;
 198         vma->vm_ops             = &vb2_common_vm_ops;
 199
 200         vma->vm_ops->open(vma);
 201
 202         pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
 203                 __func__, (unsigned long)buf->dma_addr, vma->vm_start,
 204                 buf->size);
 205
 206         return 0;
 207 }
 208
 209 /*********************************************/
 210 /*         DMABUF ops for exporters          */
 211 /*********************************************/
 212
 213 struct vb2_dc_attachment {
 214         struct sg_table sgt;
 215         enum dma_data_direction dma_dir;
 216 };
 217
 218 static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
 219         struct dma_buf_attachment *dbuf_attach)
 220 {
 221         struct vb2_dc_attachment *attach;
 222         unsigned int i;
 223         struct scatterlist *rd, *wr;
 224         struct sg_table *sgt;
 225         struct vb2_dc_buf *buf = dbuf->priv;
 226         int ret;
 227
 228         attach = kzalloc(sizeof(*attach), GFP_KERNEL);
 229         if (!attach)
 230                 return -ENOMEM;
 231
 232         sgt = &attach->sgt;
 233         /* Copy the buf->base_sgt scatter list to the attachment, as we can't
 234          * map the same scatter list to multiple attachments at the same time.
 235          */
 236         ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
 237         if (ret) {
 238                 kfree(attach);
 239                 return -ENOMEM;
 240         }
 241
 242         rd = buf->sgt_base->sgl;
 243         wr = sgt->sgl;
 244         for (i = 0; i < sgt->orig_nents; ++i) {
 245                 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
 246                 rd = sg_next(rd);
 247                 wr = sg_next(wr);
 248         }
 249
 250         attach->dma_dir = DMA_NONE;
 251         dbuf_attach->priv = attach;
 252
 253         return 0;
 254 }
 255
 256 static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
 257         struct dma_buf_attachment *db_attach)
 258 {
 259         struct vb2_dc_attachment *attach = db_attach->priv;
 260         struct sg_table *sgt;
 261
 262         if (!attach)
 263                 return;
 264
 265         sgt = &attach->sgt;
 266
 267         /* release the scatterlist cache */
 268         if (attach->dma_dir != DMA_NONE)
 269                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 270                         attach->dma_dir);
 271         sg_free_table(sgt);
 272         kfree(attach);
 273         db_attach->priv = NULL;
 274 }
 275
 276 static struct sg_table *vb2_dc_dmabuf_ops_map(
 277         struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
 278 {
 279         struct vb2_dc_attachment *attach = db_attach->priv;
 280         /* stealing dmabuf mutex to serialize map/unmap operations */
 281         struct mutex *lock = &db_attach->dmabuf->lock;
 282         struct sg_table *sgt;
 283
 284         mutex_lock(lock);
 285
 286         sgt = &attach->sgt;
 287         /* return previously mapped sg table */
 288         if (attach->dma_dir == dma_dir) {
 289                 mutex_unlock(lock);
 290                 return sgt;
 291         }
 292
 293         /* release any previous cache */
 294         if (attach->dma_dir != DMA_NONE) {
 295                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 296                         attach->dma_dir);
 297                 attach->dma_dir = DMA_NONE;
 298         }
 299
 300         /* mapping to the client with new direction */
 301         sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 302                                 dma_dir);
 303         if (!sgt->nents) {
 304                 pr_err("failed to map scatterlist\n");
 305                 mutex_unlock(lock);
 306                 return ERR_PTR(-EIO);
 307         }
 308
 309         attach->dma_dir = dma_dir;
 310
 311         mutex_unlock(lock);
 312
 313         return sgt;
 314 }
 315
 316 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 317         struct sg_table *sgt, enum dma_data_direction dma_dir)
 318 {
 319         /* nothing to be done here */
 320 }
 321
 322 static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
 323 {
 324         /* drop reference obtained in vb2_dc_get_dmabuf */
 325         vb2_dc_put(dbuf->priv);
 326 }
 327
 328 static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
 329 {
 330         struct vb2_dc_buf *buf = dbuf->priv;
 331
 332         return buf->vaddr + pgnum * PAGE_SIZE;
 333 }
 334
 335 static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
 336 {
 337         struct vb2_dc_buf *buf = dbuf->priv;
 338
 339         return buf->vaddr;
 340 }
 341
 342 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
 343         struct vm_area_struct *vma)
 344 {
 345         return vb2_dc_mmap(dbuf->priv, vma);
 346 }
 347
 348 static struct dma_buf_ops vb2_dc_dmabuf_ops = {
 349         .attach = vb2_dc_dmabuf_ops_attach,
 350         .detach = vb2_dc_dmabuf_ops_detach,
 351         .map_dma_buf = vb2_dc_dmabuf_ops_map,
 352         .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
 353         .kmap = vb2_dc_dmabuf_ops_kmap,
 354         .kmap_atomic = vb2_dc_dmabuf_ops_kmap,
 355         .vmap = vb2_dc_dmabuf_ops_vmap,
 356         .mmap = vb2_dc_dmabuf_ops_mmap,
 357         .release = vb2_dc_dmabuf_ops_release,
 358 };
 359
 360 static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
 361 {
 362         int ret;
 363         struct sg_table *sgt;
 364
 365         sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
 366         if (!sgt) {
 367                 dev_err(buf->dev, "failed to alloc sg table\n");
 368                 return NULL;
 369         }
 370
 371         ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
 372                 buf->size);
 373         if (ret < 0) {
 374                 dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
 375                 kfree(sgt);
 376                 return NULL;
 377         }
 378
 379         return sgt;
 380 }
 381
 382 static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
 383 {
 384         struct vb2_dc_buf *buf = buf_priv;
 385         struct dma_buf *dbuf;
 386         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 387
 388         exp_info.ops = &vb2_dc_dmabuf_ops;
 389         exp_info.size = buf->size;
 390         exp_info.flags = flags;
 391         exp_info.priv = buf;
 392
 393         if (!buf->sgt_base)
 394                 buf->sgt_base = vb2_dc_get_base_sgt(buf);
 395
 396         if (WARN_ON(!buf->sgt_base))
 397                 return NULL;
 398
 399         dbuf = dma_buf_export(&exp_info);
 400         if (IS_ERR(dbuf))
 401                 return NULL;
 402
 403         /* dmabuf keeps reference to vb2 buffer */
 404         atomic_inc(&buf->refcount);
 405
 406         return dbuf;
 407 }
 408
 409 /*********************************************/
 410 /*       callbacks for USERPTR buffers       */
 411 /*********************************************/
 412
 413 static void vb2_dc_put_userptr(void *buf_priv)
 414 {
 415         struct vb2_dc_buf *buf = buf_priv;
 416         struct sg_table *sgt = buf->dma_sgt;
 417         int i;
 418         struct page **pages;
 419
 420         if (sgt) {
 421                 DEFINE_DMA_ATTRS(attrs);
 422
 423                 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 424                 /*
 425                  * No need to sync to CPU, it's already synced to the CPU
 426                  * since the finish() memop will have been called before this.
 427                  */
 428                 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 429                                    buf->dma_dir, &attrs);
 430                 pages = frame_vector_pages(buf->vec);
 431                 /* sgt should exist only if vector contains pages... */
 432                 BUG_ON(IS_ERR(pages));
 433                 for (i = 0; i < frame_vector_count(buf->vec); i++)
 434                         set_page_dirty_lock(pages[i]);
 435                 sg_free_table(sgt);
 436                 kfree(sgt);
 437         }
 438         vb2_destroy_framevec(buf->vec);
 439         kfree(buf);
 440 }
 441
 442 /*
 443  * For some kind of reserved memory there might be no struct page available,
 444  * so all that can be done to support such 'pages' is to try to convert
 445  * pfn to dma address or at the last resort just assume that
 446  * dma address == physical address (like it has been assumed in earlier version
 447  * of videobuf2-dma-contig
 448  */
 449
 450 #ifdef __arch_pfn_to_dma
 451 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
 452 {
 453         return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
 454 }
 455 #elif defined(__pfn_to_bus)
 456 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
 457 {
 458         return (dma_addr_t)__pfn_to_bus(pfn);
 459 }
 460 #elif defined(__pfn_to_phys)
 461 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
 462 {
 463         return (dma_addr_t)__pfn_to_phys(pfn);
 464 }
 465 #else
 466 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
 467 {
 468         /* really, we cannot do anything better at this point */
 469         return (dma_addr_t)(pfn) << PAGE_SHIFT;
 470 }
 471 #endif
 472
 473 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 474         unsigned long size, enum dma_data_direction dma_dir)
 475 {
 476         struct vb2_dc_conf *conf = alloc_ctx;
 477         struct vb2_dc_buf *buf;
 478         struct frame_vector *vec;
 479         unsigned long offset;
 480         int n_pages, i;
 481         int ret = 0;
 482         struct sg_table *sgt;
 483         unsigned long contig_size;
 484         unsigned long dma_align = dma_get_cache_alignment();
 485         DEFINE_DMA_ATTRS(attrs);
 486
 487         dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 488
 489         /* Only cache aligned DMA transfers are reliable */
 490         if (!IS_ALIGNED(vaddr | size, dma_align)) {
 491                 pr_debug("user data must be aligned to %lu bytes\n", dma_align);
 492                 return ERR_PTR(-EINVAL);
 493         }
 494
 495         if (!size) {
 496                 pr_debug("size is zero\n");
 497                 return ERR_PTR(-EINVAL);
 498         }
 499
 500         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 501         if (!buf)
 502                 return ERR_PTR(-ENOMEM);
 503
 504         buf->dev = conf->dev;
 505         buf->dma_dir = dma_dir;
 506
 507         offset = vaddr & ~PAGE_MASK;
 508         vec = vb2_create_framevec(vaddr, size, dma_dir == DMA_FROM_DEVICE);
 509         if (IS_ERR(vec)) {
 510                 ret = PTR_ERR(vec);
 511                 goto fail_buf;
 512         }
 513         buf->vec = vec;
 514         n_pages = frame_vector_count(vec);
 515         ret = frame_vector_to_pages(vec);
 516         if (ret < 0) {
 517                 unsigned long *nums = frame_vector_pfns(vec);
 518
 519                 /*
 520                  * Failed to convert to pages... Check the memory is physically
 521                  * contiguous and use direct mapping
 522                  */
 523                 for (i = 1; i < n_pages; i++)
 524                         if (nums[i-1] + 1 != nums[i])
 525                                 goto fail_pfnvec;
 526                 buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, nums[0]);
 527                 goto out;
 528         }
 529
 530         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 531         if (!sgt) {
 532                 pr_err("failed to allocate sg table\n");
 533                 ret = -ENOMEM;
 534                 goto fail_pfnvec;
 535         }
 536
 537         ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages,
 538                 offset, size, GFP_KERNEL);
 539         if (ret) {
 540                 pr_err("failed to initialize sg table\n");
 541                 goto fail_sgt;
 542         }
 543
 544         /*
 545          * No need to sync to the device, this will happen later when the
 546          * prepare() memop is called.
 547          */
 548         sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 549                                       buf->dma_dir, &attrs);
 550         if (sgt->nents <= 0) {
 551                 pr_err("failed to map scatterlist\n");
 552                 ret = -EIO;
 553                 goto fail_sgt_init;
 554         }
 555
 556         contig_size = vb2_dc_get_contiguous_size(sgt);
 557         if (contig_size < size) {
 558                 pr_err("contiguous mapping is too small %lu/%lu\n",
 559                         contig_size, size);
 560                 ret = -EFAULT;
 561                 goto fail_map_sg;
 562         }
 563
 564         buf->dma_addr = sg_dma_address(sgt->sgl);
 565         buf->dma_sgt = sgt;
 566 out:
 567         buf->size = size;
 568
 569         return buf;
 570
 571 fail_map_sg:
 572         dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 573                            buf->dma_dir, &attrs);
 574
 575 fail_sgt_init:
 576         sg_free_table(sgt);
 577
 578 fail_sgt:
 579         kfree(sgt);
 580
 581 fail_pfnvec:
 582         vb2_destroy_framevec(vec);
 583
 584 fail_buf:
 585         kfree(buf);
 586
 587         return ERR_PTR(ret);
 588 }
 589
 590 /*********************************************/
 591 /*       callbacks for DMABUF buffers        */
 592 /*********************************************/
 593
 594 static int vb2_dc_map_dmabuf(void *mem_priv)
 595 {
 596         struct vb2_dc_buf *buf = mem_priv;
 597         struct sg_table *sgt;
 598         unsigned long contig_size;
 599
 600         if (WARN_ON(!buf->db_attach)) {
 601                 pr_err("trying to pin a non attached buffer\n");
 602                 return -EINVAL;
 603         }
 604
 605         if (WARN_ON(buf->dma_sgt)) {
 606                 pr_err("dmabuf buffer is already pinned\n");
 607                 return 0;
 608         }
 609
 610         /* get the associated scatterlist for this buffer */
 611         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 612         if (IS_ERR(sgt)) {
 613                 pr_err("Error getting dmabuf scatterlist\n");
 614                 return -EINVAL;
 615         }
 616
 617         /* checking if dmabuf is big enough to store contiguous chunk */
 618         contig_size = vb2_dc_get_contiguous_size(sgt);
 619         if (contig_size < buf->size) {
 620                 pr_err("contiguous chunk is too small %lu/%lu b\n",
 621                         contig_size, buf->size);
 622                 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 623                 return -EFAULT;
 624         }
 625
 626         buf->dma_addr = sg_dma_address(sgt->sgl);
 627         buf->dma_sgt = sgt;
 628         buf->vaddr = NULL;
 629
 630         return 0;
 631 }
 632
 633 static void vb2_dc_unmap_dmabuf(void *mem_priv)
 634 {
 635         struct vb2_dc_buf *buf = mem_priv;
 636         struct sg_table *sgt = buf->dma_sgt;
 637
 638         if (WARN_ON(!buf->db_attach)) {
 639                 pr_err("trying to unpin a not attached buffer\n");
 640                 return;
 641         }
 642
 643         if (WARN_ON(!sgt)) {
 644                 pr_err("dmabuf buffer is already unpinned\n");
 645                 return;
 646         }
 647
 648         if (buf->vaddr) {
 649                 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
 650                 buf->vaddr = NULL;
 651         }
 652         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 653
 654         buf->dma_addr = 0;
 655         buf->dma_sgt = NULL;
 656 }
 657
 658 static void vb2_dc_detach_dmabuf(void *mem_priv)
 659 {
 660         struct vb2_dc_buf *buf = mem_priv;
 661
 662         /* if vb2 works correctly you should never detach mapped buffer */
 663         if (WARN_ON(buf->dma_addr))
 664                 vb2_dc_unmap_dmabuf(buf);
 665
 666         /* detach this attachment */
 667         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 668         kfree(buf);
 669 }
 670
 671 static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 672         unsigned long size, enum dma_data_direction dma_dir)
 673 {
 674         struct vb2_dc_conf *conf = alloc_ctx;
 675         struct vb2_dc_buf *buf;
 676         struct dma_buf_attachment *dba;
 677
 678         if (dbuf->size < size)
 679                 return ERR_PTR(-EFAULT);
 680
 681         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 682         if (!buf)
 683                 return ERR_PTR(-ENOMEM);
 684
 685         buf->dev = conf->dev;
 686         /* create attachment for the dmabuf with the user device */
 687         dba = dma_buf_attach(dbuf, buf->dev);
 688         if (IS_ERR(dba)) {
 689                 pr_err("failed to attach dmabuf\n");
 690                 kfree(buf);
 691                 return dba;
 692         }
 693
 694         buf->dma_dir = dma_dir;
 695         buf->size = size;
 696         buf->db_attach = dba;
 697
 698         return buf;
 699 }
 700
 701 /*********************************************/
 702 /*       DMA CONTIG exported functions       */
 703 /*********************************************/
 704
 705 const struct vb2_mem_ops vb2_dma_contig_memops = {
 706         .alloc          = vb2_dc_alloc,
 707         .put            = vb2_dc_put,
 708         .get_dmabuf     = vb2_dc_get_dmabuf,
 709         .cookie         = vb2_dc_cookie,
 710         .vaddr          = vb2_dc_vaddr,
 711         .mmap           = vb2_dc_mmap,
 712         .get_userptr    = vb2_dc_get_userptr,
 713         .put_userptr    = vb2_dc_put_userptr,
 714         .prepare        = vb2_dc_prepare,
 715         .finish         = vb2_dc_finish,
 716         .map_dmabuf     = vb2_dc_map_dmabuf,
 717         .unmap_dmabuf   = vb2_dc_unmap_dmabuf,
 718         .attach_dmabuf  = vb2_dc_attach_dmabuf,
 719         .detach_dmabuf  = vb2_dc_detach_dmabuf,
 720         .num_users      = vb2_dc_num_users,
 721 };
 722 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
 723
 724 void *vb2_dma_contig_init_ctx(struct device *dev)
 725 {
 726         struct vb2_dc_conf *conf;
 727
 728         conf = kzalloc(sizeof *conf, GFP_KERNEL);
 729         if (!conf)
 730                 return ERR_PTR(-ENOMEM);
 731
 732         conf->dev = dev;
 733
 734         return conf;
 735 }
 736 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
 737
 738 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
 739 {
 740         if (!IS_ERR_OR_NULL(alloc_ctx))
 741                 kfree(alloc_ctx);
 742 }
 743 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
 744
 745 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
 746 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
 747 MODULE_LICENSE("GPL");