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