Pileus Git - ~andy/linux/blob - 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-core.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
  36         /* MMAP related */
  37         struct vb2_vmarea_handler       handler;
  38         atomic_t                        refcount;
  39         struct sg_table                 *sgt_base;
  40
  41         /* USERPTR related */
  42         struct vm_area_struct           *vma;
  43
  44         /* DMABUF related */
  45         struct dma_buf_attachment       *db_attach;
  46 };
  47
  48 /*********************************************/
  49 /*        scatterlist table functions        */
  50 /*********************************************/
  51
  52
  53 static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
  54         void (*cb)(struct page *pg))
  55 {
  56         struct scatterlist *s;
  57         unsigned int i;
  58
  59         for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
  60                 struct page *page = sg_page(s);
  61                 unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
  62                         >> PAGE_SHIFT;
  63                 unsigned int j;
  64
  65                 for (j = 0; j < n_pages; ++j, ++page)
  66                         cb(page);
  67         }
  68 }
  69
  70 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
  71 {
  72         struct scatterlist *s;
  73         dma_addr_t expected = sg_dma_address(sgt->sgl);
  74         unsigned int i;
  75         unsigned long size = 0;
  76
  77         for_each_sg(sgt->sgl, s, sgt->nents, i) {
  78                 if (sg_dma_address(s) != expected)
  79                         break;
  80                 expected = sg_dma_address(s) + sg_dma_len(s);
  81                 size += sg_dma_len(s);
  82         }
  83         return size;
  84 }
  85
  86 /*********************************************/
  87 /*         callbacks for all buffers         */
  88 /*********************************************/
  89
  90 static void *vb2_dc_cookie(void *buf_priv)
  91 {
  92         struct vb2_dc_buf *buf = buf_priv;
  93
  94         return &buf->dma_addr;
  95 }
  96
  97 static void *vb2_dc_vaddr(void *buf_priv)
  98 {
  99         struct vb2_dc_buf *buf = buf_priv;
 100
 101         return buf->vaddr;
 102 }
 103
 104 static unsigned int vb2_dc_num_users(void *buf_priv)
 105 {
 106         struct vb2_dc_buf *buf = buf_priv;
 107
 108         return atomic_read(&buf->refcount);
 109 }
 110
 111 static void vb2_dc_prepare(void *buf_priv)
 112 {
 113         struct vb2_dc_buf *buf = buf_priv;
 114         struct sg_table *sgt = buf->dma_sgt;
 115
 116         /* DMABUF exporter will flush the cache for us */
 117         if (!sgt || buf->db_attach)
 118                 return;
 119
 120         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 121 }
 122
 123 static void vb2_dc_finish(void *buf_priv)
 124 {
 125         struct vb2_dc_buf *buf = buf_priv;
 126         struct sg_table *sgt = buf->dma_sgt;
 127
 128         /* DMABUF exporter will flush the cache for us */
 129         if (!sgt || buf->db_attach)
 130                 return;
 131
 132         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 133 }
 134
 135 /*********************************************/
 136 /*        callbacks for MMAP buffers         */
 137 /*********************************************/
 138
 139 static void vb2_dc_put(void *buf_priv)
 140 {
 141         struct vb2_dc_buf *buf = buf_priv;
 142
 143         if (!atomic_dec_and_test(&buf->refcount))
 144                 return;
 145
 146         if (buf->sgt_base) {
 147                 sg_free_table(buf->sgt_base);
 148                 kfree(buf->sgt_base);
 149         }
 150         dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
 151         put_device(buf->dev);
 152         kfree(buf);
 153 }
 154
 155 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 156 {
 157         struct vb2_dc_conf *conf = alloc_ctx;
 158         struct device *dev = conf->dev;
 159         struct vb2_dc_buf *buf;
 160
 161         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 162         if (!buf)
 163                 return ERR_PTR(-ENOMEM);
 164
 165         /* align image size to PAGE_SIZE */
 166         size = PAGE_ALIGN(size);
 167
 168         buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
 169         if (!buf->vaddr) {
 170                 dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
 171                 kfree(buf);
 172                 return ERR_PTR(-ENOMEM);
 173         }
 174
 175         /* Prevent the device from being released while the buffer is used */
 176         buf->dev = get_device(dev);
 177         buf->size = size;
 178
 179         buf->handler.refcount = &buf->refcount;
 180         buf->handler.put = vb2_dc_put;
 181         buf->handler.arg = buf;
 182
 183         atomic_inc(&buf->refcount);
 184
 185         return buf;
 186 }
 187
 188 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 189 {
 190         struct vb2_dc_buf *buf = buf_priv;
 191         int ret;
 192
 193         if (!buf) {
 194                 printk(KERN_ERR "No buffer to map\n");
 195                 return -EINVAL;
 196         }
 197
 198         /*
 199          * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
 200          * map whole buffer
 201          */
 202         vma->vm_pgoff = 0;
 203
 204         ret = dma_mmap_coherent(buf->dev, vma, buf->vaddr,
 205                 buf->dma_addr, buf->size);
 206
 207         if (ret) {
 208                 pr_err("Remapping memory failed, error: %d\n", ret);
 209                 return ret;
 210         }
 211
 212         vma->vm_flags           |= VM_DONTEXPAND | VM_DONTDUMP;
 213         vma->vm_private_data    = &buf->handler;
 214         vma->vm_ops             = &vb2_common_vm_ops;
 215
 216         vma->vm_ops->open(vma);
 217
 218         pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
 219                 __func__, (unsigned long)buf->dma_addr, vma->vm_start,
 220                 buf->size);
 221
 222         return 0;
 223 }
 224
 225 /*********************************************/
 226 /*         DMABUF ops for exporters          */
 227 /*********************************************/
 228
 229 #ifdef HAVE_GENERIC_DMA_COHERENT
 230
 231 struct vb2_dc_attachment {
 232         struct sg_table sgt;
 233         enum dma_data_direction dir;
 234 };
 235
 236 static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
 237         struct dma_buf_attachment *dbuf_attach)
 238 {
 239         struct vb2_dc_attachment *attach;
 240         unsigned int i;
 241         struct scatterlist *rd, *wr;
 242         struct sg_table *sgt;
 243         struct vb2_dc_buf *buf = dbuf->priv;
 244         int ret;
 245
 246         attach = kzalloc(sizeof(*attach), GFP_KERNEL);
 247         if (!attach)
 248                 return -ENOMEM;
 249
 250         sgt = &attach->sgt;
 251         /* Copy the buf->base_sgt scatter list to the attachment, as we can't
 252          * map the same scatter list to multiple attachments at the same time.
 253          */
 254         ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
 255         if (ret) {
 256                 kfree(attach);
 257                 return -ENOMEM;
 258         }
 259
 260         rd = buf->sgt_base->sgl;
 261         wr = sgt->sgl;
 262         for (i = 0; i < sgt->orig_nents; ++i) {
 263                 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
 264                 rd = sg_next(rd);
 265                 wr = sg_next(wr);
 266         }
 267
 268         attach->dir = DMA_NONE;
 269         dbuf_attach->priv = attach;
 270
 271         return 0;
 272 }
 273
 274 static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
 275         struct dma_buf_attachment *db_attach)
 276 {
 277         struct vb2_dc_attachment *attach = db_attach->priv;
 278         struct sg_table *sgt;
 279
 280         if (!attach)
 281                 return;
 282
 283         sgt = &attach->sgt;
 284
 285         /* release the scatterlist cache */
 286         if (attach->dir != DMA_NONE)
 287                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 288                         attach->dir);
 289         sg_free_table(sgt);
 290         kfree(attach);
 291         db_attach->priv = NULL;
 292 }
 293
 294 static struct sg_table *vb2_dc_dmabuf_ops_map(
 295         struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
 296 {
 297         struct vb2_dc_attachment *attach = db_attach->priv;
 298         /* stealing dmabuf mutex to serialize map/unmap operations */
 299         struct mutex *lock = &db_attach->dmabuf->lock;
 300         struct sg_table *sgt;
 301         int ret;
 302
 303         mutex_lock(lock);
 304
 305         sgt = &attach->sgt;
 306         /* return previously mapped sg table */
 307         if (attach->dir == dir) {
 308                 mutex_unlock(lock);
 309                 return sgt;
 310         }
 311
 312         /* release any previous cache */
 313         if (attach->dir != DMA_NONE) {
 314                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 315                         attach->dir);
 316                 attach->dir = DMA_NONE;
 317         }
 318
 319         /* mapping to the client with new direction */
 320         ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir);
 321         if (ret <= 0) {
 322                 pr_err("failed to map scatterlist\n");
 323                 mutex_unlock(lock);
 324                 return ERR_PTR(-EIO);
 325         }
 326
 327         attach->dir = dir;
 328
 329         mutex_unlock(lock);
 330
 331         return sgt;
 332 }
 333
 334 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 335         struct sg_table *sgt, enum dma_data_direction dir)
 336 {
 337         /* nothing to be done here */
 338 }
 339
 340 static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
 341 {
 342         /* drop reference obtained in vb2_dc_get_dmabuf */
 343         vb2_dc_put(dbuf->priv);
 344 }
 345
 346 static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
 347 {
 348         struct vb2_dc_buf *buf = dbuf->priv;
 349
 350         return buf->vaddr + pgnum * PAGE_SIZE;
 351 }
 352
 353 static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
 354 {
 355         struct vb2_dc_buf *buf = dbuf->priv;
 356
 357         return buf->vaddr;
 358 }
 359
 360 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
 361         struct vm_area_struct *vma)
 362 {
 363         return vb2_dc_mmap(dbuf->priv, vma);
 364 }
 365
 366 static struct dma_buf_ops vb2_dc_dmabuf_ops = {
 367         .attach = vb2_dc_dmabuf_ops_attach,
 368         .detach = vb2_dc_dmabuf_ops_detach,
 369         .map_dma_buf = vb2_dc_dmabuf_ops_map,
 370         .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
 371         .kmap = vb2_dc_dmabuf_ops_kmap,
 372         .kmap_atomic = vb2_dc_dmabuf_ops_kmap,
 373         .vmap = vb2_dc_dmabuf_ops_vmap,
 374         .mmap = vb2_dc_dmabuf_ops_mmap,
 375         .release = vb2_dc_dmabuf_ops_release,
 376 };
 377
 378 static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
 379 {
 380         int ret;
 381         struct sg_table *sgt;
 382
 383         sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
 384         if (!sgt) {
 385                 dev_err(buf->dev, "failed to alloc sg table\n");
 386                 return NULL;
 387         }
 388
 389         ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
 390                 buf->size);
 391         if (ret < 0) {
 392                 dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
 393                 kfree(sgt);
 394                 return NULL;
 395         }
 396
 397         return sgt;
 398 }
 399
 400 static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
 401 {
 402         struct vb2_dc_buf *buf = buf_priv;
 403         struct dma_buf *dbuf;
 404
 405         if (!buf->sgt_base)
 406                 buf->sgt_base = vb2_dc_get_base_sgt(buf);
 407
 408         if (WARN_ON(!buf->sgt_base))
 409                 return NULL;
 410
 411         dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0);
 412         if (IS_ERR(dbuf))
 413                 return NULL;
 414
 415         /* dmabuf keeps reference to vb2 buffer */
 416         atomic_inc(&buf->refcount);
 417
 418         return dbuf;
 419 }
 420
 421 #endif
 422
 423 /*********************************************/
 424 /*       callbacks for USERPTR buffers       */
 425 /*********************************************/
 426
 427 static inline int vma_is_io(struct vm_area_struct *vma)
 428 {
 429         return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
 430 }
 431
 432 static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
 433         int n_pages, struct vm_area_struct *vma, int write)
 434 {
 435         if (vma_is_io(vma)) {
 436                 unsigned int i;
 437
 438                 for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
 439                         unsigned long pfn;
 440                         int ret = follow_pfn(vma, start, &pfn);
 441
 442                         if (ret) {
 443                                 pr_err("no page for address %lu\n", start);
 444                                 return ret;
 445                         }
 446                         pages[i] = pfn_to_page(pfn);
 447                 }
 448         } else {
 449                 int n;
 450
 451                 n = get_user_pages(current, current->mm, start & PAGE_MASK,
 452                         n_pages, write, 1, pages, NULL);
 453                 /* negative error means that no page was pinned */
 454                 n = max(n, 0);
 455                 if (n != n_pages) {
 456                         pr_err("got only %d of %d user pages\n", n, n_pages);
 457                         while (n)
 458                                 put_page(pages[--n]);
 459                         return -EFAULT;
 460                 }
 461         }
 462
 463         return 0;
 464 }
 465
 466 static void vb2_dc_put_dirty_page(struct page *page)
 467 {
 468         set_page_dirty_lock(page);
 469         put_page(page);
 470 }
 471
 472 static void vb2_dc_put_userptr(void *buf_priv)
 473 {
 474         struct vb2_dc_buf *buf = buf_priv;
 475         struct sg_table *sgt = buf->dma_sgt;
 476
 477         dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 478         if (!vma_is_io(buf->vma))
 479                 vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
 480
 481         sg_free_table(sgt);
 482         kfree(sgt);
 483         vb2_put_vma(buf->vma);
 484         kfree(buf);
 485 }
 486
 487 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 488         unsigned long size, int write)
 489 {
 490         struct vb2_dc_conf *conf = alloc_ctx;
 491         struct vb2_dc_buf *buf;
 492         unsigned long start;
 493         unsigned long end;
 494         unsigned long offset;
 495         struct page **pages;
 496         int n_pages;
 497         int ret = 0;
 498         struct vm_area_struct *vma;
 499         struct sg_table *sgt;
 500         unsigned long contig_size;
 501         unsigned long dma_align = dma_get_cache_alignment();
 502
 503         /* Only cache aligned DMA transfers are reliable */
 504         if (!IS_ALIGNED(vaddr | size, dma_align)) {
 505                 pr_debug("user data must be aligned to %lu bytes\n", dma_align);
 506                 return ERR_PTR(-EINVAL);
 507         }
 508
 509         if (!size) {
 510                 pr_debug("size is zero\n");
 511                 return ERR_PTR(-EINVAL);
 512         }
 513
 514         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 515         if (!buf)
 516                 return ERR_PTR(-ENOMEM);
 517
 518         buf->dev = conf->dev;
 519         buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 520
 521         start = vaddr & PAGE_MASK;
 522         offset = vaddr & ~PAGE_MASK;
 523         end = PAGE_ALIGN(vaddr + size);
 524         n_pages = (end - start) >> PAGE_SHIFT;
 525
 526         pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
 527         if (!pages) {
 528                 ret = -ENOMEM;
 529                 pr_err("failed to allocate pages table\n");
 530                 goto fail_buf;
 531         }
 532
 533         /* current->mm->mmap_sem is taken by videobuf2 core */
 534         vma = find_vma(current->mm, vaddr);
 535         if (!vma) {
 536                 pr_err("no vma for address %lu\n", vaddr);
 537                 ret = -EFAULT;
 538                 goto fail_pages;
 539         }
 540
 541         if (vma->vm_end < vaddr + size) {
 542                 pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
 543                 ret = -EFAULT;
 544                 goto fail_pages;
 545         }
 546
 547         buf->vma = vb2_get_vma(vma);
 548         if (!buf->vma) {
 549                 pr_err("failed to copy vma\n");
 550                 ret = -ENOMEM;
 551                 goto fail_pages;
 552         }
 553
 554         /* extract page list from userspace mapping */
 555         ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
 556         if (ret) {
 557                 pr_err("failed to get user pages\n");
 558                 goto fail_vma;
 559         }
 560
 561         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 562         if (!sgt) {
 563                 pr_err("failed to allocate sg table\n");
 564                 ret = -ENOMEM;
 565                 goto fail_get_user_pages;
 566         }
 567
 568         ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
 569                 offset, size, GFP_KERNEL);
 570         if (ret) {
 571                 pr_err("failed to initialize sg table\n");
 572                 goto fail_sgt;
 573         }
 574
 575         /* pages are no longer needed */
 576         kfree(pages);
 577         pages = NULL;
 578
 579         sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents,
 580                 buf->dma_dir);
 581         if (sgt->nents <= 0) {
 582                 pr_err("failed to map scatterlist\n");
 583                 ret = -EIO;
 584                 goto fail_sgt_init;
 585         }
 586
 587         contig_size = vb2_dc_get_contiguous_size(sgt);
 588         if (contig_size < size) {
 589                 pr_err("contiguous mapping is too small %lu/%lu\n",
 590                         contig_size, size);
 591                 ret = -EFAULT;
 592                 goto fail_map_sg;
 593         }
 594
 595         buf->dma_addr = sg_dma_address(sgt->sgl);
 596         buf->size = size;
 597         buf->dma_sgt = sgt;
 598
 599         return buf;
 600
 601 fail_map_sg:
 602         dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 603
 604 fail_sgt_init:
 605         if (!vma_is_io(buf->vma))
 606                 vb2_dc_sgt_foreach_page(sgt, put_page);
 607         sg_free_table(sgt);
 608
 609 fail_sgt:
 610         kfree(sgt);
 611
 612 fail_get_user_pages:
 613         if (pages && !vma_is_io(buf->vma))
 614                 while (n_pages)
 615                         put_page(pages[--n_pages]);
 616
 617 fail_vma:
 618         vb2_put_vma(buf->vma);
 619
 620 fail_pages:
 621         kfree(pages); /* kfree is NULL-proof */
 622
 623 fail_buf:
 624         kfree(buf);
 625
 626         return ERR_PTR(ret);
 627 }
 628
 629 /*********************************************/
 630 /*       callbacks for DMABUF buffers        */
 631 /*********************************************/
 632
 633 static int vb2_dc_map_dmabuf(void *mem_priv)
 634 {
 635         struct vb2_dc_buf *buf = mem_priv;
 636         struct sg_table *sgt;
 637         unsigned long contig_size;
 638
 639         if (WARN_ON(!buf->db_attach)) {
 640                 pr_err("trying to pin a non attached buffer\n");
 641                 return -EINVAL;
 642         }
 643
 644         if (WARN_ON(buf->dma_sgt)) {
 645                 pr_err("dmabuf buffer is already pinned\n");
 646                 return 0;
 647         }
 648
 649         /* get the associated scatterlist for this buffer */
 650         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 651         if (IS_ERR_OR_NULL(sgt)) {
 652                 pr_err("Error getting dmabuf scatterlist\n");
 653                 return -EINVAL;
 654         }
 655
 656         /* checking if dmabuf is big enough to store contiguous chunk */
 657         contig_size = vb2_dc_get_contiguous_size(sgt);
 658         if (contig_size < buf->size) {
 659                 pr_err("contiguous chunk is too small %lu/%lu b\n",
 660                         contig_size, buf->size);
 661                 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 662                 return -EFAULT;
 663         }
 664
 665         buf->dma_addr = sg_dma_address(sgt->sgl);
 666         buf->dma_sgt = sgt;
 667
 668         return 0;
 669 }
 670
 671 static void vb2_dc_unmap_dmabuf(void *mem_priv)
 672 {
 673         struct vb2_dc_buf *buf = mem_priv;
 674         struct sg_table *sgt = buf->dma_sgt;
 675
 676         if (WARN_ON(!buf->db_attach)) {
 677                 pr_err("trying to unpin a not attached buffer\n");
 678                 return;
 679         }
 680
 681         if (WARN_ON(!sgt)) {
 682                 pr_err("dmabuf buffer is already unpinned\n");
 683                 return;
 684         }
 685
 686         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 687
 688         buf->dma_addr = 0;
 689         buf->dma_sgt = NULL;
 690 }
 691
 692 static void vb2_dc_detach_dmabuf(void *mem_priv)
 693 {
 694         struct vb2_dc_buf *buf = mem_priv;
 695
 696         /* if vb2 works correctly you should never detach mapped buffer */
 697         if (WARN_ON(buf->dma_addr))
 698                 vb2_dc_unmap_dmabuf(buf);
 699
 700         /* detach this attachment */
 701         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 702         kfree(buf);
 703 }
 704
 705 static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 706         unsigned long size, int write)
 707 {
 708         struct vb2_dc_conf *conf = alloc_ctx;
 709         struct vb2_dc_buf *buf;
 710         struct dma_buf_attachment *dba;
 711
 712         if (dbuf->size < size)
 713                 return ERR_PTR(-EFAULT);
 714
 715         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 716         if (!buf)
 717                 return ERR_PTR(-ENOMEM);
 718
 719         buf->dev = conf->dev;
 720         /* create attachment for the dmabuf with the user device */
 721         dba = dma_buf_attach(dbuf, buf->dev);
 722         if (IS_ERR(dba)) {
 723                 pr_err("failed to attach dmabuf\n");
 724                 kfree(buf);
 725                 return dba;
 726         }
 727
 728         buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 729         buf->size = size;
 730         buf->db_attach = dba;
 731
 732         return buf;
 733 }
 734
 735 /*********************************************/
 736 /*       DMA CONTIG exported functions       */
 737 /*********************************************/
 738
 739 const struct vb2_mem_ops vb2_dma_contig_memops = {
 740         .alloc          = vb2_dc_alloc,
 741         .put            = vb2_dc_put,
 742 #ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT
 743         .get_dmabuf     = vb2_dc_get_dmabuf,
 744 #endif
 745         .cookie         = vb2_dc_cookie,
 746         .vaddr          = vb2_dc_vaddr,
 747         .mmap           = vb2_dc_mmap,
 748         .get_userptr    = vb2_dc_get_userptr,
 749         .put_userptr    = vb2_dc_put_userptr,
 750         .prepare        = vb2_dc_prepare,
 751         .finish         = vb2_dc_finish,
 752         .map_dmabuf     = vb2_dc_map_dmabuf,
 753         .unmap_dmabuf   = vb2_dc_unmap_dmabuf,
 754         .attach_dmabuf  = vb2_dc_attach_dmabuf,
 755         .detach_dmabuf  = vb2_dc_detach_dmabuf,
 756         .num_users      = vb2_dc_num_users,
 757 };
 758 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
 759
 760 void *vb2_dma_contig_init_ctx(struct device *dev)
 761 {
 762         struct vb2_dc_conf *conf;
 763
 764         conf = kzalloc(sizeof *conf, GFP_KERNEL);
 765         if (!conf)
 766                 return ERR_PTR(-ENOMEM);
 767
 768         conf->dev = dev;
 769
 770         return conf;
 771 }
 772 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
 773
 774 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
 775 {
 776         kfree(alloc_ctx);
 777 }
 778 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
 779
 780 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
 781 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
 782 MODULE_LICENSE("GPL");