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->orig_nents,
 121                                buf->dma_dir);
 122 }
 123
 124 static void vb2_dc_finish(void *buf_priv)
 125 {
 126         struct vb2_dc_buf *buf = buf_priv;
 127         struct sg_table *sgt = buf->dma_sgt;
 128
 129         /* DMABUF exporter will flush the cache for us */
 130         if (!sgt || buf->db_attach)
 131                 return;
 132
 133         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 134 }
 135
 136 /*********************************************/
 137 /*        callbacks for MMAP buffers         */
 138 /*********************************************/
 139
 140 static void vb2_dc_put(void *buf_priv)
 141 {
 142         struct vb2_dc_buf *buf = buf_priv;
 143
 144         if (!atomic_dec_and_test(&buf->refcount))
 145                 return;
 146
 147         if (buf->sgt_base) {
 148                 sg_free_table(buf->sgt_base);
 149                 kfree(buf->sgt_base);
 150         }
 151         dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
 152         put_device(buf->dev);
 153         kfree(buf);
 154 }
 155
 156 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
 157 {
 158         struct vb2_dc_conf *conf = alloc_ctx;
 159         struct device *dev = conf->dev;
 160         struct vb2_dc_buf *buf;
 161
 162         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 163         if (!buf)
 164                 return ERR_PTR(-ENOMEM);
 165
 166         buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr,
 167                                                 GFP_KERNEL | gfp_flags);
 168         if (!buf->vaddr) {
 169                 dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
 170                 kfree(buf);
 171                 return ERR_PTR(-ENOMEM);
 172         }
 173
 174         /* Prevent the device from being released while the buffer is used */
 175         buf->dev = get_device(dev);
 176         buf->size = size;
 177
 178         buf->handler.refcount = &buf->refcount;
 179         buf->handler.put = vb2_dc_put;
 180         buf->handler.arg = buf;
 181
 182         atomic_inc(&buf->refcount);
 183
 184         return buf;
 185 }
 186
 187 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 188 {
 189         struct vb2_dc_buf *buf = buf_priv;
 190         int ret;
 191
 192         if (!buf) {
 193                 printk(KERN_ERR "No buffer to map\n");
 194                 return -EINVAL;
 195         }
 196
 197         /*
 198          * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
 199          * map whole buffer
 200          */
 201         vma->vm_pgoff = 0;
 202
 203         ret = dma_mmap_coherent(buf->dev, vma, buf->vaddr,
 204                 buf->dma_addr, buf->size);
 205
 206         if (ret) {
 207                 pr_err("Remapping memory failed, error: %d\n", ret);
 208                 return ret;
 209         }
 210
 211         vma->vm_flags           |= VM_DONTEXPAND | VM_DONTDUMP;
 212         vma->vm_private_data    = &buf->handler;
 213         vma->vm_ops             = &vb2_common_vm_ops;
 214
 215         vma->vm_ops->open(vma);
 216
 217         pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
 218                 __func__, (unsigned long)buf->dma_addr, vma->vm_start,
 219                 buf->size);
 220
 221         return 0;
 222 }
 223
 224 /*********************************************/
 225 /*         DMABUF ops for exporters          */
 226 /*********************************************/
 227
 228 struct vb2_dc_attachment {
 229         struct sg_table sgt;
 230         enum dma_data_direction dir;
 231 };
 232
 233 static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
 234         struct dma_buf_attachment *dbuf_attach)
 235 {
 236         struct vb2_dc_attachment *attach;
 237         unsigned int i;
 238         struct scatterlist *rd, *wr;
 239         struct sg_table *sgt;
 240         struct vb2_dc_buf *buf = dbuf->priv;
 241         int ret;
 242
 243         attach = kzalloc(sizeof(*attach), GFP_KERNEL);
 244         if (!attach)
 245                 return -ENOMEM;
 246
 247         sgt = &attach->sgt;
 248         /* Copy the buf->base_sgt scatter list to the attachment, as we can't
 249          * map the same scatter list to multiple attachments at the same time.
 250          */
 251         ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
 252         if (ret) {
 253                 kfree(attach);
 254                 return -ENOMEM;
 255         }
 256
 257         rd = buf->sgt_base->sgl;
 258         wr = sgt->sgl;
 259         for (i = 0; i < sgt->orig_nents; ++i) {
 260                 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
 261                 rd = sg_next(rd);
 262                 wr = sg_next(wr);
 263         }
 264
 265         attach->dir = DMA_NONE;
 266         dbuf_attach->priv = attach;
 267
 268         return 0;
 269 }
 270
 271 static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
 272         struct dma_buf_attachment *db_attach)
 273 {
 274         struct vb2_dc_attachment *attach = db_attach->priv;
 275         struct sg_table *sgt;
 276
 277         if (!attach)
 278                 return;
 279
 280         sgt = &attach->sgt;
 281
 282         /* release the scatterlist cache */
 283         if (attach->dir != DMA_NONE)
 284                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 285                         attach->dir);
 286         sg_free_table(sgt);
 287         kfree(attach);
 288         db_attach->priv = NULL;
 289 }
 290
 291 static struct sg_table *vb2_dc_dmabuf_ops_map(
 292         struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
 293 {
 294         struct vb2_dc_attachment *attach = db_attach->priv;
 295         /* stealing dmabuf mutex to serialize map/unmap operations */
 296         struct mutex *lock = &db_attach->dmabuf->lock;
 297         struct sg_table *sgt;
 298         int ret;
 299
 300         mutex_lock(lock);
 301
 302         sgt = &attach->sgt;
 303         /* return previously mapped sg table */
 304         if (attach->dir == dir) {
 305                 mutex_unlock(lock);
 306                 return sgt;
 307         }
 308
 309         /* release any previous cache */
 310         if (attach->dir != DMA_NONE) {
 311                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 312                         attach->dir);
 313                 attach->dir = DMA_NONE;
 314         }
 315
 316         /* mapping to the client with new direction */
 317         ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir);
 318         if (ret <= 0) {
 319                 pr_err("failed to map scatterlist\n");
 320                 mutex_unlock(lock);
 321                 return ERR_PTR(-EIO);
 322         }
 323
 324         attach->dir = dir;
 325
 326         mutex_unlock(lock);
 327
 328         return sgt;
 329 }
 330
 331 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 332         struct sg_table *sgt, enum dma_data_direction dir)
 333 {
 334         /* nothing to be done here */
 335 }
 336
 337 static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
 338 {
 339         /* drop reference obtained in vb2_dc_get_dmabuf */
 340         vb2_dc_put(dbuf->priv);
 341 }
 342
 343 static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
 344 {
 345         struct vb2_dc_buf *buf = dbuf->priv;
 346
 347         return buf->vaddr + pgnum * PAGE_SIZE;
 348 }
 349
 350 static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
 351 {
 352         struct vb2_dc_buf *buf = dbuf->priv;
 353
 354         return buf->vaddr;
 355 }
 356
 357 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
 358         struct vm_area_struct *vma)
 359 {
 360         return vb2_dc_mmap(dbuf->priv, vma);
 361 }
 362
 363 static struct dma_buf_ops vb2_dc_dmabuf_ops = {
 364         .attach = vb2_dc_dmabuf_ops_attach,
 365         .detach = vb2_dc_dmabuf_ops_detach,
 366         .map_dma_buf = vb2_dc_dmabuf_ops_map,
 367         .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
 368         .kmap = vb2_dc_dmabuf_ops_kmap,
 369         .kmap_atomic = vb2_dc_dmabuf_ops_kmap,
 370         .vmap = vb2_dc_dmabuf_ops_vmap,
 371         .mmap = vb2_dc_dmabuf_ops_mmap,
 372         .release = vb2_dc_dmabuf_ops_release,
 373 };
 374
 375 static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
 376 {
 377         int ret;
 378         struct sg_table *sgt;
 379
 380         sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
 381         if (!sgt) {
 382                 dev_err(buf->dev, "failed to alloc sg table\n");
 383                 return NULL;
 384         }
 385
 386         ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
 387                 buf->size);
 388         if (ret < 0) {
 389                 dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
 390                 kfree(sgt);
 391                 return NULL;
 392         }
 393
 394         return sgt;
 395 }
 396
 397 static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
 398 {
 399         struct vb2_dc_buf *buf = buf_priv;
 400         struct dma_buf *dbuf;
 401
 402         if (!buf->sgt_base)
 403                 buf->sgt_base = vb2_dc_get_base_sgt(buf);
 404
 405         if (WARN_ON(!buf->sgt_base))
 406                 return NULL;
 407
 408         dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0);
 409         if (IS_ERR(dbuf))
 410                 return NULL;
 411
 412         /* dmabuf keeps reference to vb2 buffer */
 413         atomic_inc(&buf->refcount);
 414
 415         return dbuf;
 416 }
 417
 418 /*********************************************/
 419 /*       callbacks for USERPTR buffers       */
 420 /*********************************************/
 421
 422 static inline int vma_is_io(struct vm_area_struct *vma)
 423 {
 424         return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
 425 }
 426
 427 static int vb2_dc_get_user_pfn(unsigned long start, int n_pages,
 428         struct vm_area_struct *vma, unsigned long *res)
 429 {
 430         unsigned long pfn, start_pfn, prev_pfn;
 431         unsigned int i;
 432         int ret;
 433
 434         if (!vma_is_io(vma))
 435                 return -EFAULT;
 436
 437         ret = follow_pfn(vma, start, &pfn);
 438         if (ret)
 439                 return ret;
 440
 441         start_pfn = pfn;
 442         start += PAGE_SIZE;
 443
 444         for (i = 1; i < n_pages; ++i, start += PAGE_SIZE) {
 445                 prev_pfn = pfn;
 446                 ret = follow_pfn(vma, start, &pfn);
 447
 448                 if (ret) {
 449                         pr_err("no page for address %lu\n", start);
 450                         return ret;
 451                 }
 452                 if (pfn != prev_pfn + 1)
 453                         return -EINVAL;
 454         }
 455
 456         *res = start_pfn;
 457         return 0;
 458 }
 459
 460 static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
 461         int n_pages, struct vm_area_struct *vma, int write)
 462 {
 463         if (vma_is_io(vma)) {
 464                 unsigned int i;
 465
 466                 for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
 467                         unsigned long pfn;
 468                         int ret = follow_pfn(vma, start, &pfn);
 469
 470                         if (!pfn_valid(pfn))
 471                                 return -EINVAL;
 472
 473                         if (ret) {
 474                                 pr_err("no page for address %lu\n", start);
 475                                 return ret;
 476                         }
 477                         pages[i] = pfn_to_page(pfn);
 478                 }
 479         } else {
 480                 int n;
 481
 482                 n = get_user_pages(current, current->mm, start & PAGE_MASK,
 483                         n_pages, write, 1, pages, NULL);
 484                 /* negative error means that no page was pinned */
 485                 n = max(n, 0);
 486                 if (n != n_pages) {
 487                         pr_err("got only %d of %d user pages\n", n, n_pages);
 488                         while (n)
 489                                 put_page(pages[--n]);
 490                         return -EFAULT;
 491                 }
 492         }
 493
 494         return 0;
 495 }
 496
 497 static void vb2_dc_put_dirty_page(struct page *page)
 498 {
 499         set_page_dirty_lock(page);
 500         put_page(page);
 501 }
 502
 503 static void vb2_dc_put_userptr(void *buf_priv)
 504 {
 505         struct vb2_dc_buf *buf = buf_priv;
 506         struct sg_table *sgt = buf->dma_sgt;
 507
 508         if (sgt) {
 509                 dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 510                 if (!vma_is_io(buf->vma))
 511                         vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
 512
 513                 sg_free_table(sgt);
 514                 kfree(sgt);
 515         }
 516         vb2_put_vma(buf->vma);
 517         kfree(buf);
 518 }
 519
 520 /*
 521  * For some kind of reserved memory there might be no struct page available,
 522  * so all that can be done to support such 'pages' is to try to convert
 523  * pfn to dma address or at the last resort just assume that
 524  * dma address == physical address (like it has been assumed in earlier version
 525  * of videobuf2-dma-contig
 526  */
 527
 528 #ifdef __arch_pfn_to_dma
 529 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
 530 {
 531         return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
 532 }
 533 #elif defined(__pfn_to_bus)
 534 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
 535 {
 536         return (dma_addr_t)__pfn_to_bus(pfn);
 537 }
 538 #elif defined(__pfn_to_phys)
 539 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
 540 {
 541         return (dma_addr_t)__pfn_to_phys(pfn);
 542 }
 543 #else
 544 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
 545 {
 546         /* really, we cannot do anything better at this point */
 547         return (dma_addr_t)(pfn) << PAGE_SHIFT;
 548 }
 549 #endif
 550
 551 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 552         unsigned long size, int write)
 553 {
 554         struct vb2_dc_conf *conf = alloc_ctx;
 555         struct vb2_dc_buf *buf;
 556         unsigned long start;
 557         unsigned long end;
 558         unsigned long offset;
 559         struct page **pages;
 560         int n_pages;
 561         int ret = 0;
 562         struct vm_area_struct *vma;
 563         struct sg_table *sgt;
 564         unsigned long contig_size;
 565         unsigned long dma_align = dma_get_cache_alignment();
 566
 567         /* Only cache aligned DMA transfers are reliable */
 568         if (!IS_ALIGNED(vaddr | size, dma_align)) {
 569                 pr_debug("user data must be aligned to %lu bytes\n", dma_align);
 570                 return ERR_PTR(-EINVAL);
 571         }
 572
 573         if (!size) {
 574                 pr_debug("size is zero\n");
 575                 return ERR_PTR(-EINVAL);
 576         }
 577
 578         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 579         if (!buf)
 580                 return ERR_PTR(-ENOMEM);
 581
 582         buf->dev = conf->dev;
 583         buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 584
 585         start = vaddr & PAGE_MASK;
 586         offset = vaddr & ~PAGE_MASK;
 587         end = PAGE_ALIGN(vaddr + size);
 588         n_pages = (end - start) >> PAGE_SHIFT;
 589
 590         pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
 591         if (!pages) {
 592                 ret = -ENOMEM;
 593                 pr_err("failed to allocate pages table\n");
 594                 goto fail_buf;
 595         }
 596
 597         /* current->mm->mmap_sem is taken by videobuf2 core */
 598         vma = find_vma(current->mm, vaddr);
 599         if (!vma) {
 600                 pr_err("no vma for address %lu\n", vaddr);
 601                 ret = -EFAULT;
 602                 goto fail_pages;
 603         }
 604
 605         if (vma->vm_end < vaddr + size) {
 606                 pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
 607                 ret = -EFAULT;
 608                 goto fail_pages;
 609         }
 610
 611         buf->vma = vb2_get_vma(vma);
 612         if (!buf->vma) {
 613                 pr_err("failed to copy vma\n");
 614                 ret = -ENOMEM;
 615                 goto fail_pages;
 616         }
 617
 618         /* extract page list from userspace mapping */
 619         ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
 620         if (ret) {
 621                 unsigned long pfn;
 622                 if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) {
 623                         buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, pfn);
 624                         buf->size = size;
 625                         kfree(pages);
 626                         return buf;
 627                 }
 628
 629                 pr_err("failed to get user pages\n");
 630                 goto fail_vma;
 631         }
 632
 633         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 634         if (!sgt) {
 635                 pr_err("failed to allocate sg table\n");
 636                 ret = -ENOMEM;
 637                 goto fail_get_user_pages;
 638         }
 639
 640         ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
 641                 offset, size, GFP_KERNEL);
 642         if (ret) {
 643                 pr_err("failed to initialize sg table\n");
 644                 goto fail_sgt;
 645         }
 646
 647         /* pages are no longer needed */
 648         kfree(pages);
 649         pages = NULL;
 650
 651         sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents,
 652                 buf->dma_dir);
 653         if (sgt->nents <= 0) {
 654                 pr_err("failed to map scatterlist\n");
 655                 ret = -EIO;
 656                 goto fail_sgt_init;
 657         }
 658
 659         contig_size = vb2_dc_get_contiguous_size(sgt);
 660         if (contig_size < size) {
 661                 pr_err("contiguous mapping is too small %lu/%lu\n",
 662                         contig_size, size);
 663                 ret = -EFAULT;
 664                 goto fail_map_sg;
 665         }
 666
 667         buf->dma_addr = sg_dma_address(sgt->sgl);
 668         buf->size = size;
 669         buf->dma_sgt = sgt;
 670
 671         return buf;
 672
 673 fail_map_sg:
 674         dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 675
 676 fail_sgt_init:
 677         if (!vma_is_io(buf->vma))
 678                 vb2_dc_sgt_foreach_page(sgt, put_page);
 679         sg_free_table(sgt);
 680
 681 fail_sgt:
 682         kfree(sgt);
 683
 684 fail_get_user_pages:
 685         if (pages && !vma_is_io(buf->vma))
 686                 while (n_pages)
 687                         put_page(pages[--n_pages]);
 688
 689 fail_vma:
 690         vb2_put_vma(buf->vma);
 691
 692 fail_pages:
 693         kfree(pages); /* kfree is NULL-proof */
 694
 695 fail_buf:
 696         kfree(buf);
 697
 698         return ERR_PTR(ret);
 699 }
 700
 701 /*********************************************/
 702 /*       callbacks for DMABUF buffers        */
 703 /*********************************************/
 704
 705 static int vb2_dc_map_dmabuf(void *mem_priv)
 706 {
 707         struct vb2_dc_buf *buf = mem_priv;
 708         struct sg_table *sgt;
 709         unsigned long contig_size;
 710
 711         if (WARN_ON(!buf->db_attach)) {
 712                 pr_err("trying to pin a non attached buffer\n");
 713                 return -EINVAL;
 714         }
 715
 716         if (WARN_ON(buf->dma_sgt)) {
 717                 pr_err("dmabuf buffer is already pinned\n");
 718                 return 0;
 719         }
 720
 721         /* get the associated scatterlist for this buffer */
 722         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 723         if (IS_ERR_OR_NULL(sgt)) {
 724                 pr_err("Error getting dmabuf scatterlist\n");
 725                 return -EINVAL;
 726         }
 727
 728         /* checking if dmabuf is big enough to store contiguous chunk */
 729         contig_size = vb2_dc_get_contiguous_size(sgt);
 730         if (contig_size < buf->size) {
 731                 pr_err("contiguous chunk is too small %lu/%lu b\n",
 732                         contig_size, buf->size);
 733                 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 734                 return -EFAULT;
 735         }
 736
 737         buf->dma_addr = sg_dma_address(sgt->sgl);
 738         buf->dma_sgt = sgt;
 739
 740         return 0;
 741 }
 742
 743 static void vb2_dc_unmap_dmabuf(void *mem_priv)
 744 {
 745         struct vb2_dc_buf *buf = mem_priv;
 746         struct sg_table *sgt = buf->dma_sgt;
 747
 748         if (WARN_ON(!buf->db_attach)) {
 749                 pr_err("trying to unpin a not attached buffer\n");
 750                 return;
 751         }
 752
 753         if (WARN_ON(!sgt)) {
 754                 pr_err("dmabuf buffer is already unpinned\n");
 755                 return;
 756         }
 757
 758         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 759
 760         buf->dma_addr = 0;
 761         buf->dma_sgt = NULL;
 762 }
 763
 764 static void vb2_dc_detach_dmabuf(void *mem_priv)
 765 {
 766         struct vb2_dc_buf *buf = mem_priv;
 767
 768         /* if vb2 works correctly you should never detach mapped buffer */
 769         if (WARN_ON(buf->dma_addr))
 770                 vb2_dc_unmap_dmabuf(buf);
 771
 772         /* detach this attachment */
 773         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 774         kfree(buf);
 775 }
 776
 777 static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 778         unsigned long size, int write)
 779 {
 780         struct vb2_dc_conf *conf = alloc_ctx;
 781         struct vb2_dc_buf *buf;
 782         struct dma_buf_attachment *dba;
 783
 784         if (dbuf->size < size)
 785                 return ERR_PTR(-EFAULT);
 786
 787         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 788         if (!buf)
 789                 return ERR_PTR(-ENOMEM);
 790
 791         buf->dev = conf->dev;
 792         /* create attachment for the dmabuf with the user device */
 793         dba = dma_buf_attach(dbuf, buf->dev);
 794         if (IS_ERR(dba)) {
 795                 pr_err("failed to attach dmabuf\n");
 796                 kfree(buf);
 797                 return dba;
 798         }
 799
 800         buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 801         buf->size = size;
 802         buf->db_attach = dba;
 803
 804         return buf;
 805 }
 806
 807 /*********************************************/
 808 /*       DMA CONTIG exported functions       */
 809 /*********************************************/
 810
 811 const struct vb2_mem_ops vb2_dma_contig_memops = {
 812         .alloc          = vb2_dc_alloc,
 813         .put            = vb2_dc_put,
 814         .get_dmabuf     = vb2_dc_get_dmabuf,
 815         .cookie         = vb2_dc_cookie,
 816         .vaddr          = vb2_dc_vaddr,
 817         .mmap           = vb2_dc_mmap,
 818         .get_userptr    = vb2_dc_get_userptr,
 819         .put_userptr    = vb2_dc_put_userptr,
 820         .prepare        = vb2_dc_prepare,
 821         .finish         = vb2_dc_finish,
 822         .map_dmabuf     = vb2_dc_map_dmabuf,
 823         .unmap_dmabuf   = vb2_dc_unmap_dmabuf,
 824         .attach_dmabuf  = vb2_dc_attach_dmabuf,
 825         .detach_dmabuf  = vb2_dc_detach_dmabuf,
 826         .num_users      = vb2_dc_num_users,
 827 };
 828 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
 829
 830 void *vb2_dma_contig_init_ctx(struct device *dev)
 831 {
 832         struct vb2_dc_conf *conf;
 833
 834         conf = kzalloc(sizeof *conf, GFP_KERNEL);
 835         if (!conf)
 836                 return ERR_PTR(-ENOMEM);
 837
 838         conf->dev = dev;
 839
 840         return conf;
 841 }
 842 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
 843
 844 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
 845 {
 846         kfree(alloc_ctx);
 847 }
 848 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
 849
 850 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
 851 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
 852 MODULE_LICENSE("GPL");