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

   1 /*
   2  * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  *
   6  * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/mm.h>
  15 #include <linux/scatterlist.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/vmalloc.h>
  19
  20 #include <media/videobuf2-core.h>
  21 #include <media/videobuf2-memops.h>
  22 #include <media/videobuf2-dma-sg.h>
  23
  24 static int debug;
  25 module_param(debug, int, 0644);
  26
  27 #define dprintk(level, fmt, arg...)                                     \
  28         do {                                                            \
  29                 if (debug >= level)                                     \
  30                         printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg);  \
  31         } while (0)
  32
  33 struct vb2_dma_sg_conf {
  34         struct device           *dev;
  35 };
  36
  37 struct vb2_dma_sg_buf {
  38         struct device                   *dev;
  39         void                            *vaddr;
  40         struct page                     **pages;
  41         int                             offset;
  42         enum dma_data_direction         dma_dir;
  43         struct sg_table                 sg_table;
  44         /*
  45          * This will point to sg_table when used with the MMAP or USERPTR
  46          * memory model, and to the dma_buf sglist when used with the
  47          * DMABUF memory model.
  48          */
  49         struct sg_table                 *dma_sgt;
  50         size_t                          size;
  51         unsigned int                    num_pages;
  52         atomic_t                        refcount;
  53         struct vb2_vmarea_handler       handler;
  54         struct vm_area_struct           *vma;
  55
  56         struct dma_buf_attachment       *db_attach;
  57 };
  58
  59 static void vb2_dma_sg_put(void *buf_priv);
  60
  61 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
  62                 gfp_t gfp_flags)
  63 {
  64         unsigned int last_page = 0;
  65         int size = buf->size;
  66
  67         while (size > 0) {
  68                 struct page *pages;
  69                 int order;
  70                 int i;
  71
  72                 order = get_order(size);
  73                 /* Dont over allocate*/
  74                 if ((PAGE_SIZE << order) > size)
  75                         order--;
  76
  77                 pages = NULL;
  78                 while (!pages) {
  79                         pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
  80                                         __GFP_NOWARN | gfp_flags, order);
  81                         if (pages)
  82                                 break;
  83
  84                         if (order == 0) {
  85                                 while (last_page--)
  86                                         __free_page(buf->pages[last_page]);
  87                                 return -ENOMEM;
  88                         }
  89                         order--;
  90                 }
  91
  92                 split_page(pages, order);
  93                 for (i = 0; i < (1 << order); i++)
  94                         buf->pages[last_page++] = &pages[i];
  95
  96                 size -= PAGE_SIZE << order;
  97         }
  98
  99         return 0;
 100 }
 101
 102 static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
 103                               enum dma_data_direction dma_dir, gfp_t gfp_flags)
 104 {
 105         struct vb2_dma_sg_conf *conf = alloc_ctx;
 106         struct vb2_dma_sg_buf *buf;
 107         struct sg_table *sgt;
 108         int ret;
 109         int num_pages;
 110         DEFINE_DMA_ATTRS(attrs);
 111
 112         dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 113
 114         if (WARN_ON(alloc_ctx == NULL))
 115                 return NULL;
 116         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 117         if (!buf)
 118                 return NULL;
 119
 120         buf->vaddr = NULL;
 121         buf->dma_dir = dma_dir;
 122         buf->offset = 0;
 123         buf->size = size;
 124         /* size is already page aligned */
 125         buf->num_pages = size >> PAGE_SHIFT;
 126         buf->dma_sgt = &buf->sg_table;
 127
 128         buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
 129                              GFP_KERNEL);
 130         if (!buf->pages)
 131                 goto fail_pages_array_alloc;
 132
 133         ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
 134         if (ret)
 135                 goto fail_pages_alloc;
 136
 137         ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 138                         buf->num_pages, 0, size, GFP_KERNEL);
 139         if (ret)
 140                 goto fail_table_alloc;
 141
 142         /* Prevent the device from being released while the buffer is used */
 143         buf->dev = get_device(conf->dev);
 144
 145         sgt = &buf->sg_table;
 146         /*
 147          * No need to sync to the device, this will happen later when the
 148          * prepare() memop is called.
 149          */
 150         sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 151                                       buf->dma_dir, &attrs);
 152         if (!sgt->nents)
 153                 goto fail_map;
 154
 155         buf->handler.refcount = &buf->refcount;
 156         buf->handler.put = vb2_dma_sg_put;
 157         buf->handler.arg = buf;
 158
 159         atomic_inc(&buf->refcount);
 160
 161         dprintk(1, "%s: Allocated buffer of %d pages\n",
 162                 __func__, buf->num_pages);
 163         return buf;
 164
 165 fail_map:
 166         put_device(buf->dev);
 167         sg_free_table(buf->dma_sgt);
 168 fail_table_alloc:
 169         num_pages = buf->num_pages;
 170         while (num_pages--)
 171                 __free_page(buf->pages[num_pages]);
 172 fail_pages_alloc:
 173         kfree(buf->pages);
 174 fail_pages_array_alloc:
 175         kfree(buf);
 176         return NULL;
 177 }
 178
 179 static void vb2_dma_sg_put(void *buf_priv)
 180 {
 181         struct vb2_dma_sg_buf *buf = buf_priv;
 182         struct sg_table *sgt = &buf->sg_table;
 183         int i = buf->num_pages;
 184
 185         if (atomic_dec_and_test(&buf->refcount)) {
 186                 DEFINE_DMA_ATTRS(attrs);
 187
 188                 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 189                 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
 190                         buf->num_pages);
 191                 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 192                                    buf->dma_dir, &attrs);
 193                 if (buf->vaddr)
 194                         vm_unmap_ram(buf->vaddr, buf->num_pages);
 195                 sg_free_table(buf->dma_sgt);
 196                 while (--i >= 0)
 197                         __free_page(buf->pages[i]);
 198                 kfree(buf->pages);
 199                 put_device(buf->dev);
 200                 kfree(buf);
 201         }
 202 }
 203
 204 static void vb2_dma_sg_prepare(void *buf_priv)
 205 {
 206         struct vb2_dma_sg_buf *buf = buf_priv;
 207         struct sg_table *sgt = buf->dma_sgt;
 208
 209         /* DMABUF exporter will flush the cache for us */
 210         if (buf->db_attach)
 211                 return;
 212
 213         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 214 }
 215
 216 static void vb2_dma_sg_finish(void *buf_priv)
 217 {
 218         struct vb2_dma_sg_buf *buf = buf_priv;
 219         struct sg_table *sgt = buf->dma_sgt;
 220
 221         /* DMABUF exporter will flush the cache for us */
 222         if (buf->db_attach)
 223                 return;
 224
 225         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 226 }
 227
 228 static inline int vma_is_io(struct vm_area_struct *vma)
 229 {
 230         return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
 231 }
 232
 233 static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
 234                                     unsigned long size,
 235                                     enum dma_data_direction dma_dir)
 236 {
 237         struct vb2_dma_sg_conf *conf = alloc_ctx;
 238         struct vb2_dma_sg_buf *buf;
 239         unsigned long first, last;
 240         int num_pages_from_user;
 241         struct vm_area_struct *vma;
 242         struct sg_table *sgt;
 243         DEFINE_DMA_ATTRS(attrs);
 244
 245         dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 246
 247         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 248         if (!buf)
 249                 return NULL;
 250
 251         buf->vaddr = NULL;
 252         buf->dev = conf->dev;
 253         buf->dma_dir = dma_dir;
 254         buf->offset = vaddr & ~PAGE_MASK;
 255         buf->size = size;
 256         buf->dma_sgt = &buf->sg_table;
 257
 258         first = (vaddr           & PAGE_MASK) >> PAGE_SHIFT;
 259         last  = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
 260         buf->num_pages = last - first + 1;
 261
 262         buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
 263                              GFP_KERNEL);
 264         if (!buf->pages)
 265                 goto userptr_fail_alloc_pages;
 266
 267         vma = find_vma(current->mm, vaddr);
 268         if (!vma) {
 269                 dprintk(1, "no vma for address %lu\n", vaddr);
 270                 goto userptr_fail_find_vma;
 271         }
 272
 273         if (vma->vm_end < vaddr + size) {
 274                 dprintk(1, "vma at %lu is too small for %lu bytes\n",
 275                         vaddr, size);
 276                 goto userptr_fail_find_vma;
 277         }
 278
 279         buf->vma = vb2_get_vma(vma);
 280         if (!buf->vma) {
 281                 dprintk(1, "failed to copy vma\n");
 282                 goto userptr_fail_find_vma;
 283         }
 284
 285         if (vma_is_io(buf->vma)) {
 286                 for (num_pages_from_user = 0;
 287                      num_pages_from_user < buf->num_pages;
 288                      ++num_pages_from_user, vaddr += PAGE_SIZE) {
 289                         unsigned long pfn;
 290
 291                         if (follow_pfn(vma, vaddr, &pfn)) {
 292                                 dprintk(1, "no page for address %lu\n", vaddr);
 293                                 break;
 294                         }
 295                         buf->pages[num_pages_from_user] = pfn_to_page(pfn);
 296                 }
 297         } else
 298                 num_pages_from_user = get_user_pages(current, current->mm,
 299                                              vaddr & PAGE_MASK,
 300                                              buf->num_pages,
 301                                              buf->dma_dir == DMA_FROM_DEVICE,
 302                                              1, /* force */
 303                                              buf->pages,
 304                                              NULL);
 305
 306         if (num_pages_from_user != buf->num_pages)
 307                 goto userptr_fail_get_user_pages;
 308
 309         if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 310                         buf->num_pages, buf->offset, size, 0))
 311                 goto userptr_fail_alloc_table_from_pages;
 312
 313         sgt = &buf->sg_table;
 314         /*
 315          * No need to sync to the device, this will happen later when the
 316          * prepare() memop is called.
 317          */
 318         sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
 319                                       buf->dma_dir, &attrs);
 320         if (!sgt->nents)
 321                 goto userptr_fail_map;
 322
 323         return buf;
 324
 325 userptr_fail_map:
 326         sg_free_table(&buf->sg_table);
 327 userptr_fail_alloc_table_from_pages:
 328 userptr_fail_get_user_pages:
 329         dprintk(1, "get_user_pages requested/got: %d/%d]\n",
 330                 buf->num_pages, num_pages_from_user);
 331         if (!vma_is_io(buf->vma))
 332                 while (--num_pages_from_user >= 0)
 333                         put_page(buf->pages[num_pages_from_user]);
 334         vb2_put_vma(buf->vma);
 335 userptr_fail_find_vma:
 336         kfree(buf->pages);
 337 userptr_fail_alloc_pages:
 338         kfree(buf);
 339         return NULL;
 340 }
 341
 342 /*
 343  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
 344  *               be used
 345  */
 346 static void vb2_dma_sg_put_userptr(void *buf_priv)
 347 {
 348         struct vb2_dma_sg_buf *buf = buf_priv;
 349         struct sg_table *sgt = &buf->sg_table;
 350         int i = buf->num_pages;
 351         DEFINE_DMA_ATTRS(attrs);
 352
 353         dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 354
 355         dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
 356                __func__, buf->num_pages);
 357         dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
 358                            &attrs);
 359         if (buf->vaddr)
 360                 vm_unmap_ram(buf->vaddr, buf->num_pages);
 361         sg_free_table(buf->dma_sgt);
 362         while (--i >= 0) {
 363                 if (buf->dma_dir == DMA_FROM_DEVICE)
 364                         set_page_dirty_lock(buf->pages[i]);
 365                 if (!vma_is_io(buf->vma))
 366                         put_page(buf->pages[i]);
 367         }
 368         kfree(buf->pages);
 369         vb2_put_vma(buf->vma);
 370         kfree(buf);
 371 }
 372
 373 static void *vb2_dma_sg_vaddr(void *buf_priv)
 374 {
 375         struct vb2_dma_sg_buf *buf = buf_priv;
 376
 377         BUG_ON(!buf);
 378
 379         if (!buf->vaddr) {
 380                 if (buf->db_attach)
 381                         buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
 382                 else
 383                         buf->vaddr = vm_map_ram(buf->pages,
 384                                         buf->num_pages, -1, PAGE_KERNEL);
 385         }
 386
 387         /* add offset in case userptr is not page-aligned */
 388         return buf->vaddr ? buf->vaddr + buf->offset : NULL;
 389 }
 390
 391 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
 392 {
 393         struct vb2_dma_sg_buf *buf = buf_priv;
 394
 395         return atomic_read(&buf->refcount);
 396 }
 397
 398 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
 399 {
 400         struct vb2_dma_sg_buf *buf = buf_priv;
 401         unsigned long uaddr = vma->vm_start;
 402         unsigned long usize = vma->vm_end - vma->vm_start;
 403         int i = 0;
 404
 405         if (!buf) {
 406                 printk(KERN_ERR "No memory to map\n");
 407                 return -EINVAL;
 408         }
 409
 410         do {
 411                 int ret;
 412
 413                 ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
 414                 if (ret) {
 415                         printk(KERN_ERR "Remapping memory, error: %d\n", ret);
 416                         return ret;
 417                 }
 418
 419                 uaddr += PAGE_SIZE;
 420                 usize -= PAGE_SIZE;
 421         } while (usize > 0);
 422
 423
 424         /*
 425          * Use common vm_area operations to track buffer refcount.
 426          */
 427         vma->vm_private_data    = &buf->handler;
 428         vma->vm_ops             = &vb2_common_vm_ops;
 429
 430         vma->vm_ops->open(vma);
 431
 432         return 0;
 433 }
 434
 435 /*********************************************/
 436 /*         DMABUF ops for exporters          */
 437 /*********************************************/
 438
 439 struct vb2_dma_sg_attachment {
 440         struct sg_table sgt;
 441         enum dma_data_direction dma_dir;
 442 };
 443
 444 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
 445         struct dma_buf_attachment *dbuf_attach)
 446 {
 447         struct vb2_dma_sg_attachment *attach;
 448         unsigned int i;
 449         struct scatterlist *rd, *wr;
 450         struct sg_table *sgt;
 451         struct vb2_dma_sg_buf *buf = dbuf->priv;
 452         int ret;
 453
 454         attach = kzalloc(sizeof(*attach), GFP_KERNEL);
 455         if (!attach)
 456                 return -ENOMEM;
 457
 458         sgt = &attach->sgt;
 459         /* Copy the buf->base_sgt scatter list to the attachment, as we can't
 460          * map the same scatter list to multiple attachments at the same time.
 461          */
 462         ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
 463         if (ret) {
 464                 kfree(attach);
 465                 return -ENOMEM;
 466         }
 467
 468         rd = buf->dma_sgt->sgl;
 469         wr = sgt->sgl;
 470         for (i = 0; i < sgt->orig_nents; ++i) {
 471                 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
 472                 rd = sg_next(rd);
 473                 wr = sg_next(wr);
 474         }
 475
 476         attach->dma_dir = DMA_NONE;
 477         dbuf_attach->priv = attach;
 478
 479         return 0;
 480 }
 481
 482 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
 483         struct dma_buf_attachment *db_attach)
 484 {
 485         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 486         struct sg_table *sgt;
 487
 488         if (!attach)
 489                 return;
 490
 491         sgt = &attach->sgt;
 492
 493         /* release the scatterlist cache */
 494         if (attach->dma_dir != DMA_NONE)
 495                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 496                         attach->dma_dir);
 497         sg_free_table(sgt);
 498         kfree(attach);
 499         db_attach->priv = NULL;
 500 }
 501
 502 static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
 503         struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
 504 {
 505         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 506         /* stealing dmabuf mutex to serialize map/unmap operations */
 507         struct mutex *lock = &db_attach->dmabuf->lock;
 508         struct sg_table *sgt;
 509
 510         mutex_lock(lock);
 511
 512         sgt = &attach->sgt;
 513         /* return previously mapped sg table */
 514         if (attach->dma_dir == dma_dir) {
 515                 mutex_unlock(lock);
 516                 return sgt;
 517         }
 518
 519         /* release any previous cache */
 520         if (attach->dma_dir != DMA_NONE) {
 521                 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 522                         attach->dma_dir);
 523                 attach->dma_dir = DMA_NONE;
 524         }
 525
 526         /* mapping to the client with new direction */
 527         sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
 528                                 dma_dir);
 529         if (!sgt->nents) {
 530                 pr_err("failed to map scatterlist\n");
 531                 mutex_unlock(lock);
 532                 return ERR_PTR(-EIO);
 533         }
 534
 535         attach->dma_dir = dma_dir;
 536
 537         mutex_unlock(lock);
 538
 539         return sgt;
 540 }
 541
 542 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 543         struct sg_table *sgt, enum dma_data_direction dma_dir)
 544 {
 545         /* nothing to be done here */
 546 }
 547
 548 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
 549 {
 550         /* drop reference obtained in vb2_dma_sg_get_dmabuf */
 551         vb2_dma_sg_put(dbuf->priv);
 552 }
 553
 554 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
 555 {
 556         struct vb2_dma_sg_buf *buf = dbuf->priv;
 557
 558         return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
 559 }
 560
 561 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
 562 {
 563         struct vb2_dma_sg_buf *buf = dbuf->priv;
 564
 565         return vb2_dma_sg_vaddr(buf);
 566 }
 567
 568 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
 569         struct vm_area_struct *vma)
 570 {
 571         return vb2_dma_sg_mmap(dbuf->priv, vma);
 572 }
 573
 574 static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
 575         .attach = vb2_dma_sg_dmabuf_ops_attach,
 576         .detach = vb2_dma_sg_dmabuf_ops_detach,
 577         .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
 578         .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
 579         .kmap = vb2_dma_sg_dmabuf_ops_kmap,
 580         .kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
 581         .vmap = vb2_dma_sg_dmabuf_ops_vmap,
 582         .mmap = vb2_dma_sg_dmabuf_ops_mmap,
 583         .release = vb2_dma_sg_dmabuf_ops_release,
 584 };
 585
 586 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
 587 {
 588         struct vb2_dma_sg_buf *buf = buf_priv;
 589         struct dma_buf *dbuf;
 590         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 591
 592         exp_info.ops = &vb2_dma_sg_dmabuf_ops;
 593         exp_info.size = buf->size;
 594         exp_info.flags = flags;
 595         exp_info.priv = buf;
 596
 597         if (WARN_ON(!buf->dma_sgt))
 598                 return NULL;
 599
 600         dbuf = dma_buf_export(&exp_info);
 601         if (IS_ERR(dbuf))
 602                 return NULL;
 603
 604         /* dmabuf keeps reference to vb2 buffer */
 605         atomic_inc(&buf->refcount);
 606
 607         return dbuf;
 608 }
 609
 610 /*********************************************/
 611 /*       callbacks for DMABUF buffers        */
 612 /*********************************************/
 613
 614 static int vb2_dma_sg_map_dmabuf(void *mem_priv)
 615 {
 616         struct vb2_dma_sg_buf *buf = mem_priv;
 617         struct sg_table *sgt;
 618
 619         if (WARN_ON(!buf->db_attach)) {
 620                 pr_err("trying to pin a non attached buffer\n");
 621                 return -EINVAL;
 622         }
 623
 624         if (WARN_ON(buf->dma_sgt)) {
 625                 pr_err("dmabuf buffer is already pinned\n");
 626                 return 0;
 627         }
 628
 629         /* get the associated scatterlist for this buffer */
 630         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 631         if (IS_ERR(sgt)) {
 632                 pr_err("Error getting dmabuf scatterlist\n");
 633                 return -EINVAL;
 634         }
 635
 636         buf->dma_sgt = sgt;
 637         buf->vaddr = NULL;
 638
 639         return 0;
 640 }
 641
 642 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
 643 {
 644         struct vb2_dma_sg_buf *buf = mem_priv;
 645         struct sg_table *sgt = buf->dma_sgt;
 646
 647         if (WARN_ON(!buf->db_attach)) {
 648                 pr_err("trying to unpin a not attached buffer\n");
 649                 return;
 650         }
 651
 652         if (WARN_ON(!sgt)) {
 653                 pr_err("dmabuf buffer is already unpinned\n");
 654                 return;
 655         }
 656
 657         if (buf->vaddr) {
 658                 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
 659                 buf->vaddr = NULL;
 660         }
 661         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 662
 663         buf->dma_sgt = NULL;
 664 }
 665
 666 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
 667 {
 668         struct vb2_dma_sg_buf *buf = mem_priv;
 669
 670         /* if vb2 works correctly you should never detach mapped buffer */
 671         if (WARN_ON(buf->dma_sgt))
 672                 vb2_dma_sg_unmap_dmabuf(buf);
 673
 674         /* detach this attachment */
 675         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 676         kfree(buf);
 677 }
 678
 679 static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 680         unsigned long size, enum dma_data_direction dma_dir)
 681 {
 682         struct vb2_dma_sg_conf *conf = alloc_ctx;
 683         struct vb2_dma_sg_buf *buf;
 684         struct dma_buf_attachment *dba;
 685
 686         if (dbuf->size < size)
 687                 return ERR_PTR(-EFAULT);
 688
 689         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 690         if (!buf)
 691                 return ERR_PTR(-ENOMEM);
 692
 693         buf->dev = conf->dev;
 694         /* create attachment for the dmabuf with the user device */
 695         dba = dma_buf_attach(dbuf, buf->dev);
 696         if (IS_ERR(dba)) {
 697                 pr_err("failed to attach dmabuf\n");
 698                 kfree(buf);
 699                 return dba;
 700         }
 701
 702         buf->dma_dir = dma_dir;
 703         buf->size = size;
 704         buf->db_attach = dba;
 705
 706         return buf;
 707 }
 708
 709 static void *vb2_dma_sg_cookie(void *buf_priv)
 710 {
 711         struct vb2_dma_sg_buf *buf = buf_priv;
 712
 713         return buf->dma_sgt;
 714 }
 715
 716 const struct vb2_mem_ops vb2_dma_sg_memops = {
 717         .alloc          = vb2_dma_sg_alloc,
 718         .put            = vb2_dma_sg_put,
 719         .get_userptr    = vb2_dma_sg_get_userptr,
 720         .put_userptr    = vb2_dma_sg_put_userptr,
 721         .prepare        = vb2_dma_sg_prepare,
 722         .finish         = vb2_dma_sg_finish,
 723         .vaddr          = vb2_dma_sg_vaddr,
 724         .mmap           = vb2_dma_sg_mmap,
 725         .num_users      = vb2_dma_sg_num_users,
 726         .get_dmabuf     = vb2_dma_sg_get_dmabuf,
 727         .map_dmabuf     = vb2_dma_sg_map_dmabuf,
 728         .unmap_dmabuf   = vb2_dma_sg_unmap_dmabuf,
 729         .attach_dmabuf  = vb2_dma_sg_attach_dmabuf,
 730         .detach_dmabuf  = vb2_dma_sg_detach_dmabuf,
 731         .cookie         = vb2_dma_sg_cookie,
 732 };
 733 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
 734
 735 void *vb2_dma_sg_init_ctx(struct device *dev)
 736 {
 737         struct vb2_dma_sg_conf *conf;
 738
 739         conf = kzalloc(sizeof(*conf), GFP_KERNEL);
 740         if (!conf)
 741                 return ERR_PTR(-ENOMEM);
 742
 743         conf->dev = dev;
 744
 745         return conf;
 746 }
 747 EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx);
 748
 749 void vb2_dma_sg_cleanup_ctx(void *alloc_ctx)
 750 {
 751         if (!IS_ERR_OR_NULL(alloc_ctx))
 752                 kfree(alloc_ctx);
 753 }
 754 EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx);
 755
 756 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
 757 MODULE_AUTHOR("Andrzej Pietrasiewicz");
 758 MODULE_LICENSE("GPL");