linux/drivers/media/v4l2-core/videobuf-dma-sg.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * helper functions for SG DMA video4linux capture buffers
   4 *
   5 * The functions expect the hardware being able to scatter gather
   6 * (i.e. the buffers are not linear in physical memory, but fragmented
   7 * into PAGE_SIZE chunks).  They also assume the driver does not need
   8 * to touch the video data.
   9 *
  10 * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
  11 *
  12 * Highly based on video-buf written originally by:
  13 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
  14 * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
  15 * (c) 2006 Ted Walther and John Sokol
  16 */
  17
  18#include <linux/init.h>
  19#include <linux/module.h>
  20#include <linux/moduleparam.h>
  21#include <linux/sched/mm.h>
  22#include <linux/slab.h>
  23#include <linux/interrupt.h>
  24#include <linux/pgtable.h>
  25
  26#include <linux/dma-mapping.h>
  27#include <linux/vmalloc.h>
  28#include <linux/pagemap.h>
  29#include <linux/scatterlist.h>
  30#include <asm/page.h>
  31
  32#include <media/videobuf-dma-sg.h>
  33
  34#define MAGIC_DMABUF 0x19721112
  35#define MAGIC_SG_MEM 0x17890714
  36
  37#define MAGIC_CHECK(is, should)                                         \
  38        if (unlikely((is) != (should))) {                               \
  39                printk(KERN_ERR "magic mismatch: %x (expected %x)\n",   \
  40                                is, should);                            \
  41                BUG();                                                  \
  42        }
  43
  44static int debug;
  45module_param(debug, int, 0644);
  46
  47MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers");
  48MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@kernel.org>");
  49MODULE_LICENSE("GPL");
  50
  51#define dprintk(level, fmt, arg...)                                     \
  52        if (debug >= level)                                             \
  53                printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
  54
  55/* --------------------------------------------------------------------- */
  56
  57/*
  58 * Return a scatterlist for some page-aligned vmalloc()'ed memory
  59 * block (NULL on errors).  Memory for the scatterlist is allocated
  60 * using kmalloc.  The caller must free the memory.
  61 */
  62static struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt,
  63                                                  int nr_pages)
  64{
  65        struct scatterlist *sglist;
  66        struct page *pg;
  67        int i;
  68
  69        sglist = vzalloc(array_size(nr_pages, sizeof(*sglist)));
  70        if (NULL == sglist)
  71                return NULL;
  72        sg_init_table(sglist, nr_pages);
  73        for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
  74                pg = vmalloc_to_page(virt);
  75                if (NULL == pg)
  76                        goto err;
  77                BUG_ON(PageHighMem(pg));
  78                sg_set_page(&sglist[i], pg, PAGE_SIZE, 0);
  79        }
  80        return sglist;
  81
  82err:
  83        vfree(sglist);
  84        return NULL;
  85}
  86
  87/*
  88 * Return a scatterlist for a an array of userpages (NULL on errors).
  89 * Memory for the scatterlist is allocated using kmalloc.  The caller
  90 * must free the memory.
  91 */
  92static struct scatterlist *videobuf_pages_to_sg(struct page **pages,
  93                                        int nr_pages, int offset, size_t size)
  94{
  95        struct scatterlist *sglist;
  96        int i;
  97
  98        if (NULL == pages[0])
  99                return NULL;
 100        sglist = vmalloc(array_size(nr_pages, sizeof(*sglist)));
 101        if (NULL == sglist)
 102                return NULL;
 103        sg_init_table(sglist, nr_pages);
 104
 105        if (PageHighMem(pages[0]))
 106                /* DMA to highmem pages might not work */
 107                goto highmem;
 108        sg_set_page(&sglist[0], pages[0],
 109                        min_t(size_t, PAGE_SIZE - offset, size), offset);
 110        size -= min_t(size_t, PAGE_SIZE - offset, size);
 111        for (i = 1; i < nr_pages; i++) {
 112                if (NULL == pages[i])
 113                        goto nopage;
 114                if (PageHighMem(pages[i]))
 115                        goto highmem;
 116                sg_set_page(&sglist[i], pages[i], min_t(size_t, PAGE_SIZE, size), 0);
 117                size -= min_t(size_t, PAGE_SIZE, size);
 118        }
 119        return sglist;
 120
 121nopage:
 122        dprintk(2, "sgl: oops - no page\n");
 123        vfree(sglist);
 124        return NULL;
 125
 126highmem:
 127        dprintk(2, "sgl: oops - highmem page\n");
 128        vfree(sglist);
 129        return NULL;
 130}
 131
 132/* --------------------------------------------------------------------- */
 133
 134struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf)
 135{
 136        struct videobuf_dma_sg_memory *mem = buf->priv;
 137        BUG_ON(!mem);
 138
 139        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 140
 141        return &mem->dma;
 142}
 143EXPORT_SYMBOL_GPL(videobuf_to_dma);
 144
 145static void videobuf_dma_init(struct videobuf_dmabuf *dma)
 146{
 147        memset(dma, 0, sizeof(*dma));
 148        dma->magic = MAGIC_DMABUF;
 149}
 150
 151static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
 152                        int direction, unsigned long data, unsigned long size)
 153{
 154        unsigned long first, last;
 155        int err, rw = 0;
 156        unsigned int flags = FOLL_FORCE;
 157
 158        dma->direction = direction;
 159        switch (dma->direction) {
 160        case DMA_FROM_DEVICE:
 161                rw = READ;
 162                break;
 163        case DMA_TO_DEVICE:
 164                rw = WRITE;
 165                break;
 166        default:
 167                BUG();
 168        }
 169
 170        first = (data          & PAGE_MASK) >> PAGE_SHIFT;
 171        last  = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
 172        dma->offset = data & ~PAGE_MASK;
 173        dma->size = size;
 174        dma->nr_pages = last-first+1;
 175        dma->pages = kmalloc_array(dma->nr_pages, sizeof(struct page *),
 176                                   GFP_KERNEL);
 177        if (NULL == dma->pages)
 178                return -ENOMEM;
 179
 180        if (rw == READ)
 181                flags |= FOLL_WRITE;
 182
 183        dprintk(1, "init user [0x%lx+0x%lx => %lu pages]\n",
 184                data, size, dma->nr_pages);
 185
 186        err = pin_user_pages(data & PAGE_MASK, dma->nr_pages,
 187                             flags | FOLL_LONGTERM, dma->pages, NULL);
 188
 189        if (err != dma->nr_pages) {
 190                dma->nr_pages = (err >= 0) ? err : 0;
 191                dprintk(1, "pin_user_pages: err=%d [%lu]\n", err,
 192                        dma->nr_pages);
 193                return err < 0 ? err : -EINVAL;
 194        }
 195        return 0;
 196}
 197
 198static int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
 199                           unsigned long data, unsigned long size)
 200{
 201        int ret;
 202
 203        mmap_read_lock(current->mm);
 204        ret = videobuf_dma_init_user_locked(dma, direction, data, size);
 205        mmap_read_unlock(current->mm);
 206
 207        return ret;
 208}
 209
 210static int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
 211                                    unsigned long nr_pages)
 212{
 213        int i;
 214
 215        dprintk(1, "init kernel [%lu pages]\n", nr_pages);
 216
 217        dma->direction = direction;
 218        dma->vaddr_pages = kcalloc(nr_pages, sizeof(*dma->vaddr_pages),
 219                                   GFP_KERNEL);
 220        if (!dma->vaddr_pages)
 221                return -ENOMEM;
 222
 223        dma->dma_addr = kcalloc(nr_pages, sizeof(*dma->dma_addr), GFP_KERNEL);
 224        if (!dma->dma_addr) {
 225                kfree(dma->vaddr_pages);
 226                return -ENOMEM;
 227        }
 228        for (i = 0; i < nr_pages; i++) {
 229                void *addr;
 230
 231                addr = dma_alloc_coherent(dma->dev, PAGE_SIZE,
 232                                          &(dma->dma_addr[i]), GFP_KERNEL);
 233                if (addr == NULL)
 234                        goto out_free_pages;
 235
 236                dma->vaddr_pages[i] = virt_to_page(addr);
 237        }
 238        dma->vaddr = vmap(dma->vaddr_pages, nr_pages, VM_MAP | VM_IOREMAP,
 239                          PAGE_KERNEL);
 240        if (NULL == dma->vaddr) {
 241                dprintk(1, "vmalloc_32(%lu pages) failed\n", nr_pages);
 242                goto out_free_pages;
 243        }
 244
 245        dprintk(1, "vmalloc is at addr %p, size=%lu\n",
 246                dma->vaddr, nr_pages << PAGE_SHIFT);
 247
 248        memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT);
 249        dma->nr_pages = nr_pages;
 250
 251        return 0;
 252out_free_pages:
 253        while (i > 0) {
 254                void *addr;
 255
 256                i--;
 257                addr = page_address(dma->vaddr_pages[i]);
 258                dma_free_coherent(dma->dev, PAGE_SIZE, addr, dma->dma_addr[i]);
 259        }
 260        kfree(dma->dma_addr);
 261        dma->dma_addr = NULL;
 262        kfree(dma->vaddr_pages);
 263        dma->vaddr_pages = NULL;
 264
 265        return -ENOMEM;
 266
 267}
 268
 269static int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
 270                              dma_addr_t addr, unsigned long nr_pages)
 271{
 272        dprintk(1, "init overlay [%lu pages @ bus 0x%lx]\n",
 273                nr_pages, (unsigned long)addr);
 274        dma->direction = direction;
 275
 276        if (0 == addr)
 277                return -EINVAL;
 278
 279        dma->bus_addr = addr;
 280        dma->nr_pages = nr_pages;
 281
 282        return 0;
 283}
 284
 285static int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
 286{
 287        MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 288        BUG_ON(0 == dma->nr_pages);
 289
 290        if (dma->pages) {
 291                dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
 292                                                   dma->offset, dma->size);
 293        }
 294        if (dma->vaddr) {
 295                dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr,
 296                                                     dma->nr_pages);
 297        }
 298        if (dma->bus_addr) {
 299                dma->sglist = vmalloc(sizeof(*dma->sglist));
 300                if (NULL != dma->sglist) {
 301                        dma->sglen = 1;
 302                        sg_dma_address(&dma->sglist[0]) = dma->bus_addr
 303                                                        & PAGE_MASK;
 304                        dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
 305                        sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
 306                }
 307        }
 308        if (NULL == dma->sglist) {
 309                dprintk(1, "scatterlist is NULL\n");
 310                return -ENOMEM;
 311        }
 312        if (!dma->bus_addr) {
 313                dma->sglen = dma_map_sg(dev, dma->sglist,
 314                                        dma->nr_pages, dma->direction);
 315                if (0 == dma->sglen) {
 316                        printk(KERN_WARNING
 317                               "%s: videobuf_map_sg failed\n", __func__);
 318                        vfree(dma->sglist);
 319                        dma->sglist = NULL;
 320                        dma->sglen = 0;
 321                        return -ENOMEM;
 322                }
 323        }
 324
 325        return 0;
 326}
 327
 328int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
 329{
 330        MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 331
 332        if (!dma->sglen)
 333                return 0;
 334
 335        dma_unmap_sg(dev, dma->sglist, dma->nr_pages, dma->direction);
 336
 337        vfree(dma->sglist);
 338        dma->sglist = NULL;
 339        dma->sglen = 0;
 340
 341        return 0;
 342}
 343EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
 344
 345int videobuf_dma_free(struct videobuf_dmabuf *dma)
 346{
 347        int i;
 348        MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 349        BUG_ON(dma->sglen);
 350
 351        if (dma->pages) {
 352                unpin_user_pages_dirty_lock(dma->pages, dma->nr_pages,
 353                                            dma->direction == DMA_FROM_DEVICE);
 354                kfree(dma->pages);
 355                dma->pages = NULL;
 356        }
 357
 358        if (dma->dma_addr) {
 359                for (i = 0; i < dma->nr_pages; i++) {
 360                        void *addr;
 361
 362                        addr = page_address(dma->vaddr_pages[i]);
 363                        dma_free_coherent(dma->dev, PAGE_SIZE, addr,
 364                                          dma->dma_addr[i]);
 365                }
 366                kfree(dma->dma_addr);
 367                dma->dma_addr = NULL;
 368                kfree(dma->vaddr_pages);
 369                dma->vaddr_pages = NULL;
 370                vunmap(dma->vaddr);
 371                dma->vaddr = NULL;
 372        }
 373
 374        if (dma->bus_addr)
 375                dma->bus_addr = 0;
 376        dma->direction = DMA_NONE;
 377
 378        return 0;
 379}
 380EXPORT_SYMBOL_GPL(videobuf_dma_free);
 381
 382/* --------------------------------------------------------------------- */
 383
 384static void videobuf_vm_open(struct vm_area_struct *vma)
 385{
 386        struct videobuf_mapping *map = vma->vm_private_data;
 387
 388        dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
 389                map->count, vma->vm_start, vma->vm_end);
 390
 391        map->count++;
 392}
 393
 394static void videobuf_vm_close(struct vm_area_struct *vma)
 395{
 396        struct videobuf_mapping *map = vma->vm_private_data;
 397        struct videobuf_queue *q = map->q;
 398        struct videobuf_dma_sg_memory *mem;
 399        int i;
 400
 401        dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
 402                map->count, vma->vm_start, vma->vm_end);
 403
 404        map->count--;
 405        if (0 == map->count) {
 406                dprintk(1, "munmap %p q=%p\n", map, q);
 407                videobuf_queue_lock(q);
 408                for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 409                        if (NULL == q->bufs[i])
 410                                continue;
 411                        mem = q->bufs[i]->priv;
 412                        if (!mem)
 413                                continue;
 414
 415                        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 416
 417                        if (q->bufs[i]->map != map)
 418                                continue;
 419                        q->bufs[i]->map   = NULL;
 420                        q->bufs[i]->baddr = 0;
 421                        q->ops->buf_release(q, q->bufs[i]);
 422                }
 423                videobuf_queue_unlock(q);
 424                kfree(map);
 425        }
 426        return;
 427}
 428
 429/*
 430 * Get a anonymous page for the mapping.  Make sure we can DMA to that
 431 * memory location with 32bit PCI devices (i.e. don't use highmem for
 432 * now ...).  Bounce buffers don't work very well for the data rates
 433 * video capture has.
 434 */
 435static vm_fault_t videobuf_vm_fault(struct vm_fault *vmf)
 436{
 437        struct vm_area_struct *vma = vmf->vma;
 438        struct page *page;
 439
 440        dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
 441                vmf->address, vma->vm_start, vma->vm_end);
 442
 443        page = alloc_page(GFP_USER | __GFP_DMA32);
 444        if (!page)
 445                return VM_FAULT_OOM;
 446        clear_user_highpage(page, vmf->address);
 447        vmf->page = page;
 448
 449        return 0;
 450}
 451
 452static const struct vm_operations_struct videobuf_vm_ops = {
 453        .open   = videobuf_vm_open,
 454        .close  = videobuf_vm_close,
 455        .fault  = videobuf_vm_fault,
 456};
 457
 458/* ---------------------------------------------------------------------
 459 * SG handlers for the generic methods
 460 */
 461
 462/* Allocated area consists on 3 parts:
 463        struct video_buffer
 464        struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 465        struct videobuf_dma_sg_memory
 466 */
 467
 468static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
 469{
 470        struct videobuf_dma_sg_memory *mem;
 471        struct videobuf_buffer *vb;
 472
 473        vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
 474        if (!vb)
 475                return vb;
 476
 477        mem = vb->priv = ((char *)vb) + size;
 478        mem->magic = MAGIC_SG_MEM;
 479
 480        videobuf_dma_init(&mem->dma);
 481
 482        dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
 483                __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
 484                mem, (long)sizeof(*mem));
 485
 486        return vb;
 487}
 488
 489static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
 490{
 491        struct videobuf_dma_sg_memory *mem = buf->priv;
 492        BUG_ON(!mem);
 493
 494        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 495
 496        return mem->dma.vaddr;
 497}
 498
 499static int __videobuf_iolock(struct videobuf_queue *q,
 500                             struct videobuf_buffer *vb,
 501                             struct v4l2_framebuffer *fbuf)
 502{
 503        struct videobuf_dma_sg_memory *mem = vb->priv;
 504        unsigned long pages;
 505        dma_addr_t bus;
 506        int err;
 507
 508        BUG_ON(!mem);
 509
 510        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 511
 512        if (!mem->dma.dev)
 513                mem->dma.dev = q->dev;
 514        else
 515                WARN_ON(mem->dma.dev != q->dev);
 516
 517        switch (vb->memory) {
 518        case V4L2_MEMORY_MMAP:
 519        case V4L2_MEMORY_USERPTR:
 520                if (0 == vb->baddr) {
 521                        /* no userspace addr -- kernel bounce buffer */
 522                        pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
 523                        err = videobuf_dma_init_kernel(&mem->dma,
 524                                                       DMA_FROM_DEVICE,
 525                                                       pages);
 526                        if (0 != err)
 527                                return err;
 528                } else if (vb->memory == V4L2_MEMORY_USERPTR) {
 529                        /* dma directly to userspace */
 530                        err = videobuf_dma_init_user(&mem->dma,
 531                                                     DMA_FROM_DEVICE,
 532                                                     vb->baddr, vb->bsize);
 533                        if (0 != err)
 534                                return err;
 535                } else {
 536                        /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
 537                        buffers can only be called from videobuf_qbuf
 538                        we take current->mm->mmap_lock there, to prevent
 539                        locking inversion, so don't take it here */
 540
 541                        err = videobuf_dma_init_user_locked(&mem->dma,
 542                                                      DMA_FROM_DEVICE,
 543                                                      vb->baddr, vb->bsize);
 544                        if (0 != err)
 545                                return err;
 546                }
 547                break;
 548        case V4L2_MEMORY_OVERLAY:
 549                if (NULL == fbuf)
 550                        return -EINVAL;
 551                /* FIXME: need sanity checks for vb->boff */
 552                /*
 553                 * Using a double cast to avoid compiler warnings when
 554                 * building for PAE. Compiler doesn't like direct casting
 555                 * of a 32 bit ptr to 64 bit integer.
 556                 */
 557                bus   = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
 558                pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
 559                err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
 560                                                bus, pages);
 561                if (0 != err)
 562                        return err;
 563                break;
 564        default:
 565                BUG();
 566        }
 567        err = videobuf_dma_map(q->dev, &mem->dma);
 568        if (0 != err)
 569                return err;
 570
 571        return 0;
 572}
 573
 574static int __videobuf_sync(struct videobuf_queue *q,
 575                           struct videobuf_buffer *buf)
 576{
 577        struct videobuf_dma_sg_memory *mem = buf->priv;
 578        BUG_ON(!mem || !mem->dma.sglen);
 579
 580        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 581        MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF);
 582
 583        dma_sync_sg_for_cpu(q->dev, mem->dma.sglist,
 584                            mem->dma.nr_pages, mem->dma.direction);
 585
 586        return 0;
 587}
 588
 589static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 590                                  struct videobuf_buffer *buf,
 591                                  struct vm_area_struct *vma)
 592{
 593        struct videobuf_dma_sg_memory *mem = buf->priv;
 594        struct videobuf_mapping *map;
 595        unsigned int first, last, size = 0, i;
 596        int retval;
 597
 598        retval = -EINVAL;
 599
 600        BUG_ON(!mem);
 601        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 602
 603        /* look for first buffer to map */
 604        for (first = 0; first < VIDEO_MAX_FRAME; first++) {
 605                if (buf == q->bufs[first]) {
 606                        size = PAGE_ALIGN(q->bufs[first]->bsize);
 607                        break;
 608                }
 609        }
 610
 611        /* paranoia, should never happen since buf is always valid. */
 612        if (!size) {
 613                dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
 614                                (vma->vm_pgoff << PAGE_SHIFT));
 615                goto done;
 616        }
 617
 618        last = first;
 619
 620        /* create mapping + update buffer list */
 621        retval = -ENOMEM;
 622        map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
 623        if (NULL == map)
 624                goto done;
 625
 626        size = 0;
 627        for (i = first; i <= last; i++) {
 628                if (NULL == q->bufs[i])
 629                        continue;
 630                q->bufs[i]->map   = map;
 631                q->bufs[i]->baddr = vma->vm_start + size;
 632                size += PAGE_ALIGN(q->bufs[i]->bsize);
 633        }
 634
 635        map->count    = 1;
 636        map->q        = q;
 637        vma->vm_ops   = &videobuf_vm_ops;
 638        vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 639        vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
 640        vma->vm_private_data = map;
 641        dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
 642                map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last);
 643        retval = 0;
 644
 645done:
 646        return retval;
 647}
 648
 649static struct videobuf_qtype_ops sg_ops = {
 650        .magic        = MAGIC_QTYPE_OPS,
 651
 652        .alloc_vb     = __videobuf_alloc_vb,
 653        .iolock       = __videobuf_iolock,
 654        .sync         = __videobuf_sync,
 655        .mmap_mapper  = __videobuf_mmap_mapper,
 656        .vaddr        = __videobuf_to_vaddr,
 657};
 658
 659void *videobuf_sg_alloc(size_t size)
 660{
 661        struct videobuf_queue q;
 662
 663        /* Required to make generic handler to call __videobuf_alloc */
 664        q.int_ops = &sg_ops;
 665
 666        q.msize = size;
 667
 668        return videobuf_alloc_vb(&q);
 669}
 670EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
 671
 672void videobuf_queue_sg_init(struct videobuf_queue *q,
 673                         const struct videobuf_queue_ops *ops,
 674                         struct device *dev,
 675                         spinlock_t *irqlock,
 676                         enum v4l2_buf_type type,
 677                         enum v4l2_field field,
 678                         unsigned int msize,
 679                         void *priv,
 680                         struct mutex *ext_lock)
 681{
 682        videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
 683                                 priv, &sg_ops, ext_lock);
 684}
 685EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);
 686
 687