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

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