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@kernel.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@kernel.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/mm.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@kernel.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         unsigned int flags = FOLL_FORCE;
 160
 161         dma->direction = direction;
 162         switch (dma->direction) {
 163         case DMA_FROM_DEVICE:
 164                 rw = READ;
 165                 break;
 166         case DMA_TO_DEVICE:
 167                 rw = WRITE;
 168                 break;
 169         default:
 170                 BUG();
 171         }
 172
 173         first = (data          & PAGE_MASK) >> PAGE_SHIFT;
 174         last  = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
 175         dma->offset = data & ~PAGE_MASK;
 176         dma->size = size;
 177         dma->nr_pages = last-first+1;
 178         dma->pages = kmalloc(dma->nr_pages * sizeof(struct page *), GFP_KERNEL);
 179         if (NULL == dma->pages)
 180                 return -ENOMEM;
 181
 182         if (rw == READ)
 183                 flags |= FOLL_WRITE;
 184
 185         dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
 186                 data, size, dma->nr_pages);
 187
 188         err = get_user_pages_longterm(data & PAGE_MASK, dma->nr_pages,
 189                              flags, dma->pages, NULL);
 190
 191         if (err != dma->nr_pages) {
 192                 dma->nr_pages = (err >= 0) ? err : 0;
 193                 dprintk(1, "get_user_pages_longterm: err=%d [%d]\n", err,
 194                         dma->nr_pages);
 195                 return err < 0 ? err : -EINVAL;
 196         }
 197         return 0;
 198 }
 199
 200 static int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
 201                            unsigned long data, unsigned long size)
 202 {
 203         int ret;
 204
 205         down_read(&current->mm->mmap_sem);
 206         ret = videobuf_dma_init_user_locked(dma, direction, data, size);
 207         up_read(&current->mm->mmap_sem);
 208
 209         return ret;
 210 }
 211
 212 static int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
 213                              int nr_pages)
 214 {
 215         int i;
 216
 217         dprintk(1, "init kernel [%d pages]\n", nr_pages);
 218
 219         dma->direction = direction;
 220         dma->vaddr_pages = kcalloc(nr_pages, sizeof(*dma->vaddr_pages),
 221                                    GFP_KERNEL);
 222         if (!dma->vaddr_pages)
 223                 return -ENOMEM;
 224
 225         dma->dma_addr = kcalloc(nr_pages, sizeof(*dma->dma_addr), GFP_KERNEL);
 226         if (!dma->dma_addr) {
 227                 kfree(dma->vaddr_pages);
 228                 return -ENOMEM;
 229         }
 230         for (i = 0; i < nr_pages; i++) {
 231                 void *addr;
 232
 233                 addr = dma_alloc_coherent(dma->dev, PAGE_SIZE,
 234                                           &(dma->dma_addr[i]), GFP_KERNEL);
 235                 if (addr == NULL)
 236                         goto out_free_pages;
 237
 238                 dma->vaddr_pages[i] = virt_to_page(addr);
 239         }
 240         dma->vaddr = vmap(dma->vaddr_pages, nr_pages, VM_MAP | VM_IOREMAP,
 241                           PAGE_KERNEL);
 242         if (NULL == dma->vaddr) {
 243                 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
 244                 goto out_free_pages;
 245         }
 246
 247         dprintk(1, "vmalloc is at addr %p, size=%d\n",
 248                 dma->vaddr, nr_pages << PAGE_SHIFT);
 249
 250         memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT);
 251         dma->nr_pages = nr_pages;
 252
 253         return 0;
 254 out_free_pages:
 255         while (i > 0) {
 256                 void *addr;
 257
 258                 i--;
 259                 addr = page_address(dma->vaddr_pages[i]);
 260                 dma_free_coherent(dma->dev, PAGE_SIZE, addr, dma->dma_addr[i]);
 261         }
 262         kfree(dma->dma_addr);
 263         dma->dma_addr = NULL;
 264         kfree(dma->vaddr_pages);
 265         dma->vaddr_pages = NULL;
 266
 267         return -ENOMEM;
 268
 269 }
 270
 271 static int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
 272                               dma_addr_t addr, int nr_pages)
 273 {
 274         dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n",
 275                 nr_pages, (unsigned long)addr);
 276         dma->direction = direction;
 277
 278         if (0 == addr)
 279                 return -EINVAL;
 280
 281         dma->bus_addr = addr;
 282         dma->nr_pages = nr_pages;
 283
 284         return 0;
 285 }
 286
 287 static int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
 288 {
 289         MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 290         BUG_ON(0 == dma->nr_pages);
 291
 292         if (dma->pages) {
 293                 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
 294                                                    dma->offset, dma->size);
 295         }
 296         if (dma->vaddr) {
 297                 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr,
 298                                                      dma->nr_pages);
 299         }
 300         if (dma->bus_addr) {
 301                 dma->sglist = vmalloc(sizeof(*dma->sglist));
 302                 if (NULL != dma->sglist) {
 303                         dma->sglen = 1;
 304                         sg_dma_address(&dma->sglist[0]) = dma->bus_addr
 305                                                         & PAGE_MASK;
 306                         dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
 307                         sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
 308                 }
 309         }
 310         if (NULL == dma->sglist) {
 311                 dprintk(1, "scatterlist is NULL\n");
 312                 return -ENOMEM;
 313         }
 314         if (!dma->bus_addr) {
 315                 dma->sglen = dma_map_sg(dev, dma->sglist,
 316                                         dma->nr_pages, dma->direction);
 317                 if (0 == dma->sglen) {
 318                         printk(KERN_WARNING
 319                                "%s: videobuf_map_sg failed\n", __func__);
 320                         vfree(dma->sglist);
 321                         dma->sglist = NULL;
 322                         dma->sglen = 0;
 323                         return -ENOMEM;
 324                 }
 325         }
 326
 327         return 0;
 328 }
 329
 330 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
 331 {
 332         MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 333
 334         if (!dma->sglen)
 335                 return 0;
 336
 337         dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction);
 338
 339         vfree(dma->sglist);
 340         dma->sglist = NULL;
 341         dma->sglen = 0;
 342
 343         return 0;
 344 }
 345 EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
 346
 347 int videobuf_dma_free(struct videobuf_dmabuf *dma)
 348 {
 349         int i;
 350         MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 351         BUG_ON(dma->sglen);
 352
 353         if (dma->pages) {
 354                 for (i = 0; i < dma->nr_pages; i++)
 355                         put_page(dma->pages[i]);
 356                 kfree(dma->pages);
 357                 dma->pages = NULL;
 358         }
 359
 360         if (dma->dma_addr) {
 361                 for (i = 0; i < dma->nr_pages; i++) {
 362                         void *addr;
 363
 364                         addr = page_address(dma->vaddr_pages[i]);
 365                         dma_free_coherent(dma->dev, PAGE_SIZE, addr,
 366                                           dma->dma_addr[i]);
 367                 }
 368                 kfree(dma->dma_addr);
 369                 dma->dma_addr = NULL;
 370                 kfree(dma->vaddr_pages);
 371                 dma->vaddr_pages = NULL;
 372                 vunmap(dma->vaddr);
 373                 dma->vaddr = NULL;
 374         }
 375
 376         if (dma->bus_addr)
 377                 dma->bus_addr = 0;
 378         dma->direction = DMA_NONE;
 379
 380         return 0;
 381 }
 382 EXPORT_SYMBOL_GPL(videobuf_dma_free);
 383
 384 /* --------------------------------------------------------------------- */
 385
 386 static void videobuf_vm_open(struct vm_area_struct *vma)
 387 {
 388         struct videobuf_mapping *map = vma->vm_private_data;
 389
 390         dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
 391                 map->count, vma->vm_start, vma->vm_end);
 392
 393         map->count++;
 394 }
 395
 396 static void videobuf_vm_close(struct vm_area_struct *vma)
 397 {
 398         struct videobuf_mapping *map = vma->vm_private_data;
 399         struct videobuf_queue *q = map->q;
 400         struct videobuf_dma_sg_memory *mem;
 401         int i;
 402
 403         dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
 404                 map->count, vma->vm_start, vma->vm_end);
 405
 406         map->count--;
 407         if (0 == map->count) {
 408                 dprintk(1, "munmap %p q=%p\n", map, q);
 409                 videobuf_queue_lock(q);
 410                 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 411                         if (NULL == q->bufs[i])
 412                                 continue;
 413                         mem = q->bufs[i]->priv;
 414                         if (!mem)
 415                                 continue;
 416
 417                         MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 418
 419                         if (q->bufs[i]->map != map)
 420                                 continue;
 421                         q->bufs[i]->map   = NULL;
 422                         q->bufs[i]->baddr = 0;
 423                         q->ops->buf_release(q, q->bufs[i]);
 424                 }
 425                 videobuf_queue_unlock(q);
 426                 kfree(map);
 427         }
 428         return;
 429 }
 430
 431 /*
 432  * Get a anonymous page for the mapping.  Make sure we can DMA to that
 433  * memory location with 32bit PCI devices (i.e. don't use highmem for
 434  * now ...).  Bounce buffers don't work very well for the data rates
 435  * video capture has.
 436  */
 437 static int videobuf_vm_fault(struct vm_fault *vmf)
 438 {
 439         struct vm_area_struct *vma = vmf->vma;
 440         struct page *page;
 441
 442         dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
 443                 vmf->address, vma->vm_start, vma->vm_end);
 444
 445         page = alloc_page(GFP_USER | __GFP_DMA32);
 446         if (!page)
 447                 return VM_FAULT_OOM;
 448         clear_user_highpage(page, vmf->address);
 449         vmf->page = page;
 450
 451         return 0;
 452 }
 453
 454 static const struct vm_operations_struct videobuf_vm_ops = {
 455         .open   = videobuf_vm_open,
 456         .close  = videobuf_vm_close,
 457         .fault  = videobuf_vm_fault,
 458 };
 459
 460 /* ---------------------------------------------------------------------
 461  * SG handlers for the generic methods
 462  */
 463
 464 /* Allocated area consists on 3 parts:
 465         struct video_buffer
 466         struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 467         struct videobuf_dma_sg_memory
 468  */
 469
 470 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
 471 {
 472         struct videobuf_dma_sg_memory *mem;
 473         struct videobuf_buffer *vb;
 474
 475         vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
 476         if (!vb)
 477                 return vb;
 478
 479         mem = vb->priv = ((char *)vb) + size;
 480         mem->magic = MAGIC_SG_MEM;
 481
 482         videobuf_dma_init(&mem->dma);
 483
 484         dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
 485                 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
 486                 mem, (long)sizeof(*mem));
 487
 488         return vb;
 489 }
 490
 491 static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
 492 {
 493         struct videobuf_dma_sg_memory *mem = buf->priv;
 494         BUG_ON(!mem);
 495
 496         MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 497
 498         return mem->dma.vaddr;
 499 }
 500
 501 static int __videobuf_iolock(struct videobuf_queue *q,
 502                              struct videobuf_buffer *vb,
 503                              struct v4l2_framebuffer *fbuf)
 504 {
 505         int err, pages;
 506         dma_addr_t bus;
 507         struct videobuf_dma_sg_memory *mem = vb->priv;
 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_sem 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
 574 static 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.sglen, mem->dma.direction);
 585
 586         return 0;
 587 }
 588
 589 static 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
 645 done:
 646         return retval;
 647 }
 648
 649 static 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
 659 void *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 }
 670 EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
 671
 672 void 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 }
 685 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);
 686