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/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@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         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 0x%08lx, size=%d\n",
 248                                 (unsigned long)dma->vaddr,
 249                                 nr_pages << PAGE_SHIFT);
 250
 251         memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT);
 252         dma->nr_pages = nr_pages;
 253
 254         return 0;
 255 out_free_pages:
 256         while (i > 0) {
 257                 void *addr;
 258
 259                 i--;
 260                 addr = page_address(dma->vaddr_pages[i]);
 261                 dma_free_coherent(dma->dev, PAGE_SIZE, addr, dma->dma_addr[i]);
 262         }
 263         kfree(dma->dma_addr);
 264         dma->dma_addr = NULL;
 265         kfree(dma->vaddr_pages);
 266         dma->vaddr_pages = NULL;
 267
 268         return -ENOMEM;
 269
 270 }
 271
 272 static int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
 273                               dma_addr_t addr, int nr_pages)
 274 {
 275         dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n",
 276                 nr_pages, (unsigned long)addr);
 277         dma->direction = direction;
 278
 279         if (0 == addr)
 280                 return -EINVAL;
 281
 282         dma->bus_addr = addr;
 283         dma->nr_pages = nr_pages;
 284
 285         return 0;
 286 }
 287
 288 static int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
 289 {
 290         MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 291         BUG_ON(0 == dma->nr_pages);
 292
 293         if (dma->pages) {
 294                 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
 295                                                    dma->offset, dma->size);
 296         }
 297         if (dma->vaddr) {
 298                 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr,
 299                                                      dma->nr_pages);
 300         }
 301         if (dma->bus_addr) {
 302                 dma->sglist = vmalloc(sizeof(*dma->sglist));
 303                 if (NULL != dma->sglist) {
 304                         dma->sglen = 1;
 305                         sg_dma_address(&dma->sglist[0]) = dma->bus_addr
 306                                                         & PAGE_MASK;
 307                         dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
 308                         sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
 309                 }
 310         }
 311         if (NULL == dma->sglist) {
 312                 dprintk(1, "scatterlist is NULL\n");
 313                 return -ENOMEM;
 314         }
 315         if (!dma->bus_addr) {
 316                 dma->sglen = dma_map_sg(dev, dma->sglist,
 317                                         dma->nr_pages, dma->direction);
 318                 if (0 == dma->sglen) {
 319                         printk(KERN_WARNING
 320                                "%s: videobuf_map_sg failed\n", __func__);
 321                         vfree(dma->sglist);
 322                         dma->sglist = NULL;
 323                         dma->sglen = 0;
 324                         return -ENOMEM;
 325                 }
 326         }
 327
 328         return 0;
 329 }
 330
 331 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
 332 {
 333         MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 334
 335         if (!dma->sglen)
 336                 return 0;
 337
 338         dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction);
 339
 340         vfree(dma->sglist);
 341         dma->sglist = NULL;
 342         dma->sglen = 0;
 343
 344         return 0;
 345 }
 346 EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
 347
 348 int videobuf_dma_free(struct videobuf_dmabuf *dma)
 349 {
 350         int i;
 351         MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
 352         BUG_ON(dma->sglen);
 353
 354         if (dma->pages) {
 355                 for (i = 0; i < dma->nr_pages; i++)
 356                         put_page(dma->pages[i]);
 357                 kfree(dma->pages);
 358                 dma->pages = NULL;
 359         }
 360
 361         if (dma->dma_addr) {
 362                 for (i = 0; i < dma->nr_pages; i++) {
 363                         void *addr;
 364
 365                         addr = page_address(dma->vaddr_pages[i]);
 366                         dma_free_coherent(dma->dev, PAGE_SIZE, addr,
 367                                           dma->dma_addr[i]);
 368                 }
 369                 kfree(dma->dma_addr);
 370                 dma->dma_addr = NULL;
 371                 kfree(dma->vaddr_pages);
 372                 dma->vaddr_pages = NULL;
 373                 vunmap(dma->vaddr);
 374                 dma->vaddr = NULL;
 375         }
 376
 377         if (dma->bus_addr)
 378                 dma->bus_addr = 0;
 379         dma->direction = DMA_NONE;
 380
 381         return 0;
 382 }
 383 EXPORT_SYMBOL_GPL(videobuf_dma_free);
 384
 385 /* --------------------------------------------------------------------- */
 386
 387 static void videobuf_vm_open(struct vm_area_struct *vma)
 388 {
 389         struct videobuf_mapping *map = vma->vm_private_data;
 390
 391         dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
 392                 map->count, vma->vm_start, vma->vm_end);
 393
 394         map->count++;
 395 }
 396
 397 static void videobuf_vm_close(struct vm_area_struct *vma)
 398 {
 399         struct videobuf_mapping *map = vma->vm_private_data;
 400         struct videobuf_queue *q = map->q;
 401         struct videobuf_dma_sg_memory *mem;
 402         int i;
 403
 404         dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
 405                 map->count, vma->vm_start, vma->vm_end);
 406
 407         map->count--;
 408         if (0 == map->count) {
 409                 dprintk(1, "munmap %p q=%p\n", map, q);
 410                 videobuf_queue_lock(q);
 411                 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 412                         if (NULL == q->bufs[i])
 413                                 continue;
 414                         mem = q->bufs[i]->priv;
 415                         if (!mem)
 416                                 continue;
 417
 418                         MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 419
 420                         if (q->bufs[i]->map != map)
 421                                 continue;
 422                         q->bufs[i]->map   = NULL;
 423                         q->bufs[i]->baddr = 0;
 424                         q->ops->buf_release(q, q->bufs[i]);
 425                 }
 426                 videobuf_queue_unlock(q);
 427                 kfree(map);
 428         }
 429         return;
 430 }
 431
 432 /*
 433  * Get a anonymous page for the mapping.  Make sure we can DMA to that
 434  * memory location with 32bit PCI devices (i.e. don't use highmem for
 435  * now ...).  Bounce buffers don't work very well for the data rates
 436  * video capture has.
 437  */
 438 static int videobuf_vm_fault(struct vm_fault *vmf)
 439 {
 440         struct vm_area_struct *vma = vmf->vma;
 441         struct page *page;
 442
 443         dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
 444                 vmf->address, vma->vm_start, vma->vm_end);
 445
 446         page = alloc_page(GFP_USER | __GFP_DMA32);
 447         if (!page)
 448                 return VM_FAULT_OOM;
 449         clear_user_highpage(page, vmf->address);
 450         vmf->page = page;
 451
 452         return 0;
 453 }
 454
 455 static const struct vm_operations_struct videobuf_vm_ops = {
 456         .open   = videobuf_vm_open,
 457         .close  = videobuf_vm_close,
 458         .fault  = videobuf_vm_fault,
 459 };
 460
 461 /* ---------------------------------------------------------------------
 462  * SG handlers for the generic methods
 463  */
 464
 465 /* Allocated area consists on 3 parts:
 466         struct video_buffer
 467         struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 468         struct videobuf_dma_sg_memory
 469  */
 470
 471 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
 472 {
 473         struct videobuf_dma_sg_memory *mem;
 474         struct videobuf_buffer *vb;
 475
 476         vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
 477         if (!vb)
 478                 return vb;
 479
 480         mem = vb->priv = ((char *)vb) + size;
 481         mem->magic = MAGIC_SG_MEM;
 482
 483         videobuf_dma_init(&mem->dma);
 484
 485         dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
 486                 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
 487                 mem, (long)sizeof(*mem));
 488
 489         return vb;
 490 }
 491
 492 static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
 493 {
 494         struct videobuf_dma_sg_memory *mem = buf->priv;
 495         BUG_ON(!mem);
 496
 497         MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 498
 499         return mem->dma.vaddr;
 500 }
 501
 502 static int __videobuf_iolock(struct videobuf_queue *q,
 503                              struct videobuf_buffer *vb,
 504                              struct v4l2_framebuffer *fbuf)
 505 {
 506         int err, pages;
 507         dma_addr_t bus;
 508         struct videobuf_dma_sg_memory *mem = vb->priv;
 509         BUG_ON(!mem);
 510
 511         MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 512
 513         if (!mem->dma.dev)
 514                 mem->dma.dev = q->dev;
 515         else
 516                 WARN_ON(mem->dma.dev != q->dev);
 517
 518         switch (vb->memory) {
 519         case V4L2_MEMORY_MMAP:
 520         case V4L2_MEMORY_USERPTR:
 521                 if (0 == vb->baddr) {
 522                         /* no userspace addr -- kernel bounce buffer */
 523                         pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
 524                         err = videobuf_dma_init_kernel(&mem->dma,
 525                                                        DMA_FROM_DEVICE,
 526                                                        pages);
 527                         if (0 != err)
 528                                 return err;
 529                 } else if (vb->memory == V4L2_MEMORY_USERPTR) {
 530                         /* dma directly to userspace */
 531                         err = videobuf_dma_init_user(&mem->dma,
 532                                                      DMA_FROM_DEVICE,
 533                                                      vb->baddr, vb->bsize);
 534                         if (0 != err)
 535                                 return err;
 536                 } else {
 537                         /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
 538                         buffers can only be called from videobuf_qbuf
 539                         we take current->mm->mmap_sem there, to prevent
 540                         locking inversion, so don't take it here */
 541
 542                         err = videobuf_dma_init_user_locked(&mem->dma,
 543                                                       DMA_FROM_DEVICE,
 544                                                       vb->baddr, vb->bsize);
 545                         if (0 != err)
 546                                 return err;
 547                 }
 548                 break;
 549         case V4L2_MEMORY_OVERLAY:
 550                 if (NULL == fbuf)
 551                         return -EINVAL;
 552                 /* FIXME: need sanity checks for vb->boff */
 553                 /*
 554                  * Using a double cast to avoid compiler warnings when
 555                  * building for PAE. Compiler doesn't like direct casting
 556                  * of a 32 bit ptr to 64 bit integer.
 557                  */
 558                 bus   = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
 559                 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
 560                 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
 561                                                 bus, pages);
 562                 if (0 != err)
 563                         return err;
 564                 break;
 565         default:
 566                 BUG();
 567         }
 568         err = videobuf_dma_map(q->dev, &mem->dma);
 569         if (0 != err)
 570                 return err;
 571
 572         return 0;
 573 }
 574
 575 static int __videobuf_sync(struct videobuf_queue *q,
 576                            struct videobuf_buffer *buf)
 577 {
 578         struct videobuf_dma_sg_memory *mem = buf->priv;
 579         BUG_ON(!mem || !mem->dma.sglen);
 580
 581         MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 582         MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF);
 583
 584         dma_sync_sg_for_cpu(q->dev, mem->dma.sglist,
 585                             mem->dma.sglen, mem->dma.direction);
 586
 587         return 0;
 588 }
 589
 590 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 591                                   struct videobuf_buffer *buf,
 592                                   struct vm_area_struct *vma)
 593 {
 594         struct videobuf_dma_sg_memory *mem = buf->priv;
 595         struct videobuf_mapping *map;
 596         unsigned int first, last, size = 0, i;
 597         int retval;
 598
 599         retval = -EINVAL;
 600
 601         BUG_ON(!mem);
 602         MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 603
 604         /* look for first buffer to map */
 605         for (first = 0; first < VIDEO_MAX_FRAME; first++) {
 606                 if (buf == q->bufs[first]) {
 607                         size = PAGE_ALIGN(q->bufs[first]->bsize);
 608                         break;
 609                 }
 610         }
 611
 612         /* paranoia, should never happen since buf is always valid. */
 613         if (!size) {
 614                 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
 615                                 (vma->vm_pgoff << PAGE_SHIFT));
 616                 goto done;
 617         }
 618
 619         last = first;
 620
 621         /* create mapping + update buffer list */
 622         retval = -ENOMEM;
 623         map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
 624         if (NULL == map)
 625                 goto done;
 626
 627         size = 0;
 628         for (i = first; i <= last; i++) {
 629                 if (NULL == q->bufs[i])
 630                         continue;
 631                 q->bufs[i]->map   = map;
 632                 q->bufs[i]->baddr = vma->vm_start + size;
 633                 size += PAGE_ALIGN(q->bufs[i]->bsize);
 634         }
 635
 636         map->count    = 1;
 637         map->q        = q;
 638         vma->vm_ops   = &videobuf_vm_ops;
 639         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 640         vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
 641         vma->vm_private_data = map;
 642         dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
 643                 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last);
 644         retval = 0;
 645
 646 done:
 647         return retval;
 648 }
 649
 650 static struct videobuf_qtype_ops sg_ops = {
 651         .magic        = MAGIC_QTYPE_OPS,
 652
 653         .alloc_vb     = __videobuf_alloc_vb,
 654         .iolock       = __videobuf_iolock,
 655         .sync         = __videobuf_sync,
 656         .mmap_mapper  = __videobuf_mmap_mapper,
 657         .vaddr        = __videobuf_to_vaddr,
 658 };
 659
 660 void *videobuf_sg_alloc(size_t size)
 661 {
 662         struct videobuf_queue q;
 663
 664         /* Required to make generic handler to call __videobuf_alloc */
 665         q.int_ops = &sg_ops;
 666
 667         q.msize = size;
 668
 669         return videobuf_alloc_vb(&q);
 670 }
 671 EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
 672
 673 void videobuf_queue_sg_init(struct videobuf_queue *q,
 674                          const struct videobuf_queue_ops *ops,
 675                          struct device *dev,
 676                          spinlock_t *irqlock,
 677                          enum v4l2_buf_type type,
 678                          enum v4l2_field field,
 679                          unsigned int msize,
 680                          void *priv,
 681                          struct mutex *ext_lock)
 682 {
 683         videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
 684                                  priv, &sg_ops, ext_lock);
 685 }
 686 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);
 687