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

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
videobuf_vmalloc_to_sg
videobuf_pages_to_sg
videobuf_to_dma
videobuf_dma_init
videobuf_dma_init_user_locked
videobuf_dma_init_user
videobuf_dma_init_kernel
videobuf_dma_init_overlay
videobuf_dma_map
videobuf_dma_unmap
videobuf_dma_free
videobuf_vm_open
videobuf_vm_close
videobuf_vm_fault
__videobuf_alloc_vb
__videobuf_to_vaddr
__videobuf_iolock
__videobuf_sync
__videobuf_mmap_mapper
videobuf_sg_alloc
videobuf_queue_sg_init
   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 
  25 #include <linux/dma-mapping.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/pagemap.h>
  28 #include <linux/scatterlist.h>
  29 #include <asm/page.h>
  30 #include <asm/pgtable.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 
  44 static int debug;
  45 module_param(debug, int, 0644);
  46 
  47 MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers");
  48 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@kernel.org>");
  49 MODULE_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  */
  62 static 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 
  82 err:
  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  */
  92 static 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 
 121 nopage:
 122         dprintk(2, "sgl: oops - no page\n");
 123         vfree(sglist);
 124         return NULL;
 125 
 126 highmem:
 127         dprintk(2, "sgl: oops - highmem page\n");
 128         vfree(sglist);
 129         return NULL;
 130 }
 131 
 132 /* --------------------------------------------------------------------- */
 133 
 134 struct 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 }
 143 EXPORT_SYMBOL_GPL(videobuf_to_dma);
 144 
 145 static void videobuf_dma_init(struct videobuf_dmabuf *dma)
 146 {
 147         memset(dma, 0, sizeof(*dma));
 148         dma->magic = MAGIC_DMABUF;
 149 }
 150 
 151 static 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 => %d pages]\n",
 184                 data, size, dma->nr_pages);
 185 
 186         err = get_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, "get_user_pages: err=%d [%d]\n", err,
 192                         dma->nr_pages);
 193                 return err < 0 ? err : -EINVAL;
 194         }
 195         return 0;
 196 }
 197 
 198 static int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
 199                            unsigned long data, unsigned long size)
 200 {
 201         int ret;
 202 
 203         down_read(&current->mm->mmap_sem);
 204         ret = videobuf_dma_init_user_locked(dma, direction, data, size);
 205         up_read(&current->mm->mmap_sem);
 206 
 207         return ret;
 208 }
 209 
 210 static int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
 211                              int nr_pages)
 212 {
 213         int i;
 214 
 215         dprintk(1, "init kernel [%d 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(%d pages) failed\n", nr_pages);
 242                 goto out_free_pages;
 243         }
 244 
 245         dprintk(1, "vmalloc is at addr %p, size=%d\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;
 252 out_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 
 269 static int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
 270                               dma_addr_t addr, int nr_pages)
 271 {
 272         dprintk(1, "init overlay [%d 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 
 285 static 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 
 328 int 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 }
 343 EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
 344 
 345 int 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                 for (i = 0; i < dma->nr_pages; i++) {
 353                         if (dma->direction == DMA_FROM_DEVICE)
 354                                 set_page_dirty_lock(dma->pages[i]);
 355                         put_page(dma->pages[i]);
 356                 }
 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 vm_fault_t 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.nr_pages, 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
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/media/v4l2-core/videobuf-dma-sg.c

DEFINITIONS
