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 void videobuf_dma_init(struct videobuf_dmabuf *dma) 149 { 150 memset(dma, 0, sizeof(*dma)); 151 dma->magic = MAGIC_DMABUF; 152 } 153 EXPORT_SYMBOL_GPL(videobuf_dma_init); 154 155 static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, 156 int direction, unsigned long data, unsigned long size) 157 { 158 unsigned long first, last; 159 int err, rw = 0; 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 dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n", 183 data, size, dma->nr_pages); 184 185 err = get_user_pages(current, current->mm, 186 data & PAGE_MASK, dma->nr_pages, 187 rw == READ, 1, /* force */ 188 dma->pages, NULL); 189 190 if (err != dma->nr_pages) { 191 dma->nr_pages = (err >= 0) ? err : 0; 192 dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages); 193 return err < 0 ? err : -EINVAL; 194 } 195 return 0; 196 } 197 198 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(¤t->mm->mmap_sem); 204 ret = videobuf_dma_init_user_locked(dma, direction, data, size); 205 up_read(¤t->mm->mmap_sem); 206 207 return ret; 208 } 209 EXPORT_SYMBOL_GPL(videobuf_dma_init_user); 210 211 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction, 212 int nr_pages) 213 { 214 int i; 215 216 dprintk(1, "init kernel [%d pages]\n", nr_pages); 217 218 dma->direction = direction; 219 dma->vaddr_pages = kcalloc(nr_pages, sizeof(*dma->vaddr_pages), 220 GFP_KERNEL); 221 if (!dma->vaddr_pages) 222 return -ENOMEM; 223 224 dma->dma_addr = kcalloc(nr_pages, sizeof(*dma->dma_addr), GFP_KERNEL); 225 if (!dma->dma_addr) { 226 kfree(dma->vaddr_pages); 227 return -ENOMEM; 228 } 229 for (i = 0; i < nr_pages; i++) { 230 void *addr; 231 232 addr = dma_alloc_coherent(dma->dev, PAGE_SIZE, 233 &(dma->dma_addr[i]), GFP_KERNEL); 234 if (addr == NULL) 235 goto out_free_pages; 236 237 dma->vaddr_pages[i] = virt_to_page(addr); 238 } 239 dma->vaddr = vmap(dma->vaddr_pages, nr_pages, VM_MAP | VM_IOREMAP, 240 PAGE_KERNEL); 241 if (NULL == dma->vaddr) { 242 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages); 243 goto out_free_pages; 244 } 245 246 dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n", 247 (unsigned long)dma->vaddr, 248 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 EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel); 271 272 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 EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay); 288 289 int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma) 290 { 291 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 292 BUG_ON(0 == dma->nr_pages); 293 294 if (dma->pages) { 295 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages, 296 dma->offset, dma->size); 297 } 298 if (dma->vaddr) { 299 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr, 300 dma->nr_pages); 301 } 302 if (dma->bus_addr) { 303 dma->sglist = vmalloc(sizeof(*dma->sglist)); 304 if (NULL != dma->sglist) { 305 dma->sglen = 1; 306 sg_dma_address(&dma->sglist[0]) = dma->bus_addr 307 & PAGE_MASK; 308 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK; 309 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE; 310 } 311 } 312 if (NULL == dma->sglist) { 313 dprintk(1, "scatterlist is NULL\n"); 314 return -ENOMEM; 315 } 316 if (!dma->bus_addr) { 317 dma->sglen = dma_map_sg(dev, dma->sglist, 318 dma->nr_pages, dma->direction); 319 if (0 == dma->sglen) { 320 printk(KERN_WARNING 321 "%s: videobuf_map_sg failed\n", __func__); 322 vfree(dma->sglist); 323 dma->sglist = NULL; 324 dma->sglen = 0; 325 return -ENOMEM; 326 } 327 } 328 329 return 0; 330 } 331 EXPORT_SYMBOL_GPL(videobuf_dma_map); 332 333 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma) 334 { 335 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 336 337 if (!dma->sglen) 338 return 0; 339 340 dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction); 341 342 vfree(dma->sglist); 343 dma->sglist = NULL; 344 dma->sglen = 0; 345 346 return 0; 347 } 348 EXPORT_SYMBOL_GPL(videobuf_dma_unmap); 349 350 int videobuf_dma_free(struct videobuf_dmabuf *dma) 351 { 352 int i; 353 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 354 BUG_ON(dma->sglen); 355 356 if (dma->pages) { 357 for (i = 0; i < dma->nr_pages; i++) 358 page_cache_release(dma->pages[i]); 359 kfree(dma->pages); 360 dma->pages = NULL; 361 } 362 363 if (dma->dma_addr) { 364 for (i = 0; i < dma->nr_pages; i++) { 365 void *addr; 366 367 addr = page_address(dma->vaddr_pages[i]); 368 dma_free_coherent(dma->dev, PAGE_SIZE, addr, 369 dma->dma_addr[i]); 370 } 371 kfree(dma->dma_addr); 372 dma->dma_addr = NULL; 373 kfree(dma->vaddr_pages); 374 dma->vaddr_pages = NULL; 375 vunmap(dma->vaddr); 376 dma->vaddr = NULL; 377 } 378 379 if (dma->bus_addr) 380 dma->bus_addr = 0; 381 dma->direction = DMA_NONE; 382 383 return 0; 384 } 385 EXPORT_SYMBOL_GPL(videobuf_dma_free); 386 387 /* --------------------------------------------------------------------- */ 388 389 static void videobuf_vm_open(struct vm_area_struct *vma) 390 { 391 struct videobuf_mapping *map = vma->vm_private_data; 392 393 dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map, 394 map->count, vma->vm_start, vma->vm_end); 395 396 map->count++; 397 } 398 399 static void videobuf_vm_close(struct vm_area_struct *vma) 400 { 401 struct videobuf_mapping *map = vma->vm_private_data; 402 struct videobuf_queue *q = map->q; 403 struct videobuf_dma_sg_memory *mem; 404 int i; 405 406 dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map, 407 map->count, vma->vm_start, vma->vm_end); 408 409 map->count--; 410 if (0 == map->count) { 411 dprintk(1, "munmap %p q=%p\n", map, q); 412 videobuf_queue_lock(q); 413 for (i = 0; i < VIDEO_MAX_FRAME; i++) { 414 if (NULL == q->bufs[i]) 415 continue; 416 mem = q->bufs[i]->priv; 417 if (!mem) 418 continue; 419 420 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 421 422 if (q->bufs[i]->map != map) 423 continue; 424 q->bufs[i]->map = NULL; 425 q->bufs[i]->baddr = 0; 426 q->ops->buf_release(q, q->bufs[i]); 427 } 428 videobuf_queue_unlock(q); 429 kfree(map); 430 } 431 return; 432 } 433 434 /* 435 * Get a anonymous page for the mapping. Make sure we can DMA to that 436 * memory location with 32bit PCI devices (i.e. don't use highmem for 437 * now ...). Bounce buffers don't work very well for the data rates 438 * video capture has. 439 */ 440 static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 441 { 442 struct page *page; 443 444 dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n", 445 (unsigned long)vmf->virtual_address, 446 vma->vm_start, vma->vm_end); 447 448 page = alloc_page(GFP_USER | __GFP_DMA32); 449 if (!page) 450 return VM_FAULT_OOM; 451 clear_user_highpage(page, (unsigned long)vmf->virtual_address); 452 vmf->page = page; 453 454 return 0; 455 } 456 457 static const struct vm_operations_struct videobuf_vm_ops = { 458 .open = videobuf_vm_open, 459 .close = videobuf_vm_close, 460 .fault = videobuf_vm_fault, 461 }; 462 463 /* --------------------------------------------------------------------- 464 * SG handlers for the generic methods 465 */ 466 467 /* Allocated area consists on 3 parts: 468 struct video_buffer 469 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...) 470 struct videobuf_dma_sg_memory 471 */ 472 473 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size) 474 { 475 struct videobuf_dma_sg_memory *mem; 476 struct videobuf_buffer *vb; 477 478 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL); 479 if (!vb) 480 return vb; 481 482 mem = vb->priv = ((char *)vb) + size; 483 mem->magic = MAGIC_SG_MEM; 484 485 videobuf_dma_init(&mem->dma); 486 487 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n", 488 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb), 489 mem, (long)sizeof(*mem)); 490 491 return vb; 492 } 493 494 static void *__videobuf_to_vaddr(struct videobuf_buffer *buf) 495 { 496 struct videobuf_dma_sg_memory *mem = buf->priv; 497 BUG_ON(!mem); 498 499 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 500 501 return mem->dma.vaddr; 502 } 503 504 static int __videobuf_iolock(struct videobuf_queue *q, 505 struct videobuf_buffer *vb, 506 struct v4l2_framebuffer *fbuf) 507 { 508 int err, pages; 509 dma_addr_t bus; 510 struct videobuf_dma_sg_memory *mem = vb->priv; 511 BUG_ON(!mem); 512 513 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 514 515 if (!mem->dma.dev) 516 mem->dma.dev = q->dev; 517 else 518 WARN_ON(mem->dma.dev != q->dev); 519 520 switch (vb->memory) { 521 case V4L2_MEMORY_MMAP: 522 case V4L2_MEMORY_USERPTR: 523 if (0 == vb->baddr) { 524 /* no userspace addr -- kernel bounce buffer */ 525 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; 526 err = videobuf_dma_init_kernel(&mem->dma, 527 DMA_FROM_DEVICE, 528 pages); 529 if (0 != err) 530 return err; 531 } else if (vb->memory == V4L2_MEMORY_USERPTR) { 532 /* dma directly to userspace */ 533 err = videobuf_dma_init_user(&mem->dma, 534 DMA_FROM_DEVICE, 535 vb->baddr, vb->bsize); 536 if (0 != err) 537 return err; 538 } else { 539 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP 540 buffers can only be called from videobuf_qbuf 541 we take current->mm->mmap_sem there, to prevent 542 locking inversion, so don't take it here */ 543 544 err = videobuf_dma_init_user_locked(&mem->dma, 545 DMA_FROM_DEVICE, 546 vb->baddr, vb->bsize); 547 if (0 != err) 548 return err; 549 } 550 break; 551 case V4L2_MEMORY_OVERLAY: 552 if (NULL == fbuf) 553 return -EINVAL; 554 /* FIXME: need sanity checks for vb->boff */ 555 /* 556 * Using a double cast to avoid compiler warnings when 557 * building for PAE. Compiler doesn't like direct casting 558 * of a 32 bit ptr to 64 bit integer. 559 */ 560 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff; 561 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; 562 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE, 563 bus, pages); 564 if (0 != err) 565 return err; 566 break; 567 default: 568 BUG(); 569 } 570 err = videobuf_dma_map(q->dev, &mem->dma); 571 if (0 != err) 572 return err; 573 574 return 0; 575 } 576 577 static int __videobuf_sync(struct videobuf_queue *q, 578 struct videobuf_buffer *buf) 579 { 580 struct videobuf_dma_sg_memory *mem = buf->priv; 581 BUG_ON(!mem || !mem->dma.sglen); 582 583 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 584 MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF); 585 586 dma_sync_sg_for_cpu(q->dev, mem->dma.sglist, 587 mem->dma.sglen, mem->dma.direction); 588 589 return 0; 590 } 591 592 static int __videobuf_mmap_mapper(struct videobuf_queue *q, 593 struct videobuf_buffer *buf, 594 struct vm_area_struct *vma) 595 { 596 struct videobuf_dma_sg_memory *mem = buf->priv; 597 struct videobuf_mapping *map; 598 unsigned int first, last, size = 0, i; 599 int retval; 600 601 retval = -EINVAL; 602 603 BUG_ON(!mem); 604 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 605 606 /* look for first buffer to map */ 607 for (first = 0; first < VIDEO_MAX_FRAME; first++) { 608 if (buf == q->bufs[first]) { 609 size = PAGE_ALIGN(q->bufs[first]->bsize); 610 break; 611 } 612 } 613 614 /* paranoia, should never happen since buf is always valid. */ 615 if (!size) { 616 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n", 617 (vma->vm_pgoff << PAGE_SHIFT)); 618 goto done; 619 } 620 621 last = first; 622 623 /* create mapping + update buffer list */ 624 retval = -ENOMEM; 625 map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL); 626 if (NULL == map) 627 goto done; 628 629 size = 0; 630 for (i = first; i <= last; i++) { 631 if (NULL == q->bufs[i]) 632 continue; 633 q->bufs[i]->map = map; 634 q->bufs[i]->baddr = vma->vm_start + size; 635 size += PAGE_ALIGN(q->bufs[i]->bsize); 636 } 637 638 map->count = 1; 639 map->q = q; 640 vma->vm_ops = &videobuf_vm_ops; 641 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 642 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */ 643 vma->vm_private_data = map; 644 dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n", 645 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last); 646 retval = 0; 647 648 done: 649 return retval; 650 } 651 652 static struct videobuf_qtype_ops sg_ops = { 653 .magic = MAGIC_QTYPE_OPS, 654 655 .alloc_vb = __videobuf_alloc_vb, 656 .iolock = __videobuf_iolock, 657 .sync = __videobuf_sync, 658 .mmap_mapper = __videobuf_mmap_mapper, 659 .vaddr = __videobuf_to_vaddr, 660 }; 661 662 void *videobuf_sg_alloc(size_t size) 663 { 664 struct videobuf_queue q; 665 666 /* Required to make generic handler to call __videobuf_alloc */ 667 q.int_ops = &sg_ops; 668 669 q.msize = size; 670 671 return videobuf_alloc_vb(&q); 672 } 673 EXPORT_SYMBOL_GPL(videobuf_sg_alloc); 674 675 void videobuf_queue_sg_init(struct videobuf_queue *q, 676 const struct videobuf_queue_ops *ops, 677 struct device *dev, 678 spinlock_t *irqlock, 679 enum v4l2_buf_type type, 680 enum v4l2_field field, 681 unsigned int msize, 682 void *priv, 683 struct mutex *ext_lock) 684 { 685 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize, 686 priv, &sg_ops, ext_lock); 687 } 688 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init); 689 690