1 /* 2 * helper functions for SG DMA video4linux capture buffers 3 * 4 * The functions expect the hardware being able to scatter gather 5 * (i.e. the buffers are not linear in physical memory, but fragmented 6 * into PAGE_SIZE chunks). They also assume the driver does not need 7 * to touch the video data. 8 * 9 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org> 10 * 11 * Highly based on video-buf written originally by: 12 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org> 13 * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org> 14 * (c) 2006 Ted Walther and John Sokol 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License as published by 18 * the Free Software Foundation; either version 2 19 */ 20 21 #include <linux/init.h> 22 #include <linux/module.h> 23 #include <linux/moduleparam.h> 24 #include <linux/sched.h> 25 #include <linux/slab.h> 26 #include <linux/interrupt.h> 27 28 #include <linux/dma-mapping.h> 29 #include <linux/vmalloc.h> 30 #include <linux/pagemap.h> 31 #include <linux/scatterlist.h> 32 #include <asm/page.h> 33 #include <asm/pgtable.h> 34 35 #include <media/videobuf-dma-sg.h> 36 37 #define MAGIC_DMABUF 0x19721112 38 #define MAGIC_SG_MEM 0x17890714 39 40 #define MAGIC_CHECK(is, should) \ 41 if (unlikely((is) != (should))) { \ 42 printk(KERN_ERR "magic mismatch: %x (expected %x)\n", \ 43 is, should); \ 44 BUG(); \ 45 } 46 47 static int debug; 48 module_param(debug, int, 0644); 49 50 MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers"); 51 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>"); 52 MODULE_LICENSE("GPL"); 53 54 #define dprintk(level, fmt, arg...) \ 55 if (debug >= level) \ 56 printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg) 57 58 /* --------------------------------------------------------------------- */ 59 60 /* 61 * Return a scatterlist for some page-aligned vmalloc()'ed memory 62 * block (NULL on errors). Memory for the scatterlist is allocated 63 * using kmalloc. The caller must free the memory. 64 */ 65 static struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt, 66 int nr_pages) 67 { 68 struct scatterlist *sglist; 69 struct page *pg; 70 int i; 71 72 sglist = vzalloc(nr_pages * sizeof(*sglist)); 73 if (NULL == sglist) 74 return NULL; 75 sg_init_table(sglist, nr_pages); 76 for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) { 77 pg = vmalloc_to_page(virt); 78 if (NULL == pg) 79 goto err; 80 BUG_ON(PageHighMem(pg)); 81 sg_set_page(&sglist[i], pg, PAGE_SIZE, 0); 82 } 83 return sglist; 84 85 err: 86 vfree(sglist); 87 return NULL; 88 } 89 90 /* 91 * Return a scatterlist for a an array of userpages (NULL on errors). 92 * Memory for the scatterlist is allocated using kmalloc. The caller 93 * must free the memory. 94 */ 95 static struct scatterlist *videobuf_pages_to_sg(struct page **pages, 96 int nr_pages, int offset, size_t size) 97 { 98 struct scatterlist *sglist; 99 int i; 100 101 if (NULL == pages[0]) 102 return NULL; 103 sglist = vmalloc(nr_pages * sizeof(*sglist)); 104 if (NULL == sglist) 105 return NULL; 106 sg_init_table(sglist, nr_pages); 107 108 if (PageHighMem(pages[0])) 109 /* DMA to highmem pages might not work */ 110 goto highmem; 111 sg_set_page(&sglist[0], pages[0], 112 min_t(size_t, PAGE_SIZE - offset, size), offset); 113 size -= min_t(size_t, PAGE_SIZE - offset, size); 114 for (i = 1; i < nr_pages; i++) { 115 if (NULL == pages[i]) 116 goto nopage; 117 if (PageHighMem(pages[i])) 118 goto highmem; 119 sg_set_page(&sglist[i], pages[i], min_t(size_t, PAGE_SIZE, size), 0); 120 size -= min_t(size_t, PAGE_SIZE, size); 121 } 122 return sglist; 123 124 nopage: 125 dprintk(2, "sgl: oops - no page\n"); 126 vfree(sglist); 127 return NULL; 128 129 highmem: 130 dprintk(2, "sgl: oops - highmem page\n"); 131 vfree(sglist); 132 return NULL; 133 } 134 135 /* --------------------------------------------------------------------- */ 136 137 struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf) 138 { 139 struct videobuf_dma_sg_memory *mem = buf->priv; 140 BUG_ON(!mem); 141 142 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 143 144 return &mem->dma; 145 } 146 EXPORT_SYMBOL_GPL(videobuf_to_dma); 147 148 static void videobuf_dma_init(struct videobuf_dmabuf *dma) 149 { 150 memset(dma, 0, sizeof(*dma)); 151 dma->magic = MAGIC_DMABUF; 152 } 153 154 static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, 155 int direction, unsigned long data, unsigned long size) 156 { 157 unsigned long first, last; 158 int err, rw = 0; 159 160 dma->direction = direction; 161 switch (dma->direction) { 162 case DMA_FROM_DEVICE: 163 rw = READ; 164 break; 165 case DMA_TO_DEVICE: 166 rw = WRITE; 167 break; 168 default: 169 BUG(); 170 } 171 172 first = (data & PAGE_MASK) >> PAGE_SHIFT; 173 last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT; 174 dma->offset = data & ~PAGE_MASK; 175 dma->size = size; 176 dma->nr_pages = last-first+1; 177 dma->pages = kmalloc(dma->nr_pages * sizeof(struct page *), GFP_KERNEL); 178 if (NULL == dma->pages) 179 return -ENOMEM; 180 181 dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n", 182 data, size, dma->nr_pages); 183 184 err = get_user_pages(data & PAGE_MASK, dma->nr_pages, 185 rw == READ, 1, /* force */ 186 dma->pages, NULL); 187 188 if (err != dma->nr_pages) { 189 dma->nr_pages = (err >= 0) ? err : 0; 190 dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages); 191 return err < 0 ? err : -EINVAL; 192 } 193 return 0; 194 } 195 196 static int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction, 197 unsigned long data, unsigned long size) 198 { 199 int ret; 200 201 down_read(¤t->mm->mmap_sem); 202 ret = videobuf_dma_init_user_locked(dma, direction, data, size); 203 up_read(¤t->mm->mmap_sem); 204 205 return ret; 206 } 207 208 static int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction, 209 int nr_pages) 210 { 211 int i; 212 213 dprintk(1, "init kernel [%d pages]\n", nr_pages); 214 215 dma->direction = direction; 216 dma->vaddr_pages = kcalloc(nr_pages, sizeof(*dma->vaddr_pages), 217 GFP_KERNEL); 218 if (!dma->vaddr_pages) 219 return -ENOMEM; 220 221 dma->dma_addr = kcalloc(nr_pages, sizeof(*dma->dma_addr), GFP_KERNEL); 222 if (!dma->dma_addr) { 223 kfree(dma->vaddr_pages); 224 return -ENOMEM; 225 } 226 for (i = 0; i < nr_pages; i++) { 227 void *addr; 228 229 addr = dma_alloc_coherent(dma->dev, PAGE_SIZE, 230 &(dma->dma_addr[i]), GFP_KERNEL); 231 if (addr == NULL) 232 goto out_free_pages; 233 234 dma->vaddr_pages[i] = virt_to_page(addr); 235 } 236 dma->vaddr = vmap(dma->vaddr_pages, nr_pages, VM_MAP | VM_IOREMAP, 237 PAGE_KERNEL); 238 if (NULL == dma->vaddr) { 239 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages); 240 goto out_free_pages; 241 } 242 243 dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n", 244 (unsigned long)dma->vaddr, 245 nr_pages << PAGE_SHIFT); 246 247 memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT); 248 dma->nr_pages = nr_pages; 249 250 return 0; 251 out_free_pages: 252 while (i > 0) { 253 void *addr; 254 255 i--; 256 addr = page_address(dma->vaddr_pages[i]); 257 dma_free_coherent(dma->dev, PAGE_SIZE, addr, dma->dma_addr[i]); 258 } 259 kfree(dma->dma_addr); 260 dma->dma_addr = NULL; 261 kfree(dma->vaddr_pages); 262 dma->vaddr_pages = NULL; 263 264 return -ENOMEM; 265 266 } 267 268 static int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction, 269 dma_addr_t addr, int nr_pages) 270 { 271 dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n", 272 nr_pages, (unsigned long)addr); 273 dma->direction = direction; 274 275 if (0 == addr) 276 return -EINVAL; 277 278 dma->bus_addr = addr; 279 dma->nr_pages = nr_pages; 280 281 return 0; 282 } 283 284 static int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma) 285 { 286 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 287 BUG_ON(0 == dma->nr_pages); 288 289 if (dma->pages) { 290 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages, 291 dma->offset, dma->size); 292 } 293 if (dma->vaddr) { 294 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr, 295 dma->nr_pages); 296 } 297 if (dma->bus_addr) { 298 dma->sglist = vmalloc(sizeof(*dma->sglist)); 299 if (NULL != dma->sglist) { 300 dma->sglen = 1; 301 sg_dma_address(&dma->sglist[0]) = dma->bus_addr 302 & PAGE_MASK; 303 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK; 304 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE; 305 } 306 } 307 if (NULL == dma->sglist) { 308 dprintk(1, "scatterlist is NULL\n"); 309 return -ENOMEM; 310 } 311 if (!dma->bus_addr) { 312 dma->sglen = dma_map_sg(dev, dma->sglist, 313 dma->nr_pages, dma->direction); 314 if (0 == dma->sglen) { 315 printk(KERN_WARNING 316 "%s: videobuf_map_sg failed\n", __func__); 317 vfree(dma->sglist); 318 dma->sglist = NULL; 319 dma->sglen = 0; 320 return -ENOMEM; 321 } 322 } 323 324 return 0; 325 } 326 327 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma) 328 { 329 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 330 331 if (!dma->sglen) 332 return 0; 333 334 dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction); 335 336 vfree(dma->sglist); 337 dma->sglist = NULL; 338 dma->sglen = 0; 339 340 return 0; 341 } 342 EXPORT_SYMBOL_GPL(videobuf_dma_unmap); 343 344 int videobuf_dma_free(struct videobuf_dmabuf *dma) 345 { 346 int i; 347 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 348 BUG_ON(dma->sglen); 349 350 if (dma->pages) { 351 for (i = 0; i < dma->nr_pages; i++) 352 page_cache_release(dma->pages[i]); 353 kfree(dma->pages); 354 dma->pages = NULL; 355 } 356 357 if (dma->dma_addr) { 358 for (i = 0; i < dma->nr_pages; i++) { 359 void *addr; 360 361 addr = page_address(dma->vaddr_pages[i]); 362 dma_free_coherent(dma->dev, PAGE_SIZE, addr, 363 dma->dma_addr[i]); 364 } 365 kfree(dma->dma_addr); 366 dma->dma_addr = NULL; 367 kfree(dma->vaddr_pages); 368 dma->vaddr_pages = NULL; 369 vunmap(dma->vaddr); 370 dma->vaddr = NULL; 371 } 372 373 if (dma->bus_addr) 374 dma->bus_addr = 0; 375 dma->direction = DMA_NONE; 376 377 return 0; 378 } 379 EXPORT_SYMBOL_GPL(videobuf_dma_free); 380 381 /* --------------------------------------------------------------------- */ 382 383 static void videobuf_vm_open(struct vm_area_struct *vma) 384 { 385 struct videobuf_mapping *map = vma->vm_private_data; 386 387 dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map, 388 map->count, vma->vm_start, vma->vm_end); 389 390 map->count++; 391 } 392 393 static void videobuf_vm_close(struct vm_area_struct *vma) 394 { 395 struct videobuf_mapping *map = vma->vm_private_data; 396 struct videobuf_queue *q = map->q; 397 struct videobuf_dma_sg_memory *mem; 398 int i; 399 400 dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map, 401 map->count, vma->vm_start, vma->vm_end); 402 403 map->count--; 404 if (0 == map->count) { 405 dprintk(1, "munmap %p q=%p\n", map, q); 406 videobuf_queue_lock(q); 407 for (i = 0; i < VIDEO_MAX_FRAME; i++) { 408 if (NULL == q->bufs[i]) 409 continue; 410 mem = q->bufs[i]->priv; 411 if (!mem) 412 continue; 413 414 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 415 416 if (q->bufs[i]->map != map) 417 continue; 418 q->bufs[i]->map = NULL; 419 q->bufs[i]->baddr = 0; 420 q->ops->buf_release(q, q->bufs[i]); 421 } 422 videobuf_queue_unlock(q); 423 kfree(map); 424 } 425 return; 426 } 427 428 /* 429 * Get a anonymous page for the mapping. Make sure we can DMA to that 430 * memory location with 32bit PCI devices (i.e. don't use highmem for 431 * now ...). Bounce buffers don't work very well for the data rates 432 * video capture has. 433 */ 434 static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 435 { 436 struct page *page; 437 438 dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n", 439 (unsigned long)vmf->virtual_address, 440 vma->vm_start, vma->vm_end); 441 442 page = alloc_page(GFP_USER | __GFP_DMA32); 443 if (!page) 444 return VM_FAULT_OOM; 445 clear_user_highpage(page, (unsigned long)vmf->virtual_address); 446 vmf->page = page; 447 448 return 0; 449 } 450 451 static const struct vm_operations_struct videobuf_vm_ops = { 452 .open = videobuf_vm_open, 453 .close = videobuf_vm_close, 454 .fault = videobuf_vm_fault, 455 }; 456 457 /* --------------------------------------------------------------------- 458 * SG handlers for the generic methods 459 */ 460 461 /* Allocated area consists on 3 parts: 462 struct video_buffer 463 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...) 464 struct videobuf_dma_sg_memory 465 */ 466 467 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size) 468 { 469 struct videobuf_dma_sg_memory *mem; 470 struct videobuf_buffer *vb; 471 472 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL); 473 if (!vb) 474 return vb; 475 476 mem = vb->priv = ((char *)vb) + size; 477 mem->magic = MAGIC_SG_MEM; 478 479 videobuf_dma_init(&mem->dma); 480 481 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n", 482 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb), 483 mem, (long)sizeof(*mem)); 484 485 return vb; 486 } 487 488 static void *__videobuf_to_vaddr(struct videobuf_buffer *buf) 489 { 490 struct videobuf_dma_sg_memory *mem = buf->priv; 491 BUG_ON(!mem); 492 493 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 494 495 return mem->dma.vaddr; 496 } 497 498 static int __videobuf_iolock(struct videobuf_queue *q, 499 struct videobuf_buffer *vb, 500 struct v4l2_framebuffer *fbuf) 501 { 502 int err, pages; 503 dma_addr_t bus; 504 struct videobuf_dma_sg_memory *mem = vb->priv; 505 BUG_ON(!mem); 506 507 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 508 509 if (!mem->dma.dev) 510 mem->dma.dev = q->dev; 511 else 512 WARN_ON(mem->dma.dev != q->dev); 513 514 switch (vb->memory) { 515 case V4L2_MEMORY_MMAP: 516 case V4L2_MEMORY_USERPTR: 517 if (0 == vb->baddr) { 518 /* no userspace addr -- kernel bounce buffer */ 519 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; 520 err = videobuf_dma_init_kernel(&mem->dma, 521 DMA_FROM_DEVICE, 522 pages); 523 if (0 != err) 524 return err; 525 } else if (vb->memory == V4L2_MEMORY_USERPTR) { 526 /* dma directly to userspace */ 527 err = videobuf_dma_init_user(&mem->dma, 528 DMA_FROM_DEVICE, 529 vb->baddr, vb->bsize); 530 if (0 != err) 531 return err; 532 } else { 533 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP 534 buffers can only be called from videobuf_qbuf 535 we take current->mm->mmap_sem there, to prevent 536 locking inversion, so don't take it here */ 537 538 err = videobuf_dma_init_user_locked(&mem->dma, 539 DMA_FROM_DEVICE, 540 vb->baddr, vb->bsize); 541 if (0 != err) 542 return err; 543 } 544 break; 545 case V4L2_MEMORY_OVERLAY: 546 if (NULL == fbuf) 547 return -EINVAL; 548 /* FIXME: need sanity checks for vb->boff */ 549 /* 550 * Using a double cast to avoid compiler warnings when 551 * building for PAE. Compiler doesn't like direct casting 552 * of a 32 bit ptr to 64 bit integer. 553 */ 554 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff; 555 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; 556 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE, 557 bus, pages); 558 if (0 != err) 559 return err; 560 break; 561 default: 562 BUG(); 563 } 564 err = videobuf_dma_map(q->dev, &mem->dma); 565 if (0 != err) 566 return err; 567 568 return 0; 569 } 570 571 static int __videobuf_sync(struct videobuf_queue *q, 572 struct videobuf_buffer *buf) 573 { 574 struct videobuf_dma_sg_memory *mem = buf->priv; 575 BUG_ON(!mem || !mem->dma.sglen); 576 577 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 578 MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF); 579 580 dma_sync_sg_for_cpu(q->dev, mem->dma.sglist, 581 mem->dma.sglen, mem->dma.direction); 582 583 return 0; 584 } 585 586 static int __videobuf_mmap_mapper(struct videobuf_queue *q, 587 struct videobuf_buffer *buf, 588 struct vm_area_struct *vma) 589 { 590 struct videobuf_dma_sg_memory *mem = buf->priv; 591 struct videobuf_mapping *map; 592 unsigned int first, last, size = 0, i; 593 int retval; 594 595 retval = -EINVAL; 596 597 BUG_ON(!mem); 598 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 599 600 /* look for first buffer to map */ 601 for (first = 0; first < VIDEO_MAX_FRAME; first++) { 602 if (buf == q->bufs[first]) { 603 size = PAGE_ALIGN(q->bufs[first]->bsize); 604 break; 605 } 606 } 607 608 /* paranoia, should never happen since buf is always valid. */ 609 if (!size) { 610 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n", 611 (vma->vm_pgoff << PAGE_SHIFT)); 612 goto done; 613 } 614 615 last = first; 616 617 /* create mapping + update buffer list */ 618 retval = -ENOMEM; 619 map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL); 620 if (NULL == map) 621 goto done; 622 623 size = 0; 624 for (i = first; i <= last; i++) { 625 if (NULL == q->bufs[i]) 626 continue; 627 q->bufs[i]->map = map; 628 q->bufs[i]->baddr = vma->vm_start + size; 629 size += PAGE_ALIGN(q->bufs[i]->bsize); 630 } 631 632 map->count = 1; 633 map->q = q; 634 vma->vm_ops = &videobuf_vm_ops; 635 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 636 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */ 637 vma->vm_private_data = map; 638 dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n", 639 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last); 640 retval = 0; 641 642 done: 643 return retval; 644 } 645 646 static struct videobuf_qtype_ops sg_ops = { 647 .magic = MAGIC_QTYPE_OPS, 648 649 .alloc_vb = __videobuf_alloc_vb, 650 .iolock = __videobuf_iolock, 651 .sync = __videobuf_sync, 652 .mmap_mapper = __videobuf_mmap_mapper, 653 .vaddr = __videobuf_to_vaddr, 654 }; 655 656 void *videobuf_sg_alloc(size_t size) 657 { 658 struct videobuf_queue q; 659 660 /* Required to make generic handler to call __videobuf_alloc */ 661 q.int_ops = &sg_ops; 662 663 q.msize = size; 664 665 return videobuf_alloc_vb(&q); 666 } 667 EXPORT_SYMBOL_GPL(videobuf_sg_alloc); 668 669 void videobuf_queue_sg_init(struct videobuf_queue *q, 670 const struct videobuf_queue_ops *ops, 671 struct device *dev, 672 spinlock_t *irqlock, 673 enum v4l2_buf_type type, 674 enum v4l2_field field, 675 unsigned int msize, 676 void *priv, 677 struct mutex *ext_lock) 678 { 679 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize, 680 priv, &sg_ops, ext_lock); 681 } 682 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init); 683 684