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 dprintk(1, "init kernel [%d pages]\n", nr_pages); 215 216 dma->direction = direction; 217 dma->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT); 218 if (NULL == dma->vaddr) { 219 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages); 220 return -ENOMEM; 221 } 222 223 dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n", 224 (unsigned long)dma->vaddr, 225 nr_pages << PAGE_SHIFT); 226 227 memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT); 228 dma->nr_pages = nr_pages; 229 230 return 0; 231 } 232 EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel); 233 234 int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction, 235 dma_addr_t addr, int nr_pages) 236 { 237 dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n", 238 nr_pages, (unsigned long)addr); 239 dma->direction = direction; 240 241 if (0 == addr) 242 return -EINVAL; 243 244 dma->bus_addr = addr; 245 dma->nr_pages = nr_pages; 246 247 return 0; 248 } 249 EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay); 250 251 int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma) 252 { 253 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 254 BUG_ON(0 == dma->nr_pages); 255 256 if (dma->pages) { 257 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages, 258 dma->offset, dma->size); 259 } 260 if (dma->vaddr) { 261 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr, 262 dma->nr_pages); 263 } 264 if (dma->bus_addr) { 265 dma->sglist = vmalloc(sizeof(*dma->sglist)); 266 if (NULL != dma->sglist) { 267 dma->sglen = 1; 268 sg_dma_address(&dma->sglist[0]) = dma->bus_addr 269 & PAGE_MASK; 270 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK; 271 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE; 272 } 273 } 274 if (NULL == dma->sglist) { 275 dprintk(1, "scatterlist is NULL\n"); 276 return -ENOMEM; 277 } 278 if (!dma->bus_addr) { 279 dma->sglen = dma_map_sg(dev, dma->sglist, 280 dma->nr_pages, dma->direction); 281 if (0 == dma->sglen) { 282 printk(KERN_WARNING 283 "%s: videobuf_map_sg failed\n", __func__); 284 vfree(dma->sglist); 285 dma->sglist = NULL; 286 dma->sglen = 0; 287 return -ENOMEM; 288 } 289 } 290 291 return 0; 292 } 293 EXPORT_SYMBOL_GPL(videobuf_dma_map); 294 295 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma) 296 { 297 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 298 299 if (!dma->sglen) 300 return 0; 301 302 dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction); 303 304 vfree(dma->sglist); 305 dma->sglist = NULL; 306 dma->sglen = 0; 307 308 return 0; 309 } 310 EXPORT_SYMBOL_GPL(videobuf_dma_unmap); 311 312 int videobuf_dma_free(struct videobuf_dmabuf *dma) 313 { 314 int i; 315 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 316 BUG_ON(dma->sglen); 317 318 if (dma->pages) { 319 for (i = 0; i < dma->nr_pages; i++) 320 page_cache_release(dma->pages[i]); 321 kfree(dma->pages); 322 dma->pages = NULL; 323 } 324 325 vfree(dma->vaddr); 326 dma->vaddr = NULL; 327 328 if (dma->bus_addr) 329 dma->bus_addr = 0; 330 dma->direction = DMA_NONE; 331 332 return 0; 333 } 334 EXPORT_SYMBOL_GPL(videobuf_dma_free); 335 336 /* --------------------------------------------------------------------- */ 337 338 static void videobuf_vm_open(struct vm_area_struct *vma) 339 { 340 struct videobuf_mapping *map = vma->vm_private_data; 341 struct videobuf_queue *q = map->q; 342 343 dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map, 344 map->count, vma->vm_start, vma->vm_end); 345 346 videobuf_queue_lock(q); 347 map->count++; 348 videobuf_queue_unlock(q); 349 } 350 351 static void videobuf_vm_close(struct vm_area_struct *vma) 352 { 353 struct videobuf_mapping *map = vma->vm_private_data; 354 struct videobuf_queue *q = map->q; 355 struct videobuf_dma_sg_memory *mem; 356 int i; 357 358 dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map, 359 map->count, vma->vm_start, vma->vm_end); 360 361 videobuf_queue_lock(q); 362 if (!--map->count) { 363 dprintk(1, "munmap %p q=%p\n", map, q); 364 for (i = 0; i < VIDEO_MAX_FRAME; i++) { 365 if (NULL == q->bufs[i]) 366 continue; 367 mem = q->bufs[i]->priv; 368 if (!mem) 369 continue; 370 371 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 372 373 if (q->bufs[i]->map != map) 374 continue; 375 q->bufs[i]->map = NULL; 376 q->bufs[i]->baddr = 0; 377 q->ops->buf_release(q, q->bufs[i]); 378 } 379 kfree(map); 380 } 381 videobuf_queue_unlock(q); 382 return; 383 } 384 385 /* 386 * Get a anonymous page for the mapping. Make sure we can DMA to that 387 * memory location with 32bit PCI devices (i.e. don't use highmem for 388 * now ...). Bounce buffers don't work very well for the data rates 389 * video capture has. 390 */ 391 static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 392 { 393 struct page *page; 394 395 dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n", 396 (unsigned long)vmf->virtual_address, 397 vma->vm_start, vma->vm_end); 398 399 page = alloc_page(GFP_USER | __GFP_DMA32); 400 if (!page) 401 return VM_FAULT_OOM; 402 clear_user_highpage(page, (unsigned long)vmf->virtual_address); 403 vmf->page = page; 404 405 return 0; 406 } 407 408 static const struct vm_operations_struct videobuf_vm_ops = { 409 .open = videobuf_vm_open, 410 .close = videobuf_vm_close, 411 .fault = videobuf_vm_fault, 412 }; 413 414 /* --------------------------------------------------------------------- 415 * SG handlers for the generic methods 416 */ 417 418 /* Allocated area consists on 3 parts: 419 struct video_buffer 420 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...) 421 struct videobuf_dma_sg_memory 422 */ 423 424 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size) 425 { 426 struct videobuf_dma_sg_memory *mem; 427 struct videobuf_buffer *vb; 428 429 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL); 430 if (!vb) 431 return vb; 432 433 mem = vb->priv = ((char *)vb) + size; 434 mem->magic = MAGIC_SG_MEM; 435 436 videobuf_dma_init(&mem->dma); 437 438 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n", 439 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb), 440 mem, (long)sizeof(*mem)); 441 442 return vb; 443 } 444 445 static void *__videobuf_to_vaddr(struct videobuf_buffer *buf) 446 { 447 struct videobuf_dma_sg_memory *mem = buf->priv; 448 BUG_ON(!mem); 449 450 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 451 452 return mem->dma.vaddr; 453 } 454 455 static int __videobuf_iolock(struct videobuf_queue *q, 456 struct videobuf_buffer *vb, 457 struct v4l2_framebuffer *fbuf) 458 { 459 int err, pages; 460 dma_addr_t bus; 461 struct videobuf_dma_sg_memory *mem = vb->priv; 462 BUG_ON(!mem); 463 464 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 465 466 switch (vb->memory) { 467 case V4L2_MEMORY_MMAP: 468 case V4L2_MEMORY_USERPTR: 469 if (0 == vb->baddr) { 470 /* no userspace addr -- kernel bounce buffer */ 471 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; 472 err = videobuf_dma_init_kernel(&mem->dma, 473 DMA_FROM_DEVICE, 474 pages); 475 if (0 != err) 476 return err; 477 } else if (vb->memory == V4L2_MEMORY_USERPTR) { 478 /* dma directly to userspace */ 479 err = videobuf_dma_init_user(&mem->dma, 480 DMA_FROM_DEVICE, 481 vb->baddr, vb->bsize); 482 if (0 != err) 483 return err; 484 } else { 485 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP 486 buffers can only be called from videobuf_qbuf 487 we take current->mm->mmap_sem there, to prevent 488 locking inversion, so don't take it here */ 489 490 err = videobuf_dma_init_user_locked(&mem->dma, 491 DMA_FROM_DEVICE, 492 vb->baddr, vb->bsize); 493 if (0 != err) 494 return err; 495 } 496 break; 497 case V4L2_MEMORY_OVERLAY: 498 if (NULL == fbuf) 499 return -EINVAL; 500 /* FIXME: need sanity checks for vb->boff */ 501 /* 502 * Using a double cast to avoid compiler warnings when 503 * building for PAE. Compiler doesn't like direct casting 504 * of a 32 bit ptr to 64 bit integer. 505 */ 506 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff; 507 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; 508 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE, 509 bus, pages); 510 if (0 != err) 511 return err; 512 break; 513 default: 514 BUG(); 515 } 516 err = videobuf_dma_map(q->dev, &mem->dma); 517 if (0 != err) 518 return err; 519 520 return 0; 521 } 522 523 static int __videobuf_sync(struct videobuf_queue *q, 524 struct videobuf_buffer *buf) 525 { 526 struct videobuf_dma_sg_memory *mem = buf->priv; 527 BUG_ON(!mem || !mem->dma.sglen); 528 529 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 530 MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF); 531 532 dma_sync_sg_for_cpu(q->dev, mem->dma.sglist, 533 mem->dma.sglen, mem->dma.direction); 534 535 return 0; 536 } 537 538 static int __videobuf_mmap_mapper(struct videobuf_queue *q, 539 struct videobuf_buffer *buf, 540 struct vm_area_struct *vma) 541 { 542 struct videobuf_dma_sg_memory *mem = buf->priv; 543 struct videobuf_mapping *map; 544 unsigned int first, last, size = 0, i; 545 int retval; 546 547 retval = -EINVAL; 548 549 BUG_ON(!mem); 550 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 551 552 /* look for first buffer to map */ 553 for (first = 0; first < VIDEO_MAX_FRAME; first++) { 554 if (buf == q->bufs[first]) { 555 size = PAGE_ALIGN(q->bufs[first]->bsize); 556 break; 557 } 558 } 559 560 /* paranoia, should never happen since buf is always valid. */ 561 if (!size) { 562 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n", 563 (vma->vm_pgoff << PAGE_SHIFT)); 564 goto done; 565 } 566 567 last = first; 568 569 /* create mapping + update buffer list */ 570 retval = -ENOMEM; 571 map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL); 572 if (NULL == map) 573 goto done; 574 575 size = 0; 576 for (i = first; i <= last; i++) { 577 if (NULL == q->bufs[i]) 578 continue; 579 q->bufs[i]->map = map; 580 q->bufs[i]->baddr = vma->vm_start + size; 581 size += PAGE_ALIGN(q->bufs[i]->bsize); 582 } 583 584 map->count = 1; 585 map->q = q; 586 vma->vm_ops = &videobuf_vm_ops; 587 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 588 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */ 589 vma->vm_private_data = map; 590 dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n", 591 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last); 592 retval = 0; 593 594 done: 595 return retval; 596 } 597 598 static struct videobuf_qtype_ops sg_ops = { 599 .magic = MAGIC_QTYPE_OPS, 600 601 .alloc_vb = __videobuf_alloc_vb, 602 .iolock = __videobuf_iolock, 603 .sync = __videobuf_sync, 604 .mmap_mapper = __videobuf_mmap_mapper, 605 .vaddr = __videobuf_to_vaddr, 606 }; 607 608 void *videobuf_sg_alloc(size_t size) 609 { 610 struct videobuf_queue q; 611 612 /* Required to make generic handler to call __videobuf_alloc */ 613 q.int_ops = &sg_ops; 614 615 q.msize = size; 616 617 return videobuf_alloc_vb(&q); 618 } 619 EXPORT_SYMBOL_GPL(videobuf_sg_alloc); 620 621 void videobuf_queue_sg_init(struct videobuf_queue *q, 622 const struct videobuf_queue_ops *ops, 623 struct device *dev, 624 spinlock_t *irqlock, 625 enum v4l2_buf_type type, 626 enum v4l2_field field, 627 unsigned int msize, 628 void *priv, 629 struct mutex *ext_lock) 630 { 631 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize, 632 priv, &sg_ops, ext_lock); 633 } 634 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init); 635 636