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(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: err=%d [%d]\n", err, dma->nr_pages); 194 return err < 0 ? err : -EINVAL; 195 } 196 return 0; 197 } 198 199 static int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction, 200 unsigned long data, unsigned long size) 201 { 202 int ret; 203 204 down_read(¤t->mm->mmap_sem); 205 ret = videobuf_dma_init_user_locked(dma, direction, data, size); 206 up_read(¤t->mm->mmap_sem); 207 208 return ret; 209 } 210 211 static 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 } 270 271 static int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction, 272 dma_addr_t addr, int nr_pages) 273 { 274 dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n", 275 nr_pages, (unsigned long)addr); 276 dma->direction = direction; 277 278 if (0 == addr) 279 return -EINVAL; 280 281 dma->bus_addr = addr; 282 dma->nr_pages = nr_pages; 283 284 return 0; 285 } 286 287 static int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma) 288 { 289 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 290 BUG_ON(0 == dma->nr_pages); 291 292 if (dma->pages) { 293 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages, 294 dma->offset, dma->size); 295 } 296 if (dma->vaddr) { 297 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr, 298 dma->nr_pages); 299 } 300 if (dma->bus_addr) { 301 dma->sglist = vmalloc(sizeof(*dma->sglist)); 302 if (NULL != dma->sglist) { 303 dma->sglen = 1; 304 sg_dma_address(&dma->sglist[0]) = dma->bus_addr 305 & PAGE_MASK; 306 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK; 307 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE; 308 } 309 } 310 if (NULL == dma->sglist) { 311 dprintk(1, "scatterlist is NULL\n"); 312 return -ENOMEM; 313 } 314 if (!dma->bus_addr) { 315 dma->sglen = dma_map_sg(dev, dma->sglist, 316 dma->nr_pages, dma->direction); 317 if (0 == dma->sglen) { 318 printk(KERN_WARNING 319 "%s: videobuf_map_sg failed\n", __func__); 320 vfree(dma->sglist); 321 dma->sglist = NULL; 322 dma->sglen = 0; 323 return -ENOMEM; 324 } 325 } 326 327 return 0; 328 } 329 330 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma) 331 { 332 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 333 334 if (!dma->sglen) 335 return 0; 336 337 dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction); 338 339 vfree(dma->sglist); 340 dma->sglist = NULL; 341 dma->sglen = 0; 342 343 return 0; 344 } 345 EXPORT_SYMBOL_GPL(videobuf_dma_unmap); 346 347 int videobuf_dma_free(struct videobuf_dmabuf *dma) 348 { 349 int i; 350 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 351 BUG_ON(dma->sglen); 352 353 if (dma->pages) { 354 for (i = 0; i < dma->nr_pages; i++) 355 put_page(dma->pages[i]); 356 kfree(dma->pages); 357 dma->pages = NULL; 358 } 359 360 if (dma->dma_addr) { 361 for (i = 0; i < dma->nr_pages; i++) { 362 void *addr; 363 364 addr = page_address(dma->vaddr_pages[i]); 365 dma_free_coherent(dma->dev, PAGE_SIZE, addr, 366 dma->dma_addr[i]); 367 } 368 kfree(dma->dma_addr); 369 dma->dma_addr = NULL; 370 kfree(dma->vaddr_pages); 371 dma->vaddr_pages = NULL; 372 vunmap(dma->vaddr); 373 dma->vaddr = NULL; 374 } 375 376 if (dma->bus_addr) 377 dma->bus_addr = 0; 378 dma->direction = DMA_NONE; 379 380 return 0; 381 } 382 EXPORT_SYMBOL_GPL(videobuf_dma_free); 383 384 /* --------------------------------------------------------------------- */ 385 386 static void videobuf_vm_open(struct vm_area_struct *vma) 387 { 388 struct videobuf_mapping *map = vma->vm_private_data; 389 390 dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map, 391 map->count, vma->vm_start, vma->vm_end); 392 393 map->count++; 394 } 395 396 static void videobuf_vm_close(struct vm_area_struct *vma) 397 { 398 struct videobuf_mapping *map = vma->vm_private_data; 399 struct videobuf_queue *q = map->q; 400 struct videobuf_dma_sg_memory *mem; 401 int i; 402 403 dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map, 404 map->count, vma->vm_start, vma->vm_end); 405 406 map->count--; 407 if (0 == map->count) { 408 dprintk(1, "munmap %p q=%p\n", map, q); 409 videobuf_queue_lock(q); 410 for (i = 0; i < VIDEO_MAX_FRAME; i++) { 411 if (NULL == q->bufs[i]) 412 continue; 413 mem = q->bufs[i]->priv; 414 if (!mem) 415 continue; 416 417 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 418 419 if (q->bufs[i]->map != map) 420 continue; 421 q->bufs[i]->map = NULL; 422 q->bufs[i]->baddr = 0; 423 q->ops->buf_release(q, q->bufs[i]); 424 } 425 videobuf_queue_unlock(q); 426 kfree(map); 427 } 428 return; 429 } 430 431 /* 432 * Get a anonymous page for the mapping. Make sure we can DMA to that 433 * memory location with 32bit PCI devices (i.e. don't use highmem for 434 * now ...). Bounce buffers don't work very well for the data rates 435 * video capture has. 436 */ 437 static int videobuf_vm_fault(struct vm_fault *vmf) 438 { 439 struct vm_area_struct *vma = vmf->vma; 440 struct page *page; 441 442 dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n", 443 vmf->address, vma->vm_start, vma->vm_end); 444 445 page = alloc_page(GFP_USER | __GFP_DMA32); 446 if (!page) 447 return VM_FAULT_OOM; 448 clear_user_highpage(page, vmf->address); 449 vmf->page = page; 450 451 return 0; 452 } 453 454 static const struct vm_operations_struct videobuf_vm_ops = { 455 .open = videobuf_vm_open, 456 .close = videobuf_vm_close, 457 .fault = videobuf_vm_fault, 458 }; 459 460 /* --------------------------------------------------------------------- 461 * SG handlers for the generic methods 462 */ 463 464 /* Allocated area consists on 3 parts: 465 struct video_buffer 466 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...) 467 struct videobuf_dma_sg_memory 468 */ 469 470 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size) 471 { 472 struct videobuf_dma_sg_memory *mem; 473 struct videobuf_buffer *vb; 474 475 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL); 476 if (!vb) 477 return vb; 478 479 mem = vb->priv = ((char *)vb) + size; 480 mem->magic = MAGIC_SG_MEM; 481 482 videobuf_dma_init(&mem->dma); 483 484 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n", 485 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb), 486 mem, (long)sizeof(*mem)); 487 488 return vb; 489 } 490 491 static void *__videobuf_to_vaddr(struct videobuf_buffer *buf) 492 { 493 struct videobuf_dma_sg_memory *mem = buf->priv; 494 BUG_ON(!mem); 495 496 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 497 498 return mem->dma.vaddr; 499 } 500 501 static int __videobuf_iolock(struct videobuf_queue *q, 502 struct videobuf_buffer *vb, 503 struct v4l2_framebuffer *fbuf) 504 { 505 int err, pages; 506 dma_addr_t bus; 507 struct videobuf_dma_sg_memory *mem = vb->priv; 508 BUG_ON(!mem); 509 510 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 511 512 if (!mem->dma.dev) 513 mem->dma.dev = q->dev; 514 else 515 WARN_ON(mem->dma.dev != q->dev); 516 517 switch (vb->memory) { 518 case V4L2_MEMORY_MMAP: 519 case V4L2_MEMORY_USERPTR: 520 if (0 == vb->baddr) { 521 /* no userspace addr -- kernel bounce buffer */ 522 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; 523 err = videobuf_dma_init_kernel(&mem->dma, 524 DMA_FROM_DEVICE, 525 pages); 526 if (0 != err) 527 return err; 528 } else if (vb->memory == V4L2_MEMORY_USERPTR) { 529 /* dma directly to userspace */ 530 err = videobuf_dma_init_user(&mem->dma, 531 DMA_FROM_DEVICE, 532 vb->baddr, vb->bsize); 533 if (0 != err) 534 return err; 535 } else { 536 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP 537 buffers can only be called from videobuf_qbuf 538 we take current->mm->mmap_sem there, to prevent 539 locking inversion, so don't take it here */ 540 541 err = videobuf_dma_init_user_locked(&mem->dma, 542 DMA_FROM_DEVICE, 543 vb->baddr, vb->bsize); 544 if (0 != err) 545 return err; 546 } 547 break; 548 case V4L2_MEMORY_OVERLAY: 549 if (NULL == fbuf) 550 return -EINVAL; 551 /* FIXME: need sanity checks for vb->boff */ 552 /* 553 * Using a double cast to avoid compiler warnings when 554 * building for PAE. Compiler doesn't like direct casting 555 * of a 32 bit ptr to 64 bit integer. 556 */ 557 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff; 558 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; 559 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE, 560 bus, pages); 561 if (0 != err) 562 return err; 563 break; 564 default: 565 BUG(); 566 } 567 err = videobuf_dma_map(q->dev, &mem->dma); 568 if (0 != err) 569 return err; 570 571 return 0; 572 } 573 574 static int __videobuf_sync(struct videobuf_queue *q, 575 struct videobuf_buffer *buf) 576 { 577 struct videobuf_dma_sg_memory *mem = buf->priv; 578 BUG_ON(!mem || !mem->dma.sglen); 579 580 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 581 MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF); 582 583 dma_sync_sg_for_cpu(q->dev, mem->dma.sglist, 584 mem->dma.sglen, mem->dma.direction); 585 586 return 0; 587 } 588 589 static int __videobuf_mmap_mapper(struct videobuf_queue *q, 590 struct videobuf_buffer *buf, 591 struct vm_area_struct *vma) 592 { 593 struct videobuf_dma_sg_memory *mem = buf->priv; 594 struct videobuf_mapping *map; 595 unsigned int first, last, size = 0, i; 596 int retval; 597 598 retval = -EINVAL; 599 600 BUG_ON(!mem); 601 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); 602 603 /* look for first buffer to map */ 604 for (first = 0; first < VIDEO_MAX_FRAME; first++) { 605 if (buf == q->bufs[first]) { 606 size = PAGE_ALIGN(q->bufs[first]->bsize); 607 break; 608 } 609 } 610 611 /* paranoia, should never happen since buf is always valid. */ 612 if (!size) { 613 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n", 614 (vma->vm_pgoff << PAGE_SHIFT)); 615 goto done; 616 } 617 618 last = first; 619 620 /* create mapping + update buffer list */ 621 retval = -ENOMEM; 622 map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL); 623 if (NULL == map) 624 goto done; 625 626 size = 0; 627 for (i = first; i <= last; i++) { 628 if (NULL == q->bufs[i]) 629 continue; 630 q->bufs[i]->map = map; 631 q->bufs[i]->baddr = vma->vm_start + size; 632 size += PAGE_ALIGN(q->bufs[i]->bsize); 633 } 634 635 map->count = 1; 636 map->q = q; 637 vma->vm_ops = &videobuf_vm_ops; 638 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 639 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */ 640 vma->vm_private_data = map; 641 dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n", 642 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last); 643 retval = 0; 644 645 done: 646 return retval; 647 } 648 649 static struct videobuf_qtype_ops sg_ops = { 650 .magic = MAGIC_QTYPE_OPS, 651 652 .alloc_vb = __videobuf_alloc_vb, 653 .iolock = __videobuf_iolock, 654 .sync = __videobuf_sync, 655 .mmap_mapper = __videobuf_mmap_mapper, 656 .vaddr = __videobuf_to_vaddr, 657 }; 658 659 void *videobuf_sg_alloc(size_t size) 660 { 661 struct videobuf_queue q; 662 663 /* Required to make generic handler to call __videobuf_alloc */ 664 q.int_ops = &sg_ops; 665 666 q.msize = size; 667 668 return videobuf_alloc_vb(&q); 669 } 670 EXPORT_SYMBOL_GPL(videobuf_sg_alloc); 671 672 void videobuf_queue_sg_init(struct videobuf_queue *q, 673 const struct videobuf_queue_ops *ops, 674 struct device *dev, 675 spinlock_t *irqlock, 676 enum v4l2_buf_type type, 677 enum v4l2_field field, 678 unsigned int msize, 679 void *priv, 680 struct mutex *ext_lock) 681 { 682 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize, 683 priv, &sg_ops, ext_lock); 684 } 685 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init); 686 687