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@kernel.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@kernel.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@kernel.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(array_size(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(array_size(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_array(dma->nr_pages, sizeof(struct page *), 179 GFP_KERNEL); 180 if (NULL == dma->pages) 181 return -ENOMEM; 182 183 if (rw == READ) 184 flags |= FOLL_WRITE; 185 186 dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n", 187 data, size, dma->nr_pages); 188 189 err = get_user_pages(data & PAGE_MASK, dma->nr_pages, 190 flags | FOLL_LONGTERM, dma->pages, NULL); 191 192 if (err != dma->nr_pages) { 193 dma->nr_pages = (err >= 0) ? err : 0; 194 dprintk(1, "get_user_pages: err=%d [%d]\n", err, 195 dma->nr_pages); 196 return err < 0 ? err : -EINVAL; 197 } 198 return 0; 199 } 200 201 static int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction, 202 unsigned long data, unsigned long size) 203 { 204 int ret; 205 206 down_read(¤t->mm->mmap_sem); 207 ret = videobuf_dma_init_user_locked(dma, direction, data, size); 208 up_read(¤t->mm->mmap_sem); 209 210 return ret; 211 } 212 213 static int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction, 214 int nr_pages) 215 { 216 int i; 217 218 dprintk(1, "init kernel [%d pages]\n", nr_pages); 219 220 dma->direction = direction; 221 dma->vaddr_pages = kcalloc(nr_pages, sizeof(*dma->vaddr_pages), 222 GFP_KERNEL); 223 if (!dma->vaddr_pages) 224 return -ENOMEM; 225 226 dma->dma_addr = kcalloc(nr_pages, sizeof(*dma->dma_addr), GFP_KERNEL); 227 if (!dma->dma_addr) { 228 kfree(dma->vaddr_pages); 229 return -ENOMEM; 230 } 231 for (i = 0; i < nr_pages; i++) { 232 void *addr; 233 234 addr = dma_alloc_coherent(dma->dev, PAGE_SIZE, 235 &(dma->dma_addr[i]), GFP_KERNEL); 236 if (addr == NULL) 237 goto out_free_pages; 238 239 dma->vaddr_pages[i] = virt_to_page(addr); 240 } 241 dma->vaddr = vmap(dma->vaddr_pages, nr_pages, VM_MAP | VM_IOREMAP, 242 PAGE_KERNEL); 243 if (NULL == dma->vaddr) { 244 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages); 245 goto out_free_pages; 246 } 247 248 dprintk(1, "vmalloc is at addr %p, size=%d\n", 249 dma->vaddr, nr_pages << PAGE_SHIFT); 250 251 memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT); 252 dma->nr_pages = nr_pages; 253 254 return 0; 255 out_free_pages: 256 while (i > 0) { 257 void *addr; 258 259 i--; 260 addr = page_address(dma->vaddr_pages[i]); 261 dma_free_coherent(dma->dev, PAGE_SIZE, addr, dma->dma_addr[i]); 262 } 263 kfree(dma->dma_addr); 264 dma->dma_addr = NULL; 265 kfree(dma->vaddr_pages); 266 dma->vaddr_pages = NULL; 267 268 return -ENOMEM; 269 270 } 271 272 static 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 } 287 288 static int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma) 289 { 290 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 291 BUG_ON(0 == dma->nr_pages); 292 293 if (dma->pages) { 294 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages, 295 dma->offset, dma->size); 296 } 297 if (dma->vaddr) { 298 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr, 299 dma->nr_pages); 300 } 301 if (dma->bus_addr) { 302 dma->sglist = vmalloc(sizeof(*dma->sglist)); 303 if (NULL != dma->sglist) { 304 dma->sglen = 1; 305 sg_dma_address(&dma->sglist[0]) = dma->bus_addr 306 & PAGE_MASK; 307 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK; 308 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE; 309 } 310 } 311 if (NULL == dma->sglist) { 312 dprintk(1, "scatterlist is NULL\n"); 313 return -ENOMEM; 314 } 315 if (!dma->bus_addr) { 316 dma->sglen = dma_map_sg(dev, dma->sglist, 317 dma->nr_pages, dma->direction); 318 if (0 == dma->sglen) { 319 printk(KERN_WARNING 320 "%s: videobuf_map_sg failed\n", __func__); 321 vfree(dma->sglist); 322 dma->sglist = NULL; 323 dma->sglen = 0; 324 return -ENOMEM; 325 } 326 } 327 328 return 0; 329 } 330 331 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma) 332 { 333 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 334 335 if (!dma->sglen) 336 return 0; 337 338 dma_unmap_sg(dev, dma->sglist, dma->nr_pages, dma->direction); 339 340 vfree(dma->sglist); 341 dma->sglist = NULL; 342 dma->sglen = 0; 343 344 return 0; 345 } 346 EXPORT_SYMBOL_GPL(videobuf_dma_unmap); 347 348 int videobuf_dma_free(struct videobuf_dmabuf *dma) 349 { 350 int i; 351 MAGIC_CHECK(dma->magic, MAGIC_DMABUF); 352 BUG_ON(dma->sglen); 353 354 if (dma->pages) { 355 for (i = 0; i < dma->nr_pages; i++) 356 put_page(dma->pages[i]); 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); 687 688