1/* 2 * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2 3 * 4 * Copyright (C) 2010 Samsung Electronics 5 * 6 * Author: Pawel Osciak <pawel@osciak.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation. 11 */ 12 13#include <linux/dma-buf.h> 14#include <linux/module.h> 15#include <linux/refcount.h> 16#include <linux/scatterlist.h> 17#include <linux/sched.h> 18#include <linux/slab.h> 19#include <linux/dma-mapping.h> 20#include <linux/highmem.h> 21 22#include <media/videobuf2-v4l2.h> 23#include <media/videobuf2-dma-contig.h> 24#include <media/videobuf2-memops.h> 25 26struct vb2_dc_buf { 27 struct device *dev; 28 void *vaddr; 29 unsigned long size; 30 void *cookie; 31 dma_addr_t dma_addr; 32 unsigned long attrs; 33 enum dma_data_direction dma_dir; 34 struct sg_table *dma_sgt; 35 struct frame_vector *vec; 36 37 /* MMAP related */ 38 struct vb2_vmarea_handler handler; 39 refcount_t refcount; 40 struct sg_table *sgt_base; 41 42 /* DMABUF related */ 43 struct dma_buf_attachment *db_attach; 44 45 struct vb2_buffer *vb; 46 bool non_coherent_mem; 47}; 48 49/*********************************************/ 50/* scatterlist table functions */ 51/*********************************************/ 52 53static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt) 54{ 55 struct scatterlist *s; 56 dma_addr_t expected = sg_dma_address(sgt->sgl); 57 unsigned int i; 58 unsigned long size = 0; 59 60 for_each_sgtable_dma_sg(sgt, s, i) { 61 if (sg_dma_address(s) != expected) 62 break; 63 expected += sg_dma_len(s); 64 size += sg_dma_len(s); 65 } 66 return size; 67} 68 69/*********************************************/ 70/* callbacks for all buffers */ 71/*********************************************/ 72 73static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv) 74{ 75 struct vb2_dc_buf *buf = buf_priv; 76 77 return &buf->dma_addr; 78} 79 80/* 81 * This function may fail if: 82 * 83 * - dma_buf_vmap() fails 84 * E.g. due to lack of virtual mapping address space, or due to 85 * dmabuf->ops misconfiguration. 86 * 87 * - dma_vmap_noncontiguous() fails 88 * For instance, when requested buffer size is larger than totalram_pages(). 89 * Relevant for buffers that use non-coherent memory. 90 * 91 * - Queue DMA attrs have DMA_ATTR_NO_KERNEL_MAPPING set 92 * Relevant for buffers that use coherent memory. 93 */ 94static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv) 95{ 96 struct vb2_dc_buf *buf = buf_priv; 97 98 if (buf->vaddr) 99 return buf->vaddr; 100 101 if (buf->db_attach) { 102 struct iosys_map map; 103 104 if (!dma_buf_vmap_unlocked(buf->db_attach->dmabuf, &map)) 105 buf->vaddr = map.vaddr; 106 107 return buf->vaddr; 108 } 109 110 if (buf->non_coherent_mem) 111 buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size, 112 buf->dma_sgt); 113 return buf->vaddr; 114} 115 116static unsigned int vb2_dc_num_users(void *buf_priv) 117{ 118 struct vb2_dc_buf *buf = buf_priv; 119 120 return refcount_read(&buf->refcount); 121} 122 123static void vb2_dc_prepare(void *buf_priv) 124{ 125 struct vb2_dc_buf *buf = buf_priv; 126 struct sg_table *sgt = buf->dma_sgt; 127 128 /* This takes care of DMABUF and user-enforced cache sync hint */ 129 if (buf->vb->skip_cache_sync_on_prepare) 130 return; 131 132 if (!buf->non_coherent_mem) 133 return; 134 135 /* Non-coherent MMAP only */ 136 if (buf->vaddr) 137 flush_kernel_vmap_range(buf->vaddr, buf->size); 138 139 /* For both USERPTR and non-coherent MMAP */ 140 dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir); 141} 142 143static void vb2_dc_finish(void *buf_priv) 144{ 145 struct vb2_dc_buf *buf = buf_priv; 146 struct sg_table *sgt = buf->dma_sgt; 147 148 /* This takes care of DMABUF and user-enforced cache sync hint */ 149 if (buf->vb->skip_cache_sync_on_finish) 150 return; 151 152 if (!buf->non_coherent_mem) 153 return; 154 155 /* Non-coherent MMAP only */ 156 if (buf->vaddr) 157 invalidate_kernel_vmap_range(buf->vaddr, buf->size); 158 159 /* For both USERPTR and non-coherent MMAP */ 160 dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir); 161} 162 163/*********************************************/ 164/* callbacks for MMAP buffers */ 165/*********************************************/ 166 167static void vb2_dc_put(void *buf_priv) 168{ 169 struct vb2_dc_buf *buf = buf_priv; 170 171 if (!refcount_dec_and_test(&buf->refcount)) 172 return; 173 174 if (buf->non_coherent_mem) { 175 if (buf->vaddr) 176 dma_vunmap_noncontiguous(buf->dev, buf->vaddr); 177 dma_free_noncontiguous(buf->dev, buf->size, 178 buf->dma_sgt, buf->dma_dir); 179 } else { 180 if (buf->sgt_base) { 181 sg_free_table(buf->sgt_base); 182 kfree(buf->sgt_base); 183 } 184 dma_free_attrs(buf->dev, buf->size, buf->cookie, 185 buf->dma_addr, buf->attrs); 186 } 187 put_device(buf->dev); 188 kfree(buf); 189} 190 191static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf) 192{ 193 struct vb2_queue *q = buf->vb->vb2_queue; 194 195 buf->cookie = dma_alloc_attrs(buf->dev, 196 buf->size, 197 &buf->dma_addr, 198 GFP_KERNEL | q->gfp_flags, 199 buf->attrs); 200 if (!buf->cookie) 201 return -ENOMEM; 202 203 if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING) 204 return 0; 205 206 buf->vaddr = buf->cookie; 207 return 0; 208} 209 210static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf) 211{ 212 struct vb2_queue *q = buf->vb->vb2_queue; 213 214 buf->dma_sgt = dma_alloc_noncontiguous(buf->dev, 215 buf->size, 216 buf->dma_dir, 217 GFP_KERNEL | q->gfp_flags, 218 buf->attrs); 219 if (!buf->dma_sgt) 220 return -ENOMEM; 221 222 buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl); 223 224 /* 225 * For non-coherent buffers the kernel mapping is created on demand 226 * in vb2_dc_vaddr(). 227 */ 228 return 0; 229} 230 231static void *vb2_dc_alloc(struct vb2_buffer *vb, 232 struct device *dev, 233 unsigned long size) 234{ 235 struct vb2_dc_buf *buf; 236 int ret; 237 238 if (WARN_ON(!dev)) 239 return ERR_PTR(-EINVAL); 240 241 buf = kzalloc(sizeof *buf, GFP_KERNEL); 242 if (!buf) 243 return ERR_PTR(-ENOMEM); 244 245 buf->attrs = vb->vb2_queue->dma_attrs; 246 buf->dma_dir = vb->vb2_queue->dma_dir; 247 buf->vb = vb; 248 buf->non_coherent_mem = vb->vb2_queue->non_coherent_mem; 249 250 buf->size = size; 251 /* Prevent the device from being released while the buffer is used */ 252 buf->dev = get_device(dev); 253 254 if (buf->non_coherent_mem) 255 ret = vb2_dc_alloc_non_coherent(buf); 256 else 257 ret = vb2_dc_alloc_coherent(buf); 258 259 if (ret) { 260 dev_err(dev, "dma alloc of size %lu failed\n", size); 261 kfree(buf); 262 return ERR_PTR(-ENOMEM); 263 } 264 265 buf->handler.refcount = &buf->refcount; 266 buf->handler.put = vb2_dc_put; 267 buf->handler.arg = buf; 268 269 refcount_set(&buf->refcount, 1); 270 271 return buf; 272} 273 274static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma) 275{ 276 struct vb2_dc_buf *buf = buf_priv; 277 int ret; 278 279 if (!buf) { 280 printk(KERN_ERR "No buffer to map\n"); 281 return -EINVAL; 282 } 283 284 if (buf->non_coherent_mem) 285 ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size, 286 buf->dma_sgt); 287 else 288 ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr, 289 buf->size, buf->attrs); 290 if (ret) { 291 pr_err("Remapping memory failed, error: %d\n", ret); 292 return ret; 293 } 294 295 vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP); 296 vma->vm_private_data = &buf->handler; 297 vma->vm_ops = &vb2_common_vm_ops; 298 299 vma->vm_ops->open(vma); 300 301 pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %lu\n", 302 __func__, (unsigned long)buf->dma_addr, vma->vm_start, 303 buf->size); 304 305 return 0; 306} 307 308/*********************************************/ 309/* DMABUF ops for exporters */ 310/*********************************************/ 311 312struct vb2_dc_attachment { 313 struct sg_table sgt; 314 enum dma_data_direction dma_dir; 315}; 316 317static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, 318 struct dma_buf_attachment *dbuf_attach) 319{ 320 struct vb2_dc_attachment *attach; 321 unsigned int i; 322 struct scatterlist *rd, *wr; 323 struct sg_table *sgt; 324 struct vb2_dc_buf *buf = dbuf->priv; 325 int ret; 326 327 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 328 if (!attach) 329 return -ENOMEM; 330 331 sgt = &attach->sgt; 332 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 333 * map the same scatter list to multiple attachments at the same time. 334 */ 335 ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL); 336 if (ret) { 337 kfree(attach); 338 return -ENOMEM; 339 } 340 341 rd = buf->sgt_base->sgl; 342 wr = sgt->sgl; 343 for (i = 0; i < sgt->orig_nents; ++i) { 344 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 345 rd = sg_next(rd); 346 wr = sg_next(wr); 347 } 348 349 attach->dma_dir = DMA_NONE; 350 dbuf_attach->priv = attach; 351 352 return 0; 353} 354 355static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf, 356 struct dma_buf_attachment *db_attach) 357{ 358 struct vb2_dc_attachment *attach = db_attach->priv; 359 struct sg_table *sgt; 360 361 if (!attach) 362 return; 363 364 sgt = &attach->sgt; 365 366 /* release the scatterlist cache */ 367 if (attach->dma_dir != DMA_NONE) 368 /* 369 * Cache sync can be skipped here, as the vb2_dc memory is 370 * allocated from device coherent memory, which means the 371 * memory locations do not require any explicit cache 372 * maintenance prior or after being used by the device. 373 */ 374 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 375 DMA_ATTR_SKIP_CPU_SYNC); 376 sg_free_table(sgt); 377 kfree(attach); 378 db_attach->priv = NULL; 379} 380 381static struct sg_table *vb2_dc_dmabuf_ops_map( 382 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 383{ 384 struct vb2_dc_attachment *attach = db_attach->priv; 385 struct sg_table *sgt; 386 387 sgt = &attach->sgt; 388 /* return previously mapped sg table */ 389 if (attach->dma_dir == dma_dir) 390 return sgt; 391 392 /* release any previous cache */ 393 if (attach->dma_dir != DMA_NONE) { 394 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 395 DMA_ATTR_SKIP_CPU_SYNC); 396 attach->dma_dir = DMA_NONE; 397 } 398 399 /* 400 * mapping to the client with new direction, no cache sync 401 * required see comment in vb2_dc_dmabuf_ops_detach() 402 */ 403 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 404 DMA_ATTR_SKIP_CPU_SYNC)) { 405 pr_err("failed to map scatterlist\n"); 406 return ERR_PTR(-EIO); 407 } 408 409 attach->dma_dir = dma_dir; 410 411 return sgt; 412} 413 414static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, 415 struct sg_table *sgt, enum dma_data_direction dma_dir) 416{ 417 /* nothing to be done here */ 418} 419 420static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf) 421{ 422 /* drop reference obtained in vb2_dc_get_dmabuf */ 423 vb2_dc_put(dbuf->priv); 424} 425 426static int 427vb2_dc_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, 428 enum dma_data_direction direction) 429{ 430 return 0; 431} 432 433static int 434vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, 435 enum dma_data_direction direction) 436{ 437 return 0; 438} 439 440static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct iosys_map *map) 441{ 442 struct vb2_dc_buf *buf; 443 void *vaddr; 444 445 buf = dbuf->priv; 446 vaddr = vb2_dc_vaddr(buf->vb, buf); 447 if (!vaddr) 448 return -EINVAL; 449 450 iosys_map_set_vaddr(map, vaddr); 451 452 return 0; 453} 454 455static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf, 456 struct vm_area_struct *vma) 457{ 458 return vb2_dc_mmap(dbuf->priv, vma); 459} 460 461static const struct dma_buf_ops vb2_dc_dmabuf_ops = { 462 .attach = vb2_dc_dmabuf_ops_attach, 463 .detach = vb2_dc_dmabuf_ops_detach, 464 .map_dma_buf = vb2_dc_dmabuf_ops_map, 465 .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap, 466 .begin_cpu_access = vb2_dc_dmabuf_ops_begin_cpu_access, 467 .end_cpu_access = vb2_dc_dmabuf_ops_end_cpu_access, 468 .vmap = vb2_dc_dmabuf_ops_vmap, 469 .mmap = vb2_dc_dmabuf_ops_mmap, 470 .release = vb2_dc_dmabuf_ops_release, 471}; 472 473static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf) 474{ 475 int ret; 476 struct sg_table *sgt; 477 478 if (buf->non_coherent_mem) 479 return buf->dma_sgt; 480 481 sgt = kmalloc(sizeof(*sgt), GFP_KERNEL); 482 if (!sgt) { 483 dev_err(buf->dev, "failed to alloc sg table\n"); 484 return NULL; 485 } 486 487 ret = dma_get_sgtable_attrs(buf->dev, sgt, buf->cookie, buf->dma_addr, 488 buf->size, buf->attrs); 489 if (ret < 0) { 490 dev_err(buf->dev, "failed to get scatterlist from DMA API\n"); 491 kfree(sgt); 492 return NULL; 493 } 494 495 return sgt; 496} 497 498static struct dma_buf *vb2_dc_get_dmabuf(struct vb2_buffer *vb, 499 void *buf_priv, 500 unsigned long flags) 501{ 502 struct vb2_dc_buf *buf = buf_priv; 503 struct dma_buf *dbuf; 504 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 505 506 exp_info.ops = &vb2_dc_dmabuf_ops; 507 exp_info.size = buf->size; 508 exp_info.flags = flags; 509 exp_info.priv = buf; 510 511 if (!buf->sgt_base) 512 buf->sgt_base = vb2_dc_get_base_sgt(buf); 513 514 if (WARN_ON(!buf->sgt_base)) 515 return NULL; 516 517 dbuf = dma_buf_export(&exp_info); 518 if (IS_ERR(dbuf)) 519 return NULL; 520 521 /* dmabuf keeps reference to vb2 buffer */ 522 refcount_inc(&buf->refcount); 523 524 return dbuf; 525} 526 527/*********************************************/ 528/* callbacks for USERPTR buffers */ 529/*********************************************/ 530 531static void vb2_dc_put_userptr(void *buf_priv) 532{ 533 struct vb2_dc_buf *buf = buf_priv; 534 struct sg_table *sgt = buf->dma_sgt; 535 int i; 536 struct page **pages; 537 538 if (sgt) { 539 /* 540 * No need to sync to CPU, it's already synced to the CPU 541 * since the finish() memop will have been called before this. 542 */ 543 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, 544 DMA_ATTR_SKIP_CPU_SYNC); 545 if (buf->dma_dir == DMA_FROM_DEVICE || 546 buf->dma_dir == DMA_BIDIRECTIONAL) { 547 pages = frame_vector_pages(buf->vec); 548 /* sgt should exist only if vector contains pages... */ 549 if (!WARN_ON_ONCE(IS_ERR(pages))) 550 for (i = 0; i < frame_vector_count(buf->vec); i++) 551 set_page_dirty_lock(pages[i]); 552 } 553 sg_free_table(sgt); 554 kfree(sgt); 555 } else { 556 dma_unmap_resource(buf->dev, buf->dma_addr, buf->size, 557 buf->dma_dir, 0); 558 } 559 vb2_destroy_framevec(buf->vec); 560 kfree(buf); 561} 562 563static void *vb2_dc_get_userptr(struct vb2_buffer *vb, struct device *dev, 564 unsigned long vaddr, unsigned long size) 565{ 566 struct vb2_dc_buf *buf; 567 struct frame_vector *vec; 568 unsigned int offset; 569 int n_pages, i; 570 int ret = 0; 571 struct sg_table *sgt; 572 unsigned long contig_size; 573 unsigned long dma_align = dma_get_cache_alignment(); 574 575 /* Only cache aligned DMA transfers are reliable */ 576 if (!IS_ALIGNED(vaddr | size, dma_align)) { 577 pr_debug("user data must be aligned to %lu bytes\n", dma_align); 578 return ERR_PTR(-EINVAL); 579 } 580 581 if (!size) { 582 pr_debug("size is zero\n"); 583 return ERR_PTR(-EINVAL); 584 } 585 586 if (WARN_ON(!dev)) 587 return ERR_PTR(-EINVAL); 588 589 buf = kzalloc(sizeof *buf, GFP_KERNEL); 590 if (!buf) 591 return ERR_PTR(-ENOMEM); 592 593 buf->dev = dev; 594 buf->dma_dir = vb->vb2_queue->dma_dir; 595 buf->vb = vb; 596 597 offset = lower_32_bits(offset_in_page(vaddr)); 598 vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE || 599 buf->dma_dir == DMA_BIDIRECTIONAL); 600 if (IS_ERR(vec)) { 601 ret = PTR_ERR(vec); 602 goto fail_buf; 603 } 604 buf->vec = vec; 605 n_pages = frame_vector_count(vec); 606 ret = frame_vector_to_pages(vec); 607 if (ret < 0) { 608 unsigned long *nums = frame_vector_pfns(vec); 609 610 /* 611 * Failed to convert to pages... Check the memory is physically 612 * contiguous and use direct mapping 613 */ 614 for (i = 1; i < n_pages; i++) 615 if (nums[i-1] + 1 != nums[i]) 616 goto fail_pfnvec; 617 buf->dma_addr = dma_map_resource(buf->dev, 618 __pfn_to_phys(nums[0]), size, buf->dma_dir, 0); 619 if (dma_mapping_error(buf->dev, buf->dma_addr)) { 620 ret = -ENOMEM; 621 goto fail_pfnvec; 622 } 623 goto out; 624 } 625 626 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL); 627 if (!sgt) { 628 pr_err("failed to allocate sg table\n"); 629 ret = -ENOMEM; 630 goto fail_pfnvec; 631 } 632 633 ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages, 634 offset, size, GFP_KERNEL); 635 if (ret) { 636 pr_err("failed to initialize sg table\n"); 637 goto fail_sgt; 638 } 639 640 /* 641 * No need to sync to the device, this will happen later when the 642 * prepare() memop is called. 643 */ 644 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir, 645 DMA_ATTR_SKIP_CPU_SYNC)) { 646 pr_err("failed to map scatterlist\n"); 647 ret = -EIO; 648 goto fail_sgt_init; 649 } 650 651 contig_size = vb2_dc_get_contiguous_size(sgt); 652 if (contig_size < size) { 653 pr_err("contiguous mapping is too small %lu/%lu\n", 654 contig_size, size); 655 ret = -EFAULT; 656 goto fail_map_sg; 657 } 658 659 buf->dma_addr = sg_dma_address(sgt->sgl); 660 buf->dma_sgt = sgt; 661 buf->non_coherent_mem = 1; 662 663out: 664 buf->size = size; 665 666 return buf; 667 668fail_map_sg: 669 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 670 671fail_sgt_init: 672 sg_free_table(sgt); 673 674fail_sgt: 675 kfree(sgt); 676 677fail_pfnvec: 678 vb2_destroy_framevec(vec); 679 680fail_buf: 681 kfree(buf); 682 683 return ERR_PTR(ret); 684} 685 686/*********************************************/ 687/* callbacks for DMABUF buffers */ 688/*********************************************/ 689 690static int vb2_dc_map_dmabuf(void *mem_priv) 691{ 692 struct vb2_dc_buf *buf = mem_priv; 693 struct sg_table *sgt; 694 unsigned long contig_size; 695 696 if (WARN_ON(!buf->db_attach)) { 697 pr_err("trying to pin a non attached buffer\n"); 698 return -EINVAL; 699 } 700 701 if (WARN_ON(buf->dma_sgt)) { 702 pr_err("dmabuf buffer is already pinned\n"); 703 return 0; 704 } 705 706 /* get the associated scatterlist for this buffer */ 707 sgt = dma_buf_map_attachment_unlocked(buf->db_attach, buf->dma_dir); 708 if (IS_ERR(sgt)) { 709 pr_err("Error getting dmabuf scatterlist\n"); 710 return -EINVAL; 711 } 712 713 /* checking if dmabuf is big enough to store contiguous chunk */ 714 contig_size = vb2_dc_get_contiguous_size(sgt); 715 if (contig_size < buf->size) { 716 pr_err("contiguous chunk is too small %lu/%lu\n", 717 contig_size, buf->size); 718 dma_buf_unmap_attachment_unlocked(buf->db_attach, sgt, 719 buf->dma_dir); 720 return -EFAULT; 721 } 722 723 buf->dma_addr = sg_dma_address(sgt->sgl); 724 buf->dma_sgt = sgt; 725 buf->vaddr = NULL; 726 727 return 0; 728} 729 730static void vb2_dc_unmap_dmabuf(void *mem_priv) 731{ 732 struct vb2_dc_buf *buf = mem_priv; 733 struct sg_table *sgt = buf->dma_sgt; 734 struct iosys_map map = IOSYS_MAP_INIT_VADDR(buf->vaddr); 735 736 if (WARN_ON(!buf->db_attach)) { 737 pr_err("trying to unpin a not attached buffer\n"); 738 return; 739 } 740 741 if (WARN_ON(!sgt)) { 742 pr_err("dmabuf buffer is already unpinned\n"); 743 return; 744 } 745 746 if (buf->vaddr) { 747 dma_buf_vunmap_unlocked(buf->db_attach->dmabuf, &map); 748 buf->vaddr = NULL; 749 } 750 dma_buf_unmap_attachment_unlocked(buf->db_attach, sgt, buf->dma_dir); 751 752 buf->dma_addr = 0; 753 buf->dma_sgt = NULL; 754} 755 756static void vb2_dc_detach_dmabuf(void *mem_priv) 757{ 758 struct vb2_dc_buf *buf = mem_priv; 759 760 /* if vb2 works correctly you should never detach mapped buffer */ 761 if (WARN_ON(buf->dma_addr)) 762 vb2_dc_unmap_dmabuf(buf); 763 764 /* detach this attachment */ 765 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); 766 kfree(buf); 767} 768 769static void *vb2_dc_attach_dmabuf(struct vb2_buffer *vb, struct device *dev, 770 struct dma_buf *dbuf, unsigned long size) 771{ 772 struct vb2_dc_buf *buf; 773 struct dma_buf_attachment *dba; 774 775 if (dbuf->size < size) 776 return ERR_PTR(-EFAULT); 777 778 if (WARN_ON(!dev)) 779 return ERR_PTR(-EINVAL); 780 781 buf = kzalloc(sizeof(*buf), GFP_KERNEL); 782 if (!buf) 783 return ERR_PTR(-ENOMEM); 784 785 buf->dev = dev; 786 buf->vb = vb; 787 788 /* create attachment for the dmabuf with the user device */ 789 dba = dma_buf_attach(dbuf, buf->dev); 790 if (IS_ERR(dba)) { 791 pr_err("failed to attach dmabuf\n"); 792 kfree(buf); 793 return dba; 794 } 795 796 buf->dma_dir = vb->vb2_queue->dma_dir; 797 buf->size = size; 798 buf->db_attach = dba; 799 800 return buf; 801} 802 803/*********************************************/ 804/* DMA CONTIG exported functions */ 805/*********************************************/ 806 807const struct vb2_mem_ops vb2_dma_contig_memops = { 808 .alloc = vb2_dc_alloc, 809 .put = vb2_dc_put, 810 .get_dmabuf = vb2_dc_get_dmabuf, 811 .cookie = vb2_dc_cookie, 812 .vaddr = vb2_dc_vaddr, 813 .mmap = vb2_dc_mmap, 814 .get_userptr = vb2_dc_get_userptr, 815 .put_userptr = vb2_dc_put_userptr, 816 .prepare = vb2_dc_prepare, 817 .finish = vb2_dc_finish, 818 .map_dmabuf = vb2_dc_map_dmabuf, 819 .unmap_dmabuf = vb2_dc_unmap_dmabuf, 820 .attach_dmabuf = vb2_dc_attach_dmabuf, 821 .detach_dmabuf = vb2_dc_detach_dmabuf, 822 .num_users = vb2_dc_num_users, 823}; 824EXPORT_SYMBOL_GPL(vb2_dma_contig_memops); 825 826/** 827 * vb2_dma_contig_set_max_seg_size() - configure DMA max segment size 828 * @dev: device for configuring DMA parameters 829 * @size: size of DMA max segment size to set 830 * 831 * To allow mapping the scatter-list into a single chunk in the DMA 832 * address space, the device is required to have the DMA max segment 833 * size parameter set to a value larger than the buffer size. Otherwise, 834 * the DMA-mapping subsystem will split the mapping into max segment 835 * size chunks. This function sets the DMA max segment size 836 * parameter to let DMA-mapping map a buffer as a single chunk in DMA 837 * address space. 838 * This code assumes that the DMA-mapping subsystem will merge all 839 * scatterlist segments if this is really possible (for example when 840 * an IOMMU is available and enabled). 841 * Ideally, this parameter should be set by the generic bus code, but it 842 * is left with the default 64KiB value due to historical litmiations in 843 * other subsystems (like limited USB host drivers) and there no good 844 * place to set it to the proper value. 845 * This function should be called from the drivers, which are known to 846 * operate on platforms with IOMMU and provide access to shared buffers 847 * (either USERPTR or DMABUF). This should be done before initializing 848 * videobuf2 queue. 849 */ 850int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size) 851{ 852 if (!dev->dma_parms) { 853 dev_err(dev, "Failed to set max_seg_size: dma_parms is NULL\n"); 854 return -ENODEV; 855 } 856 if (dma_get_max_seg_size(dev) < size) 857 return dma_set_max_seg_size(dev, size); 858 859 return 0; 860} 861EXPORT_SYMBOL_GPL(vb2_dma_contig_set_max_seg_size); 862 863MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2"); 864MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>"); 865MODULE_LICENSE("GPL"); 866MODULE_IMPORT_NS(DMA_BUF); 867