1 /* 2 * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2 3 * 4 * Copyright (C) 2010 Samsung Electronics 5 * 6 * Author: Andrzej Pietrasiewicz <andrzejtp2010@gmail.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/module.h> 14 #include <linux/mm.h> 15 #include <linux/refcount.h> 16 #include <linux/scatterlist.h> 17 #include <linux/sched.h> 18 #include <linux/slab.h> 19 #include <linux/vmalloc.h> 20 21 #include <media/videobuf2-v4l2.h> 22 #include <media/videobuf2-memops.h> 23 #include <media/videobuf2-dma-sg.h> 24 25 static int debug; 26 module_param(debug, int, 0644); 27 28 #define dprintk(level, fmt, arg...) \ 29 do { \ 30 if (debug >= level) \ 31 printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \ 32 } while (0) 33 34 struct vb2_dma_sg_buf { 35 struct device *dev; 36 void *vaddr; 37 struct page **pages; 38 struct frame_vector *vec; 39 int offset; 40 enum dma_data_direction dma_dir; 41 struct sg_table sg_table; 42 /* 43 * This will point to sg_table when used with the MMAP or USERPTR 44 * memory model, and to the dma_buf sglist when used with the 45 * DMABUF memory model. 46 */ 47 struct sg_table *dma_sgt; 48 size_t size; 49 unsigned int num_pages; 50 refcount_t refcount; 51 struct vb2_vmarea_handler handler; 52 53 struct dma_buf_attachment *db_attach; 54 55 struct vb2_buffer *vb; 56 }; 57 58 static void vb2_dma_sg_put(void *buf_priv); 59 60 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf, 61 gfp_t gfp_flags) 62 { 63 unsigned int last_page = 0; 64 unsigned long size = buf->size; 65 66 while (size > 0) { 67 struct page *pages; 68 int order; 69 int i; 70 71 order = get_order(size); 72 /* Don't over allocate*/ 73 if ((PAGE_SIZE << order) > size) 74 order--; 75 76 pages = NULL; 77 while (!pages) { 78 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO | 79 __GFP_NOWARN | gfp_flags, order); 80 if (pages) 81 break; 82 83 if (order == 0) { 84 while (last_page--) 85 __free_page(buf->pages[last_page]); 86 return -ENOMEM; 87 } 88 order--; 89 } 90 91 split_page(pages, order); 92 for (i = 0; i < (1 << order); i++) 93 buf->pages[last_page++] = &pages[i]; 94 95 size -= PAGE_SIZE << order; 96 } 97 98 return 0; 99 } 100 101 static void *vb2_dma_sg_alloc(struct vb2_buffer *vb, struct device *dev, 102 unsigned long size) 103 { 104 struct vb2_dma_sg_buf *buf; 105 struct sg_table *sgt; 106 int ret; 107 int num_pages; 108 109 if (WARN_ON(!dev) || WARN_ON(!size)) 110 return ERR_PTR(-EINVAL); 111 112 buf = kzalloc(sizeof *buf, GFP_KERNEL); 113 if (!buf) 114 return ERR_PTR(-ENOMEM); 115 116 buf->vaddr = NULL; 117 buf->dma_dir = vb->vb2_queue->dma_dir; 118 buf->offset = 0; 119 buf->size = size; 120 /* size is already page aligned */ 121 buf->num_pages = size >> PAGE_SHIFT; 122 buf->dma_sgt = &buf->sg_table; 123 124 /* 125 * NOTE: dma-sg allocates memory using the page allocator directly, so 126 * there is no memory consistency guarantee, hence dma-sg ignores DMA 127 * attributes passed from the upper layer. 128 */ 129 buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *), 130 GFP_KERNEL | __GFP_ZERO); 131 if (!buf->pages) 132 goto fail_pages_array_alloc; 133 134 ret = vb2_dma_sg_alloc_compacted(buf, vb->vb2_queue->gfp_flags); 135 if (ret) 136 goto fail_pages_alloc; 137 138 ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, 139 buf->num_pages, 0, size, GFP_KERNEL); 140 if (ret) 141 goto fail_table_alloc; 142 143 /* Prevent the device from being released while the buffer is used */ 144 buf->dev = get_device(dev); 145 146 sgt = &buf->sg_table; 147 /* 148 * No need to sync to the device, this will happen later when the 149 * prepare() memop is called. 150 */ 151 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir, 152 DMA_ATTR_SKIP_CPU_SYNC)) 153 goto fail_map; 154 155 buf->handler.refcount = &buf->refcount; 156 buf->handler.put = vb2_dma_sg_put; 157 buf->handler.arg = buf; 158 buf->vb = vb; 159 160 refcount_set(&buf->refcount, 1); 161 162 dprintk(1, "%s: Allocated buffer of %d pages\n", 163 __func__, buf->num_pages); 164 return buf; 165 166 fail_map: 167 put_device(buf->dev); 168 sg_free_table(buf->dma_sgt); 169 fail_table_alloc: 170 num_pages = buf->num_pages; 171 while (num_pages--) 172 __free_page(buf->pages[num_pages]); 173 fail_pages_alloc: 174 kvfree(buf->pages); 175 fail_pages_array_alloc: 176 kfree(buf); 177 return ERR_PTR(-ENOMEM); 178 } 179 180 static void vb2_dma_sg_put(void *buf_priv) 181 { 182 struct vb2_dma_sg_buf *buf = buf_priv; 183 struct sg_table *sgt = &buf->sg_table; 184 int i = buf->num_pages; 185 186 if (refcount_dec_and_test(&buf->refcount)) { 187 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__, 188 buf->num_pages); 189 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, 190 DMA_ATTR_SKIP_CPU_SYNC); 191 if (buf->vaddr) 192 vm_unmap_ram(buf->vaddr, buf->num_pages); 193 sg_free_table(buf->dma_sgt); 194 while (--i >= 0) 195 __free_page(buf->pages[i]); 196 kvfree(buf->pages); 197 put_device(buf->dev); 198 kfree(buf); 199 } 200 } 201 202 static void vb2_dma_sg_prepare(void *buf_priv) 203 { 204 struct vb2_dma_sg_buf *buf = buf_priv; 205 struct sg_table *sgt = buf->dma_sgt; 206 207 if (buf->vb->skip_cache_sync_on_prepare) 208 return; 209 210 dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir); 211 } 212 213 static void vb2_dma_sg_finish(void *buf_priv) 214 { 215 struct vb2_dma_sg_buf *buf = buf_priv; 216 struct sg_table *sgt = buf->dma_sgt; 217 218 if (buf->vb->skip_cache_sync_on_finish) 219 return; 220 221 dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir); 222 } 223 224 static void *vb2_dma_sg_get_userptr(struct vb2_buffer *vb, struct device *dev, 225 unsigned long vaddr, unsigned long size) 226 { 227 struct vb2_dma_sg_buf *buf; 228 struct sg_table *sgt; 229 struct frame_vector *vec; 230 231 if (WARN_ON(!dev)) 232 return ERR_PTR(-EINVAL); 233 234 buf = kzalloc(sizeof *buf, GFP_KERNEL); 235 if (!buf) 236 return ERR_PTR(-ENOMEM); 237 238 buf->vaddr = NULL; 239 buf->dev = dev; 240 buf->dma_dir = vb->vb2_queue->dma_dir; 241 buf->offset = vaddr & ~PAGE_MASK; 242 buf->size = size; 243 buf->dma_sgt = &buf->sg_table; 244 buf->vb = vb; 245 vec = vb2_create_framevec(vaddr, size); 246 if (IS_ERR(vec)) 247 goto userptr_fail_pfnvec; 248 buf->vec = vec; 249 250 buf->pages = frame_vector_pages(vec); 251 if (IS_ERR(buf->pages)) 252 goto userptr_fail_sgtable; 253 buf->num_pages = frame_vector_count(vec); 254 255 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, 256 buf->num_pages, buf->offset, size, 0)) 257 goto userptr_fail_sgtable; 258 259 sgt = &buf->sg_table; 260 /* 261 * No need to sync to the device, this will happen later when the 262 * prepare() memop is called. 263 */ 264 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir, 265 DMA_ATTR_SKIP_CPU_SYNC)) 266 goto userptr_fail_map; 267 268 return buf; 269 270 userptr_fail_map: 271 sg_free_table(&buf->sg_table); 272 userptr_fail_sgtable: 273 vb2_destroy_framevec(vec); 274 userptr_fail_pfnvec: 275 kfree(buf); 276 return ERR_PTR(-ENOMEM); 277 } 278 279 /* 280 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 281 * be used 282 */ 283 static void vb2_dma_sg_put_userptr(void *buf_priv) 284 { 285 struct vb2_dma_sg_buf *buf = buf_priv; 286 struct sg_table *sgt = &buf->sg_table; 287 int i = buf->num_pages; 288 289 dprintk(1, "%s: Releasing userspace buffer of %d pages\n", 290 __func__, buf->num_pages); 291 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 292 if (buf->vaddr) 293 vm_unmap_ram(buf->vaddr, buf->num_pages); 294 sg_free_table(buf->dma_sgt); 295 if (buf->dma_dir == DMA_FROM_DEVICE || 296 buf->dma_dir == DMA_BIDIRECTIONAL) 297 while (--i >= 0) 298 set_page_dirty_lock(buf->pages[i]); 299 vb2_destroy_framevec(buf->vec); 300 kfree(buf); 301 } 302 303 static void *vb2_dma_sg_vaddr(struct vb2_buffer *vb, void *buf_priv) 304 { 305 struct vb2_dma_sg_buf *buf = buf_priv; 306 struct dma_buf_map map; 307 int ret; 308 309 BUG_ON(!buf); 310 311 if (!buf->vaddr) { 312 if (buf->db_attach) { 313 ret = dma_buf_vmap(buf->db_attach->dmabuf, &map); 314 buf->vaddr = ret ? NULL : map.vaddr; 315 } else { 316 buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1); 317 } 318 } 319 320 /* add offset in case userptr is not page-aligned */ 321 return buf->vaddr ? buf->vaddr + buf->offset : NULL; 322 } 323 324 static unsigned int vb2_dma_sg_num_users(void *buf_priv) 325 { 326 struct vb2_dma_sg_buf *buf = buf_priv; 327 328 return refcount_read(&buf->refcount); 329 } 330 331 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) 332 { 333 struct vb2_dma_sg_buf *buf = buf_priv; 334 int err; 335 336 if (!buf) { 337 printk(KERN_ERR "No memory to map\n"); 338 return -EINVAL; 339 } 340 341 err = vm_map_pages(vma, buf->pages, buf->num_pages); 342 if (err) { 343 printk(KERN_ERR "Remapping memory, error: %d\n", err); 344 return err; 345 } 346 347 /* 348 * Use common vm_area operations to track buffer refcount. 349 */ 350 vma->vm_private_data = &buf->handler; 351 vma->vm_ops = &vb2_common_vm_ops; 352 353 vma->vm_ops->open(vma); 354 355 return 0; 356 } 357 358 /*********************************************/ 359 /* DMABUF ops for exporters */ 360 /*********************************************/ 361 362 struct vb2_dma_sg_attachment { 363 struct sg_table sgt; 364 enum dma_data_direction dma_dir; 365 }; 366 367 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, 368 struct dma_buf_attachment *dbuf_attach) 369 { 370 struct vb2_dma_sg_attachment *attach; 371 unsigned int i; 372 struct scatterlist *rd, *wr; 373 struct sg_table *sgt; 374 struct vb2_dma_sg_buf *buf = dbuf->priv; 375 int ret; 376 377 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 378 if (!attach) 379 return -ENOMEM; 380 381 sgt = &attach->sgt; 382 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 383 * map the same scatter list to multiple attachments at the same time. 384 */ 385 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); 386 if (ret) { 387 kfree(attach); 388 return -ENOMEM; 389 } 390 391 rd = buf->dma_sgt->sgl; 392 wr = sgt->sgl; 393 for (i = 0; i < sgt->orig_nents; ++i) { 394 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 395 rd = sg_next(rd); 396 wr = sg_next(wr); 397 } 398 399 attach->dma_dir = DMA_NONE; 400 dbuf_attach->priv = attach; 401 402 return 0; 403 } 404 405 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, 406 struct dma_buf_attachment *db_attach) 407 { 408 struct vb2_dma_sg_attachment *attach = db_attach->priv; 409 struct sg_table *sgt; 410 411 if (!attach) 412 return; 413 414 sgt = &attach->sgt; 415 416 /* release the scatterlist cache */ 417 if (attach->dma_dir != DMA_NONE) 418 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0); 419 sg_free_table(sgt); 420 kfree(attach); 421 db_attach->priv = NULL; 422 } 423 424 static struct sg_table *vb2_dma_sg_dmabuf_ops_map( 425 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 426 { 427 struct vb2_dma_sg_attachment *attach = db_attach->priv; 428 /* stealing dmabuf mutex to serialize map/unmap operations */ 429 struct mutex *lock = &db_attach->dmabuf->lock; 430 struct sg_table *sgt; 431 432 mutex_lock(lock); 433 434 sgt = &attach->sgt; 435 /* return previously mapped sg table */ 436 if (attach->dma_dir == dma_dir) { 437 mutex_unlock(lock); 438 return sgt; 439 } 440 441 /* release any previous cache */ 442 if (attach->dma_dir != DMA_NONE) { 443 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0); 444 attach->dma_dir = DMA_NONE; 445 } 446 447 /* mapping to the client with new direction */ 448 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) { 449 pr_err("failed to map scatterlist\n"); 450 mutex_unlock(lock); 451 return ERR_PTR(-EIO); 452 } 453 454 attach->dma_dir = dma_dir; 455 456 mutex_unlock(lock); 457 458 return sgt; 459 } 460 461 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, 462 struct sg_table *sgt, enum dma_data_direction dma_dir) 463 { 464 /* nothing to be done here */ 465 } 466 467 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) 468 { 469 /* drop reference obtained in vb2_dma_sg_get_dmabuf */ 470 vb2_dma_sg_put(dbuf->priv); 471 } 472 473 static int 474 vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, 475 enum dma_data_direction direction) 476 { 477 struct vb2_dma_sg_buf *buf = dbuf->priv; 478 struct sg_table *sgt = buf->dma_sgt; 479 480 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); 481 return 0; 482 } 483 484 static int 485 vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, 486 enum dma_data_direction direction) 487 { 488 struct vb2_dma_sg_buf *buf = dbuf->priv; 489 struct sg_table *sgt = buf->dma_sgt; 490 491 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); 492 return 0; 493 } 494 495 static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map) 496 { 497 struct vb2_dma_sg_buf *buf = dbuf->priv; 498 499 dma_buf_map_set_vaddr(map, buf->vaddr); 500 501 return 0; 502 } 503 504 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, 505 struct vm_area_struct *vma) 506 { 507 return vb2_dma_sg_mmap(dbuf->priv, vma); 508 } 509 510 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { 511 .attach = vb2_dma_sg_dmabuf_ops_attach, 512 .detach = vb2_dma_sg_dmabuf_ops_detach, 513 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, 514 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, 515 .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access, 516 .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access, 517 .vmap = vb2_dma_sg_dmabuf_ops_vmap, 518 .mmap = vb2_dma_sg_dmabuf_ops_mmap, 519 .release = vb2_dma_sg_dmabuf_ops_release, 520 }; 521 522 static struct dma_buf *vb2_dma_sg_get_dmabuf(struct vb2_buffer *vb, 523 void *buf_priv, 524 unsigned long flags) 525 { 526 struct vb2_dma_sg_buf *buf = buf_priv; 527 struct dma_buf *dbuf; 528 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 529 530 exp_info.ops = &vb2_dma_sg_dmabuf_ops; 531 exp_info.size = buf->size; 532 exp_info.flags = flags; 533 exp_info.priv = buf; 534 535 if (WARN_ON(!buf->dma_sgt)) 536 return NULL; 537 538 dbuf = dma_buf_export(&exp_info); 539 if (IS_ERR(dbuf)) 540 return NULL; 541 542 /* dmabuf keeps reference to vb2 buffer */ 543 refcount_inc(&buf->refcount); 544 545 return dbuf; 546 } 547 548 /*********************************************/ 549 /* callbacks for DMABUF buffers */ 550 /*********************************************/ 551 552 static int vb2_dma_sg_map_dmabuf(void *mem_priv) 553 { 554 struct vb2_dma_sg_buf *buf = mem_priv; 555 struct sg_table *sgt; 556 557 if (WARN_ON(!buf->db_attach)) { 558 pr_err("trying to pin a non attached buffer\n"); 559 return -EINVAL; 560 } 561 562 if (WARN_ON(buf->dma_sgt)) { 563 pr_err("dmabuf buffer is already pinned\n"); 564 return 0; 565 } 566 567 /* get the associated scatterlist for this buffer */ 568 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); 569 if (IS_ERR(sgt)) { 570 pr_err("Error getting dmabuf scatterlist\n"); 571 return -EINVAL; 572 } 573 574 buf->dma_sgt = sgt; 575 buf->vaddr = NULL; 576 577 return 0; 578 } 579 580 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) 581 { 582 struct vb2_dma_sg_buf *buf = mem_priv; 583 struct sg_table *sgt = buf->dma_sgt; 584 struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(buf->vaddr); 585 586 if (WARN_ON(!buf->db_attach)) { 587 pr_err("trying to unpin a not attached buffer\n"); 588 return; 589 } 590 591 if (WARN_ON(!sgt)) { 592 pr_err("dmabuf buffer is already unpinned\n"); 593 return; 594 } 595 596 if (buf->vaddr) { 597 dma_buf_vunmap(buf->db_attach->dmabuf, &map); 598 buf->vaddr = NULL; 599 } 600 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); 601 602 buf->dma_sgt = NULL; 603 } 604 605 static void vb2_dma_sg_detach_dmabuf(void *mem_priv) 606 { 607 struct vb2_dma_sg_buf *buf = mem_priv; 608 609 /* if vb2 works correctly you should never detach mapped buffer */ 610 if (WARN_ON(buf->dma_sgt)) 611 vb2_dma_sg_unmap_dmabuf(buf); 612 613 /* detach this attachment */ 614 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); 615 kfree(buf); 616 } 617 618 static void *vb2_dma_sg_attach_dmabuf(struct vb2_buffer *vb, struct device *dev, 619 struct dma_buf *dbuf, unsigned long size) 620 { 621 struct vb2_dma_sg_buf *buf; 622 struct dma_buf_attachment *dba; 623 624 if (WARN_ON(!dev)) 625 return ERR_PTR(-EINVAL); 626 627 if (dbuf->size < size) 628 return ERR_PTR(-EFAULT); 629 630 buf = kzalloc(sizeof(*buf), GFP_KERNEL); 631 if (!buf) 632 return ERR_PTR(-ENOMEM); 633 634 buf->dev = dev; 635 /* create attachment for the dmabuf with the user device */ 636 dba = dma_buf_attach(dbuf, buf->dev); 637 if (IS_ERR(dba)) { 638 pr_err("failed to attach dmabuf\n"); 639 kfree(buf); 640 return dba; 641 } 642 643 buf->dma_dir = vb->vb2_queue->dma_dir; 644 buf->size = size; 645 buf->db_attach = dba; 646 buf->vb = vb; 647 648 return buf; 649 } 650 651 static void *vb2_dma_sg_cookie(struct vb2_buffer *vb, void *buf_priv) 652 { 653 struct vb2_dma_sg_buf *buf = buf_priv; 654 655 return buf->dma_sgt; 656 } 657 658 const struct vb2_mem_ops vb2_dma_sg_memops = { 659 .alloc = vb2_dma_sg_alloc, 660 .put = vb2_dma_sg_put, 661 .get_userptr = vb2_dma_sg_get_userptr, 662 .put_userptr = vb2_dma_sg_put_userptr, 663 .prepare = vb2_dma_sg_prepare, 664 .finish = vb2_dma_sg_finish, 665 .vaddr = vb2_dma_sg_vaddr, 666 .mmap = vb2_dma_sg_mmap, 667 .num_users = vb2_dma_sg_num_users, 668 .get_dmabuf = vb2_dma_sg_get_dmabuf, 669 .map_dmabuf = vb2_dma_sg_map_dmabuf, 670 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf, 671 .attach_dmabuf = vb2_dma_sg_attach_dmabuf, 672 .detach_dmabuf = vb2_dma_sg_detach_dmabuf, 673 .cookie = vb2_dma_sg_cookie, 674 }; 675 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); 676 677 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); 678 MODULE_AUTHOR("Andrzej Pietrasiewicz"); 679 MODULE_LICENSE("GPL"); 680 MODULE_IMPORT_NS(DMA_BUF); 681