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 56 static void vb2_dma_sg_put(void *buf_priv); 57 58 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf, 59 gfp_t gfp_flags) 60 { 61 unsigned int last_page = 0; 62 unsigned long size = buf->size; 63 64 while (size > 0) { 65 struct page *pages; 66 int order; 67 int i; 68 69 order = get_order(size); 70 /* Don't over allocate*/ 71 if ((PAGE_SIZE << order) > size) 72 order--; 73 74 pages = NULL; 75 while (!pages) { 76 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO | 77 __GFP_NOWARN | gfp_flags, order); 78 if (pages) 79 break; 80 81 if (order == 0) { 82 while (last_page--) 83 __free_page(buf->pages[last_page]); 84 return -ENOMEM; 85 } 86 order--; 87 } 88 89 split_page(pages, order); 90 for (i = 0; i < (1 << order); i++) 91 buf->pages[last_page++] = &pages[i]; 92 93 size -= PAGE_SIZE << order; 94 } 95 96 return 0; 97 } 98 99 static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs, 100 unsigned long size, enum dma_data_direction dma_dir, 101 gfp_t gfp_flags) 102 { 103 struct vb2_dma_sg_buf *buf; 104 struct sg_table *sgt; 105 int ret; 106 int num_pages; 107 108 if (WARN_ON(!dev)) 109 return ERR_PTR(-EINVAL); 110 111 buf = kzalloc(sizeof *buf, GFP_KERNEL); 112 if (!buf) 113 return ERR_PTR(-ENOMEM); 114 115 buf->vaddr = NULL; 116 buf->dma_dir = dma_dir; 117 buf->offset = 0; 118 buf->size = size; 119 /* size is already page aligned */ 120 buf->num_pages = size >> PAGE_SHIFT; 121 buf->dma_sgt = &buf->sg_table; 122 123 /* 124 * NOTE: dma-sg allocates memory using the page allocator directly, so 125 * there is no memory consistency guarantee, hence dma-sg ignores DMA 126 * attributes passed from the upper layer. That means that 127 * V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers. 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, 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 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 152 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 153 if (!sgt->nents) 154 goto fail_map; 155 156 buf->handler.refcount = &buf->refcount; 157 buf->handler.put = vb2_dma_sg_put; 158 buf->handler.arg = buf; 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_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 190 buf->dma_dir, 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 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents, 208 buf->dma_dir); 209 } 210 211 static void vb2_dma_sg_finish(void *buf_priv) 212 { 213 struct vb2_dma_sg_buf *buf = buf_priv; 214 struct sg_table *sgt = buf->dma_sgt; 215 216 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir); 217 } 218 219 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr, 220 unsigned long size, 221 enum dma_data_direction dma_dir) 222 { 223 struct vb2_dma_sg_buf *buf; 224 struct sg_table *sgt; 225 struct frame_vector *vec; 226 227 if (WARN_ON(!dev)) 228 return ERR_PTR(-EINVAL); 229 230 buf = kzalloc(sizeof *buf, GFP_KERNEL); 231 if (!buf) 232 return ERR_PTR(-ENOMEM); 233 234 buf->vaddr = NULL; 235 buf->dev = dev; 236 buf->dma_dir = dma_dir; 237 buf->offset = vaddr & ~PAGE_MASK; 238 buf->size = size; 239 buf->dma_sgt = &buf->sg_table; 240 vec = vb2_create_framevec(vaddr, size); 241 if (IS_ERR(vec)) 242 goto userptr_fail_pfnvec; 243 buf->vec = vec; 244 245 buf->pages = frame_vector_pages(vec); 246 if (IS_ERR(buf->pages)) 247 goto userptr_fail_sgtable; 248 buf->num_pages = frame_vector_count(vec); 249 250 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, 251 buf->num_pages, buf->offset, size, 0)) 252 goto userptr_fail_sgtable; 253 254 sgt = &buf->sg_table; 255 /* 256 * No need to sync to the device, this will happen later when the 257 * prepare() memop is called. 258 */ 259 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 260 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 261 if (!sgt->nents) 262 goto userptr_fail_map; 263 264 return buf; 265 266 userptr_fail_map: 267 sg_free_table(&buf->sg_table); 268 userptr_fail_sgtable: 269 vb2_destroy_framevec(vec); 270 userptr_fail_pfnvec: 271 kfree(buf); 272 return ERR_PTR(-ENOMEM); 273 } 274 275 /* 276 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 277 * be used 278 */ 279 static void vb2_dma_sg_put_userptr(void *buf_priv) 280 { 281 struct vb2_dma_sg_buf *buf = buf_priv; 282 struct sg_table *sgt = &buf->sg_table; 283 int i = buf->num_pages; 284 285 dprintk(1, "%s: Releasing userspace buffer of %d pages\n", 286 __func__, buf->num_pages); 287 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir, 288 DMA_ATTR_SKIP_CPU_SYNC); 289 if (buf->vaddr) 290 vm_unmap_ram(buf->vaddr, buf->num_pages); 291 sg_free_table(buf->dma_sgt); 292 if (buf->dma_dir == DMA_FROM_DEVICE || 293 buf->dma_dir == DMA_BIDIRECTIONAL) 294 while (--i >= 0) 295 set_page_dirty_lock(buf->pages[i]); 296 vb2_destroy_framevec(buf->vec); 297 kfree(buf); 298 } 299 300 static void *vb2_dma_sg_vaddr(void *buf_priv) 301 { 302 struct vb2_dma_sg_buf *buf = buf_priv; 303 struct dma_buf_map map; 304 int ret; 305 306 BUG_ON(!buf); 307 308 if (!buf->vaddr) { 309 if (buf->db_attach) { 310 ret = dma_buf_vmap(buf->db_attach->dmabuf, &map); 311 buf->vaddr = ret ? NULL : map.vaddr; 312 } else { 313 buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1); 314 } 315 } 316 317 /* add offset in case userptr is not page-aligned */ 318 return buf->vaddr ? buf->vaddr + buf->offset : NULL; 319 } 320 321 static unsigned int vb2_dma_sg_num_users(void *buf_priv) 322 { 323 struct vb2_dma_sg_buf *buf = buf_priv; 324 325 return refcount_read(&buf->refcount); 326 } 327 328 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) 329 { 330 struct vb2_dma_sg_buf *buf = buf_priv; 331 int err; 332 333 if (!buf) { 334 printk(KERN_ERR "No memory to map\n"); 335 return -EINVAL; 336 } 337 338 err = vm_map_pages(vma, buf->pages, buf->num_pages); 339 if (err) { 340 printk(KERN_ERR "Remapping memory, error: %d\n", err); 341 return err; 342 } 343 344 /* 345 * Use common vm_area operations to track buffer refcount. 346 */ 347 vma->vm_private_data = &buf->handler; 348 vma->vm_ops = &vb2_common_vm_ops; 349 350 vma->vm_ops->open(vma); 351 352 return 0; 353 } 354 355 /*********************************************/ 356 /* DMABUF ops for exporters */ 357 /*********************************************/ 358 359 struct vb2_dma_sg_attachment { 360 struct sg_table sgt; 361 enum dma_data_direction dma_dir; 362 }; 363 364 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, 365 struct dma_buf_attachment *dbuf_attach) 366 { 367 struct vb2_dma_sg_attachment *attach; 368 unsigned int i; 369 struct scatterlist *rd, *wr; 370 struct sg_table *sgt; 371 struct vb2_dma_sg_buf *buf = dbuf->priv; 372 int ret; 373 374 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 375 if (!attach) 376 return -ENOMEM; 377 378 sgt = &attach->sgt; 379 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 380 * map the same scatter list to multiple attachments at the same time. 381 */ 382 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); 383 if (ret) { 384 kfree(attach); 385 return -ENOMEM; 386 } 387 388 rd = buf->dma_sgt->sgl; 389 wr = sgt->sgl; 390 for (i = 0; i < sgt->orig_nents; ++i) { 391 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 392 rd = sg_next(rd); 393 wr = sg_next(wr); 394 } 395 396 attach->dma_dir = DMA_NONE; 397 dbuf_attach->priv = attach; 398 399 return 0; 400 } 401 402 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, 403 struct dma_buf_attachment *db_attach) 404 { 405 struct vb2_dma_sg_attachment *attach = db_attach->priv; 406 struct sg_table *sgt; 407 408 if (!attach) 409 return; 410 411 sgt = &attach->sgt; 412 413 /* release the scatterlist cache */ 414 if (attach->dma_dir != DMA_NONE) 415 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 416 attach->dma_dir); 417 sg_free_table(sgt); 418 kfree(attach); 419 db_attach->priv = NULL; 420 } 421 422 static struct sg_table *vb2_dma_sg_dmabuf_ops_map( 423 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 424 { 425 struct vb2_dma_sg_attachment *attach = db_attach->priv; 426 /* stealing dmabuf mutex to serialize map/unmap operations */ 427 struct mutex *lock = &db_attach->dmabuf->lock; 428 struct sg_table *sgt; 429 430 mutex_lock(lock); 431 432 sgt = &attach->sgt; 433 /* return previously mapped sg table */ 434 if (attach->dma_dir == dma_dir) { 435 mutex_unlock(lock); 436 return sgt; 437 } 438 439 /* release any previous cache */ 440 if (attach->dma_dir != DMA_NONE) { 441 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 442 attach->dma_dir); 443 attach->dma_dir = DMA_NONE; 444 } 445 446 /* mapping to the client with new direction */ 447 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 448 dma_dir); 449 if (!sgt->nents) { 450 pr_err("failed to map scatterlist\n"); 451 mutex_unlock(lock); 452 return ERR_PTR(-EIO); 453 } 454 455 attach->dma_dir = dma_dir; 456 457 mutex_unlock(lock); 458 459 return sgt; 460 } 461 462 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, 463 struct sg_table *sgt, enum dma_data_direction dma_dir) 464 { 465 /* nothing to be done here */ 466 } 467 468 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) 469 { 470 /* drop reference obtained in vb2_dma_sg_get_dmabuf */ 471 vb2_dma_sg_put(dbuf->priv); 472 } 473 474 static int 475 vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, 476 enum dma_data_direction direction) 477 { 478 struct vb2_dma_sg_buf *buf = dbuf->priv; 479 struct sg_table *sgt = buf->dma_sgt; 480 481 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); 482 return 0; 483 } 484 485 static int 486 vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, 487 enum dma_data_direction direction) 488 { 489 struct vb2_dma_sg_buf *buf = dbuf->priv; 490 struct sg_table *sgt = buf->dma_sgt; 491 492 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); 493 return 0; 494 } 495 496 static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map) 497 { 498 struct vb2_dma_sg_buf *buf = dbuf->priv; 499 500 dma_buf_map_set_vaddr(map, buf->vaddr); 501 502 return 0; 503 } 504 505 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, 506 struct vm_area_struct *vma) 507 { 508 return vb2_dma_sg_mmap(dbuf->priv, vma); 509 } 510 511 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { 512 .attach = vb2_dma_sg_dmabuf_ops_attach, 513 .detach = vb2_dma_sg_dmabuf_ops_detach, 514 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, 515 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, 516 .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access, 517 .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access, 518 .vmap = vb2_dma_sg_dmabuf_ops_vmap, 519 .mmap = vb2_dma_sg_dmabuf_ops_mmap, 520 .release = vb2_dma_sg_dmabuf_ops_release, 521 }; 522 523 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags) 524 { 525 struct vb2_dma_sg_buf *buf = buf_priv; 526 struct dma_buf *dbuf; 527 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 528 529 exp_info.ops = &vb2_dma_sg_dmabuf_ops; 530 exp_info.size = buf->size; 531 exp_info.flags = flags; 532 exp_info.priv = buf; 533 534 if (WARN_ON(!buf->dma_sgt)) 535 return NULL; 536 537 dbuf = dma_buf_export(&exp_info); 538 if (IS_ERR(dbuf)) 539 return NULL; 540 541 /* dmabuf keeps reference to vb2 buffer */ 542 refcount_inc(&buf->refcount); 543 544 return dbuf; 545 } 546 547 /*********************************************/ 548 /* callbacks for DMABUF buffers */ 549 /*********************************************/ 550 551 static int vb2_dma_sg_map_dmabuf(void *mem_priv) 552 { 553 struct vb2_dma_sg_buf *buf = mem_priv; 554 struct sg_table *sgt; 555 556 if (WARN_ON(!buf->db_attach)) { 557 pr_err("trying to pin a non attached buffer\n"); 558 return -EINVAL; 559 } 560 561 if (WARN_ON(buf->dma_sgt)) { 562 pr_err("dmabuf buffer is already pinned\n"); 563 return 0; 564 } 565 566 /* get the associated scatterlist for this buffer */ 567 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); 568 if (IS_ERR(sgt)) { 569 pr_err("Error getting dmabuf scatterlist\n"); 570 return -EINVAL; 571 } 572 573 buf->dma_sgt = sgt; 574 buf->vaddr = NULL; 575 576 return 0; 577 } 578 579 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) 580 { 581 struct vb2_dma_sg_buf *buf = mem_priv; 582 struct sg_table *sgt = buf->dma_sgt; 583 struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(buf->vaddr); 584 585 if (WARN_ON(!buf->db_attach)) { 586 pr_err("trying to unpin a not attached buffer\n"); 587 return; 588 } 589 590 if (WARN_ON(!sgt)) { 591 pr_err("dmabuf buffer is already unpinned\n"); 592 return; 593 } 594 595 if (buf->vaddr) { 596 dma_buf_vunmap(buf->db_attach->dmabuf, &map); 597 buf->vaddr = NULL; 598 } 599 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); 600 601 buf->dma_sgt = NULL; 602 } 603 604 static void vb2_dma_sg_detach_dmabuf(void *mem_priv) 605 { 606 struct vb2_dma_sg_buf *buf = mem_priv; 607 608 /* if vb2 works correctly you should never detach mapped buffer */ 609 if (WARN_ON(buf->dma_sgt)) 610 vb2_dma_sg_unmap_dmabuf(buf); 611 612 /* detach this attachment */ 613 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); 614 kfree(buf); 615 } 616 617 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf, 618 unsigned long size, enum dma_data_direction dma_dir) 619 { 620 struct vb2_dma_sg_buf *buf; 621 struct dma_buf_attachment *dba; 622 623 if (WARN_ON(!dev)) 624 return ERR_PTR(-EINVAL); 625 626 if (dbuf->size < size) 627 return ERR_PTR(-EFAULT); 628 629 buf = kzalloc(sizeof(*buf), GFP_KERNEL); 630 if (!buf) 631 return ERR_PTR(-ENOMEM); 632 633 buf->dev = dev; 634 /* create attachment for the dmabuf with the user device */ 635 dba = dma_buf_attach(dbuf, buf->dev); 636 if (IS_ERR(dba)) { 637 pr_err("failed to attach dmabuf\n"); 638 kfree(buf); 639 return dba; 640 } 641 642 buf->dma_dir = dma_dir; 643 buf->size = size; 644 buf->db_attach = dba; 645 646 return buf; 647 } 648 649 static void *vb2_dma_sg_cookie(void *buf_priv) 650 { 651 struct vb2_dma_sg_buf *buf = buf_priv; 652 653 return buf->dma_sgt; 654 } 655 656 const struct vb2_mem_ops vb2_dma_sg_memops = { 657 .alloc = vb2_dma_sg_alloc, 658 .put = vb2_dma_sg_put, 659 .get_userptr = vb2_dma_sg_get_userptr, 660 .put_userptr = vb2_dma_sg_put_userptr, 661 .prepare = vb2_dma_sg_prepare, 662 .finish = vb2_dma_sg_finish, 663 .vaddr = vb2_dma_sg_vaddr, 664 .mmap = vb2_dma_sg_mmap, 665 .num_users = vb2_dma_sg_num_users, 666 .get_dmabuf = vb2_dma_sg_get_dmabuf, 667 .map_dmabuf = vb2_dma_sg_map_dmabuf, 668 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf, 669 .attach_dmabuf = vb2_dma_sg_attach_dmabuf, 670 .detach_dmabuf = vb2_dma_sg_detach_dmabuf, 671 .cookie = vb2_dma_sg_cookie, 672 }; 673 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); 674 675 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); 676 MODULE_AUTHOR("Andrzej Pietrasiewicz"); 677 MODULE_LICENSE("GPL"); 678