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