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. 127 */ 128 buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *), 129 GFP_KERNEL | __GFP_ZERO); 130 if (!buf->pages) 131 goto fail_pages_array_alloc; 132 133 ret = vb2_dma_sg_alloc_compacted(buf, 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; 157 158 refcount_set(&buf->refcount, 1); 159 160 dprintk(1, "%s: Allocated buffer of %d pages\n", 161 __func__, buf->num_pages); 162 return buf; 163 164 fail_map: 165 put_device(buf->dev); 166 sg_free_table(buf->dma_sgt); 167 fail_table_alloc: 168 num_pages = buf->num_pages; 169 while (num_pages--) 170 __free_page(buf->pages[num_pages]); 171 fail_pages_alloc: 172 kvfree(buf->pages); 173 fail_pages_array_alloc: 174 kfree(buf); 175 return ERR_PTR(-ENOMEM); 176 } 177 178 static void vb2_dma_sg_put(void *buf_priv) 179 { 180 struct vb2_dma_sg_buf *buf = buf_priv; 181 struct sg_table *sgt = &buf->sg_table; 182 int i = buf->num_pages; 183 184 if (refcount_dec_and_test(&buf->refcount)) { 185 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__, 186 buf->num_pages); 187 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, 188 DMA_ATTR_SKIP_CPU_SYNC); 189 if (buf->vaddr) 190 vm_unmap_ram(buf->vaddr, buf->num_pages); 191 sg_free_table(buf->dma_sgt); 192 while (--i >= 0) 193 __free_page(buf->pages[i]); 194 kvfree(buf->pages); 195 put_device(buf->dev); 196 kfree(buf); 197 } 198 } 199 200 static void vb2_dma_sg_prepare(void *buf_priv) 201 { 202 struct vb2_dma_sg_buf *buf = buf_priv; 203 struct sg_table *sgt = buf->dma_sgt; 204 205 dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir); 206 } 207 208 static void vb2_dma_sg_finish(void *buf_priv) 209 { 210 struct vb2_dma_sg_buf *buf = buf_priv; 211 struct sg_table *sgt = buf->dma_sgt; 212 213 dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir); 214 } 215 216 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr, 217 unsigned long size, 218 enum dma_data_direction dma_dir) 219 { 220 struct vb2_dma_sg_buf *buf; 221 struct sg_table *sgt; 222 struct frame_vector *vec; 223 224 if (WARN_ON(!dev)) 225 return ERR_PTR(-EINVAL); 226 227 buf = kzalloc(sizeof *buf, GFP_KERNEL); 228 if (!buf) 229 return ERR_PTR(-ENOMEM); 230 231 buf->vaddr = NULL; 232 buf->dev = dev; 233 buf->dma_dir = dma_dir; 234 buf->offset = vaddr & ~PAGE_MASK; 235 buf->size = size; 236 buf->dma_sgt = &buf->sg_table; 237 vec = vb2_create_framevec(vaddr, size); 238 if (IS_ERR(vec)) 239 goto userptr_fail_pfnvec; 240 buf->vec = vec; 241 242 buf->pages = frame_vector_pages(vec); 243 if (IS_ERR(buf->pages)) 244 goto userptr_fail_sgtable; 245 buf->num_pages = frame_vector_count(vec); 246 247 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, 248 buf->num_pages, buf->offset, size, 0)) 249 goto userptr_fail_sgtable; 250 251 sgt = &buf->sg_table; 252 /* 253 * No need to sync to the device, this will happen later when the 254 * prepare() memop is called. 255 */ 256 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir, 257 DMA_ATTR_SKIP_CPU_SYNC)) 258 goto userptr_fail_map; 259 260 return buf; 261 262 userptr_fail_map: 263 sg_free_table(&buf->sg_table); 264 userptr_fail_sgtable: 265 vb2_destroy_framevec(vec); 266 userptr_fail_pfnvec: 267 kfree(buf); 268 return ERR_PTR(-ENOMEM); 269 } 270 271 /* 272 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 273 * be used 274 */ 275 static void vb2_dma_sg_put_userptr(void *buf_priv) 276 { 277 struct vb2_dma_sg_buf *buf = buf_priv; 278 struct sg_table *sgt = &buf->sg_table; 279 int i = buf->num_pages; 280 281 dprintk(1, "%s: Releasing userspace buffer of %d pages\n", 282 __func__, buf->num_pages); 283 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 284 if (buf->vaddr) 285 vm_unmap_ram(buf->vaddr, buf->num_pages); 286 sg_free_table(buf->dma_sgt); 287 if (buf->dma_dir == DMA_FROM_DEVICE || 288 buf->dma_dir == DMA_BIDIRECTIONAL) 289 while (--i >= 0) 290 set_page_dirty_lock(buf->pages[i]); 291 vb2_destroy_framevec(buf->vec); 292 kfree(buf); 293 } 294 295 static void *vb2_dma_sg_vaddr(void *buf_priv) 296 { 297 struct vb2_dma_sg_buf *buf = buf_priv; 298 struct dma_buf_map map; 299 int ret; 300 301 BUG_ON(!buf); 302 303 if (!buf->vaddr) { 304 if (buf->db_attach) { 305 ret = dma_buf_vmap(buf->db_attach->dmabuf, &map); 306 buf->vaddr = ret ? NULL : map.vaddr; 307 } else { 308 buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1); 309 } 310 } 311 312 /* add offset in case userptr is not page-aligned */ 313 return buf->vaddr ? buf->vaddr + buf->offset : NULL; 314 } 315 316 static unsigned int vb2_dma_sg_num_users(void *buf_priv) 317 { 318 struct vb2_dma_sg_buf *buf = buf_priv; 319 320 return refcount_read(&buf->refcount); 321 } 322 323 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) 324 { 325 struct vb2_dma_sg_buf *buf = buf_priv; 326 int err; 327 328 if (!buf) { 329 printk(KERN_ERR "No memory to map\n"); 330 return -EINVAL; 331 } 332 333 err = vm_map_pages(vma, buf->pages, buf->num_pages); 334 if (err) { 335 printk(KERN_ERR "Remapping memory, error: %d\n", err); 336 return err; 337 } 338 339 /* 340 * Use common vm_area operations to track buffer refcount. 341 */ 342 vma->vm_private_data = &buf->handler; 343 vma->vm_ops = &vb2_common_vm_ops; 344 345 vma->vm_ops->open(vma); 346 347 return 0; 348 } 349 350 /*********************************************/ 351 /* DMABUF ops for exporters */ 352 /*********************************************/ 353 354 struct vb2_dma_sg_attachment { 355 struct sg_table sgt; 356 enum dma_data_direction dma_dir; 357 }; 358 359 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, 360 struct dma_buf_attachment *dbuf_attach) 361 { 362 struct vb2_dma_sg_attachment *attach; 363 unsigned int i; 364 struct scatterlist *rd, *wr; 365 struct sg_table *sgt; 366 struct vb2_dma_sg_buf *buf = dbuf->priv; 367 int ret; 368 369 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 370 if (!attach) 371 return -ENOMEM; 372 373 sgt = &attach->sgt; 374 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 375 * map the same scatter list to multiple attachments at the same time. 376 */ 377 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); 378 if (ret) { 379 kfree(attach); 380 return -ENOMEM; 381 } 382 383 rd = buf->dma_sgt->sgl; 384 wr = sgt->sgl; 385 for (i = 0; i < sgt->orig_nents; ++i) { 386 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 387 rd = sg_next(rd); 388 wr = sg_next(wr); 389 } 390 391 attach->dma_dir = DMA_NONE; 392 dbuf_attach->priv = attach; 393 394 return 0; 395 } 396 397 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, 398 struct dma_buf_attachment *db_attach) 399 { 400 struct vb2_dma_sg_attachment *attach = db_attach->priv; 401 struct sg_table *sgt; 402 403 if (!attach) 404 return; 405 406 sgt = &attach->sgt; 407 408 /* release the scatterlist cache */ 409 if (attach->dma_dir != DMA_NONE) 410 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0); 411 sg_free_table(sgt); 412 kfree(attach); 413 db_attach->priv = NULL; 414 } 415 416 static struct sg_table *vb2_dma_sg_dmabuf_ops_map( 417 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 418 { 419 struct vb2_dma_sg_attachment *attach = db_attach->priv; 420 /* stealing dmabuf mutex to serialize map/unmap operations */ 421 struct mutex *lock = &db_attach->dmabuf->lock; 422 struct sg_table *sgt; 423 424 mutex_lock(lock); 425 426 sgt = &attach->sgt; 427 /* return previously mapped sg table */ 428 if (attach->dma_dir == dma_dir) { 429 mutex_unlock(lock); 430 return sgt; 431 } 432 433 /* release any previous cache */ 434 if (attach->dma_dir != DMA_NONE) { 435 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0); 436 attach->dma_dir = DMA_NONE; 437 } 438 439 /* mapping to the client with new direction */ 440 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) { 441 pr_err("failed to map scatterlist\n"); 442 mutex_unlock(lock); 443 return ERR_PTR(-EIO); 444 } 445 446 attach->dma_dir = dma_dir; 447 448 mutex_unlock(lock); 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, struct dma_buf_map *map) 488 { 489 struct vb2_dma_sg_buf *buf = dbuf->priv; 490 491 dma_buf_map_set_vaddr(map, buf->vaddr); 492 493 return 0; 494 } 495 496 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, 497 struct vm_area_struct *vma) 498 { 499 return vb2_dma_sg_mmap(dbuf->priv, vma); 500 } 501 502 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { 503 .attach = vb2_dma_sg_dmabuf_ops_attach, 504 .detach = vb2_dma_sg_dmabuf_ops_detach, 505 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, 506 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, 507 .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access, 508 .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access, 509 .vmap = vb2_dma_sg_dmabuf_ops_vmap, 510 .mmap = vb2_dma_sg_dmabuf_ops_mmap, 511 .release = vb2_dma_sg_dmabuf_ops_release, 512 }; 513 514 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags) 515 { 516 struct vb2_dma_sg_buf *buf = buf_priv; 517 struct dma_buf *dbuf; 518 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 519 520 exp_info.ops = &vb2_dma_sg_dmabuf_ops; 521 exp_info.size = buf->size; 522 exp_info.flags = flags; 523 exp_info.priv = buf; 524 525 if (WARN_ON(!buf->dma_sgt)) 526 return NULL; 527 528 dbuf = dma_buf_export(&exp_info); 529 if (IS_ERR(dbuf)) 530 return NULL; 531 532 /* dmabuf keeps reference to vb2 buffer */ 533 refcount_inc(&buf->refcount); 534 535 return dbuf; 536 } 537 538 /*********************************************/ 539 /* callbacks for DMABUF buffers */ 540 /*********************************************/ 541 542 static int vb2_dma_sg_map_dmabuf(void *mem_priv) 543 { 544 struct vb2_dma_sg_buf *buf = mem_priv; 545 struct sg_table *sgt; 546 547 if (WARN_ON(!buf->db_attach)) { 548 pr_err("trying to pin a non attached buffer\n"); 549 return -EINVAL; 550 } 551 552 if (WARN_ON(buf->dma_sgt)) { 553 pr_err("dmabuf buffer is already pinned\n"); 554 return 0; 555 } 556 557 /* get the associated scatterlist for this buffer */ 558 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); 559 if (IS_ERR(sgt)) { 560 pr_err("Error getting dmabuf scatterlist\n"); 561 return -EINVAL; 562 } 563 564 buf->dma_sgt = sgt; 565 buf->vaddr = NULL; 566 567 return 0; 568 } 569 570 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) 571 { 572 struct vb2_dma_sg_buf *buf = mem_priv; 573 struct sg_table *sgt = buf->dma_sgt; 574 struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(buf->vaddr); 575 576 if (WARN_ON(!buf->db_attach)) { 577 pr_err("trying to unpin a not attached buffer\n"); 578 return; 579 } 580 581 if (WARN_ON(!sgt)) { 582 pr_err("dmabuf buffer is already unpinned\n"); 583 return; 584 } 585 586 if (buf->vaddr) { 587 dma_buf_vunmap(buf->db_attach->dmabuf, &map); 588 buf->vaddr = NULL; 589 } 590 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); 591 592 buf->dma_sgt = NULL; 593 } 594 595 static void vb2_dma_sg_detach_dmabuf(void *mem_priv) 596 { 597 struct vb2_dma_sg_buf *buf = mem_priv; 598 599 /* if vb2 works correctly you should never detach mapped buffer */ 600 if (WARN_ON(buf->dma_sgt)) 601 vb2_dma_sg_unmap_dmabuf(buf); 602 603 /* detach this attachment */ 604 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); 605 kfree(buf); 606 } 607 608 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf, 609 unsigned long size, enum dma_data_direction dma_dir) 610 { 611 struct vb2_dma_sg_buf *buf; 612 struct dma_buf_attachment *dba; 613 614 if (WARN_ON(!dev)) 615 return ERR_PTR(-EINVAL); 616 617 if (dbuf->size < size) 618 return ERR_PTR(-EFAULT); 619 620 buf = kzalloc(sizeof(*buf), GFP_KERNEL); 621 if (!buf) 622 return ERR_PTR(-ENOMEM); 623 624 buf->dev = dev; 625 /* create attachment for the dmabuf with the user device */ 626 dba = dma_buf_attach(dbuf, buf->dev); 627 if (IS_ERR(dba)) { 628 pr_err("failed to attach dmabuf\n"); 629 kfree(buf); 630 return dba; 631 } 632 633 buf->dma_dir = dma_dir; 634 buf->size = size; 635 buf->db_attach = dba; 636 637 return buf; 638 } 639 640 static void *vb2_dma_sg_cookie(void *buf_priv) 641 { 642 struct vb2_dma_sg_buf *buf = buf_priv; 643 644 return buf->dma_sgt; 645 } 646 647 const struct vb2_mem_ops vb2_dma_sg_memops = { 648 .alloc = vb2_dma_sg_alloc, 649 .put = vb2_dma_sg_put, 650 .get_userptr = vb2_dma_sg_get_userptr, 651 .put_userptr = vb2_dma_sg_put_userptr, 652 .prepare = vb2_dma_sg_prepare, 653 .finish = vb2_dma_sg_finish, 654 .vaddr = vb2_dma_sg_vaddr, 655 .mmap = vb2_dma_sg_mmap, 656 .num_users = vb2_dma_sg_num_users, 657 .get_dmabuf = vb2_dma_sg_get_dmabuf, 658 .map_dmabuf = vb2_dma_sg_map_dmabuf, 659 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf, 660 .attach_dmabuf = vb2_dma_sg_attach_dmabuf, 661 .detach_dmabuf = vb2_dma_sg_detach_dmabuf, 662 .cookie = vb2_dma_sg_cookie, 663 }; 664 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); 665 666 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); 667 MODULE_AUTHOR("Andrzej Pietrasiewicz"); 668 MODULE_LICENSE("GPL"); 669