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 <andrzej.p@samsung.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/scatterlist.h> 16#include <linux/sched.h> 17#include <linux/slab.h> 18#include <linux/vmalloc.h> 19 20#include <media/videobuf2-v4l2.h> 21#include <media/videobuf2-memops.h> 22#include <media/videobuf2-dma-sg.h> 23 24static int debug; 25module_param(debug, int, 0644); 26 27#define dprintk(level, fmt, arg...) \ 28 do { \ 29 if (debug >= level) \ 30 printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \ 31 } while (0) 32 33struct vb2_dma_sg_conf { 34 struct device *dev; 35}; 36 37struct vb2_dma_sg_buf { 38 struct device *dev; 39 void *vaddr; 40 struct page **pages; 41 struct frame_vector *vec; 42 int offset; 43 enum dma_data_direction dma_dir; 44 struct sg_table sg_table; 45 /* 46 * This will point to sg_table when used with the MMAP or USERPTR 47 * memory model, and to the dma_buf sglist when used with the 48 * DMABUF memory model. 49 */ 50 struct sg_table *dma_sgt; 51 size_t size; 52 unsigned int num_pages; 53 atomic_t refcount; 54 struct vb2_vmarea_handler handler; 55 56 struct dma_buf_attachment *db_attach; 57}; 58 59static void vb2_dma_sg_put(void *buf_priv); 60 61static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf, 62 gfp_t gfp_flags) 63{ 64 unsigned int last_page = 0; 65 int size = buf->size; 66 67 while (size > 0) { 68 struct page *pages; 69 int order; 70 int i; 71 72 order = get_order(size); 73 /* Dont over allocate*/ 74 if ((PAGE_SIZE << order) > size) 75 order--; 76 77 pages = NULL; 78 while (!pages) { 79 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO | 80 __GFP_NOWARN | gfp_flags, order); 81 if (pages) 82 break; 83 84 if (order == 0) { 85 while (last_page--) 86 __free_page(buf->pages[last_page]); 87 return -ENOMEM; 88 } 89 order--; 90 } 91 92 split_page(pages, order); 93 for (i = 0; i < (1 << order); i++) 94 buf->pages[last_page++] = &pages[i]; 95 96 size -= PAGE_SIZE << order; 97 } 98 99 return 0; 100} 101 102static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, 103 enum dma_data_direction dma_dir, gfp_t gfp_flags) 104{ 105 struct vb2_dma_sg_conf *conf = alloc_ctx; 106 struct vb2_dma_sg_buf *buf; 107 struct sg_table *sgt; 108 int ret; 109 int num_pages; 110 DEFINE_DMA_ATTRS(attrs); 111 112 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); 113 114 if (WARN_ON(alloc_ctx == NULL)) 115 return NULL; 116 buf = kzalloc(sizeof *buf, GFP_KERNEL); 117 if (!buf) 118 return NULL; 119 120 buf->vaddr = NULL; 121 buf->dma_dir = dma_dir; 122 buf->offset = 0; 123 buf->size = size; 124 /* size is already page aligned */ 125 buf->num_pages = size >> PAGE_SHIFT; 126 buf->dma_sgt = &buf->sg_table; 127 128 buf->pages = kzalloc(buf->num_pages * sizeof(struct page *), 129 GFP_KERNEL); 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(conf->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 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 151 buf->dma_dir, &attrs); 152 if (!sgt->nents) 153 goto fail_map; 154 155 buf->handler.refcount = &buf->refcount; 156 buf->handler.put = vb2_dma_sg_put; 157 buf->handler.arg = buf; 158 159 atomic_inc(&buf->refcount); 160 161 dprintk(1, "%s: Allocated buffer of %d pages\n", 162 __func__, buf->num_pages); 163 return buf; 164 165fail_map: 166 put_device(buf->dev); 167 sg_free_table(buf->dma_sgt); 168fail_table_alloc: 169 num_pages = buf->num_pages; 170 while (num_pages--) 171 __free_page(buf->pages[num_pages]); 172fail_pages_alloc: 173 kfree(buf->pages); 174fail_pages_array_alloc: 175 kfree(buf); 176 return NULL; 177} 178 179static 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 (atomic_dec_and_test(&buf->refcount)) { 186 DEFINE_DMA_ATTRS(attrs); 187 188 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); 189 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__, 190 buf->num_pages); 191 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 192 buf->dma_dir, &attrs); 193 if (buf->vaddr) 194 vm_unmap_ram(buf->vaddr, buf->num_pages); 195 sg_free_table(buf->dma_sgt); 196 while (--i >= 0) 197 __free_page(buf->pages[i]); 198 kfree(buf->pages); 199 put_device(buf->dev); 200 kfree(buf); 201 } 202} 203 204static void vb2_dma_sg_prepare(void *buf_priv) 205{ 206 struct vb2_dma_sg_buf *buf = buf_priv; 207 struct sg_table *sgt = buf->dma_sgt; 208 209 /* DMABUF exporter will flush the cache for us */ 210 if (buf->db_attach) 211 return; 212 213 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents, 214 buf->dma_dir); 215} 216 217static void vb2_dma_sg_finish(void *buf_priv) 218{ 219 struct vb2_dma_sg_buf *buf = buf_priv; 220 struct sg_table *sgt = buf->dma_sgt; 221 222 /* DMABUF exporter will flush the cache for us */ 223 if (buf->db_attach) 224 return; 225 226 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir); 227} 228 229static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, 230 unsigned long size, 231 enum dma_data_direction dma_dir) 232{ 233 struct vb2_dma_sg_conf *conf = alloc_ctx; 234 struct vb2_dma_sg_buf *buf; 235 struct sg_table *sgt; 236 DEFINE_DMA_ATTRS(attrs); 237 struct frame_vector *vec; 238 239 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); 240 buf = kzalloc(sizeof *buf, GFP_KERNEL); 241 if (!buf) 242 return NULL; 243 244 buf->vaddr = NULL; 245 buf->dev = conf->dev; 246 buf->dma_dir = dma_dir; 247 buf->offset = vaddr & ~PAGE_MASK; 248 buf->size = size; 249 buf->dma_sgt = &buf->sg_table; 250 vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE); 251 if (IS_ERR(vec)) 252 goto userptr_fail_pfnvec; 253 buf->vec = vec; 254 255 buf->pages = frame_vector_pages(vec); 256 if (IS_ERR(buf->pages)) 257 goto userptr_fail_sgtable; 258 buf->num_pages = frame_vector_count(vec); 259 260 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, 261 buf->num_pages, buf->offset, size, 0)) 262 goto userptr_fail_sgtable; 263 264 sgt = &buf->sg_table; 265 /* 266 * No need to sync to the device, this will happen later when the 267 * prepare() memop is called. 268 */ 269 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 270 buf->dma_dir, &attrs); 271 if (!sgt->nents) 272 goto userptr_fail_map; 273 274 return buf; 275 276userptr_fail_map: 277 sg_free_table(&buf->sg_table); 278userptr_fail_sgtable: 279 vb2_destroy_framevec(vec); 280userptr_fail_pfnvec: 281 kfree(buf); 282 return NULL; 283} 284 285/* 286 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 287 * be used 288 */ 289static void vb2_dma_sg_put_userptr(void *buf_priv) 290{ 291 struct vb2_dma_sg_buf *buf = buf_priv; 292 struct sg_table *sgt = &buf->sg_table; 293 int i = buf->num_pages; 294 DEFINE_DMA_ATTRS(attrs); 295 296 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); 297 298 dprintk(1, "%s: Releasing userspace buffer of %d pages\n", 299 __func__, buf->num_pages); 300 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir, 301 &attrs); 302 if (buf->vaddr) 303 vm_unmap_ram(buf->vaddr, buf->num_pages); 304 sg_free_table(buf->dma_sgt); 305 while (--i >= 0) { 306 if (buf->dma_dir == DMA_FROM_DEVICE) 307 set_page_dirty_lock(buf->pages[i]); 308 } 309 vb2_destroy_framevec(buf->vec); 310 kfree(buf); 311} 312 313static void *vb2_dma_sg_vaddr(void *buf_priv) 314{ 315 struct vb2_dma_sg_buf *buf = buf_priv; 316 317 BUG_ON(!buf); 318 319 if (!buf->vaddr) { 320 if (buf->db_attach) 321 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf); 322 else 323 buf->vaddr = vm_map_ram(buf->pages, 324 buf->num_pages, -1, PAGE_KERNEL); 325 } 326 327 /* add offset in case userptr is not page-aligned */ 328 return buf->vaddr ? buf->vaddr + buf->offset : NULL; 329} 330 331static unsigned int vb2_dma_sg_num_users(void *buf_priv) 332{ 333 struct vb2_dma_sg_buf *buf = buf_priv; 334 335 return atomic_read(&buf->refcount); 336} 337 338static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) 339{ 340 struct vb2_dma_sg_buf *buf = buf_priv; 341 unsigned long uaddr = vma->vm_start; 342 unsigned long usize = vma->vm_end - vma->vm_start; 343 int i = 0; 344 345 if (!buf) { 346 printk(KERN_ERR "No memory to map\n"); 347 return -EINVAL; 348 } 349 350 do { 351 int ret; 352 353 ret = vm_insert_page(vma, uaddr, buf->pages[i++]); 354 if (ret) { 355 printk(KERN_ERR "Remapping memory, error: %d\n", ret); 356 return ret; 357 } 358 359 uaddr += PAGE_SIZE; 360 usize -= PAGE_SIZE; 361 } while (usize > 0); 362 363 364 /* 365 * Use common vm_area operations to track buffer refcount. 366 */ 367 vma->vm_private_data = &buf->handler; 368 vma->vm_ops = &vb2_common_vm_ops; 369 370 vma->vm_ops->open(vma); 371 372 return 0; 373} 374 375/*********************************************/ 376/* DMABUF ops for exporters */ 377/*********************************************/ 378 379struct vb2_dma_sg_attachment { 380 struct sg_table sgt; 381 enum dma_data_direction dma_dir; 382}; 383 384static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev, 385 struct dma_buf_attachment *dbuf_attach) 386{ 387 struct vb2_dma_sg_attachment *attach; 388 unsigned int i; 389 struct scatterlist *rd, *wr; 390 struct sg_table *sgt; 391 struct vb2_dma_sg_buf *buf = dbuf->priv; 392 int ret; 393 394 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 395 if (!attach) 396 return -ENOMEM; 397 398 sgt = &attach->sgt; 399 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 400 * map the same scatter list to multiple attachments at the same time. 401 */ 402 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); 403 if (ret) { 404 kfree(attach); 405 return -ENOMEM; 406 } 407 408 rd = buf->dma_sgt->sgl; 409 wr = sgt->sgl; 410 for (i = 0; i < sgt->orig_nents; ++i) { 411 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 412 rd = sg_next(rd); 413 wr = sg_next(wr); 414 } 415 416 attach->dma_dir = DMA_NONE; 417 dbuf_attach->priv = attach; 418 419 return 0; 420} 421 422static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, 423 struct dma_buf_attachment *db_attach) 424{ 425 struct vb2_dma_sg_attachment *attach = db_attach->priv; 426 struct sg_table *sgt; 427 428 if (!attach) 429 return; 430 431 sgt = &attach->sgt; 432 433 /* release the scatterlist cache */ 434 if (attach->dma_dir != DMA_NONE) 435 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 436 attach->dma_dir); 437 sg_free_table(sgt); 438 kfree(attach); 439 db_attach->priv = NULL; 440} 441 442static struct sg_table *vb2_dma_sg_dmabuf_ops_map( 443 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 444{ 445 struct vb2_dma_sg_attachment *attach = db_attach->priv; 446 /* stealing dmabuf mutex to serialize map/unmap operations */ 447 struct mutex *lock = &db_attach->dmabuf->lock; 448 struct sg_table *sgt; 449 450 mutex_lock(lock); 451 452 sgt = &attach->sgt; 453 /* return previously mapped sg table */ 454 if (attach->dma_dir == dma_dir) { 455 mutex_unlock(lock); 456 return sgt; 457 } 458 459 /* release any previous cache */ 460 if (attach->dma_dir != DMA_NONE) { 461 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 462 attach->dma_dir); 463 attach->dma_dir = DMA_NONE; 464 } 465 466 /* mapping to the client with new direction */ 467 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 468 dma_dir); 469 if (!sgt->nents) { 470 pr_err("failed to map scatterlist\n"); 471 mutex_unlock(lock); 472 return ERR_PTR(-EIO); 473 } 474 475 attach->dma_dir = dma_dir; 476 477 mutex_unlock(lock); 478 479 return sgt; 480} 481 482static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, 483 struct sg_table *sgt, enum dma_data_direction dma_dir) 484{ 485 /* nothing to be done here */ 486} 487 488static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) 489{ 490 /* drop reference obtained in vb2_dma_sg_get_dmabuf */ 491 vb2_dma_sg_put(dbuf->priv); 492} 493 494static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum) 495{ 496 struct vb2_dma_sg_buf *buf = dbuf->priv; 497 498 return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL; 499} 500 501static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) 502{ 503 struct vb2_dma_sg_buf *buf = dbuf->priv; 504 505 return vb2_dma_sg_vaddr(buf); 506} 507 508static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, 509 struct vm_area_struct *vma) 510{ 511 return vb2_dma_sg_mmap(dbuf->priv, vma); 512} 513 514static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { 515 .attach = vb2_dma_sg_dmabuf_ops_attach, 516 .detach = vb2_dma_sg_dmabuf_ops_detach, 517 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, 518 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, 519 .kmap = vb2_dma_sg_dmabuf_ops_kmap, 520 .kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap, 521 .vmap = vb2_dma_sg_dmabuf_ops_vmap, 522 .mmap = vb2_dma_sg_dmabuf_ops_mmap, 523 .release = vb2_dma_sg_dmabuf_ops_release, 524}; 525 526static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags) 527{ 528 struct vb2_dma_sg_buf *buf = buf_priv; 529 struct dma_buf *dbuf; 530 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 531 532 exp_info.ops = &vb2_dma_sg_dmabuf_ops; 533 exp_info.size = buf->size; 534 exp_info.flags = flags; 535 exp_info.priv = buf; 536 537 if (WARN_ON(!buf->dma_sgt)) 538 return NULL; 539 540 dbuf = dma_buf_export(&exp_info); 541 if (IS_ERR(dbuf)) 542 return NULL; 543 544 /* dmabuf keeps reference to vb2 buffer */ 545 atomic_inc(&buf->refcount); 546 547 return dbuf; 548} 549 550/*********************************************/ 551/* callbacks for DMABUF buffers */ 552/*********************************************/ 553 554static int vb2_dma_sg_map_dmabuf(void *mem_priv) 555{ 556 struct vb2_dma_sg_buf *buf = mem_priv; 557 struct sg_table *sgt; 558 559 if (WARN_ON(!buf->db_attach)) { 560 pr_err("trying to pin a non attached buffer\n"); 561 return -EINVAL; 562 } 563 564 if (WARN_ON(buf->dma_sgt)) { 565 pr_err("dmabuf buffer is already pinned\n"); 566 return 0; 567 } 568 569 /* get the associated scatterlist for this buffer */ 570 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); 571 if (IS_ERR(sgt)) { 572 pr_err("Error getting dmabuf scatterlist\n"); 573 return -EINVAL; 574 } 575 576 buf->dma_sgt = sgt; 577 buf->vaddr = NULL; 578 579 return 0; 580} 581 582static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) 583{ 584 struct vb2_dma_sg_buf *buf = mem_priv; 585 struct sg_table *sgt = buf->dma_sgt; 586 587 if (WARN_ON(!buf->db_attach)) { 588 pr_err("trying to unpin a not attached buffer\n"); 589 return; 590 } 591 592 if (WARN_ON(!sgt)) { 593 pr_err("dmabuf buffer is already unpinned\n"); 594 return; 595 } 596 597 if (buf->vaddr) { 598 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr); 599 buf->vaddr = NULL; 600 } 601 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); 602 603 buf->dma_sgt = NULL; 604} 605 606static void vb2_dma_sg_detach_dmabuf(void *mem_priv) 607{ 608 struct vb2_dma_sg_buf *buf = mem_priv; 609 610 /* if vb2 works correctly you should never detach mapped buffer */ 611 if (WARN_ON(buf->dma_sgt)) 612 vb2_dma_sg_unmap_dmabuf(buf); 613 614 /* detach this attachment */ 615 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); 616 kfree(buf); 617} 618 619static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf, 620 unsigned long size, enum dma_data_direction dma_dir) 621{ 622 struct vb2_dma_sg_conf *conf = alloc_ctx; 623 struct vb2_dma_sg_buf *buf; 624 struct dma_buf_attachment *dba; 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 = conf->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 649static 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 656const 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}; 673EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); 674 675void *vb2_dma_sg_init_ctx(struct device *dev) 676{ 677 struct vb2_dma_sg_conf *conf; 678 679 conf = kzalloc(sizeof(*conf), GFP_KERNEL); 680 if (!conf) 681 return ERR_PTR(-ENOMEM); 682 683 conf->dev = dev; 684 685 return conf; 686} 687EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx); 688 689void vb2_dma_sg_cleanup_ctx(void *alloc_ctx) 690{ 691 if (!IS_ERR_OR_NULL(alloc_ctx)) 692 kfree(alloc_ctx); 693} 694EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx); 695 696MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); 697MODULE_AUTHOR("Andrzej Pietrasiewicz"); 698MODULE_LICENSE("GPL"); 699