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; 298 299 BUG_ON(!buf); 300 301 if (!buf->vaddr) { 302 if (buf->db_attach) 303 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf); 304 else 305 buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1); 306 } 307 308 /* add offset in case userptr is not page-aligned */ 309 return buf->vaddr ? buf->vaddr + buf->offset : NULL; 310 } 311 312 static unsigned int vb2_dma_sg_num_users(void *buf_priv) 313 { 314 struct vb2_dma_sg_buf *buf = buf_priv; 315 316 return refcount_read(&buf->refcount); 317 } 318 319 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) 320 { 321 struct vb2_dma_sg_buf *buf = buf_priv; 322 int err; 323 324 if (!buf) { 325 printk(KERN_ERR "No memory to map\n"); 326 return -EINVAL; 327 } 328 329 err = vm_map_pages(vma, buf->pages, buf->num_pages); 330 if (err) { 331 printk(KERN_ERR "Remapping memory, error: %d\n", err); 332 return err; 333 } 334 335 /* 336 * Use common vm_area operations to track buffer refcount. 337 */ 338 vma->vm_private_data = &buf->handler; 339 vma->vm_ops = &vb2_common_vm_ops; 340 341 vma->vm_ops->open(vma); 342 343 return 0; 344 } 345 346 /*********************************************/ 347 /* DMABUF ops for exporters */ 348 /*********************************************/ 349 350 struct vb2_dma_sg_attachment { 351 struct sg_table sgt; 352 enum dma_data_direction dma_dir; 353 }; 354 355 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, 356 struct dma_buf_attachment *dbuf_attach) 357 { 358 struct vb2_dma_sg_attachment *attach; 359 unsigned int i; 360 struct scatterlist *rd, *wr; 361 struct sg_table *sgt; 362 struct vb2_dma_sg_buf *buf = dbuf->priv; 363 int ret; 364 365 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 366 if (!attach) 367 return -ENOMEM; 368 369 sgt = &attach->sgt; 370 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 371 * map the same scatter list to multiple attachments at the same time. 372 */ 373 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); 374 if (ret) { 375 kfree(attach); 376 return -ENOMEM; 377 } 378 379 rd = buf->dma_sgt->sgl; 380 wr = sgt->sgl; 381 for (i = 0; i < sgt->orig_nents; ++i) { 382 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 383 rd = sg_next(rd); 384 wr = sg_next(wr); 385 } 386 387 attach->dma_dir = DMA_NONE; 388 dbuf_attach->priv = attach; 389 390 return 0; 391 } 392 393 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, 394 struct dma_buf_attachment *db_attach) 395 { 396 struct vb2_dma_sg_attachment *attach = db_attach->priv; 397 struct sg_table *sgt; 398 399 if (!attach) 400 return; 401 402 sgt = &attach->sgt; 403 404 /* release the scatterlist cache */ 405 if (attach->dma_dir != DMA_NONE) 406 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0); 407 sg_free_table(sgt); 408 kfree(attach); 409 db_attach->priv = NULL; 410 } 411 412 static struct sg_table *vb2_dma_sg_dmabuf_ops_map( 413 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 414 { 415 struct vb2_dma_sg_attachment *attach = db_attach->priv; 416 /* stealing dmabuf mutex to serialize map/unmap operations */ 417 struct mutex *lock = &db_attach->dmabuf->lock; 418 struct sg_table *sgt; 419 420 mutex_lock(lock); 421 422 sgt = &attach->sgt; 423 /* return previously mapped sg table */ 424 if (attach->dma_dir == dma_dir) { 425 mutex_unlock(lock); 426 return sgt; 427 } 428 429 /* release any previous cache */ 430 if (attach->dma_dir != DMA_NONE) { 431 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0); 432 attach->dma_dir = DMA_NONE; 433 } 434 435 /* mapping to the client with new direction */ 436 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) { 437 pr_err("failed to map scatterlist\n"); 438 mutex_unlock(lock); 439 return ERR_PTR(-EIO); 440 } 441 442 attach->dma_dir = dma_dir; 443 444 mutex_unlock(lock); 445 446 return sgt; 447 } 448 449 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, 450 struct sg_table *sgt, enum dma_data_direction dma_dir) 451 { 452 /* nothing to be done here */ 453 } 454 455 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) 456 { 457 /* drop reference obtained in vb2_dma_sg_get_dmabuf */ 458 vb2_dma_sg_put(dbuf->priv); 459 } 460 461 static int 462 vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, 463 enum dma_data_direction direction) 464 { 465 struct vb2_dma_sg_buf *buf = dbuf->priv; 466 struct sg_table *sgt = buf->dma_sgt; 467 468 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); 469 return 0; 470 } 471 472 static int 473 vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, 474 enum dma_data_direction direction) 475 { 476 struct vb2_dma_sg_buf *buf = dbuf->priv; 477 struct sg_table *sgt = buf->dma_sgt; 478 479 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); 480 return 0; 481 } 482 483 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) 484 { 485 struct vb2_dma_sg_buf *buf = dbuf->priv; 486 487 return vb2_dma_sg_vaddr(buf); 488 } 489 490 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, 491 struct vm_area_struct *vma) 492 { 493 return vb2_dma_sg_mmap(dbuf->priv, vma); 494 } 495 496 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { 497 .attach = vb2_dma_sg_dmabuf_ops_attach, 498 .detach = vb2_dma_sg_dmabuf_ops_detach, 499 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, 500 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, 501 .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access, 502 .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access, 503 .vmap = vb2_dma_sg_dmabuf_ops_vmap, 504 .mmap = vb2_dma_sg_dmabuf_ops_mmap, 505 .release = vb2_dma_sg_dmabuf_ops_release, 506 }; 507 508 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags) 509 { 510 struct vb2_dma_sg_buf *buf = buf_priv; 511 struct dma_buf *dbuf; 512 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 513 514 exp_info.ops = &vb2_dma_sg_dmabuf_ops; 515 exp_info.size = buf->size; 516 exp_info.flags = flags; 517 exp_info.priv = buf; 518 519 if (WARN_ON(!buf->dma_sgt)) 520 return NULL; 521 522 dbuf = dma_buf_export(&exp_info); 523 if (IS_ERR(dbuf)) 524 return NULL; 525 526 /* dmabuf keeps reference to vb2 buffer */ 527 refcount_inc(&buf->refcount); 528 529 return dbuf; 530 } 531 532 /*********************************************/ 533 /* callbacks for DMABUF buffers */ 534 /*********************************************/ 535 536 static int vb2_dma_sg_map_dmabuf(void *mem_priv) 537 { 538 struct vb2_dma_sg_buf *buf = mem_priv; 539 struct sg_table *sgt; 540 541 if (WARN_ON(!buf->db_attach)) { 542 pr_err("trying to pin a non attached buffer\n"); 543 return -EINVAL; 544 } 545 546 if (WARN_ON(buf->dma_sgt)) { 547 pr_err("dmabuf buffer is already pinned\n"); 548 return 0; 549 } 550 551 /* get the associated scatterlist for this buffer */ 552 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); 553 if (IS_ERR(sgt)) { 554 pr_err("Error getting dmabuf scatterlist\n"); 555 return -EINVAL; 556 } 557 558 buf->dma_sgt = sgt; 559 buf->vaddr = NULL; 560 561 return 0; 562 } 563 564 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) 565 { 566 struct vb2_dma_sg_buf *buf = mem_priv; 567 struct sg_table *sgt = buf->dma_sgt; 568 569 if (WARN_ON(!buf->db_attach)) { 570 pr_err("trying to unpin a not attached buffer\n"); 571 return; 572 } 573 574 if (WARN_ON(!sgt)) { 575 pr_err("dmabuf buffer is already unpinned\n"); 576 return; 577 } 578 579 if (buf->vaddr) { 580 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr); 581 buf->vaddr = NULL; 582 } 583 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); 584 585 buf->dma_sgt = NULL; 586 } 587 588 static void vb2_dma_sg_detach_dmabuf(void *mem_priv) 589 { 590 struct vb2_dma_sg_buf *buf = mem_priv; 591 592 /* if vb2 works correctly you should never detach mapped buffer */ 593 if (WARN_ON(buf->dma_sgt)) 594 vb2_dma_sg_unmap_dmabuf(buf); 595 596 /* detach this attachment */ 597 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); 598 kfree(buf); 599 } 600 601 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf, 602 unsigned long size, enum dma_data_direction dma_dir) 603 { 604 struct vb2_dma_sg_buf *buf; 605 struct dma_buf_attachment *dba; 606 607 if (WARN_ON(!dev)) 608 return ERR_PTR(-EINVAL); 609 610 if (dbuf->size < size) 611 return ERR_PTR(-EFAULT); 612 613 buf = kzalloc(sizeof(*buf), GFP_KERNEL); 614 if (!buf) 615 return ERR_PTR(-ENOMEM); 616 617 buf->dev = dev; 618 /* create attachment for the dmabuf with the user device */ 619 dba = dma_buf_attach(dbuf, buf->dev); 620 if (IS_ERR(dba)) { 621 pr_err("failed to attach dmabuf\n"); 622 kfree(buf); 623 return dba; 624 } 625 626 buf->dma_dir = dma_dir; 627 buf->size = size; 628 buf->db_attach = dba; 629 630 return buf; 631 } 632 633 static void *vb2_dma_sg_cookie(void *buf_priv) 634 { 635 struct vb2_dma_sg_buf *buf = buf_priv; 636 637 return buf->dma_sgt; 638 } 639 640 const struct vb2_mem_ops vb2_dma_sg_memops = { 641 .alloc = vb2_dma_sg_alloc, 642 .put = vb2_dma_sg_put, 643 .get_userptr = vb2_dma_sg_get_userptr, 644 .put_userptr = vb2_dma_sg_put_userptr, 645 .prepare = vb2_dma_sg_prepare, 646 .finish = vb2_dma_sg_finish, 647 .vaddr = vb2_dma_sg_vaddr, 648 .mmap = vb2_dma_sg_mmap, 649 .num_users = vb2_dma_sg_num_users, 650 .get_dmabuf = vb2_dma_sg_get_dmabuf, 651 .map_dmabuf = vb2_dma_sg_map_dmabuf, 652 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf, 653 .attach_dmabuf = vb2_dma_sg_attach_dmabuf, 654 .detach_dmabuf = vb2_dma_sg_detach_dmabuf, 655 .cookie = vb2_dma_sg_cookie, 656 }; 657 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); 658 659 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); 660 MODULE_AUTHOR("Andrzej Pietrasiewicz"); 661 MODULE_LICENSE("GPL"); 662