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/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 int 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 /* Dont 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 buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *), 124 GFP_KERNEL | __GFP_ZERO); 125 if (!buf->pages) 126 goto fail_pages_array_alloc; 127 128 ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags); 129 if (ret) 130 goto fail_pages_alloc; 131 132 ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, 133 buf->num_pages, 0, size, GFP_KERNEL); 134 if (ret) 135 goto fail_table_alloc; 136 137 /* Prevent the device from being released while the buffer is used */ 138 buf->dev = get_device(dev); 139 140 sgt = &buf->sg_table; 141 /* 142 * No need to sync to the device, this will happen later when the 143 * prepare() memop is called. 144 */ 145 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 146 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 147 if (!sgt->nents) 148 goto fail_map; 149 150 buf->handler.refcount = &buf->refcount; 151 buf->handler.put = vb2_dma_sg_put; 152 buf->handler.arg = buf; 153 154 refcount_set(&buf->refcount, 1); 155 156 dprintk(1, "%s: Allocated buffer of %d pages\n", 157 __func__, buf->num_pages); 158 return buf; 159 160 fail_map: 161 put_device(buf->dev); 162 sg_free_table(buf->dma_sgt); 163 fail_table_alloc: 164 num_pages = buf->num_pages; 165 while (num_pages--) 166 __free_page(buf->pages[num_pages]); 167 fail_pages_alloc: 168 kvfree(buf->pages); 169 fail_pages_array_alloc: 170 kfree(buf); 171 return ERR_PTR(-ENOMEM); 172 } 173 174 static void vb2_dma_sg_put(void *buf_priv) 175 { 176 struct vb2_dma_sg_buf *buf = buf_priv; 177 struct sg_table *sgt = &buf->sg_table; 178 int i = buf->num_pages; 179 180 if (refcount_dec_and_test(&buf->refcount)) { 181 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__, 182 buf->num_pages); 183 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 184 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 185 if (buf->vaddr) 186 vm_unmap_ram(buf->vaddr, buf->num_pages); 187 sg_free_table(buf->dma_sgt); 188 while (--i >= 0) 189 __free_page(buf->pages[i]); 190 kvfree(buf->pages); 191 put_device(buf->dev); 192 kfree(buf); 193 } 194 } 195 196 static void vb2_dma_sg_prepare(void *buf_priv) 197 { 198 struct vb2_dma_sg_buf *buf = buf_priv; 199 struct sg_table *sgt = buf->dma_sgt; 200 201 /* DMABUF exporter will flush the cache for us */ 202 if (buf->db_attach) 203 return; 204 205 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents, 206 buf->dma_dir); 207 } 208 209 static void vb2_dma_sg_finish(void *buf_priv) 210 { 211 struct vb2_dma_sg_buf *buf = buf_priv; 212 struct sg_table *sgt = buf->dma_sgt; 213 214 /* DMABUF exporter will flush the cache for us */ 215 if (buf->db_attach) 216 return; 217 218 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir); 219 } 220 221 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr, 222 unsigned long size, 223 enum dma_data_direction dma_dir) 224 { 225 struct vb2_dma_sg_buf *buf; 226 struct sg_table *sgt; 227 struct frame_vector *vec; 228 229 if (WARN_ON(!dev)) 230 return ERR_PTR(-EINVAL); 231 232 buf = kzalloc(sizeof *buf, GFP_KERNEL); 233 if (!buf) 234 return ERR_PTR(-ENOMEM); 235 236 buf->vaddr = NULL; 237 buf->dev = dev; 238 buf->dma_dir = dma_dir; 239 buf->offset = vaddr & ~PAGE_MASK; 240 buf->size = size; 241 buf->dma_sgt = &buf->sg_table; 242 vec = vb2_create_framevec(vaddr, size, dma_dir == DMA_FROM_DEVICE || 243 dma_dir == DMA_BIDIRECTIONAL); 244 if (IS_ERR(vec)) 245 goto userptr_fail_pfnvec; 246 buf->vec = vec; 247 248 buf->pages = frame_vector_pages(vec); 249 if (IS_ERR(buf->pages)) 250 goto userptr_fail_sgtable; 251 buf->num_pages = frame_vector_count(vec); 252 253 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, 254 buf->num_pages, buf->offset, size, 0)) 255 goto userptr_fail_sgtable; 256 257 sgt = &buf->sg_table; 258 /* 259 * No need to sync to the device, this will happen later when the 260 * prepare() memop is called. 261 */ 262 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 263 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 264 if (!sgt->nents) 265 goto userptr_fail_map; 266 267 return buf; 268 269 userptr_fail_map: 270 sg_free_table(&buf->sg_table); 271 userptr_fail_sgtable: 272 vb2_destroy_framevec(vec); 273 userptr_fail_pfnvec: 274 kfree(buf); 275 return ERR_PTR(-ENOMEM); 276 } 277 278 /* 279 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 280 * be used 281 */ 282 static void vb2_dma_sg_put_userptr(void *buf_priv) 283 { 284 struct vb2_dma_sg_buf *buf = buf_priv; 285 struct sg_table *sgt = &buf->sg_table; 286 int i = buf->num_pages; 287 288 dprintk(1, "%s: Releasing userspace buffer of %d pages\n", 289 __func__, buf->num_pages); 290 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir, 291 DMA_ATTR_SKIP_CPU_SYNC); 292 if (buf->vaddr) 293 vm_unmap_ram(buf->vaddr, buf->num_pages); 294 sg_free_table(buf->dma_sgt); 295 if (buf->dma_dir == DMA_FROM_DEVICE || 296 buf->dma_dir == DMA_BIDIRECTIONAL) 297 while (--i >= 0) 298 set_page_dirty_lock(buf->pages[i]); 299 vb2_destroy_framevec(buf->vec); 300 kfree(buf); 301 } 302 303 static void *vb2_dma_sg_vaddr(void *buf_priv) 304 { 305 struct vb2_dma_sg_buf *buf = buf_priv; 306 307 BUG_ON(!buf); 308 309 if (!buf->vaddr) { 310 if (buf->db_attach) 311 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf); 312 else 313 buf->vaddr = vm_map_ram(buf->pages, 314 buf->num_pages, -1, PAGE_KERNEL); 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 unsigned long uaddr = vma->vm_start; 332 unsigned long usize = vma->vm_end - vma->vm_start; 333 int i = 0; 334 335 if (!buf) { 336 printk(KERN_ERR "No memory to map\n"); 337 return -EINVAL; 338 } 339 340 do { 341 int ret; 342 343 ret = vm_insert_page(vma, uaddr, buf->pages[i++]); 344 if (ret) { 345 printk(KERN_ERR "Remapping memory, error: %d\n", ret); 346 return ret; 347 } 348 349 uaddr += PAGE_SIZE; 350 usize -= PAGE_SIZE; 351 } while (usize > 0); 352 353 354 /* 355 * Use common vm_area operations to track buffer refcount. 356 */ 357 vma->vm_private_data = &buf->handler; 358 vma->vm_ops = &vb2_common_vm_ops; 359 360 vma->vm_ops->open(vma); 361 362 return 0; 363 } 364 365 /*********************************************/ 366 /* DMABUF ops for exporters */ 367 /*********************************************/ 368 369 struct vb2_dma_sg_attachment { 370 struct sg_table sgt; 371 enum dma_data_direction dma_dir; 372 }; 373 374 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, 375 struct dma_buf_attachment *dbuf_attach) 376 { 377 struct vb2_dma_sg_attachment *attach; 378 unsigned int i; 379 struct scatterlist *rd, *wr; 380 struct sg_table *sgt; 381 struct vb2_dma_sg_buf *buf = dbuf->priv; 382 int ret; 383 384 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 385 if (!attach) 386 return -ENOMEM; 387 388 sgt = &attach->sgt; 389 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 390 * map the same scatter list to multiple attachments at the same time. 391 */ 392 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); 393 if (ret) { 394 kfree(attach); 395 return -ENOMEM; 396 } 397 398 rd = buf->dma_sgt->sgl; 399 wr = sgt->sgl; 400 for (i = 0; i < sgt->orig_nents; ++i) { 401 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 402 rd = sg_next(rd); 403 wr = sg_next(wr); 404 } 405 406 attach->dma_dir = DMA_NONE; 407 dbuf_attach->priv = attach; 408 409 return 0; 410 } 411 412 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, 413 struct dma_buf_attachment *db_attach) 414 { 415 struct vb2_dma_sg_attachment *attach = db_attach->priv; 416 struct sg_table *sgt; 417 418 if (!attach) 419 return; 420 421 sgt = &attach->sgt; 422 423 /* release the scatterlist cache */ 424 if (attach->dma_dir != DMA_NONE) 425 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 426 attach->dma_dir); 427 sg_free_table(sgt); 428 kfree(attach); 429 db_attach->priv = NULL; 430 } 431 432 static struct sg_table *vb2_dma_sg_dmabuf_ops_map( 433 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 434 { 435 struct vb2_dma_sg_attachment *attach = db_attach->priv; 436 /* stealing dmabuf mutex to serialize map/unmap operations */ 437 struct mutex *lock = &db_attach->dmabuf->lock; 438 struct sg_table *sgt; 439 440 mutex_lock(lock); 441 442 sgt = &attach->sgt; 443 /* return previously mapped sg table */ 444 if (attach->dma_dir == dma_dir) { 445 mutex_unlock(lock); 446 return sgt; 447 } 448 449 /* release any previous cache */ 450 if (attach->dma_dir != DMA_NONE) { 451 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 452 attach->dma_dir); 453 attach->dma_dir = DMA_NONE; 454 } 455 456 /* mapping to the client with new direction */ 457 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 458 dma_dir); 459 if (!sgt->nents) { 460 pr_err("failed to map scatterlist\n"); 461 mutex_unlock(lock); 462 return ERR_PTR(-EIO); 463 } 464 465 attach->dma_dir = dma_dir; 466 467 mutex_unlock(lock); 468 469 return sgt; 470 } 471 472 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, 473 struct sg_table *sgt, enum dma_data_direction dma_dir) 474 { 475 /* nothing to be done here */ 476 } 477 478 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) 479 { 480 /* drop reference obtained in vb2_dma_sg_get_dmabuf */ 481 vb2_dma_sg_put(dbuf->priv); 482 } 483 484 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum) 485 { 486 struct vb2_dma_sg_buf *buf = dbuf->priv; 487 488 return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL; 489 } 490 491 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) 492 { 493 struct vb2_dma_sg_buf *buf = dbuf->priv; 494 495 return vb2_dma_sg_vaddr(buf); 496 } 497 498 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, 499 struct vm_area_struct *vma) 500 { 501 return vb2_dma_sg_mmap(dbuf->priv, vma); 502 } 503 504 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { 505 .attach = vb2_dma_sg_dmabuf_ops_attach, 506 .detach = vb2_dma_sg_dmabuf_ops_detach, 507 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, 508 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, 509 .map = vb2_dma_sg_dmabuf_ops_kmap, 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(void *buf_priv, unsigned long flags) 516 { 517 struct vb2_dma_sg_buf *buf = buf_priv; 518 struct dma_buf *dbuf; 519 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 520 521 exp_info.ops = &vb2_dma_sg_dmabuf_ops; 522 exp_info.size = buf->size; 523 exp_info.flags = flags; 524 exp_info.priv = buf; 525 526 if (WARN_ON(!buf->dma_sgt)) 527 return NULL; 528 529 dbuf = dma_buf_export(&exp_info); 530 if (IS_ERR(dbuf)) 531 return NULL; 532 533 /* dmabuf keeps reference to vb2 buffer */ 534 refcount_inc(&buf->refcount); 535 536 return dbuf; 537 } 538 539 /*********************************************/ 540 /* callbacks for DMABUF buffers */ 541 /*********************************************/ 542 543 static int vb2_dma_sg_map_dmabuf(void *mem_priv) 544 { 545 struct vb2_dma_sg_buf *buf = mem_priv; 546 struct sg_table *sgt; 547 548 if (WARN_ON(!buf->db_attach)) { 549 pr_err("trying to pin a non attached buffer\n"); 550 return -EINVAL; 551 } 552 553 if (WARN_ON(buf->dma_sgt)) { 554 pr_err("dmabuf buffer is already pinned\n"); 555 return 0; 556 } 557 558 /* get the associated scatterlist for this buffer */ 559 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); 560 if (IS_ERR(sgt)) { 561 pr_err("Error getting dmabuf scatterlist\n"); 562 return -EINVAL; 563 } 564 565 buf->dma_sgt = sgt; 566 buf->vaddr = NULL; 567 568 return 0; 569 } 570 571 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) 572 { 573 struct vb2_dma_sg_buf *buf = mem_priv; 574 struct sg_table *sgt = buf->dma_sgt; 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, buf->vaddr); 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