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 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 /* 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 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 int err; 332 333 if (!buf) { 334 printk(KERN_ERR "No memory to map\n"); 335 return -EINVAL; 336 } 337 338 err = vm_map_pages(vma, buf->pages, buf->num_pages); 339 if (err) { 340 printk(KERN_ERR "Remapping memory, error: %d\n", err); 341 return err; 342 } 343 344 /* 345 * Use common vm_area operations to track buffer refcount. 346 */ 347 vma->vm_private_data = &buf->handler; 348 vma->vm_ops = &vb2_common_vm_ops; 349 350 vma->vm_ops->open(vma); 351 352 return 0; 353 } 354 355 /*********************************************/ 356 /* DMABUF ops for exporters */ 357 /*********************************************/ 358 359 struct vb2_dma_sg_attachment { 360 struct sg_table sgt; 361 enum dma_data_direction dma_dir; 362 }; 363 364 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, 365 struct dma_buf_attachment *dbuf_attach) 366 { 367 struct vb2_dma_sg_attachment *attach; 368 unsigned int i; 369 struct scatterlist *rd, *wr; 370 struct sg_table *sgt; 371 struct vb2_dma_sg_buf *buf = dbuf->priv; 372 int ret; 373 374 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 375 if (!attach) 376 return -ENOMEM; 377 378 sgt = &attach->sgt; 379 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 380 * map the same scatter list to multiple attachments at the same time. 381 */ 382 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); 383 if (ret) { 384 kfree(attach); 385 return -ENOMEM; 386 } 387 388 rd = buf->dma_sgt->sgl; 389 wr = sgt->sgl; 390 for (i = 0; i < sgt->orig_nents; ++i) { 391 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 392 rd = sg_next(rd); 393 wr = sg_next(wr); 394 } 395 396 attach->dma_dir = DMA_NONE; 397 dbuf_attach->priv = attach; 398 399 return 0; 400 } 401 402 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, 403 struct dma_buf_attachment *db_attach) 404 { 405 struct vb2_dma_sg_attachment *attach = db_attach->priv; 406 struct sg_table *sgt; 407 408 if (!attach) 409 return; 410 411 sgt = &attach->sgt; 412 413 /* release the scatterlist cache */ 414 if (attach->dma_dir != DMA_NONE) 415 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 416 attach->dma_dir); 417 sg_free_table(sgt); 418 kfree(attach); 419 db_attach->priv = NULL; 420 } 421 422 static struct sg_table *vb2_dma_sg_dmabuf_ops_map( 423 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 424 { 425 struct vb2_dma_sg_attachment *attach = db_attach->priv; 426 /* stealing dmabuf mutex to serialize map/unmap operations */ 427 struct mutex *lock = &db_attach->dmabuf->lock; 428 struct sg_table *sgt; 429 430 mutex_lock(lock); 431 432 sgt = &attach->sgt; 433 /* return previously mapped sg table */ 434 if (attach->dma_dir == dma_dir) { 435 mutex_unlock(lock); 436 return sgt; 437 } 438 439 /* release any previous cache */ 440 if (attach->dma_dir != DMA_NONE) { 441 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 442 attach->dma_dir); 443 attach->dma_dir = DMA_NONE; 444 } 445 446 /* mapping to the client with new direction */ 447 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 448 dma_dir); 449 if (!sgt->nents) { 450 pr_err("failed to map scatterlist\n"); 451 mutex_unlock(lock); 452 return ERR_PTR(-EIO); 453 } 454 455 attach->dma_dir = dma_dir; 456 457 mutex_unlock(lock); 458 459 return sgt; 460 } 461 462 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, 463 struct sg_table *sgt, enum dma_data_direction dma_dir) 464 { 465 /* nothing to be done here */ 466 } 467 468 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) 469 { 470 /* drop reference obtained in vb2_dma_sg_get_dmabuf */ 471 vb2_dma_sg_put(dbuf->priv); 472 } 473 474 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum) 475 { 476 struct vb2_dma_sg_buf *buf = dbuf->priv; 477 478 return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL; 479 } 480 481 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) 482 { 483 struct vb2_dma_sg_buf *buf = dbuf->priv; 484 485 return vb2_dma_sg_vaddr(buf); 486 } 487 488 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, 489 struct vm_area_struct *vma) 490 { 491 return vb2_dma_sg_mmap(dbuf->priv, vma); 492 } 493 494 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { 495 .attach = vb2_dma_sg_dmabuf_ops_attach, 496 .detach = vb2_dma_sg_dmabuf_ops_detach, 497 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, 498 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, 499 .map = vb2_dma_sg_dmabuf_ops_kmap, 500 .vmap = vb2_dma_sg_dmabuf_ops_vmap, 501 .mmap = vb2_dma_sg_dmabuf_ops_mmap, 502 .release = vb2_dma_sg_dmabuf_ops_release, 503 }; 504 505 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags) 506 { 507 struct vb2_dma_sg_buf *buf = buf_priv; 508 struct dma_buf *dbuf; 509 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 510 511 exp_info.ops = &vb2_dma_sg_dmabuf_ops; 512 exp_info.size = buf->size; 513 exp_info.flags = flags; 514 exp_info.priv = buf; 515 516 if (WARN_ON(!buf->dma_sgt)) 517 return NULL; 518 519 dbuf = dma_buf_export(&exp_info); 520 if (IS_ERR(dbuf)) 521 return NULL; 522 523 /* dmabuf keeps reference to vb2 buffer */ 524 refcount_inc(&buf->refcount); 525 526 return dbuf; 527 } 528 529 /*********************************************/ 530 /* callbacks for DMABUF buffers */ 531 /*********************************************/ 532 533 static int vb2_dma_sg_map_dmabuf(void *mem_priv) 534 { 535 struct vb2_dma_sg_buf *buf = mem_priv; 536 struct sg_table *sgt; 537 538 if (WARN_ON(!buf->db_attach)) { 539 pr_err("trying to pin a non attached buffer\n"); 540 return -EINVAL; 541 } 542 543 if (WARN_ON(buf->dma_sgt)) { 544 pr_err("dmabuf buffer is already pinned\n"); 545 return 0; 546 } 547 548 /* get the associated scatterlist for this buffer */ 549 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); 550 if (IS_ERR(sgt)) { 551 pr_err("Error getting dmabuf scatterlist\n"); 552 return -EINVAL; 553 } 554 555 buf->dma_sgt = sgt; 556 buf->vaddr = NULL; 557 558 return 0; 559 } 560 561 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) 562 { 563 struct vb2_dma_sg_buf *buf = mem_priv; 564 struct sg_table *sgt = buf->dma_sgt; 565 566 if (WARN_ON(!buf->db_attach)) { 567 pr_err("trying to unpin a not attached buffer\n"); 568 return; 569 } 570 571 if (WARN_ON(!sgt)) { 572 pr_err("dmabuf buffer is already unpinned\n"); 573 return; 574 } 575 576 if (buf->vaddr) { 577 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr); 578 buf->vaddr = NULL; 579 } 580 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); 581 582 buf->dma_sgt = NULL; 583 } 584 585 static void vb2_dma_sg_detach_dmabuf(void *mem_priv) 586 { 587 struct vb2_dma_sg_buf *buf = mem_priv; 588 589 /* if vb2 works correctly you should never detach mapped buffer */ 590 if (WARN_ON(buf->dma_sgt)) 591 vb2_dma_sg_unmap_dmabuf(buf); 592 593 /* detach this attachment */ 594 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); 595 kfree(buf); 596 } 597 598 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf, 599 unsigned long size, enum dma_data_direction dma_dir) 600 { 601 struct vb2_dma_sg_buf *buf; 602 struct dma_buf_attachment *dba; 603 604 if (WARN_ON(!dev)) 605 return ERR_PTR(-EINVAL); 606 607 if (dbuf->size < size) 608 return ERR_PTR(-EFAULT); 609 610 buf = kzalloc(sizeof(*buf), GFP_KERNEL); 611 if (!buf) 612 return ERR_PTR(-ENOMEM); 613 614 buf->dev = dev; 615 /* create attachment for the dmabuf with the user device */ 616 dba = dma_buf_attach(dbuf, buf->dev); 617 if (IS_ERR(dba)) { 618 pr_err("failed to attach dmabuf\n"); 619 kfree(buf); 620 return dba; 621 } 622 623 buf->dma_dir = dma_dir; 624 buf->size = size; 625 buf->db_attach = dba; 626 627 return buf; 628 } 629 630 static void *vb2_dma_sg_cookie(void *buf_priv) 631 { 632 struct vb2_dma_sg_buf *buf = buf_priv; 633 634 return buf->dma_sgt; 635 } 636 637 const struct vb2_mem_ops vb2_dma_sg_memops = { 638 .alloc = vb2_dma_sg_alloc, 639 .put = vb2_dma_sg_put, 640 .get_userptr = vb2_dma_sg_get_userptr, 641 .put_userptr = vb2_dma_sg_put_userptr, 642 .prepare = vb2_dma_sg_prepare, 643 .finish = vb2_dma_sg_finish, 644 .vaddr = vb2_dma_sg_vaddr, 645 .mmap = vb2_dma_sg_mmap, 646 .num_users = vb2_dma_sg_num_users, 647 .get_dmabuf = vb2_dma_sg_get_dmabuf, 648 .map_dmabuf = vb2_dma_sg_map_dmabuf, 649 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf, 650 .attach_dmabuf = vb2_dma_sg_attach_dmabuf, 651 .detach_dmabuf = vb2_dma_sg_detach_dmabuf, 652 .cookie = vb2_dma_sg_cookie, 653 }; 654 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); 655 656 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); 657 MODULE_AUTHOR("Andrzej Pietrasiewicz"); 658 MODULE_LICENSE("GPL"); 659