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 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); 243 if (IS_ERR(vec)) 244 goto userptr_fail_pfnvec; 245 buf->vec = vec; 246 247 buf->pages = frame_vector_pages(vec); 248 if (IS_ERR(buf->pages)) 249 goto userptr_fail_sgtable; 250 buf->num_pages = frame_vector_count(vec); 251 252 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, 253 buf->num_pages, buf->offset, size, 0)) 254 goto userptr_fail_sgtable; 255 256 sgt = &buf->sg_table; 257 /* 258 * No need to sync to the device, this will happen later when the 259 * prepare() memop is called. 260 */ 261 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, 262 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 263 if (!sgt->nents) 264 goto userptr_fail_map; 265 266 return buf; 267 268 userptr_fail_map: 269 sg_free_table(&buf->sg_table); 270 userptr_fail_sgtable: 271 vb2_destroy_framevec(vec); 272 userptr_fail_pfnvec: 273 kfree(buf); 274 return ERR_PTR(-ENOMEM); 275 } 276 277 /* 278 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 279 * be used 280 */ 281 static void vb2_dma_sg_put_userptr(void *buf_priv) 282 { 283 struct vb2_dma_sg_buf *buf = buf_priv; 284 struct sg_table *sgt = &buf->sg_table; 285 int i = buf->num_pages; 286 287 dprintk(1, "%s: Releasing userspace buffer of %d pages\n", 288 __func__, buf->num_pages); 289 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir, 290 DMA_ATTR_SKIP_CPU_SYNC); 291 if (buf->vaddr) 292 vm_unmap_ram(buf->vaddr, buf->num_pages); 293 sg_free_table(buf->dma_sgt); 294 if (buf->dma_dir == DMA_FROM_DEVICE || 295 buf->dma_dir == DMA_BIDIRECTIONAL) 296 while (--i >= 0) 297 set_page_dirty_lock(buf->pages[i]); 298 vb2_destroy_framevec(buf->vec); 299 kfree(buf); 300 } 301 302 static void *vb2_dma_sg_vaddr(void *buf_priv) 303 { 304 struct vb2_dma_sg_buf *buf = buf_priv; 305 306 BUG_ON(!buf); 307 308 if (!buf->vaddr) { 309 if (buf->db_attach) 310 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf); 311 else 312 buf->vaddr = vm_map_ram(buf->pages, 313 buf->num_pages, -1, PAGE_KERNEL); 314 } 315 316 /* add offset in case userptr is not page-aligned */ 317 return buf->vaddr ? buf->vaddr + buf->offset : NULL; 318 } 319 320 static unsigned int vb2_dma_sg_num_users(void *buf_priv) 321 { 322 struct vb2_dma_sg_buf *buf = buf_priv; 323 324 return refcount_read(&buf->refcount); 325 } 326 327 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) 328 { 329 struct vb2_dma_sg_buf *buf = buf_priv; 330 int err; 331 332 if (!buf) { 333 printk(KERN_ERR "No memory to map\n"); 334 return -EINVAL; 335 } 336 337 err = vm_map_pages(vma, buf->pages, buf->num_pages); 338 if (err) { 339 printk(KERN_ERR "Remapping memory, error: %d\n", err); 340 return err; 341 } 342 343 /* 344 * Use common vm_area operations to track buffer refcount. 345 */ 346 vma->vm_private_data = &buf->handler; 347 vma->vm_ops = &vb2_common_vm_ops; 348 349 vma->vm_ops->open(vma); 350 351 return 0; 352 } 353 354 /*********************************************/ 355 /* DMABUF ops for exporters */ 356 /*********************************************/ 357 358 struct vb2_dma_sg_attachment { 359 struct sg_table sgt; 360 enum dma_data_direction dma_dir; 361 }; 362 363 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, 364 struct dma_buf_attachment *dbuf_attach) 365 { 366 struct vb2_dma_sg_attachment *attach; 367 unsigned int i; 368 struct scatterlist *rd, *wr; 369 struct sg_table *sgt; 370 struct vb2_dma_sg_buf *buf = dbuf->priv; 371 int ret; 372 373 attach = kzalloc(sizeof(*attach), GFP_KERNEL); 374 if (!attach) 375 return -ENOMEM; 376 377 sgt = &attach->sgt; 378 /* Copy the buf->base_sgt scatter list to the attachment, as we can't 379 * map the same scatter list to multiple attachments at the same time. 380 */ 381 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); 382 if (ret) { 383 kfree(attach); 384 return -ENOMEM; 385 } 386 387 rd = buf->dma_sgt->sgl; 388 wr = sgt->sgl; 389 for (i = 0; i < sgt->orig_nents; ++i) { 390 sg_set_page(wr, sg_page(rd), rd->length, rd->offset); 391 rd = sg_next(rd); 392 wr = sg_next(wr); 393 } 394 395 attach->dma_dir = DMA_NONE; 396 dbuf_attach->priv = attach; 397 398 return 0; 399 } 400 401 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, 402 struct dma_buf_attachment *db_attach) 403 { 404 struct vb2_dma_sg_attachment *attach = db_attach->priv; 405 struct sg_table *sgt; 406 407 if (!attach) 408 return; 409 410 sgt = &attach->sgt; 411 412 /* release the scatterlist cache */ 413 if (attach->dma_dir != DMA_NONE) 414 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 415 attach->dma_dir); 416 sg_free_table(sgt); 417 kfree(attach); 418 db_attach->priv = NULL; 419 } 420 421 static struct sg_table *vb2_dma_sg_dmabuf_ops_map( 422 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) 423 { 424 struct vb2_dma_sg_attachment *attach = db_attach->priv; 425 /* stealing dmabuf mutex to serialize map/unmap operations */ 426 struct mutex *lock = &db_attach->dmabuf->lock; 427 struct sg_table *sgt; 428 429 mutex_lock(lock); 430 431 sgt = &attach->sgt; 432 /* return previously mapped sg table */ 433 if (attach->dma_dir == dma_dir) { 434 mutex_unlock(lock); 435 return sgt; 436 } 437 438 /* release any previous cache */ 439 if (attach->dma_dir != DMA_NONE) { 440 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 441 attach->dma_dir); 442 attach->dma_dir = DMA_NONE; 443 } 444 445 /* mapping to the client with new direction */ 446 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, 447 dma_dir); 448 if (!sgt->nents) { 449 pr_err("failed to map scatterlist\n"); 450 mutex_unlock(lock); 451 return ERR_PTR(-EIO); 452 } 453 454 attach->dma_dir = dma_dir; 455 456 mutex_unlock(lock); 457 458 return sgt; 459 } 460 461 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, 462 struct sg_table *sgt, enum dma_data_direction dma_dir) 463 { 464 /* nothing to be done here */ 465 } 466 467 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) 468 { 469 /* drop reference obtained in vb2_dma_sg_get_dmabuf */ 470 vb2_dma_sg_put(dbuf->priv); 471 } 472 473 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum) 474 { 475 struct vb2_dma_sg_buf *buf = dbuf->priv; 476 477 return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL; 478 } 479 480 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) 481 { 482 struct vb2_dma_sg_buf *buf = dbuf->priv; 483 484 return vb2_dma_sg_vaddr(buf); 485 } 486 487 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, 488 struct vm_area_struct *vma) 489 { 490 return vb2_dma_sg_mmap(dbuf->priv, vma); 491 } 492 493 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { 494 .attach = vb2_dma_sg_dmabuf_ops_attach, 495 .detach = vb2_dma_sg_dmabuf_ops_detach, 496 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, 497 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, 498 .map = vb2_dma_sg_dmabuf_ops_kmap, 499 .vmap = vb2_dma_sg_dmabuf_ops_vmap, 500 .mmap = vb2_dma_sg_dmabuf_ops_mmap, 501 .release = vb2_dma_sg_dmabuf_ops_release, 502 }; 503 504 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags) 505 { 506 struct vb2_dma_sg_buf *buf = buf_priv; 507 struct dma_buf *dbuf; 508 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 509 510 exp_info.ops = &vb2_dma_sg_dmabuf_ops; 511 exp_info.size = buf->size; 512 exp_info.flags = flags; 513 exp_info.priv = buf; 514 515 if (WARN_ON(!buf->dma_sgt)) 516 return NULL; 517 518 dbuf = dma_buf_export(&exp_info); 519 if (IS_ERR(dbuf)) 520 return NULL; 521 522 /* dmabuf keeps reference to vb2 buffer */ 523 refcount_inc(&buf->refcount); 524 525 return dbuf; 526 } 527 528 /*********************************************/ 529 /* callbacks for DMABUF buffers */ 530 /*********************************************/ 531 532 static int vb2_dma_sg_map_dmabuf(void *mem_priv) 533 { 534 struct vb2_dma_sg_buf *buf = mem_priv; 535 struct sg_table *sgt; 536 537 if (WARN_ON(!buf->db_attach)) { 538 pr_err("trying to pin a non attached buffer\n"); 539 return -EINVAL; 540 } 541 542 if (WARN_ON(buf->dma_sgt)) { 543 pr_err("dmabuf buffer is already pinned\n"); 544 return 0; 545 } 546 547 /* get the associated scatterlist for this buffer */ 548 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); 549 if (IS_ERR(sgt)) { 550 pr_err("Error getting dmabuf scatterlist\n"); 551 return -EINVAL; 552 } 553 554 buf->dma_sgt = sgt; 555 buf->vaddr = NULL; 556 557 return 0; 558 } 559 560 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) 561 { 562 struct vb2_dma_sg_buf *buf = mem_priv; 563 struct sg_table *sgt = buf->dma_sgt; 564 565 if (WARN_ON(!buf->db_attach)) { 566 pr_err("trying to unpin a not attached buffer\n"); 567 return; 568 } 569 570 if (WARN_ON(!sgt)) { 571 pr_err("dmabuf buffer is already unpinned\n"); 572 return; 573 } 574 575 if (buf->vaddr) { 576 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr); 577 buf->vaddr = NULL; 578 } 579 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); 580 581 buf->dma_sgt = NULL; 582 } 583 584 static void vb2_dma_sg_detach_dmabuf(void *mem_priv) 585 { 586 struct vb2_dma_sg_buf *buf = mem_priv; 587 588 /* if vb2 works correctly you should never detach mapped buffer */ 589 if (WARN_ON(buf->dma_sgt)) 590 vb2_dma_sg_unmap_dmabuf(buf); 591 592 /* detach this attachment */ 593 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); 594 kfree(buf); 595 } 596 597 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf, 598 unsigned long size, enum dma_data_direction dma_dir) 599 { 600 struct vb2_dma_sg_buf *buf; 601 struct dma_buf_attachment *dba; 602 603 if (WARN_ON(!dev)) 604 return ERR_PTR(-EINVAL); 605 606 if (dbuf->size < size) 607 return ERR_PTR(-EFAULT); 608 609 buf = kzalloc(sizeof(*buf), GFP_KERNEL); 610 if (!buf) 611 return ERR_PTR(-ENOMEM); 612 613 buf->dev = dev; 614 /* create attachment for the dmabuf with the user device */ 615 dba = dma_buf_attach(dbuf, buf->dev); 616 if (IS_ERR(dba)) { 617 pr_err("failed to attach dmabuf\n"); 618 kfree(buf); 619 return dba; 620 } 621 622 buf->dma_dir = dma_dir; 623 buf->size = size; 624 buf->db_attach = dba; 625 626 return buf; 627 } 628 629 static void *vb2_dma_sg_cookie(void *buf_priv) 630 { 631 struct vb2_dma_sg_buf *buf = buf_priv; 632 633 return buf->dma_sgt; 634 } 635 636 const struct vb2_mem_ops vb2_dma_sg_memops = { 637 .alloc = vb2_dma_sg_alloc, 638 .put = vb2_dma_sg_put, 639 .get_userptr = vb2_dma_sg_get_userptr, 640 .put_userptr = vb2_dma_sg_put_userptr, 641 .prepare = vb2_dma_sg_prepare, 642 .finish = vb2_dma_sg_finish, 643 .vaddr = vb2_dma_sg_vaddr, 644 .mmap = vb2_dma_sg_mmap, 645 .num_users = vb2_dma_sg_num_users, 646 .get_dmabuf = vb2_dma_sg_get_dmabuf, 647 .map_dmabuf = vb2_dma_sg_map_dmabuf, 648 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf, 649 .attach_dmabuf = vb2_dma_sg_attach_dmabuf, 650 .detach_dmabuf = vb2_dma_sg_detach_dmabuf, 651 .cookie = vb2_dma_sg_cookie, 652 }; 653 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); 654 655 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); 656 MODULE_AUTHOR("Andrzej Pietrasiewicz"); 657 MODULE_LICENSE("GPL"); 658