680 lines · c
1/*2 * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf23 *4 * Copyright (C) 2010 Samsung Electronics5 *6 * Author: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>7 *8 * This program is free software; you can redistribute it and/or modify9 * it under the terms of the GNU General Public License as published by10 * 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 25static int debug;26module_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 34struct 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 USERPTR44 * memory model, and to the dma_buf sglist when used with the45 * 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 struct vb2_buffer *vb;56};57 58static void vb2_dma_sg_put(void *buf_priv);59 60static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,61 gfp_t gfp_flags)62{63 unsigned int last_page = 0;64 unsigned long size = buf->size;65 66 while (size > 0) {67 struct page *pages;68 int order;69 int i;70 71 order = get_order(size);72 /* Don't over allocate*/73 if ((PAGE_SIZE << order) > size)74 order--;75 76 pages = NULL;77 while (!pages) {78 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |79 __GFP_NOWARN | gfp_flags, order);80 if (pages)81 break;82 83 if (order == 0) {84 while (last_page--)85 __free_page(buf->pages[last_page]);86 return -ENOMEM;87 }88 order--;89 }90 91 split_page(pages, order);92 for (i = 0; i < (1 << order); i++)93 buf->pages[last_page++] = &pages[i];94 95 size -= PAGE_SIZE << order;96 }97 98 return 0;99}100 101static void *vb2_dma_sg_alloc(struct vb2_buffer *vb, struct device *dev,102 unsigned long size)103{104 struct vb2_dma_sg_buf *buf;105 struct sg_table *sgt;106 int ret;107 int num_pages;108 109 if (WARN_ON(!dev) || WARN_ON(!size))110 return ERR_PTR(-EINVAL);111 112 buf = kzalloc(sizeof *buf, GFP_KERNEL);113 if (!buf)114 return ERR_PTR(-ENOMEM);115 116 buf->vaddr = NULL;117 buf->dma_dir = vb->vb2_queue->dma_dir;118 buf->offset = 0;119 buf->size = size;120 /* size is already page aligned */121 buf->num_pages = size >> PAGE_SHIFT;122 buf->dma_sgt = &buf->sg_table;123 124 /*125 * NOTE: dma-sg allocates memory using the page allocator directly, so126 * there is no memory consistency guarantee, hence dma-sg ignores DMA127 * attributes passed from the upper layer.128 */129 buf->pages = kvcalloc(buf->num_pages, sizeof(struct page *), GFP_KERNEL);130 if (!buf->pages)131 goto fail_pages_array_alloc;132 133 ret = vb2_dma_sg_alloc_compacted(buf, vb->vb2_queue->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 the148 * 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 buf->vb = vb;158 159 refcount_set(&buf->refcount, 1);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 kvfree(buf->pages);174fail_pages_array_alloc:175 kfree(buf);176 return ERR_PTR(-ENOMEM);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 (refcount_dec_and_test(&buf->refcount)) {186 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,187 buf->num_pages);188 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,189 DMA_ATTR_SKIP_CPU_SYNC);190 if (buf->vaddr)191 vm_unmap_ram(buf->vaddr, buf->num_pages);192 sg_free_table(buf->dma_sgt);193 while (--i >= 0)194 __free_page(buf->pages[i]);195 kvfree(buf->pages);196 put_device(buf->dev);197 kfree(buf);198 }199}200 201static void vb2_dma_sg_prepare(void *buf_priv)202{203 struct vb2_dma_sg_buf *buf = buf_priv;204 struct sg_table *sgt = buf->dma_sgt;205 206 if (buf->vb->skip_cache_sync_on_prepare)207 return;208 209 dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);210}211 212static void vb2_dma_sg_finish(void *buf_priv)213{214 struct vb2_dma_sg_buf *buf = buf_priv;215 struct sg_table *sgt = buf->dma_sgt;216 217 if (buf->vb->skip_cache_sync_on_finish)218 return;219 220 dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);221}222 223static void *vb2_dma_sg_get_userptr(struct vb2_buffer *vb, struct device *dev,224 unsigned long vaddr, unsigned long size)225{226 struct vb2_dma_sg_buf *buf;227 struct sg_table *sgt;228 struct frame_vector *vec;229 230 if (WARN_ON(!dev))231 return ERR_PTR(-EINVAL);232 233 buf = kzalloc(sizeof *buf, GFP_KERNEL);234 if (!buf)235 return ERR_PTR(-ENOMEM);236 237 buf->vaddr = NULL;238 buf->dev = dev;239 buf->dma_dir = vb->vb2_queue->dma_dir;240 buf->offset = vaddr & ~PAGE_MASK;241 buf->size = size;242 buf->dma_sgt = &buf->sg_table;243 buf->vb = vb;244 vec = vb2_create_framevec(vaddr, size,245 buf->dma_dir == DMA_FROM_DEVICE ||246 buf->dma_dir == DMA_BIDIRECTIONAL);247 if (IS_ERR(vec))248 goto userptr_fail_pfnvec;249 buf->vec = vec;250 251 buf->pages = frame_vector_pages(vec);252 if (IS_ERR(buf->pages))253 goto userptr_fail_sgtable;254 buf->num_pages = frame_vector_count(vec);255 256 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,257 buf->num_pages, buf->offset, size, 0))258 goto userptr_fail_sgtable;259 260 sgt = &buf->sg_table;261 /*262 * No need to sync to the device, this will happen later when the263 * prepare() memop is called.264 */265 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,266 DMA_ATTR_SKIP_CPU_SYNC))267 goto userptr_fail_map;268 269 return buf;270 271userptr_fail_map:272 sg_free_table(&buf->sg_table);273userptr_fail_sgtable:274 vb2_destroy_framevec(vec);275userptr_fail_pfnvec:276 kfree(buf);277 return ERR_PTR(-ENOMEM);278}279 280/*281 * @put_userptr: inform the allocator that a USERPTR buffer will no longer282 * be used283 */284static void vb2_dma_sg_put_userptr(void *buf_priv)285{286 struct vb2_dma_sg_buf *buf = buf_priv;287 struct sg_table *sgt = &buf->sg_table;288 int i = buf->num_pages;289 290 dprintk(1, "%s: Releasing userspace buffer of %d pages\n",291 __func__, buf->num_pages);292 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);293 if (buf->vaddr)294 vm_unmap_ram(buf->vaddr, buf->num_pages);295 sg_free_table(buf->dma_sgt);296 if (buf->dma_dir == DMA_FROM_DEVICE ||297 buf->dma_dir == DMA_BIDIRECTIONAL)298 while (--i >= 0)299 set_page_dirty_lock(buf->pages[i]);300 vb2_destroy_framevec(buf->vec);301 kfree(buf);302}303 304static void *vb2_dma_sg_vaddr(struct vb2_buffer *vb, void *buf_priv)305{306 struct vb2_dma_sg_buf *buf = buf_priv;307 struct iosys_map map;308 int ret;309 310 BUG_ON(!buf);311 312 if (!buf->vaddr) {313 if (buf->db_attach) {314 ret = dma_buf_vmap_unlocked(buf->db_attach->dmabuf, &map);315 buf->vaddr = ret ? NULL : map.vaddr;316 } else {317 buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1);318 }319 }320 321 /* add offset in case userptr is not page-aligned */322 return buf->vaddr ? buf->vaddr + buf->offset : NULL;323}324 325static unsigned int vb2_dma_sg_num_users(void *buf_priv)326{327 struct vb2_dma_sg_buf *buf = buf_priv;328 329 return refcount_read(&buf->refcount);330}331 332static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)333{334 struct vb2_dma_sg_buf *buf = buf_priv;335 int err;336 337 if (!buf) {338 printk(KERN_ERR "No memory to map\n");339 return -EINVAL;340 }341 342 err = vm_map_pages(vma, buf->pages, buf->num_pages);343 if (err) {344 printk(KERN_ERR "Remapping memory, error: %d\n", err);345 return err;346 }347 348 /*349 * Use common vm_area operations to track buffer refcount.350 */351 vma->vm_private_data = &buf->handler;352 vma->vm_ops = &vb2_common_vm_ops;353 354 vma->vm_ops->open(vma);355 356 return 0;357}358 359/*********************************************/360/* DMABUF ops for exporters */361/*********************************************/362 363struct vb2_dma_sg_attachment {364 struct sg_table sgt;365 enum dma_data_direction dma_dir;366};367 368static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf,369 struct dma_buf_attachment *dbuf_attach)370{371 struct vb2_dma_sg_attachment *attach;372 unsigned int i;373 struct scatterlist *rd, *wr;374 struct sg_table *sgt;375 struct vb2_dma_sg_buf *buf = dbuf->priv;376 int ret;377 378 attach = kzalloc(sizeof(*attach), GFP_KERNEL);379 if (!attach)380 return -ENOMEM;381 382 sgt = &attach->sgt;383 /* Copy the buf->base_sgt scatter list to the attachment, as we can't384 * map the same scatter list to multiple attachments at the same time.385 */386 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);387 if (ret) {388 kfree(attach);389 return -ENOMEM;390 }391 392 rd = buf->dma_sgt->sgl;393 wr = sgt->sgl;394 for (i = 0; i < sgt->orig_nents; ++i) {395 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);396 rd = sg_next(rd);397 wr = sg_next(wr);398 }399 400 attach->dma_dir = DMA_NONE;401 dbuf_attach->priv = attach;402 403 return 0;404}405 406static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,407 struct dma_buf_attachment *db_attach)408{409 struct vb2_dma_sg_attachment *attach = db_attach->priv;410 struct sg_table *sgt;411 412 if (!attach)413 return;414 415 sgt = &attach->sgt;416 417 /* release the scatterlist cache */418 if (attach->dma_dir != DMA_NONE)419 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);420 sg_free_table(sgt);421 kfree(attach);422 db_attach->priv = NULL;423}424 425static struct sg_table *vb2_dma_sg_dmabuf_ops_map(426 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)427{428 struct vb2_dma_sg_attachment *attach = db_attach->priv;429 struct sg_table *sgt;430 431 sgt = &attach->sgt;432 /* return previously mapped sg table */433 if (attach->dma_dir == dma_dir)434 return sgt;435 436 /* release any previous cache */437 if (attach->dma_dir != DMA_NONE) {438 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);439 attach->dma_dir = DMA_NONE;440 }441 442 /* mapping to the client with new direction */443 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {444 pr_err("failed to map scatterlist\n");445 return ERR_PTR(-EIO);446 }447 448 attach->dma_dir = dma_dir;449 450 return sgt;451}452 453static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,454 struct sg_table *sgt, enum dma_data_direction dma_dir)455{456 /* nothing to be done here */457}458 459static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)460{461 /* drop reference obtained in vb2_dma_sg_get_dmabuf */462 vb2_dma_sg_put(dbuf->priv);463}464 465static int466vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,467 enum dma_data_direction direction)468{469 struct vb2_dma_sg_buf *buf = dbuf->priv;470 struct sg_table *sgt = buf->dma_sgt;471 472 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);473 return 0;474}475 476static int477vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,478 enum dma_data_direction direction)479{480 struct vb2_dma_sg_buf *buf = dbuf->priv;481 struct sg_table *sgt = buf->dma_sgt;482 483 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);484 return 0;485}486 487static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf,488 struct iosys_map *map)489{490 struct vb2_dma_sg_buf *buf;491 void *vaddr;492 493 buf = dbuf->priv;494 vaddr = vb2_dma_sg_vaddr(buf->vb, buf);495 if (!vaddr)496 return -EINVAL;497 498 iosys_map_set_vaddr(map, vaddr);499 500 return 0;501}502 503static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,504 struct vm_area_struct *vma)505{506 return vb2_dma_sg_mmap(dbuf->priv, vma);507}508 509static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {510 .attach = vb2_dma_sg_dmabuf_ops_attach,511 .detach = vb2_dma_sg_dmabuf_ops_detach,512 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,513 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,514 .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access,515 .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access,516 .vmap = vb2_dma_sg_dmabuf_ops_vmap,517 .mmap = vb2_dma_sg_dmabuf_ops_mmap,518 .release = vb2_dma_sg_dmabuf_ops_release,519};520 521static struct dma_buf *vb2_dma_sg_get_dmabuf(struct vb2_buffer *vb,522 void *buf_priv,523 unsigned long flags)524{525 struct vb2_dma_sg_buf *buf = buf_priv;526 struct dma_buf *dbuf;527 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);528 529 exp_info.ops = &vb2_dma_sg_dmabuf_ops;530 exp_info.size = buf->size;531 exp_info.flags = flags;532 exp_info.priv = buf;533 534 if (WARN_ON(!buf->dma_sgt))535 return NULL;536 537 dbuf = dma_buf_export(&exp_info);538 if (IS_ERR(dbuf))539 return NULL;540 541 /* dmabuf keeps reference to vb2 buffer */542 refcount_inc(&buf->refcount);543 544 return dbuf;545}546 547/*********************************************/548/* callbacks for DMABUF buffers */549/*********************************************/550 551static int vb2_dma_sg_map_dmabuf(void *mem_priv)552{553 struct vb2_dma_sg_buf *buf = mem_priv;554 struct sg_table *sgt;555 556 if (WARN_ON(!buf->db_attach)) {557 pr_err("trying to pin a non attached buffer\n");558 return -EINVAL;559 }560 561 if (WARN_ON(buf->dma_sgt)) {562 pr_err("dmabuf buffer is already pinned\n");563 return 0;564 }565 566 /* get the associated scatterlist for this buffer */567 sgt = dma_buf_map_attachment_unlocked(buf->db_attach, buf->dma_dir);568 if (IS_ERR(sgt)) {569 pr_err("Error getting dmabuf scatterlist\n");570 return -EINVAL;571 }572 573 buf->dma_sgt = sgt;574 buf->vaddr = NULL;575 576 return 0;577}578 579static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)580{581 struct vb2_dma_sg_buf *buf = mem_priv;582 struct sg_table *sgt = buf->dma_sgt;583 struct iosys_map map = IOSYS_MAP_INIT_VADDR(buf->vaddr);584 585 if (WARN_ON(!buf->db_attach)) {586 pr_err("trying to unpin a not attached buffer\n");587 return;588 }589 590 if (WARN_ON(!sgt)) {591 pr_err("dmabuf buffer is already unpinned\n");592 return;593 }594 595 if (buf->vaddr) {596 dma_buf_vunmap_unlocked(buf->db_attach->dmabuf, &map);597 buf->vaddr = NULL;598 }599 dma_buf_unmap_attachment_unlocked(buf->db_attach, sgt, buf->dma_dir);600 601 buf->dma_sgt = NULL;602}603 604static void vb2_dma_sg_detach_dmabuf(void *mem_priv)605{606 struct vb2_dma_sg_buf *buf = mem_priv;607 608 /* if vb2 works correctly you should never detach mapped buffer */609 if (WARN_ON(buf->dma_sgt))610 vb2_dma_sg_unmap_dmabuf(buf);611 612 /* detach this attachment */613 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);614 kfree(buf);615}616 617static void *vb2_dma_sg_attach_dmabuf(struct vb2_buffer *vb, struct device *dev,618 struct dma_buf *dbuf, unsigned long size)619{620 struct vb2_dma_sg_buf *buf;621 struct dma_buf_attachment *dba;622 623 if (WARN_ON(!dev))624 return ERR_PTR(-EINVAL);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 = 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 = vb->vb2_queue->dma_dir;643 buf->size = size;644 buf->db_attach = dba;645 buf->vb = vb;646 647 return buf;648}649 650static void *vb2_dma_sg_cookie(struct vb2_buffer *vb, void *buf_priv)651{652 struct vb2_dma_sg_buf *buf = buf_priv;653 654 return buf->dma_sgt;655}656 657const struct vb2_mem_ops vb2_dma_sg_memops = {658 .alloc = vb2_dma_sg_alloc,659 .put = vb2_dma_sg_put,660 .get_userptr = vb2_dma_sg_get_userptr,661 .put_userptr = vb2_dma_sg_put_userptr,662 .prepare = vb2_dma_sg_prepare,663 .finish = vb2_dma_sg_finish,664 .vaddr = vb2_dma_sg_vaddr,665 .mmap = vb2_dma_sg_mmap,666 .num_users = vb2_dma_sg_num_users,667 .get_dmabuf = vb2_dma_sg_get_dmabuf,668 .map_dmabuf = vb2_dma_sg_map_dmabuf,669 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,670 .attach_dmabuf = vb2_dma_sg_attach_dmabuf,671 .detach_dmabuf = vb2_dma_sg_detach_dmabuf,672 .cookie = vb2_dma_sg_cookie,673};674EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);675 676MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");677MODULE_AUTHOR("Andrzej Pietrasiewicz");678MODULE_LICENSE("GPL");679MODULE_IMPORT_NS(DMA_BUF);680