- 根目录:
- drivers
- media
- v4l2-core
- videobuf2-dma-sg.c
/*
* videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-memops.h>
#include <media/videobuf2-dma-sg.h>
static int debug;
module_param(debug, int, 0644);
#define dprintk(level, fmt, arg...) \
do { \
if (debug >= level) \
printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \
} while (0)
struct vb2_dma_sg_conf {
struct device *dev;
};
struct vb2_dma_sg_buf {
struct device *dev;
void *vaddr;
struct page **pages;
struct frame_vector *vec;
int offset;
enum dma_data_direction dma_dir;
struct sg_table sg_table;
/*
* This will point to sg_table when used with the MMAP or USERPTR
* memory model, and to the dma_buf sglist when used with the
* DMABUF memory model.
*/
struct sg_table *dma_sgt;
size_t size;
unsigned int num_pages;
atomic_t refcount;
struct vb2_vmarea_handler handler;
struct dma_buf_attachment *db_attach;
};
static void vb2_dma_sg_put(void *buf_priv);
static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
gfp_t gfp_flags)
{
unsigned int last_page = 0;
int size = buf->size;
while (size > 0) {
struct page *pages;
int order;
int i;
order = get_order(size);
/* Dont over allocate*/
if ((PAGE_SIZE << order) > size)
order--;
pages = NULL;
while (!pages) {
pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
__GFP_NOWARN | gfp_flags, order);
if (pages)
break;
if (order == 0) {
while (last_page--)
__free_page(buf->pages[last_page]);
return -ENOMEM;
}
order--;
}
split_page(pages, order);
for (i = 0; i < (1 << order); i++)
buf->pages[last_page++] = &pages[i];
size -= PAGE_SIZE << order;
}
return 0;
}
static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
enum dma_data_direction dma_dir, gfp_t gfp_flags)
{
struct vb2_dma_sg_conf *conf = alloc_ctx;
struct vb2_dma_sg_buf *buf;
struct sg_table *sgt;
int ret;
int num_pages;
DEFINE_DMA_ATTRS(attrs);
dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
if (WARN_ON(alloc_ctx == NULL))
return NULL;
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)
return NULL;
buf->vaddr = NULL;
buf->dma_dir = dma_dir;
buf->offset = 0;
buf->size = size;
/* size is already page aligned */
buf->num_pages = size >> PAGE_SHIFT;
buf->dma_sgt = &buf->sg_table;
buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
GFP_KERNEL);
if (!buf->pages)
goto fail_pages_array_alloc;
ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
if (ret)
goto fail_pages_alloc;
ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
buf->num_pages, 0, size, GFP_KERNEL);
if (ret)
goto fail_table_alloc;
/* Prevent the device from being released while the buffer is used */
buf->dev = get_device(conf->dev);
sgt = &buf->sg_table;
/*
* No need to sync to the device, this will happen later when the
* prepare() memop is called.
*/
sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
buf->dma_dir, &attrs);
if (!sgt->nents)
goto fail_map;
buf->handler.refcount = &buf->refcount;
buf->handler.put = vb2_dma_sg_put;
buf->handler.arg = buf;
atomic_inc(&buf->refcount);
dprintk(1, "%s: Allocated buffer of %d pages\n",
__func__, buf->num_pages);
return buf;
fail_map:
put_device(buf->dev);
sg_free_table(buf->dma_sgt);
fail_table_alloc:
num_pages = buf->num_pages;
while (num_pages--)
__free_page(buf->pages[num_pages]);
fail_pages_alloc:
kfree(buf->pages);
fail_pages_array_alloc:
kfree(buf);
return NULL;
}
static void vb2_dma_sg_put(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
struct sg_table *sgt = &buf->sg_table;
int i = buf->num_pages;
if (atomic_dec_and_test(&buf->refcount)) {
DEFINE_DMA_ATTRS(attrs);
dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
buf->num_pages);
dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
buf->dma_dir, &attrs);
if (buf->vaddr)
vm_unmap_ram(buf->vaddr, buf->num_pages);
sg_free_table(buf->dma_sgt);
while (--i >= 0)
__free_page(buf->pages[i]);
kfree(buf->pages);
put_device(buf->dev);
kfree(buf);
}
}
static void vb2_dma_sg_prepare(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
/* DMABUF exporter will flush the cache for us */
if (buf->db_attach)
return;
dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
buf->dma_dir);
}
static void vb2_dma_sg_finish(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
/* DMABUF exporter will flush the cache for us */
if (buf->db_attach)
return;
dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
}
static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
unsigned long size,
enum dma_data_direction dma_dir)
{
struct vb2_dma_sg_conf *conf = alloc_ctx;
struct vb2_dma_sg_buf *buf;
struct sg_table *sgt;
DEFINE_DMA_ATTRS(attrs);
struct frame_vector *vec;
dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)
return NULL;
buf->vaddr = NULL;
buf->dev = conf->dev;
buf->dma_dir = dma_dir;
buf->offset = vaddr & ~PAGE_MASK;
buf->size = size;
buf->dma_sgt = &buf->sg_table;
vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE);
if (IS_ERR(vec))
goto userptr_fail_pfnvec;
buf->vec = vec;
buf->pages = frame_vector_pages(vec);
if (IS_ERR(buf->pages))
goto userptr_fail_sgtable;
buf->num_pages = frame_vector_count(vec);
if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
buf->num_pages, buf->offset, size, 0))
goto userptr_fail_sgtable;
sgt = &buf->sg_table;
/*
* No need to sync to the device, this will happen later when the
* prepare() memop is called.
*/
sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
buf->dma_dir, &attrs);
if (!sgt->nents)
goto userptr_fail_map;
return buf;
userptr_fail_map:
sg_free_table(&buf->sg_table);
userptr_fail_sgtable:
vb2_destroy_framevec(vec);
userptr_fail_pfnvec:
kfree(buf);
return NULL;
}
/*
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used
*/
static void vb2_dma_sg_put_userptr(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
struct sg_table *sgt = &buf->sg_table;
int i = buf->num_pages;
DEFINE_DMA_ATTRS(attrs);
dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
__func__, buf->num_pages);
dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
&attrs);
if (buf->vaddr)
vm_unmap_ram(buf->vaddr, buf->num_pages);
sg_free_table(buf->dma_sgt);
while (--i >= 0) {
if (buf->dma_dir == DMA_FROM_DEVICE)
set_page_dirty_lock(buf->pages[i]);
}
vb2_destroy_framevec(buf->vec);
kfree(buf);
}
static void *vb2_dma_sg_vaddr(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
BUG_ON(!buf);
if (!buf->vaddr) {
if (buf->db_attach)
buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
else
buf->vaddr = vm_map_ram(buf->pages,
buf->num_pages, -1, PAGE_KERNEL);
}
/* add offset in case userptr is not page-aligned */
return buf->vaddr ? buf->vaddr + buf->offset : NULL;
}
static unsigned int vb2_dma_sg_num_users(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
return atomic_read(&buf->refcount);
}
static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
{
struct vb2_dma_sg_buf *buf = buf_priv;
unsigned long uaddr = vma->vm_start;
unsigned long usize = vma->vm_end - vma->vm_start;
int i = 0;
if (!buf) {
printk(KERN_ERR "No memory to map\n");
return -EINVAL;
}
do {
int ret;
ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
if (ret) {
printk(KERN_ERR "Remapping memory, error: %d\n", ret);
return ret;
}
uaddr += PAGE_SIZE;
usize -= PAGE_SIZE;
} while (usize > 0);
/*
* Use common vm_area operations to track buffer refcount.
*/
vma->vm_private_data = &buf->handler;
vma->vm_ops = &vb2_common_vm_ops;
vma->vm_ops->open(vma);
return 0;
}
/*********************************************/
/* DMABUF ops for exporters */
/*********************************************/
struct vb2_dma_sg_attachment {
struct sg_table sgt;
enum dma_data_direction dma_dir;
};
static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
struct dma_buf_attachment *dbuf_attach)
{
struct vb2_dma_sg_attachment *attach;
unsigned int i;
struct scatterlist *rd, *wr;
struct sg_table *sgt;
struct vb2_dma_sg_buf *buf = dbuf->priv;
int ret;
attach = kzalloc(sizeof(*attach), GFP_KERNEL);
if (!attach)
return -ENOMEM;
sgt = &attach->sgt;
/* Copy the buf->base_sgt scatter list to the attachment, as we can't
* map the same scatter list to multiple attachments at the same time.
*/
ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
if (ret) {
kfree(attach);
return -ENOMEM;
}
rd = buf->dma_sgt->sgl;
wr = sgt->sgl;
for (i = 0; i < sgt->orig_nents; ++i) {
sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
rd = sg_next(rd);
wr = sg_next(wr);
}
attach->dma_dir = DMA_NONE;
dbuf_attach->priv = attach;
return 0;
}
static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
struct dma_buf_attachment *db_attach)
{
struct vb2_dma_sg_attachment *attach = db_attach->priv;
struct sg_table *sgt;
if (!attach)
return;
sgt = &attach->sgt;
/* release the scatterlist cache */
if (attach->dma_dir != DMA_NONE)
dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
attach->dma_dir);
sg_free_table(sgt);
kfree(attach);
db_attach->priv = NULL;
}
static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
{
struct vb2_dma_sg_attachment *attach = db_attach->priv;
/* stealing dmabuf mutex to serialize map/unmap operations */
struct mutex *lock = &db_attach->dmabuf->lock;
struct sg_table *sgt;
mutex_lock(lock);
sgt = &attach->sgt;
/* return previously mapped sg table */
if (attach->dma_dir == dma_dir) {
mutex_unlock(lock);
return sgt;
}
/* release any previous cache */
if (attach->dma_dir != DMA_NONE) {
dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
attach->dma_dir);
attach->dma_dir = DMA_NONE;
}
/* mapping to the client with new direction */
sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
dma_dir);
if (!sgt->nents) {
pr_err("failed to map scatterlist\n");
mutex_unlock(lock);
return ERR_PTR(-EIO);
}
attach->dma_dir = dma_dir;
mutex_unlock(lock);
return sgt;
}
static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
struct sg_table *sgt, enum dma_data_direction dma_dir)
{
/* nothing to be done here */
}
static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
{
/* drop reference obtained in vb2_dma_sg_get_dmabuf */
vb2_dma_sg_put(dbuf->priv);
}
static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
{
struct vb2_dma_sg_buf *buf = dbuf->priv;
return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
}
static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
{
struct vb2_dma_sg_buf *buf = dbuf->priv;
return vb2_dma_sg_vaddr(buf);
}
static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
struct vm_area_struct *vma)
{
return vb2_dma_sg_mmap(dbuf->priv, vma);
}
static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
.attach = vb2_dma_sg_dmabuf_ops_attach,
.detach = vb2_dma_sg_dmabuf_ops_detach,
.map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
.unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
.kmap = vb2_dma_sg_dmabuf_ops_kmap,
.kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
.vmap = vb2_dma_sg_dmabuf_ops_vmap,
.mmap = vb2_dma_sg_dmabuf_ops_mmap,
.release = vb2_dma_sg_dmabuf_ops_release,
};
static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
{
struct vb2_dma_sg_buf *buf = buf_priv;
struct dma_buf *dbuf;
DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
exp_info.ops = &vb2_dma_sg_dmabuf_ops;
exp_info.size = buf->size;
exp_info.flags = flags;
exp_info.priv = buf;
if (WARN_ON(!buf->dma_sgt))
return NULL;
dbuf = dma_buf_export(&exp_info);
if (IS_ERR(dbuf))
return NULL;
/* dmabuf keeps reference to vb2 buffer */
atomic_inc(&buf->refcount);
return dbuf;
}
/*********************************************/
/* callbacks for DMABUF buffers */
/*********************************************/
static int vb2_dma_sg_map_dmabuf(void *mem_priv)
{
struct vb2_dma_sg_buf *buf = mem_priv;
struct sg_table *sgt;
if (WARN_ON(!buf->db_attach)) {
pr_err("trying to pin a non attached buffer\n");
return -EINVAL;
}
if (WARN_ON(buf->dma_sgt)) {
pr_err("dmabuf buffer is already pinned\n");
return 0;
}
/* get the associated scatterlist for this buffer */
sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
if (IS_ERR(sgt)) {
pr_err("Error getting dmabuf scatterlist\n");
return -EINVAL;
}
buf->dma_sgt = sgt;
buf->vaddr = NULL;
return 0;
}
static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
{
struct vb2_dma_sg_buf *buf = mem_priv;
struct sg_table *sgt = buf->dma_sgt;
if (WARN_ON(!buf->db_attach)) {
pr_err("trying to unpin a not attached buffer\n");
return;
}
if (WARN_ON(!sgt)) {
pr_err("dmabuf buffer is already unpinned\n");
return;
}
if (buf->vaddr) {
dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
buf->vaddr = NULL;
}
dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
buf->dma_sgt = NULL;
}
static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
{
struct vb2_dma_sg_buf *buf = mem_priv;
/* if vb2 works correctly you should never detach mapped buffer */
if (WARN_ON(buf->dma_sgt))
vb2_dma_sg_unmap_dmabuf(buf);
/* detach this attachment */
dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
kfree(buf);
}
static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
unsigned long size, enum dma_data_direction dma_dir)
{
struct vb2_dma_sg_conf *conf = alloc_ctx;
struct vb2_dma_sg_buf *buf;
struct dma_buf_attachment *dba;
if (dbuf->size < size)
return ERR_PTR(-EFAULT);
buf = kzalloc(sizeof(*buf), GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
buf->dev = conf->dev;
/* create attachment for the dmabuf with the user device */
dba = dma_buf_attach(dbuf, buf->dev);
if (IS_ERR(dba)) {
pr_err("failed to attach dmabuf\n");
kfree(buf);
return dba;
}
buf->dma_dir = dma_dir;
buf->size = size;
buf->db_attach = dba;
return buf;
}
static void *vb2_dma_sg_cookie(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
return buf->dma_sgt;
}
const struct vb2_mem_ops vb2_dma_sg_memops = {
.alloc = vb2_dma_sg_alloc,
.put = vb2_dma_sg_put,
.get_userptr = vb2_dma_sg_get_userptr,
.put_userptr = vb2_dma_sg_put_userptr,
.prepare = vb2_dma_sg_prepare,
.finish = vb2_dma_sg_finish,
.vaddr = vb2_dma_sg_vaddr,
.mmap = vb2_dma_sg_mmap,
.num_users = vb2_dma_sg_num_users,
.get_dmabuf = vb2_dma_sg_get_dmabuf,
.map_dmabuf = vb2_dma_sg_map_dmabuf,
.unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
.attach_dmabuf = vb2_dma_sg_attach_dmabuf,
.detach_dmabuf = vb2_dma_sg_detach_dmabuf,
.cookie = vb2_dma_sg_cookie,
};
EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
void *vb2_dma_sg_init_ctx(struct device *dev)
{
struct vb2_dma_sg_conf *conf;
conf = kzalloc(sizeof(*conf), GFP_KERNEL);
if (!conf)
return ERR_PTR(-ENOMEM);
conf->dev = dev;
return conf;
}
EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx);
void vb2_dma_sg_cleanup_ctx(void *alloc_ctx)
{
if (!IS_ERR_OR_NULL(alloc_ctx))
kfree(alloc_ctx);
}
EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx);
MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
MODULE_AUTHOR("Andrzej Pietrasiewicz");
MODULE_LICENSE("GPL");