linux/drivers/media/v4l2-core/videobuf2-dma-contig.c

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/*
* videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Pawel Osciak <pawel@osciak.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/dma-buf.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <media/videobuf2-core.h>
#include <media/videobuf2-dma-contig.h>
#include <media/videobuf2-memops.h>
struct vb2_dc_conf {
struct device *dev;
};
struct vb2_dc_buf {
struct device *dev;
void *vaddr;
unsigned long size;
dma_addr_t dma_addr;
enum dma_data_direction dma_dir;
struct sg_table *dma_sgt;
/* MMAP related */
struct vb2_vmarea_handler handler;
atomic_t refcount;
/* USERPTR related */
struct vm_area_struct *vma;
/* DMABUF related */
struct dma_buf_attachment *db_attach;
};
/*********************************************/
/* scatterlist table functions */
/*********************************************/
static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
void (*cb)(struct page *pg))
{
struct scatterlist *s;
unsigned int i;
for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
struct page *page = sg_page(s);
unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
>> PAGE_SHIFT;
unsigned int j;
for (j = 0; j < n_pages; ++j, ++page)
cb(page);
}
}
static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
{
struct scatterlist *s;
dma_addr_t expected = sg_dma_address(sgt->sgl);
unsigned int i;
unsigned long size = 0;
for_each_sg(sgt->sgl, s, sgt->nents, i) {
if (sg_dma_address(s) != expected)
break;
expected = sg_dma_address(s) + sg_dma_len(s);
size += sg_dma_len(s);
}
return size;
}
/*********************************************/
/* callbacks for all buffers */
/*********************************************/
static void *vb2_dc_cookie(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
return &buf->dma_addr;
}
static void *vb2_dc_vaddr(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
return buf->vaddr;
}
static unsigned int vb2_dc_num_users(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
return atomic_read(&buf->refcount);
}
static void vb2_dc_prepare(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
/* DMABUF exporter will flush the cache for us */
if (!sgt || buf->db_attach)
return;
dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
}
static void vb2_dc_finish(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
/* DMABUF exporter will flush the cache for us */
if (!sgt || buf->db_attach)
return;
dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
}
/*********************************************/
/* callbacks for MMAP buffers */
/*********************************************/
static void vb2_dc_put(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
if (!atomic_dec_and_test(&buf->refcount))
return;
dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
kfree(buf);
}
static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
{
struct vb2_dc_conf *conf = alloc_ctx;
struct device *dev = conf->dev;
struct vb2_dc_buf *buf;
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
if (!buf->vaddr) {
dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
kfree(buf);
return ERR_PTR(-ENOMEM);
}
buf->dev = dev;
buf->size = size;
buf->handler.refcount = &buf->refcount;
buf->handler.put = vb2_dc_put;
buf->handler.arg = buf;
atomic_inc(&buf->refcount);
return buf;
}
static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
{
struct vb2_dc_buf *buf = buf_priv;
if (!buf) {
printk(KERN_ERR "No buffer to map\n");
return -EINVAL;
}
return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
&vb2_common_vm_ops, &buf->handler);
}
/*********************************************/
/* callbacks for USERPTR buffers */
/*********************************************/
static inline int vma_is_io(struct vm_area_struct *vma)
{
return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
}
static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
int n_pages, struct vm_area_struct *vma, int write)
{
if (vma_is_io(vma)) {
unsigned int i;
for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
unsigned long pfn;
int ret = follow_pfn(vma, start, &pfn);
if (ret) {
pr_err("no page for address %lu\n", start);
return ret;
}
pages[i] = pfn_to_page(pfn);
}
} else {
int n;
n = get_user_pages(current, current->mm, start & PAGE_MASK,
n_pages, write, 1, pages, NULL);
/* negative error means that no page was pinned */
n = max(n, 0);
if (n != n_pages) {
pr_err("got only %d of %d user pages\n", n, n_pages);
while (n)
put_page(pages[--n]);
return -EFAULT;
}
}
return 0;
}
static void vb2_dc_put_dirty_page(struct page *page)
{
set_page_dirty_lock(page);
put_page(page);
}
static void vb2_dc_put_userptr(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
if (!vma_is_io(buf->vma))
vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
sg_free_table(sgt);
kfree(sgt);
vb2_put_vma(buf->vma);
kfree(buf);
}
static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write)
{
struct vb2_dc_conf *conf = alloc_ctx;
struct vb2_dc_buf *buf;
unsigned long start;
unsigned long end;
unsigned long offset;
struct page **pages;
int n_pages;
int ret = 0;
struct vm_area_struct *vma;
struct sg_table *sgt;
unsigned long contig_size;
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
buf->dev = conf->dev;
buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
start = vaddr & PAGE_MASK;
offset = vaddr & ~PAGE_MASK;
end = PAGE_ALIGN(vaddr + size);
n_pages = (end - start) >> PAGE_SHIFT;
pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
if (!pages) {
ret = -ENOMEM;
pr_err("failed to allocate pages table\n");
goto fail_buf;
}
/* current->mm->mmap_sem is taken by videobuf2 core */
vma = find_vma(current->mm, vaddr);
if (!vma) {
pr_err("no vma for address %lu\n", vaddr);
ret = -EFAULT;
goto fail_pages;
}
if (vma->vm_end < vaddr + size) {
pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
ret = -EFAULT;
goto fail_pages;
}
buf->vma = vb2_get_vma(vma);
if (!buf->vma) {
pr_err("failed to copy vma\n");
ret = -ENOMEM;
goto fail_pages;
}
/* extract page list from userspace mapping */
ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
if (ret) {
pr_err("failed to get user pages\n");
goto fail_vma;
}
sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt) {
pr_err("failed to allocate sg table\n");
ret = -ENOMEM;
goto fail_get_user_pages;
}
ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
offset, size, GFP_KERNEL);
if (ret) {
pr_err("failed to initialize sg table\n");
goto fail_sgt;
}
/* pages are no longer needed */
kfree(pages);
pages = NULL;
sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents,
buf->dma_dir);
if (sgt->nents <= 0) {
pr_err("failed to map scatterlist\n");
ret = -EIO;
goto fail_sgt_init;
}
contig_size = vb2_dc_get_contiguous_size(sgt);
if (contig_size < size) {
pr_err("contiguous mapping is too small %lu/%lu\n",
contig_size, size);
ret = -EFAULT;
goto fail_map_sg;
}
buf->dma_addr = sg_dma_address(sgt->sgl);
buf->size = size;
buf->dma_sgt = sgt;
return buf;
fail_map_sg:
dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
fail_sgt_init:
if (!vma_is_io(buf->vma))
vb2_dc_sgt_foreach_page(sgt, put_page);
sg_free_table(sgt);
fail_sgt:
kfree(sgt);
fail_get_user_pages:
if (pages && !vma_is_io(buf->vma))
while (n_pages)
put_page(pages[--n_pages]);
fail_vma:
vb2_put_vma(buf->vma);
fail_pages:
kfree(pages); /* kfree is NULL-proof */
fail_buf:
kfree(buf);
return ERR_PTR(ret);
}
/*********************************************/
/* callbacks for DMABUF buffers */
/*********************************************/
static int vb2_dc_map_dmabuf(void *mem_priv)
{
struct vb2_dc_buf *buf = mem_priv;
struct sg_table *sgt;
unsigned long contig_size;
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_OR_NULL(sgt)) {
pr_err("Error getting dmabuf scatterlist\n");
return -EINVAL;
}
/* checking if dmabuf is big enough to store contiguous chunk */
contig_size = vb2_dc_get_contiguous_size(sgt);
if (contig_size < buf->size) {
pr_err("contiguous chunk is too small %lu/%lu b\n",
contig_size, buf->size);
dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
return -EFAULT;
}
buf->dma_addr = sg_dma_address(sgt->sgl);
buf->dma_sgt = sgt;
return 0;
}
static void vb2_dc_unmap_dmabuf(void *mem_priv)
{
struct vb2_dc_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;
}
dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
buf->dma_addr = 0;
buf->dma_sgt = NULL;
}
static void vb2_dc_detach_dmabuf(void *mem_priv)
{
struct vb2_dc_buf *buf = mem_priv;
/* if vb2 works correctly you should never detach mapped buffer */
if (WARN_ON(buf->dma_addr))
vb2_dc_unmap_dmabuf(buf);
/* detach this attachment */
dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
kfree(buf);
}
static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
unsigned long size, int write)
{
struct vb2_dc_conf *conf = alloc_ctx;
struct vb2_dc_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 = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
buf->size = size;
buf->db_attach = dba;
return buf;
}
/*********************************************/
/* DMA CONTIG exported functions */
/*********************************************/
const struct vb2_mem_ops vb2_dma_contig_memops = {
.alloc = vb2_dc_alloc,
.put = vb2_dc_put,
.cookie = vb2_dc_cookie,
.vaddr = vb2_dc_vaddr,
.mmap = vb2_dc_mmap,
.get_userptr = vb2_dc_get_userptr,
.put_userptr = vb2_dc_put_userptr,
.prepare = vb2_dc_prepare,
.finish = vb2_dc_finish,
.map_dmabuf = vb2_dc_map_dmabuf,
.unmap_dmabuf = vb2_dc_unmap_dmabuf,
.attach_dmabuf = vb2_dc_attach_dmabuf,
.detach_dmabuf = vb2_dc_detach_dmabuf,
.num_users = vb2_dc_num_users,
};
EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
void *vb2_dma_contig_init_ctx(struct device *dev)
{
struct vb2_dc_conf *conf;
conf = kzalloc(sizeof *conf, GFP_KERNEL);
if (!conf)
return ERR_PTR(-ENOMEM);
conf->dev = dev;
return conf;
}
EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
{
kfree(alloc_ctx);
}
EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
MODULE_LICENSE("GPL");