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[media] v4l: vb2-dma-contig: add support for dma_buf importing 

This patch makes changes for adding dma-contig as a dma_buf user. It provides
function implementations for the {attach, detach, map, unmap}_dmabuf()
mem_ops of DMABUF memory type.
	[author of the original patch]
	[integration with refactored dma-contig allocator]

Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Sumit Semwal 2012-06-14 10:37:45 -03:00 committed by Mauro Carvalho Chehab
parent 199d101efd
commit 8c417d03a8
2 changed files with 119 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/media/v4l2-core/Kconfig
View File

@ -69,6 +69,7 @@ config VIDEOBUF2_DMA_CONTIG
tristate
select VIDEOBUF2_CORE
select VIDEOBUF2_MEMOPS
select DMA_SHARED_BUFFER
config VIDEOBUF2_VMALLOC
tristate

120
drivers/media/v4l2-core/videobuf2-dma-contig.c
View File

@ -10,6 +10,7 @@
* the Free Software Foundation.
*/
#include <linux/dma-buf.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>
@ -38,6 +39,9 @@ struct vb2_dc_buf {
/* USERPTR related */
struct vm_area_struct *vma;
/* DMABUF related */
struct dma_buf_attachment *db_attach;
};
/*********************************************/
@ -108,7 +112,8 @@ static void vb2_dc_prepare(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
if (!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);
@ -119,7 +124,8 @@ static void vb2_dc_finish(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
if (!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);
@ -376,6 +382,112 @@ fail_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 */
/*********************************************/
@ -390,6 +502,10 @@ const struct vb2_mem_ops vb2_dma_contig_memops = {
.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);