Commit 8c417d03 authored by Sumit Semwal's avatar Sumit Semwal Committed by Mauro Carvalho Chehab
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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: default avatarSumit Semwal <sumit.semwal@ti.com>
Signed-off-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: default avatarTomasz Stanislawski <t.stanislaws@samsung.com>
Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 199d101e

drivers/media/v4l2-core/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ config VIDEOBUF2_DMA_CONTIG 
	tristate

	select VIDEOBUF2_CORE

	select VIDEOBUF2_MEMOPS

	select DMA_SHARED_BUFFER



config VIDEOBUF2_VMALLOC

	tristate

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

+118 −2
Original line number Diff line number Diff line
@@ -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);

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