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Commit 46506350 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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[media] vb2-vmalloc: add support for dmabuf exports 



Add support for DMABUF exporting to the vb2-vmalloc implementation.

All memory models now have support for both importing and exporting of DMABUFs.

Signed-off-by: default avatarHans Verkuil <hansverk@cisco.com>
Acked-by: default avatarPawel Osciak <pawel@osciak.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 041c7b6a

drivers/media/v4l2-core/videobuf2-vmalloc.c

+171 −0
Original line number Diff line number Diff line
@@ -212,6 +212,176 @@ static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma) 
	return 0;

}



/*********************************************/

/*         DMABUF ops for exporters          */

/*********************************************/



struct vb2_vmalloc_attachment {

	struct sg_table sgt;

	enum dma_data_direction dma_dir;

};



static int vb2_vmalloc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,

	struct dma_buf_attachment *dbuf_attach)

{

	struct vb2_vmalloc_attachment *attach;

	struct vb2_vmalloc_buf *buf = dbuf->priv;

	int num_pages = PAGE_ALIGN(buf->size) / PAGE_SIZE;

	struct sg_table *sgt;

	struct scatterlist *sg;

	void *vaddr = buf->vaddr;

	int ret;

	int i;



	attach = kzalloc(sizeof(*attach), GFP_KERNEL);

	if (!attach)

		return -ENOMEM;



	sgt = &attach->sgt;

	ret = sg_alloc_table(sgt, num_pages, GFP_KERNEL);

	if (ret) {

		kfree(attach);

		return ret;

	}

	for_each_sg(sgt->sgl, sg, sgt->nents, i) {

		struct page *page = vmalloc_to_page(vaddr);



		if (!page) {

			sg_free_table(sgt);

			kfree(attach);

			return -ENOMEM;

		}

		sg_set_page(sg, page, PAGE_SIZE, 0);

		vaddr += PAGE_SIZE;

	}



	attach->dma_dir = DMA_NONE;

	dbuf_attach->priv = attach;

	return 0;

}



static void vb2_vmalloc_dmabuf_ops_detach(struct dma_buf *dbuf,

	struct dma_buf_attachment *db_attach)

{

	struct vb2_vmalloc_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_vmalloc_dmabuf_ops_map(

	struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)

{

	struct vb2_vmalloc_attachment *attach = db_attach->priv;

	/* stealing dmabuf mutex to serialize map/unmap operations */

	struct mutex *lock = &db_attach->dmabuf->lock;

	struct sg_table *sgt;

	int ret;



	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 */

	ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dma_dir);

	if (ret <= 0) {

		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_vmalloc_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_vmalloc_dmabuf_ops_release(struct dma_buf *dbuf)

{

	/* drop reference obtained in vb2_vmalloc_get_dmabuf */

	vb2_vmalloc_put(dbuf->priv);

}



static void *vb2_vmalloc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)

{

	struct vb2_vmalloc_buf *buf = dbuf->priv;



	return buf->vaddr + pgnum * PAGE_SIZE;

}



static void *vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf)

{

	struct vb2_vmalloc_buf *buf = dbuf->priv;



	return buf->vaddr;

}



static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,

	struct vm_area_struct *vma)

{

	return vb2_vmalloc_mmap(dbuf->priv, vma);

}



static struct dma_buf_ops vb2_vmalloc_dmabuf_ops = {

	.attach = vb2_vmalloc_dmabuf_ops_attach,

	.detach = vb2_vmalloc_dmabuf_ops_detach,

	.map_dma_buf = vb2_vmalloc_dmabuf_ops_map,

	.unmap_dma_buf = vb2_vmalloc_dmabuf_ops_unmap,

	.kmap = vb2_vmalloc_dmabuf_ops_kmap,

	.kmap_atomic = vb2_vmalloc_dmabuf_ops_kmap,

	.vmap = vb2_vmalloc_dmabuf_ops_vmap,

	.mmap = vb2_vmalloc_dmabuf_ops_mmap,

	.release = vb2_vmalloc_dmabuf_ops_release,

};



static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flags)

{

	struct vb2_vmalloc_buf *buf = buf_priv;

	struct dma_buf *dbuf;



	if (WARN_ON(!buf->vaddr))

		return NULL;



	dbuf = dma_buf_export(buf, &vb2_vmalloc_dmabuf_ops, buf->size, flags, NULL);

	if (IS_ERR(dbuf))

		return NULL;



	/* dmabuf keeps reference to vb2 buffer */

	atomic_inc(&buf->refcount);



	return dbuf;

}



/*********************************************/

/*       callbacks for DMABUF buffers        */

/*********************************************/
@@ -268,6 +438,7 @@ const struct vb2_mem_ops vb2_vmalloc_memops = { 
	.put		= vb2_vmalloc_put,

	.get_userptr	= vb2_vmalloc_get_userptr,

	.put_userptr	= vb2_vmalloc_put_userptr,

	.get_dmabuf	= vb2_vmalloc_get_dmabuf,

	.map_dmabuf	= vb2_vmalloc_map_dmabuf,

	.unmap_dmabuf	= vb2_vmalloc_unmap_dmabuf,

	.attach_dmabuf	= vb2_vmalloc_attach_dmabuf,