Re: [PATCHv10 20/26] v4l: vb2-dma-contig: add support for DMABUF exporting

2012-10-11 Thread Laurent Pinchart 
Hi Tomasz,

On Wednesday 10 October 2012 16:46:39 Tomasz Stanislawski wrote:
 This patch adds support for exporting a dma-contig buffer using
 DMABUF interface.
 
 Signed-off-by: Tomasz Stanislawski t.stanisl...@samsung.com
 Signed-off-by: Kyungmin Park kyungmin.p...@samsung.com
 Acked-by: Hans Verkuil hans.verk...@cisco.com

Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com

 ---
  drivers/media/v4l2-core/videobuf2-dma-contig.c |  200 +
  1 file changed, 200 insertions(+)
 
 diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
 b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 0e065ce..b138b5c
 100644
 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
 +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
 @@ -36,6 +36,7 @@ struct vb2_dc_buf {
   /* MMAP related */
   struct vb2_vmarea_handler   handler;
   atomic_trefcount;
 + struct sg_table *sgt_base;
 
   /* USERPTR related */
   struct vm_area_struct   *vma;
 @@ -142,6 +143,10 @@ static void vb2_dc_put(void *buf_priv)
   if (!atomic_dec_and_test(buf-refcount))
   return;
 
 + if (buf-sgt_base) {
 + sg_free_table(buf-sgt_base);
 + kfree(buf-sgt_base);
 + }
   dma_free_coherent(buf-dev, buf-size, buf-vaddr, buf-dma_addr);
   kfree(buf);
  }
 @@ -213,6 +218,200 @@ static int vb2_dc_mmap(void *buf_priv, struct
 vm_area_struct *vma) }
 
  /*/
 +/* DMABUF ops for exporters  */
 +/*/
 +
 +struct vb2_dc_attachment {
 + struct sg_table sgt;
 + enum dma_data_direction dir;
 +};
 +
 +static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device
 *dev, +   struct dma_buf_attachment *dbuf_attach)
 +{
 + struct vb2_dc_attachment *attach;
 + unsigned int i;
 + struct scatterlist *rd, *wr;
 + struct sg_table *sgt;
 + struct vb2_dc_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-sgt_base-orig_nents, GFP_KERNEL);
 + if (ret) {
 + kfree(attach);
 + return -ENOMEM;
 + }
 +
 + rd = buf-sgt_base-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-dir = DMA_NONE;
 + dbuf_attach-priv = attach;
 +
 + return 0;
 +}
 +
 +static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
 + struct dma_buf_attachment *db_attach)
 +{
 + struct vb2_dc_attachment *attach = db_attach-priv;
 + struct sg_table *sgt;
 +
 + if (!attach)
 + return;
 +
 + sgt = attach-sgt;
 +
 + /* release the scatterlist cache */
 + if (attach-dir != DMA_NONE)
 + dma_unmap_sg(db_attach-dev, sgt-sgl, sgt-orig_nents,
 + attach-dir);
 + sg_free_table(sgt);
 + kfree(attach);
 + db_attach-priv = NULL;
 +}
 +
 +static struct sg_table *vb2_dc_dmabuf_ops_map(
 + struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
 +{
 + struct vb2_dc_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-dir == dir) {
 + mutex_unlock(lock);
 + return sgt;
 + }
 +
 + /* release any previous cache */
 + if (attach-dir != DMA_NONE) {
 + dma_unmap_sg(db_attach-dev, sgt-sgl, sgt-orig_nents,
 + attach-dir);
 + attach-dir = DMA_NONE;
 + }
 +
 + /* mapping to the client with new direction */
 + ret = dma_map_sg(db_attach-dev, sgt-sgl, sgt-orig_nents, dir);
 + if (ret = 0) {
 + pr_err(failed to map scatterlist\n);
 + mutex_unlock(lock);
 + return ERR_PTR(-EIO);
 + }
 +
 + attach-dir = dir;
 +
 + mutex_unlock(lock);
 +
 + return sgt;
 +}
 +
 +static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 + struct sg_table *sgt, enum dma_data_direction dir)
 +{
 + /* nothing to be done here */
 +}
 +
 +static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
 +{
 + /* drop reference obtained in vb2_dc_get_dmabuf */
 + vb2_dc_put(dbuf-priv);
 +}
 +
 +static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long
 pgnum) +{
 + struct

[PATCHv10 20/26] v4l: vb2-dma-contig: add support for DMABUF exporting

2012-10-10 Thread Tomasz Stanislawski 
This patch adds support for exporting a dma-contig buffer using
DMABUF interface.

Signed-off-by: Tomasz Stanislawski t.stanisl...@samsung.com
Signed-off-by: Kyungmin Park kyungmin.p...@samsung.com
Acked-by: Hans Verkuil hans.verk...@cisco.com
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |  200 
 1 file changed, 200 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c 
b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 0e065ce..b138b5c 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -36,6 +36,7 @@ struct vb2_dc_buf {
/* MMAP related */
struct vb2_vmarea_handler   handler;
atomic_trefcount;
+   struct sg_table *sgt_base;
 
/* USERPTR related */
struct vm_area_struct   *vma;
@@ -142,6 +143,10 @@ static void vb2_dc_put(void *buf_priv)
if (!atomic_dec_and_test(buf-refcount))
return;
 
+   if (buf-sgt_base) {
+   sg_free_table(buf-sgt_base);
+   kfree(buf-sgt_base);
+   }
dma_free_coherent(buf-dev, buf-size, buf-vaddr, buf-dma_addr);
kfree(buf);
 }
@@ -213,6 +218,200 @@ static int vb2_dc_mmap(void *buf_priv, struct 
vm_area_struct *vma)
 }
 
 /*/
+/* DMABUF ops for exporters  */
+/*/
+
+struct vb2_dc_attachment {
+   struct sg_table sgt;
+   enum dma_data_direction dir;
+};
+
+static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
+   struct dma_buf_attachment *dbuf_attach)
+{
+   struct vb2_dc_attachment *attach;
+   unsigned int i;
+   struct scatterlist *rd, *wr;
+   struct sg_table *sgt;
+   struct vb2_dc_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-sgt_base-orig_nents, GFP_KERNEL);
+   if (ret) {
+   kfree(attach);
+   return -ENOMEM;
+   }
+
+   rd = buf-sgt_base-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-dir = DMA_NONE;
+   dbuf_attach-priv = attach;
+
+   return 0;
+}
+
+static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
+   struct dma_buf_attachment *db_attach)
+{
+   struct vb2_dc_attachment *attach = db_attach-priv;
+   struct sg_table *sgt;
+
+   if (!attach)
+   return;
+
+   sgt = attach-sgt;
+
+   /* release the scatterlist cache */
+   if (attach-dir != DMA_NONE)
+   dma_unmap_sg(db_attach-dev, sgt-sgl, sgt-orig_nents,
+   attach-dir);
+   sg_free_table(sgt);
+   kfree(attach);
+   db_attach-priv = NULL;
+}
+
+static struct sg_table *vb2_dc_dmabuf_ops_map(
+   struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
+{
+   struct vb2_dc_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-dir == dir) {
+   mutex_unlock(lock);
+   return sgt;
+   }
+
+   /* release any previous cache */
+   if (attach-dir != DMA_NONE) {
+   dma_unmap_sg(db_attach-dev, sgt-sgl, sgt-orig_nents,
+   attach-dir);
+   attach-dir = DMA_NONE;
+   }
+
+   /* mapping to the client with new direction */
+   ret = dma_map_sg(db_attach-dev, sgt-sgl, sgt-orig_nents, dir);
+   if (ret = 0) {
+   pr_err(failed to map scatterlist\n);
+   mutex_unlock(lock);
+   return ERR_PTR(-EIO);
+   }
+
+   attach-dir = dir;
+
+   mutex_unlock(lock);
+
+   return sgt;
+}
+
+static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
+   struct sg_table *sgt, enum dma_data_direction dir)
+{
+   /* nothing to be done here */
+}
+
+static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
+{
+   /* drop reference obtained in vb2_dc_get_dmabuf */
+   vb2_dc_put(dbuf-priv);
+}
+
+static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
+{
+   struct vb2_dc_buf *buf = dbuf-priv;
+
+   return buf-vaddr + pgnum * PAGE_SIZE;
+}
+
+static void