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.
Signed-off-by: Sumit Semwal <sumit.semwal@xxxxxx>
Signed-off-by: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
---
drivers/media/video/videobuf2-dma-contig.c | 125 ++++++++++++++++++++++++++++
1 files changed, 125 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c
index f17ad98..e671371 100644
--- a/drivers/media/video/videobuf2-dma-contig.c
+++ b/drivers/media/video/videobuf2-dma-contig.c
@@ -13,6 +13,8 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-buf.h>
#include <media/videobuf2-core.h>
#include <media/videobuf2-memops.h>
@@ -27,6 +29,7 @@ struct vb2_dc_buf {
dma_addr_t dma_addr;
unsigned long size;
struct vm_area_struct *vma;
+ struct dma_buf_attachment *db_attach;
atomic_t refcount;
struct vb2_vmarea_handler handler;
};
@@ -37,6 +40,7 @@ static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size)
{
struct vb2_dc_conf *conf = alloc_ctx;
struct vb2_dc_buf *buf;
+ /* TODO: add db_attach processing while adding DMABUF as exporter */
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)
@@ -106,6 +110,8 @@ static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
return -EINVAL;
}
+ WARN_ON(buf->db_attach);
+
return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
&vb2_common_vm_ops, &buf->handler);
}
@@ -148,6 +154,121 @@ static void vb2_dma_contig_put_userptr(void *mem_priv)
kfree(buf);
}
+static int vb2_dma_contig_map_dmabuf(void *mem_priv,
+ enum dma_data_direction direction)
+{
+ struct vb2_dc_buf *buf = mem_priv;
+ struct dma_buf *dmabuf;
+ struct sg_table *sg;
+
+ if (!buf || !buf->db_attach) {
+ printk(KERN_ERR "No dma buffer to pin\n");
+ return -EINVAL;
+ }
+
+ WARN_ON(buf->dma_addr);
+
+ if (direction == DMA_NONE) {
+ printk(KERN_ERR "Incorrect DMA direction\n");
+ return -EINVAL;
+ }
+
+ dmabuf = buf->db_attach->dmabuf;
+
+ /* get the associated scatterlist for this buffer */
+ sg = dma_buf_map_attachment(buf->db_attach, direction);
+
+ if (!sg) {
+ printk(KERN_ERR "Error getting dmabuf scatterlist\n");
+ return -EINVAL;
+ }
+
+ /*
+ * convert sglist to paddr:
+ * Assumption: for dma-contig, dmabuf would map to single entry
+ * Will return an error if it has more than one.
+ */
+ if (sg->nents > 1) {
+ printk(KERN_ERR
+ "dmabuf scatterlist has more than 1 entry\n");
+ return -EINVAL;
+ }
+
+ buf->dma_addr = sg_dma_address(sg->sgl);
+ /* TODO: check the buffer size as per S_FMT */
+ buf->size = sg_dma_len(sg->sgl);
+
+ /* save this scatterlist in dmabuf for put_scatterlist */
+ dmabuf->priv = sg;
+
+ return 0;
+}
+
+static void vb2_dma_contig_unmap_dmabuf(void *mem_priv)
+{
+ struct vb2_dc_buf *buf = mem_priv;
+ struct dma_buf *dmabuf;
+ struct sg_table *sg;
+
+ if (!buf || !buf->db_attach)
+ return;
+
+ WARN_ON(!buf->dma_addr);
+
+ dmabuf = buf->db_attach->dmabuf;
+ sg = dmabuf->priv;
+
+ /* Put the sg for this buffer */
+ dma_buf_unmap_attachment(buf->db_attach, sg);
+
+ buf->dma_addr = 0;
+ buf->size = 0;
+}
+
+static void *vb2_dma_contig_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf)
+{
+ struct vb2_dc_conf *conf = alloc_ctx;
+ struct vb2_dc_buf *buf;
+ struct dma_buf_attachment *dba;
+
+ buf = kzalloc(sizeof *buf, GFP_KERNEL);
+ if (!buf)
+ return ERR_PTR(-ENOMEM);
+
+ /* create attachment for the dmabuf with the user device */
+ dba = dma_buf_attach(dbuf, conf->dev);
+ if (IS_ERR(dba)) {
+ printk(KERN_ERR "failed to attach dmabuf\n");
+ kfree(buf);
+ return dba;
+ }
+
+ buf->conf = conf;
+ buf->size = dba->dmabuf->size;
+ buf->db_attach = dba;
+ buf->dma_addr = 0; /* dma_addr is available only after map */
+
+ return buf;
+}
+
+static void vb2_dma_contig_detach_dmabuf(void *mem_priv)
+{
+ struct vb2_dc_buf *buf = mem_priv;
+
+ if (!buf)
+ return;
+
+ if (buf->dma_addr) {
+ vb2_dma_contig_unmap_dmabuf(buf);
+ }
+
+ /* detach this attachment */
+ dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
+ buf->db_attach = NULL;
+
+ kfree(buf);
+}
+
const struct vb2_mem_ops vb2_dma_contig_memops = {
.alloc = vb2_dma_contig_alloc,
.put = vb2_dma_contig_put,
@@ -156,6 +277,10 @@ const struct vb2_mem_ops vb2_dma_contig_memops = {
.mmap = vb2_dma_contig_mmap,
.get_userptr = vb2_dma_contig_get_userptr,
.put_userptr = vb2_dma_contig_put_userptr,
+ .map_dmabuf = vb2_dma_contig_map_dmabuf,
+ .unmap_dmabuf = vb2_dma_contig_unmap_dmabuf,
+ .attach_dmabuf = vb2_dma_contig_attach_dmabuf,
+ .detach_dmabuf = vb2_dma_contig_detach_dmabuf,
.num_users = vb2_dma_contig_num_users,
};
EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
--
1.7.5.4
--
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