@@ -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);
@@ -377,6 +383,112 @@ fail_buf:
}
/*********************************************/
+/* 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);