From: Heng-Ruey Hsu <henryhsu@xxxxxxxxxxxx>
DMA allocations for MMAP type are uncached by default. But for
some cases, CPU has to access the buffers. ie: memcpy for format
converter. Supporting cacheable MMAP improves huge performance.
Signed-off-by: Heng-Ruey Hsu <henryhsu@xxxxxxxxxxxx>
Tested-by: Heng-ruey Hsu <henryhsu@xxxxxxxxxxxx>
Reviewed-by: Tomasz Figa <tfiga@xxxxxxxxxxxx>
Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
---
drivers/media/v4l2-core/videobuf2-dma-contig.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index fb6a177..c953c24 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -42,6 +42,12 @@ struct vb2_dc_buf {
};
/*********************************************/
+/* Forward declarations */
+/*********************************************/
+
+static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf);
+
+/*********************************************/
/* scatterlist table functions */
/*********************************************/
@@ -129,6 +135,10 @@ static void vb2_dc_put(void *buf_priv)
sg_free_table(buf->sgt_base);
kfree(buf->sgt_base);
}
+ if (buf->dma_sgt) {
+ sg_free_table(buf->dma_sgt);
+ kfree(buf->dma_sgt);
+ }
dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
buf->attrs);
put_device(buf->dev);
@@ -170,6 +180,10 @@ static void *vb2_dc_alloc(struct device *dev, unsigned long attrs,
buf->handler.put = vb2_dc_put;
buf->handler.arg = buf;
+ if (!(buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
+ (buf->attrs & DMA_ATTR_NON_CONSISTENT))
+ buf->dma_sgt = vb2_dc_get_base_sgt(buf);
+
atomic_inc(&buf->refcount);
return buf;
@@ -205,6 +219,11 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
vma->vm_ops->open(vma);
+ if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
+ (buf->attrs & DMA_ATTR_NON_CONSISTENT) &&
+ !buf->dma_sgt)
+ buf->dma_sgt = vb2_dc_get_base_sgt(buf);
+
pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
__func__, (unsigned long)buf->dma_addr, vma->vm_start,
buf->size);
--
2.7.4
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