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-rw-r--r--drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
index f36dc6258900..b8b07c1de2a8 100644
--- a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
+++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
@@ -11,6 +11,7 @@
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
+#include <linux/of_device.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
@@ -155,6 +156,27 @@ static int sun4i_csi_probe(struct platform_device *pdev)
subdev = &csi->subdev;
vdev = &csi->vdev;
+ /*
+ * On Allwinner SoCs, some high memory bandwidth devices do DMA
+ * directly over the memory bus (called MBUS), instead of the
+ * system bus. The memory bus has a different addressing scheme
+ * without the DRAM starting offset.
+ *
+ * In some cases this can be described by an interconnect in
+ * the device tree. In other cases where the hardware is not
+ * fully understood and the interconnect is left out of the
+ * device tree, fall back to a default offset.
+ */
+ if (of_find_property(csi->dev->of_node, "interconnects", NULL)) {
+ ret = of_dma_configure(csi->dev, csi->dev->of_node, true);
+ if (ret)
+ return ret;
+ } else {
+#ifdef PHYS_PFN_OFFSET
+ csi->dev->dma_pfn_offset = PHYS_PFN_OFFSET;
+#endif
+ }
+
csi->mdev.dev = csi->dev;
strscpy(csi->mdev.model, "Allwinner Video Capture Device",
sizeof(csi->mdev.model));