[RFC PATCH v4 4/8] bux/cdx: support dma configuration for CDX devices

[Nipun Gupta <nipun.gupta@amd.com>]

With CDX bus supported in SMMU, devices on CDX bus can be
configured to support DMA configuration. This change adds
the dma configure callback for CDX bus.

Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
---
 drivers/bus/cdx/cdx.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/bus/cdx/cdx.c b/drivers/bus/cdx/cdx.c
index 5a366f4ae69c..b2a7e0b34df8 100644
--- a/drivers/bus/cdx/cdx.c
+++ b/drivers/bus/cdx/cdx.c
@@ -57,6 +57,7 @@
 
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/of_device.h>
 #include <linux/slab.h>
 #include <linux/cdx/cdx_bus.h>
 
@@ -180,10 +181,26 @@ static void cdx_remove(struct device *dev)
 		cdx_drv->remove(cdx_dev);
 }
 
+static int cdx_dma_configure(struct device *dev)
+{
+	struct cdx_device *cdx_dev = to_cdx_device(dev);
+	u32 input_id = cdx_dev->req_id;
+	int ret;
+
+	ret = of_dma_configure_id(dev, dev->parent->of_node, 0, &input_id);
+	if (ret) {
+		dev_err(dev, "of_dma_configure_id() failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 struct bus_type cdx_bus_type = {
 	.name		= "cdx",
 	.match		= cdx_bus_match,
 	.remove		= cdx_remove,
+	.dma_configure  = cdx_dma_configure,
 };
 EXPORT_SYMBOL_GPL(cdx_bus_type);
 
-- 
2.25.1