iommu: provide helper function to configure an IOMMU for an of master
The generic IOMMU device-tree bindings can be used to add arbitrary OF
masters to an IOMMU with a compliant binding.
This patch introduces of_iommu_configure, which does exactly that.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 89b9034..73236d3 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -18,6 +18,7 @@
*/
#include <linux/export.h>
+#include <linux/iommu.h>
#include <linux/limits.h>
#include <linux/of.h>
#include <linux/of_iommu.h>
@@ -93,6 +94,38 @@
}
EXPORT_SYMBOL_GPL(of_get_dma_window);
+struct iommu_ops *of_iommu_configure(struct device *dev)
+{
+ struct of_phandle_args iommu_spec;
+ struct device_node *np;
+ struct iommu_ops *ops = NULL;
+ int idx = 0;
+
+ /*
+ * We don't currently walk up the tree looking for a parent IOMMU.
+ * See the `Notes:' section of
+ * Documentation/devicetree/bindings/iommu/iommu.txt
+ */
+ while (!of_parse_phandle_with_args(dev->of_node, "iommus",
+ "#iommu-cells", idx,
+ &iommu_spec)) {
+ np = iommu_spec.np;
+ ops = of_iommu_get_ops(np);
+
+ if (!ops || !ops->of_xlate || ops->of_xlate(dev, &iommu_spec))
+ goto err_put_node;
+
+ of_node_put(np);
+ idx++;
+ }
+
+ return ops;
+
+err_put_node:
+ of_node_put(np);
+ return NULL;
+}
+
void __init of_iommu_init(void)
{
struct device_node *np;