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authorWill Deacon <will.deacon@arm.com>2014-08-27 16:20:32 +0100
committerWill Deacon <will.deacon@arm.com>2014-12-01 16:50:38 +0000
commit7eba1d51485197fa77c43c42eae3ce04b4b1c1c0 (patch)
treeace7a25c7d2aaf0e6250d60db0ee08faf55bf201 /drivers/iommu
parentd0f60a44f5120a8e1c48995285c7d8d1e4915b35 (diff)
downloadlinux-7eba1d51485197fa77c43c42eae3ce04b4b1c1c0.tar.gz
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>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/Kconfig2
-rw-r--r--drivers/iommu/of_iommu.c33
2 files changed, 34 insertions, 1 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index dd5112265cc9..6d13f962f156 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -15,7 +15,7 @@ if IOMMU_SUPPORT
 
 config OF_IOMMU
        def_bool y
-       depends on OF
+       depends on OF && IOMMU_API
 
 config FSL_PAMU
 	bool "Freescale IOMMU support"
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 89b903406968..73236d3cc955 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 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
 }
 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;