Merge tag 'of-iommu-configure' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into next/iommu-config

Pull "Automatic DMA configuration for OF-based IOMMU masters" from Will Deacon:

This series adds automatic IOMMU and DMA-mapping configuration for
OF-based DMA masters described using the generic IOMMU devicetree
bindings. Although there is plenty of future work around splitting up
iommu_ops, adding default IOMMU domains and sorting out automatic IOMMU
group creation for the platform_bus, this is already useful enough for
people to port over their IOMMU drivers and start using the new probing
infrastructure (indeed, Marek has patches queued for the Exynos IOMMU).

* tag 'of-iommu-configure' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux:
  iommu: store DT-probed IOMMU data privately
  arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops
  arm: call iommu_init before of_platform_populate
  dma-mapping: detect and configure IOMMU in of_dma_configure
  iommu: fix initialization without 'add_device' callback
  iommu: provide helper function to configure an IOMMU for an of master
  iommu: add new iommu_ops callback for adding an OF device
  dma-mapping: replace set_arch_dma_coherent_ops with arch_setup_dma_ops
  iommu: provide early initialisation hook for IOMMU drivers

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

3 files changed, 91 insertions, 2 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/iommu.c b/drivers/iommu/iommu.c
index ed8b04867b1f..02f798b7e295 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -737,7 +737,7 @@ static int add_iommu_group(struct device *dev, void *data)
 	const struct iommu_ops *ops = cb->ops;
 
 	if (!ops->add_device)
-		return -ENODEV;
+		return 0;
 
 	WARN_ON(dev->iommu_group);
 
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index e550ccb7634e..af1dc6a1c0a1 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -18,9 +18,14 @@
  */
 
 #include <linux/export.h>
+#include <linux/iommu.h>
 #include <linux/limits.h>
 #include <linux/of.h>
 #include <linux/of_iommu.h>
+#include <linux/slab.h>
+
+static const struct of_device_id __iommu_of_table_sentinel
+	__used __section(__iommu_of_table_end);
 
 /**
  * of_get_dma_window - Parse *dma-window property and returns 0 if found.
@@ -89,3 +94,87 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_get_dma_window);
+
+struct of_iommu_node {
+	struct list_head list;
+	struct device_node *np;
+	struct iommu_ops *ops;
+};
+static LIST_HEAD(of_iommu_list);
+static DEFINE_SPINLOCK(of_iommu_lock);
+
+void of_iommu_set_ops(struct device_node *np, struct iommu_ops *ops)
+{
+	struct of_iommu_node *iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
+
+	if (WARN_ON(!iommu))
+		return;
+
+	INIT_LIST_HEAD(&iommu->list);
+	iommu->np = np;
+	iommu->ops = ops;
+	spin_lock(&of_iommu_lock);
+	list_add_tail(&iommu->list, &of_iommu_list);
+	spin_unlock(&of_iommu_lock);
+}
+
+struct iommu_ops *of_iommu_get_ops(struct device_node *np)
+{
+	struct of_iommu_node *node;
+	struct iommu_ops *ops = NULL;
+
+	spin_lock(&of_iommu_lock);
+	list_for_each_entry(node, &of_iommu_list, list)
+		if (node->np == np) {
+			ops = node->ops;
+			break;
+		}
+	spin_unlock(&of_iommu_lock);
+	return ops;
+}
+
+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;
+	const struct of_device_id *match, *matches = &__iommu_of_table;
+
+	for_each_matching_node_and_match(np, matches, &match) {
+		const of_iommu_init_fn init_fn = match->data;
+
+		if (init_fn(np))
+			pr_err("Failed to initialise IOMMU %s\n",
+				of_node_full_name(np));
+	}
+}