iommu/exynos: Ensure that SYSMMU is added only once to its master device

This patch prepares Exynos IOMMU driver for deferred probing
support. Once it gets added, of_xlate() callback might be called
more than once for the same SYSMMU controller and master device
(for example it happens when masters device driver fails with
EPROBE_DEFER). This patch adds a check, which ensures that SYSMMU
controller is added to its master device (owner) only once.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index dda4e59..91f7827 100644 (file)
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -1253,7 +1253,7 @@ static int exynos_iommu_of_xlate(struct device *dev,
 {
        struct exynos_iommu_owner *owner = dev->archdata.iommu;
        struct platform_device *sysmmu = of_find_device_by_node(spec->np);
-       struct sysmmu_drvdata *data;
+       struct sysmmu_drvdata *data, *entry;
 
        if (!sysmmu)
                return -ENODEV;
@@ -1272,6 +1272,10 @@ static int exynos_iommu_of_xlate(struct device *dev,
                dev->archdata.iommu = owner;
        }
 
+       list_for_each_entry(entry, &owner->controllers, owner_node)
+               if (entry == data)
+                       return 0;
+
        list_add_tail(&data->owner_node, &owner->controllers);
        data->master = dev;