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authorLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>2017-04-10 16:51:02 +0530
committerJoerg Roedel <jroedel@suse.de>2017-04-20 16:31:07 +0200
commit7b07cbefb68d486febf47e13b570fed53d9296b4 (patch)
tree111db4d3e44fbb0315528b6dc51979b8081cb7ce /include/linux/of_device.h
parent09515ef5ddad71c7820e5e428da418b709feeb26 (diff)
iommu: of: Handle IOMMU lookup failure with deferred probing or error
Failures to look up an IOMMU when parsing the DT iommus property need to be handled separately from the .of_xlate() failures to support deferred probing. The lack of a registered IOMMU can be caused by the lack of a driver for the IOMMU, the IOMMU device probe not having been performed yet, having been deferred, or having failed. The first case occurs when the device tree describes the bus master and IOMMU topology correctly but no device driver exists for the IOMMU yet or the device driver has not been compiled in. Return NULL, the caller will configure the device without an IOMMU. The second and third cases are handled by deferring the probe of the bus master device which will eventually get reprobed after the IOMMU. The last case is currently handled by deferring the probe of the bus master device as well. A mechanism to either configure the bus master device without an IOMMU or to fail the bus master device probe depending on whether the IOMMU is optional or mandatory would be a good enhancement. Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Laurent Pichart <laurent.pinchart+renesas@ideasonboard.com> Signed-off-by: Sricharan R <sricharan@codeaurora.org> Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'include/linux/of_device.h')
-rw-r--r--include/linux/of_device.h9
1 files changed, 6 insertions, 3 deletions
diff --git a/include/linux/of_device.h b/include/linux/of_device.h
index af984551cc2b..2cacdd81062e 100644
--- a/include/linux/of_device.h
+++ b/include/linux/of_device.h
@@ -55,7 +55,7 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
return of_node_get(cpu_dev->of_node);
}
-void of_dma_configure(struct device *dev, struct device_node *np);
+int of_dma_configure(struct device *dev, struct device_node *np);
void of_dma_deconfigure(struct device *dev);
#else /* CONFIG_OF */
@@ -104,8 +104,11 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
{
return NULL;
}
-static inline void of_dma_configure(struct device *dev, struct device_node *np)
-{}
+
+static inline int of_dma_configure(struct device *dev, struct device_node *np)
+{
+ return 0;
+}
static inline void of_dma_deconfigure(struct device *dev)
{}
#endif /* CONFIG_OF */