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authorLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>2017-04-10 13:21:02 +0200
committerJoerg Roedel <jroedel@suse.de>2017-04-20 16:31:07 +0200
commit7b07cbefb68d486febf47e13b570fed53d9296b4 (patch)
tree111db4d3e44fbb0315528b6dc51979b8081cb7ce /drivers/base
parentof/acpi: Configure dma operations at probe time for platform/amba/pci bus dev... (diff)
downloadlinux-7b07cbefb68d486febf47e13b570fed53d9296b4.tar.xz
linux-7b07cbefb68d486febf47e13b570fed53d9296b4.zip
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 'drivers/base')
-rw-r--r--drivers/base/dma-mapping.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index 449b948c7427..82bd45ced7ff 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -353,6 +353,7 @@ int dma_configure(struct device *dev)
{
struct device *bridge = NULL, *dma_dev = dev;
enum dev_dma_attr attr;
+ int ret = 0;
if (dev_is_pci(dev)) {
bridge = pci_get_host_bridge_device(to_pci_dev(dev));
@@ -363,7 +364,7 @@ int dma_configure(struct device *dev)
}
if (dma_dev->of_node) {
- of_dma_configure(dev, dma_dev->of_node);
+ ret = of_dma_configure(dev, dma_dev->of_node);
} else if (has_acpi_companion(dma_dev)) {
attr = acpi_get_dma_attr(to_acpi_device_node(dma_dev->fwnode));
if (attr != DEV_DMA_NOT_SUPPORTED)
@@ -373,7 +374,7 @@ int dma_configure(struct device *dev)
if (bridge)
pci_put_host_bridge_device(bridge);
- return 0;
+ return ret;
}
void dma_deconfigure(struct device *dev)