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iommu/arm-smmu: Play nice on non-ARM/SMMU systems 

Currently the driver registers IOMMU bus operations for all busses even
if no ARM SMMU is present on a system. Depending on the driver probing
order this prevents the driver for the real IOMMU to register itself as
the bus-wide IOMMU.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Thierry Reding 2014-11-07 15:26:18 +00:00 committed by Will Deacon
parent cfdeec22e4
commit 0e7d37adbe
1 changed files with 12 additions and 0 deletions
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12
drivers/iommu/arm-smmu.c
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@ -2075,8 +2075,20 @@ static struct platform_driver arm_smmu_driver = {
static int __init arm_smmu_init(void) static int __init arm_smmu_init(void)
{ {
struct device_node *np;
int ret; int ret;
/*
* Play nice with systems that don't have an ARM SMMU by checking that
* an ARM SMMU exists in the system before proceeding with the driver
* and IOMMU bus operation registration.
*/
np = of_find_matching_node(NULL, arm_smmu_of_match);
if (!np)
return 0;
of_node_put(np);
ret = platform_driver_register(&arm_smmu_driver); ret = platform_driver_register(&arm_smmu_driver);
if (ret) if (ret)
return ret; return ret;