iommu/arm-smmu: Play nice on non-ARM/SMMU systems
PATCH 1/1 iommu/arm-smmu: Play nice on non-ARM/SMMU systems
From: Thierry Reding <[email protected]>
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.
--- drivers/iommu/arm-smmu.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
drivers/iommu/arm-smmu.c +12 -0
@@ -2072,8 +2072,20 @@ static struct platform_driver arm_smmu_driver = {static int __init arm_smmu_init (void ) { +struct device_node *np;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);if (ret)return ret;
Signature · 1 line
2.1.3
PATCH 1/1 iommu/arm-smmu: Play nice on non-ARM/SMMU systems
Quoted 24 lines · Thierry Reding
From: Thierry Reding <[email protected]>
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 <[email protected]>--- drivers/iommu/arm-smmu.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)drivers/iommu/arm-smmu.c +2
-0@@ -2072,8 +2072,20 @@ static struct platform_driver arm_smmu_driver = {static int __init arm_smmu_init (void ) { +struct device_node *np;int ret; +/*
drivers/iommu/arm-smmu.c static struct platform_driver arm_smmu_driver = { · line 2088
Quoted 10 lines
drivers/iommu/arm-smmu.c +10
-0+* 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); +
Hopefully, this will be solved shortly by the of_iommu_configure series I've been dragging my feet with recently. However, since that's not done yet, this looks like the best thing for now, even if it's a bit of a bodge.
Have you checked/updated other IOMMMU drivers too?
Will
PATCH 1/1 iommu/arm-smmu: Play nice on non-ARM/SMMU systems
Quoted 40 lines · Will Deacon
Quoted 24 lines · Thierry Reding
From: Thierry Reding <[email protected]>
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 <[email protected]>--- drivers/iommu/arm-smmu.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)drivers/iommu/arm-smmu.c +2
-0@@ -2072,8 +2072,20 @@ static struct platform_driver arm_smmu_driver = {static int __init arm_smmu_init (void ) { +struct device_node *np;int ret; +/* drivers/iommu/arm-smmu.c static struct platform_driver arm_smmu_driver = { · line 2088
Quoted 10 lines
drivers/iommu/arm-smmu.c +10
-0+* 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); +Hopefully, this will be solved shortly by the
of_iommu_configureseries I've been dragging my feet with recently. However, since that's not done yet, this looks like the best thing for now, even if it's a bit of a bodge.
Quoted 1 line
Have you checked/updated other IOMMMU drivers too?
ARM SMMU was the only one being enabled on 64-bit where I noticed this, but from a quick glance a couple of the other ARM driver are affected as well. I'll see if I can find the time to come up with a similar patch.
Of course if these IOMMU drivers were proper drivers and bind to a device, then this problem wouldn't exist in the first place.
Thierry
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