Re: [PATCH] iommu/arm-smmu: support SMMU module probing from the IORT

[John Garry]

On 25/11/2019 16:04, Lorenzo Pieralisi wrote:
> On Fri, Nov 22, 2019 at 06:41:25PM +0100, Ard Biesheuvel wrote:
> > Add support for SMMU drivers built as modules to the ACPI/IORT device
> > probing path, by deferring the probe of the master if the SMMU driver is
> > known to exist but has not been loaded yet. Given that the IORT code
> > registers a platform device for each SMMU that it discovers, we can
> > easily trigger the udev based autoloading of the SMMU drivers by making
> > the platform device identifier part of the module alias.
> >
> > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> > ---
> >   drivers/acpi/arm64/iort.c   | 4 ++--
> >   drivers/iommu/arm-smmu-v3.c | 1 +
> >   drivers/iommu/arm-smmu.c    | 1 +
> >   3 files changed, 4 insertions(+), 2 deletions(-)
>
> I think it is best if Will picks this up and add it to the
> series that modularize the SMMU drivers:
>
> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>

Tested-by: John Garry <john.garry@xxxxxxxxxx> # only manual smmu ko loading

> > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> > index 5a7551d060f2..a696457a9b11 100644
> > --- a/drivers/acpi/arm64/iort.c
> > +++ b/drivers/acpi/arm64/iort.c
> > @@ -850,9 +850,9 @@ static inline bool iort_iommu_driver_enabled(u8 type)
> >   {
> >   	switch (type) {
> >   	case ACPI_IORT_NODE_SMMU_V3:
> > -		return IS_BUILTIN(CONFIG_ARM_SMMU_V3);
> > +		return IS_ENABLED(CONFIG_ARM_SMMU_V3);
> >   	case ACPI_IORT_NODE_SMMU:
> > -		return IS_BUILTIN(CONFIG_ARM_SMMU);
> > +		return IS_ENABLED(CONFIG_ARM_SMMU);
> >   	default:
> >   		pr_warn("IORT node type %u does not describe an SMMU\n", type);
> >   		return false;
> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> > index 7669beafc493..bf6a1e8eb9b0 100644
> > --- a/drivers/iommu/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm-smmu-v3.c
> > @@ -3733,4 +3733,5 @@ module_platform_driver(arm_smmu_driver);
> >   
> >   MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
> >   MODULE_AUTHOR("Will Deacon <will@xxxxxxxxxx>");
> > +MODULE_ALIAS("platform:arm-smmu-v3");
> >   MODULE_LICENSE("GPL v2");
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> > index d55acc48aee3..db5106b0955b 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -2292,4 +2292,5 @@ module_platform_driver(arm_smmu_driver);
> >   
> >   MODULE_DESCRIPTION("IOMMU API for ARM architected SMMU implementations");
> >   MODULE_AUTHOR("Will Deacon <will@xxxxxxxxxx>");
> > +MODULE_ALIAS("platform:arm-smmu");
> >   MODULE_LICENSE("GPL v2");
> > --
> > 2.20.1
> .