[PATCH 5/5] iommu/arm-smmu: fix compilation issue when !CONFIG_ARM_AMBA

[Will Deacon]

On Thu, Feb 13, 2014 at 04:55:25PM +0000, Timur Tabi wrote:
> On Thu, Feb 6, 2014 at 12:09 PM, Will Deacon <will.deacon at arm.com> wrote:
> 
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> > index 0ae4dd39197f..6fe7922ecc1d 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -2004,8 +2004,10 @@ static int __init arm_smmu_init(void)
> >         if (!iommu_present(&platform_bus_type))
> >                 bus_set_iommu(&platform_bus_type, &arm_smmu_ops);
> >
> > +#ifdef CONFIG_ARM_AMBA
> >         if (!iommu_present(&amba_bustype))
> >                 bus_set_iommu(&amba_bustype, &arm_smmu_ops);
> > +#endif
> 
> So I admit I don't know much about the ARM kernel (yet), but doesn't
> this break multi-arch?  That is, we can't support one binary that runs
> on a processor with AMBA and one without?

Huh?

It's harmless to enable CONFIG_ARM_AMBA, even if you don't have any AMBA
devices in your SoC, it just makes your binary a bit bigger because you're
compiling in code that you don't need. Instead, you might elect to set
CONFIG_ARM_AMBA=n, at which point the arm-smmu driver will fail to build
without this patch.

Will