On Thu, Jul 2, 2020 at 7:18 AM Will Deacon <w...@kernel.org> wrote: > On Thu, Jun 25, 2020 at 12:10:39AM +0000, John Stultz wrote: > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > > index b510f67dfa49..714893535dd2 100644 > > --- a/drivers/iommu/Kconfig > > +++ b/drivers/iommu/Kconfig > > @@ -381,6 +381,7 @@ config SPAPR_TCE_IOMMU > > config ARM_SMMU > > tristate "ARM Ltd. System MMU (SMMU) Support" > > depends on (ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)) && > > MMU > > + depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y > > select IOMMU_API > > select IOMMU_IO_PGTABLE_LPAE > > select ARM_DMA_USE_IOMMU if ARM > > This looks like a giant hack. Is there another way to handle this?
Sorry for the slow response here. So, I agree the syntax looks strange (requiring a comment obviously isn't a good sign), but it's a fairly common way to ensure drivers don't get built in if they optionally depend on another driver that can be built as a module. See "RFKILL || !RFKILL", "EXTCON || !EXTCON", or "USB_GADGET || !USB_GADGET" in various Kconfig files. I'm open to using a different method, and in a different thread you suggested using something like symbol_get(). I need to look into it more, but that approach looks even more messy and prone to runtime failures. Blocking the unwanted case at build time seems a bit cleaner to me, even if the syntax is odd. thanks -john
