[PATCH] powerpc/powernv/pci: Fix build of pci-ioda.o

[Oliver O'Halloran]

On Wed, Jul 29, 2020 at 8:35 AM Gustavo Romero <gromero at linux.ibm.com> wrote:
>
> Currently pnv_ioda_setup_bus_dma() is outside of a CONFIG_IOMMU_API guard
> and if CONFIG_IOMMU_API=n the build can fail if the compiler sets
> -Werror=unused-function, because pnv_ioda_setup_bus_dma() is only used in
> functions guarded by a CONFIG_IOMMU_API guard.
>
> That issue can be easily reproduced using the skiroot_defconfig. For other
> configs, like powernv_defconfig, that issue is hidden by the fact that
> if CONFIG_IOMMU_SUPPORT is enabled plus other common IOMMU options, like
> CONFIG_OF_IOMMU, by default CONFIG_IOMMU_API is enabled as well. Hence, for
> powernv_defconfig, it's necessary to set CONFIG_IOMMU_SUPPORT=n to make the
> build fail, because CONFIG_PCI=y and pci-ioda.c is included in the build,
> but since CONFIG_IOMMU_SUPPORT=n the CONFIG_IOMMU_API is disabled, breaking
> the build.
>
> This commit fixes that build issue by moving the pnv_ioda_setup_bus_dma()
> inside a CONFIG_IOMMU_API guard, so when CONFIG_IOMMU_API is disabled that
> function is not defined.

I think a fix for this is already in -next.