Re: [PATCH 2/2] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module

[Will Deacon <will@kernel.org>]

On Tue, May 18, 2021 at 09:19:22PM +0000, John Stultz wrote:
> Allow the qcom_scm driver to be loadable as a permenent module.
> 
> This still uses the "depends on QCOM_SCM || !QCOM_SCM" bit to
> ensure that drivers that call into the qcom_scm driver are
> also built as modules. While not ideal in some cases its the
> only safe way I can find to avoid build errors without having
> those drivers select QCOM_SCM and have to force it on (as
> QCOM_SCM=n can be valid for those drivers).
> 
> Reviving this now that Saravana's fw_devlink defaults to on,
> which should avoid loading troubles seen before.
> 
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Andy Gross <agross@kernel.org>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Marc Zyngier <maz@kernel.org>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Vinod Koul <vkoul@kernel.org>
> Cc: Kalle Valo <kvalo@codeaurora.org>
> Cc: Maulik Shah <mkshah@codeaurora.org>
> Cc: Lina Iyer <ilina@codeaurora.org>
> Cc: Saravana Kannan <saravanak@google.com>
> Cc: Todd Kjos <tkjos@google.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-arm-msm@vger.kernel.org
> Cc: iommu@lists.linux-foundation.org
> Cc: linux-gpio@vger.kernel.org
> Acked-by: Kalle Valo <kvalo@codeaurora.org>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
> v3:
> * Fix __arm_smccc_smc build issue reported by
>   kernel test robot <lkp@intel.com>
> v4:
> * Add "depends on QCOM_SCM || !QCOM_SCM" bit to ath10k
>   config that requires it.
> v5:
> * Fix QCOM_QCM typo in Kconfig, it should be QCOM_SCM
> ---
>  drivers/firmware/Kconfig                | 2 +-
>  drivers/firmware/Makefile               | 3 ++-
>  drivers/firmware/qcom_scm.c             | 4 ++++
>  drivers/iommu/Kconfig                   | 2 ++
>  drivers/net/wireless/ath/ath10k/Kconfig | 1 +
>  5 files changed, 10 insertions(+), 2 deletions(-)

[...]

> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 1f111b399bcab..38f7b7a8e2843 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -253,6 +253,7 @@ config SPAPR_TCE_IOMMU
>  config ARM_SMMU
>  	tristate "ARM Ltd. System MMU (SMMU) Support"
>  	depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> +	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
> @@ -382,6 +383,7 @@ config QCOM_IOMMU
>  	# Note: iommu drivers cannot (yet?) be built as modules
>  	bool "Qualcomm IOMMU Support"
>  	depends on ARCH_QCOM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> +	depends on QCOM_SCM=y
>  	select IOMMU_API
>  	select IOMMU_IO_PGTABLE_LPAE
>  	select ARM_DMA_USE_IOMMU

For this part:

Acked-by: Will Deacon <will@kernel.org>

Will