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Date:   Sat, 17 Jul 2021 00:01:11 -0500
From:   Bjorn Andersson <bjorn.andersson@linaro.org>
To:     John Stultz <john.stultz@linaro.org>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, Andy Gross <agross@kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Vinod Koul <vkoul@kernel.org>,
        Kalle Valo <kvalo@codeaurora.org>,
        Maulik Shah <mkshah@codeaurora.org>,
        Saravana Kannan <saravanak@google.com>,
        Todd Kjos <tkjos@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-arm-msm@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-gpio@vger.kernel.org
Subject: Re: [PATCH] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable
 as a permenent module
Message-ID: <YPJkF21ItYlKODyq@yoga>
References: <20210707045320.529186-1-john.stultz@linaro.org>
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In-Reply-To: <20210707045320.529186-1-john.stultz@linaro.org>
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On Tue 06 Jul 23:53 CDT 2021, 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.
> 

Are you (in this last paragraph) saying that all those who have been
burnt by fw_devlink during the last months and therefor run with it
disabled will have a less fun experience once this is merged?


(I'm picking this up, but I don't fancy the idea that some people are
turning the boot process into a lottery)

Regards,
Bjorn

> 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: 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: 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>
> Acked-by: Will Deacon <will@kernel.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/firmware/Kconfig b/drivers/firmware/Kconfig
> index db0ea2d2d75a..af53778edc7e 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -235,7 +235,7 @@ config INTEL_STRATIX10_RSU
>  	  Say Y here if you want Intel RSU support.
>  
>  config QCOM_SCM
> -	bool
> +	tristate "Qcom SCM driver"
>  	depends on ARM || ARM64
>  	depends on HAVE_ARM_SMCCC
>  	select RESET_CONTROLLER
> diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
> index 5e013b6a3692..523173cbff33 100644
> --- a/drivers/firmware/Makefile
> +++ b/drivers/firmware/Makefile
> @@ -17,7 +17,8 @@ obj-$(CONFIG_ISCSI_IBFT)	+= iscsi_ibft.o
>  obj-$(CONFIG_FIRMWARE_MEMMAP)	+= memmap.o
>  obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
>  obj-$(CONFIG_FW_CFG_SYSFS)	+= qemu_fw_cfg.o
> -obj-$(CONFIG_QCOM_SCM)		+= qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
> +obj-$(CONFIG_QCOM_SCM)		+= qcom-scm.o
> +qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
>  obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
>  obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
>  obj-$(CONFIG_TURRIS_MOX_RWTM)	+= turris-mox-rwtm.o
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index ee9cb545e73b..bb9ce3f92931 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -1296,6 +1296,7 @@ static const struct of_device_id qcom_scm_dt_match[] = {
>  	{ .compatible = "qcom,scm" },
>  	{}
>  };
> +MODULE_DEVICE_TABLE(of, qcom_scm_dt_match);
>  
>  static struct platform_driver qcom_scm_driver = {
>  	.driver = {
> @@ -1312,3 +1313,6 @@ static int __init qcom_scm_init(void)
>  	return platform_driver_register(&qcom_scm_driver);
>  }
>  subsys_initcall(qcom_scm_init);
> +
> +MODULE_DESCRIPTION("Qualcomm Technologies, Inc. SCM driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 07b7c25cbed8..f61516c17589 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
> diff --git a/drivers/net/wireless/ath/ath10k/Kconfig b/drivers/net/wireless/ath/ath10k/Kconfig
> index 40f91bc8514d..741289e385d5 100644
> --- a/drivers/net/wireless/ath/ath10k/Kconfig
> +++ b/drivers/net/wireless/ath/ath10k/Kconfig
> @@ -44,6 +44,7 @@ config ATH10K_SNOC
>  	tristate "Qualcomm ath10k SNOC support"
>  	depends on ATH10K
>  	depends on ARCH_QCOM || COMPILE_TEST
> +	depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
>  	select QCOM_QMI_HELPERS
>  	help
>  	  This module adds support for integrated WCN3990 chip connected
> -- 
> 2.25.1
>