Re: [PATCH v2 2/2] qcom_scm: hide Kconfig symbol
From: John Stultz <hidden>
Date: 2021-10-12 03:11:41
Also in:
dri-devel, linux-arm-kernel, linux-arm-msm, linux-gpio, linux-iommu, linux-media, linux-mips, linux-mmc, linux-riscv, linux-wireless, lkml
On Thu, Oct 7, 2021 at 8:10 AM Arnd Bergmann [off-list ref] wrote:
From: Arnd Bergmann <arnd@arndb.de> Now that SCM can be a loadable module, we have to add another dependency to avoid link failures when ipa or adreno-gpu are built-in: aarch64-linux-ld: drivers/net/ipa/ipa_main.o: in function `ipa_probe': ipa_main.c:(.text+0xfc4): undefined reference to `qcom_scm_is_available' ld.lld: error: undefined symbol: qcom_scm_is_availablequoted
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referenced by adreno_gpu.c gpu/drm/msm/adreno/adreno_gpu.o:(adreno_zap_shader_load) in archive drivers/built-in.aThis can happen when CONFIG_ARCH_QCOM is disabled and we don't select QCOM_MDT_LOADER, but some other module selects QCOM_SCM. Ideally we'd use a similar dependency here to what we have for QCOM_RPROC_COMMON, but that causes dependency loops from other things selecting QCOM_SCM. This appears to be an endless problem, so try something different this time: - CONFIG_QCOM_SCM becomes a hidden symbol that nothing 'depends on' but that is simply selected by all of its users - All the stubs in include/linux/qcom_scm.h can go away - arm-smccc.h needs to provide a stub for __arm_smccc_smc() to allow compile-testing QCOM_SCM on all architectures. - To avoid a circular dependency chain involving RESET_CONTROLLER and PINCTRL_SUNXI, drop the 'select RESET_CONTROLLER' statement. According to my testing this still builds fine, and the QCOM platform selects this symbol already. Acked-by: Kalle Valo <redacted> Acked-by: Alex Elder <redacted> Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- Changes in v2: - fix the iommu dependencies
Hey Arnd, Thanks again so much for working out these details. Also my apologies, as Bjorn asked for me to test this patch, but I wasn't able to get to it before it landed. Unfortunately I've hit an issue that is keeping the db845c from booting with this.
quoted hunk ↗ jump to hunk
diff --git a/drivers/iommu/arm/arm-smmu/Makefile b/drivers/iommu/arm/arm-smmu/Makefile index e240a7bcf310..b0cc01aa20c9 100644 --- a/drivers/iommu/arm/arm-smmu/Makefile +++ b/drivers/iommu/arm/arm-smmu/Makefile@@ -1,4 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_QCOM_IOMMU) += qcom_iommu.o obj-$(CONFIG_ARM_SMMU) += arm_smmu.o -arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-nvidia.o arm-smmu-qcom.o +arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-nvidia.o +arm_smmu-$(CONFIG_ARM_SMMU_QCOM) += arm-smmu-qcom.odiff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c index 9f465e146799..2c25cce38060 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c@@ -215,7 +215,8 @@ struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu) of_device_is_compatible(np, "nvidia,tegra186-smmu")) return nvidia_smmu_impl_init(smmu); - smmu = qcom_smmu_impl_init(smmu); + if (IS_ENABLED(CONFIG_ARM_SMMU_QCOM)) + smmu = qcom_smmu_impl_init(smmu); if (of_device_is_compatible(np, "marvell,ap806-smmu-500")) smmu->impl = &mrvl_mmu500_impl;
The problem with these two chunks is that there is currently no CONFIG_ARM_SMMU_QCOM option. :) Was that something you intended to add in the patch? I'm working up a Kconfig patch to do so, so I'll send that out in a second here, but let me know if you already have that somewhere (I suspect you implemented it and just forgot to add the change to the commit), as I'm sure your Kconfig help text will be better than mine. :) Again, I'm so sorry I didn't get over to testing your patch before seeing this here! thanks -john