Messages in this thread Patches in this message | | | Date | Wed, 15 Mar 2023 07:27:14 -0500 | Subject | Re: [PATCH v2] irqchip/gicv3: Workaround for NVIDIA erratum T241-FABRIC-4 | From | Shanker Donthineni <> |
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Hi Marc,
On 3/15/23 03:34, Marc Zyngier wrote: > Please don't duplicate existing code. There is already the required > infrastructure in drivers/firmware/smccc/soc_id.c. All you need to do > is: > > - disassociate the SMCCC probing from the device registration > > - probe the SOC_ID early > > - add accessors for the relevant data > > - select ARM_SMCCC_SOD_ID/ARM_SMCCC_DISCOVERY from the GICv3 Kconfig
I have not modified soc_id.c as it expects to be loaded as a module with the use of module_init() and module_exit() functions. The exported symbols in soc_id driver cannot be accessed from the built-in code.
Agree, the SOD-ID discovery code was duplicated.
Please guide me if the below approach is okay?
1) Probe the SOC-ID in arm_smccc_version_init() and export two functions arm_smccc_get_soc_id_version() and arm_smccc_get_soc_id_revision().
--- a/drivers/firmware/smccc/smccc.c +++ b/drivers/firmware/smccc/smccc.c @@ -17,9 +17,13 @@ static enum arm_smccc_conduit smccc_conduit = SMCCC_CONDUIT_NONE;
bool __ro_after_init smccc_trng_available = false; u64 __ro_after_init smccc_has_sve_hint = false; +s32 __ro_after_init smccc_soc_id_version = SMCCC_RET_NOT_SUPPORTED; +s32 __ro_after_init smccc_soc_id_revision = SMCCC_RET_NOT_SUPPORTED;
void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit) { + struct arm_smccc_res res; + smccc_version = version; smccc_conduit = conduit;
@@ -27,6 +31,18 @@ void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit) if (IS_ENABLED(CONFIG_ARM64_SVE) && smccc_version >= ARM_SMCCC_VERSION_1_3) smccc_has_sve_hint = true; + + if ((smccc_version >= ARM_SMCCC_VERSION_1_2) && + (smccc_conduit != SMCCC_CONDUIT_NONE)) { + arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, + ARM_SMCCC_ARCH_SOC_ID, &res); + if ((s32)res.a0 >= 0) { + arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res); + smccc_soc_id_version = (s32)res.a0; + arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res); + smccc_soc_id_revision = (s32)res.a0; + } + } }
+s32 arm_smccc_get_soc_id_version(void) +{ + return smccc_soc_id_version; +} +EXPORT_SYMBOL_GPL(arm_smccc_get_soc_id_version); + +s32 arm_smccc_get_soc_id_revision(void) +{ + return smccc_soc_id_revision; +} +EXPORT_SYMBOL_GPL(arm_smccc_get_soc_id_revision);
--- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h +/** + * arm_smccc_get_soc_id_version() + * + * Returns the SOC ID version. + * + * When ARM_SMCCC_ARCH_SOC_ID is not present, returns SMCCC_RET_NOT_SUPPORTED. + */ +s32 arm_smccc_get_soc_id_version(void); +/** + * arm_smccc_get_soc_id_revision() + * + * Returns the SOC ID revision. + * + * When ARM_SMCCC_ARCH_SOC_ID is not present, returns SMCCC_RET_NOT_SUPPORTED. + */ +s32 arm_smccc_get_soc_id_revision(void);
2) Use the exported functions in soc_id module.
--- a/drivers/firmware/smccc/soc_id.c +++ b/drivers/firmware/smccc/soc_id.c @@ -42,41 +42,23 @@ static int __init smccc_soc_init(void) if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2) return 0;
- if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) { - pr_err("%s: invalid SMCCC conduit\n", __func__); - return -EOPNOTSUPP; - } - - arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, - ARM_SMCCC_ARCH_SOC_ID, &res); - - if ((int)res.a0 == SMCCC_RET_NOT_SUPPORTED) { + soc_id_version = arm_smccc_get_soc_id_version(); + if (soc_id_version == SMCCC_RET_NOT_SUPPORTED) { pr_info("ARCH_SOC_ID not implemented, skipping ....\n"); return 0; }
- if ((int)res.a0 < 0) { - pr_info("ARCH_FEATURES(ARCH_SOC_ID) returned error: %lx\n", - res.a0); - return -EINVAL; - } - - arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res); - if ((int)res.a0 < 0) { + if (soc_id_version < 0) { pr_err("ARCH_SOC_ID(0) returned error: %lx\n", res.a0); return -EINVAL; }
- soc_id_version = res.a0; - - arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res); - if ((int)res.a0 < 0) { + soc_id_rev = arm_smccc_get_soc_id_revision(); + if (soc_id_rev < 0) { pr_err("ARCH_SOC_ID(1) returned error: %lx\n", res.a0); return -EINVAL; }
- soc_id_rev = res.a0;
Kconfig: --- a/drivers/irqchip/Kconfig +++ b/drivers/irqchip/Kconfig @@ -35,6 +35,7 @@ config ARM_GIC_V3 select IRQ_DOMAIN_HIERARCHY select PARTITION_PERCPU select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP + select HAVE_ARM_SMCCC_DISCOVERY
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