On Wed, Mar 15, 2023 at 07:27:14AM -0500, Shanker Donthineni wrote:
> 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);
>
>
Overall, it looks OK to me. However I see neither the gic nor the soc_id
can be build as module atm. So do we really need the export symbols if no
other modules are using it ?
--
Regards,
Sudeep
