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SubjectRe: [PATCH v2 13/16] firmware/psci: Expose SMCCC version through psci_ops
On Mon, Jan 29, 2018 at 05:45:56PM +0000, Marc Zyngier wrote:
> Since PSCI 1.0 allows the SMCCC version to be (indirectly) probed,
> let's do that at boot time, and expose the version of the calling
> convention as part of the psci_ops structure.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> drivers/firmware/psci.c | 21 +++++++++++++++++++++
> include/linux/psci.h | 6 ++++++
> 2 files changed, 27 insertions(+)
>
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index e9493da2b111..dd035aaa1c33 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -511,6 +511,26 @@ static void __init psci_init_migrate(void)
> pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
> }
>
> +static void __init psci_init_smccc(u32 ver)
> +{
> + int feature = PSCI_RET_NOT_SUPPORTED;
> +
> + if (PSCI_VERSION_MAJOR(ver) >= 1)
> + feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
> +
> + if (feature == PSCI_RET_NOT_SUPPORTED) {
> + psci_ops.variant = SMCCC_VARIANT_1_0;
> + } else {
> + ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
> + if (ver != ARM_SMCCC_VERSION_1_1)
> + psci_ops.variant = SMCCC_VARIANT_1_0;
> + else
> + psci_ops.variant = SMCCC_VARIANT_1_1;
> + }
> +
> + pr_info("SMC Calling Convention v1.%d\n", psci_ops.variant);
> +}
> +
> static void __init psci_0_2_set_functions(void)
> {
> pr_info("Using standard PSCI v0.2 function IDs\n");
> @@ -557,6 +577,7 @@ static int __init psci_probe(void)
> psci_0_2_set_functions();
>
> psci_init_migrate();
> + psci_init_smccc(ver);

Given that SMCCC_VARIANT_1_0 is already the default value (unless you do
the same we did with the conduit) we can move psci_init_smccc() call
inside the if below (that is there to detect a callable psci_features())
and remove the check in psci_init_smccc(), up to you.

>
> if (PSCI_VERSION_MAJOR(ver) >= 1) {
> psci_init_cpu_suspend();
> diff --git a/include/linux/psci.h b/include/linux/psci.h
> index f2679e5faa4f..83fd16a37be3 100644
> --- a/include/linux/psci.h
> +++ b/include/linux/psci.h
> @@ -31,6 +31,11 @@ enum psci_conduit {
> PSCI_CONDUIT_HVC,
> };
>
> +enum smccc_variant {
> + SMCCC_VARIANT_1_0,
> + SMCCC_VARIANT_1_1,
> +};
> +
> struct psci_operations {
> u32 (*get_version)(void);
> int (*cpu_suspend)(u32 state, unsigned long entry_point);
> @@ -41,6 +46,7 @@ struct psci_operations {
> unsigned long lowest_affinity_level);
> int (*migrate_info_type)(void);
> enum psci_conduit conduit;
> + enum smccc_variant variant;

Nit: I would add an smccc_ prefix to the variant field (or rename it
to smccc_version).

You can add my:

Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

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