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    SubjectRe: [PATCH v3 14/18] firmware/psci: Expose SMCCC version through psci_ops
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    On 01/02/18 11:46, 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.
    >
    > Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
    > ---
    > drivers/firmware/psci.c | 19 +++++++++++++++++++
    > include/linux/psci.h | 6 ++++++
    > 2 files changed, 25 insertions(+)
    >
    > diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
    > index e9493da2b111..8631906c414c 100644
    > --- a/drivers/firmware/psci.c
    > +++ b/drivers/firmware/psci.c
    > @@ -61,6 +61,7 @@ bool psci_tos_resident_on(int cpu)
    >
    > struct psci_operations psci_ops = {
    > .conduit = PSCI_CONDUIT_NONE,
    > + .smccc_version = SMCCC_VERSION_1_0,
    > };
    >
    > typedef unsigned long (psci_fn)(unsigned long, unsigned long,
    > @@ -511,6 +512,23 @@ 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;
    > +
    > + feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
    > +
    > + if (feature != PSCI_RET_NOT_SUPPORTED) {
    > + ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
    > + if (ver != ARM_SMCCC_VERSION_1_1)
    > + psci_ops.smccc_version = SMCCC_VERSION_1_0;

    AFAICS, unless you somehow run psci_probe() twice *and* have
    schizophrenic firmware, this assignment now does precisely nothing.

    With the condition flipped and the redundant else case removed (or an
    explanation of why I'm wrong...)

    Reviewed-by: Robin Murphy <robin.murphy@arm.com>

    > + else
    > + psci_ops.smccc_version = SMCCC_VERSION_1_1;
    > + }
    > +
    > + pr_info("SMC Calling Convention v1.%d\n", psci_ops.smccc_version);
    > +}
    > +
    > static void __init psci_0_2_set_functions(void)
    > {
    > pr_info("Using standard PSCI v0.2 function IDs\n");
    > @@ -559,6 +577,7 @@ static int __init psci_probe(void)
    > psci_init_migrate();
    >
    > if (PSCI_VERSION_MAJOR(ver) >= 1) {
    > + psci_init_smccc(ver);
    > psci_init_cpu_suspend();
    > psci_init_system_suspend();
    > }
    > diff --git a/include/linux/psci.h b/include/linux/psci.h
    > index f2679e5faa4f..8b1b3b5935ab 100644
    > --- a/include/linux/psci.h
    > +++ b/include/linux/psci.h
    > @@ -31,6 +31,11 @@ enum psci_conduit {
    > PSCI_CONDUIT_HVC,
    > };
    >
    > +enum smccc_version {
    > + SMCCC_VERSION_1_0,
    > + SMCCC_VERSION_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_version smccc_version;
    > };
    >
    > extern struct psci_operations psci_ops;
    >

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