firmware/psci: Expose SMCCC version through psci_ops

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>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index e9493da2b111e67ce5169bd91f031e29e0be92fc..c80ec1d03274413863fb8e3f917f26daa8f868c2 100644 (file)
--- 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 +512,31 @@ 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(void)
+{
+       u32 ver = ARM_SMCCC_VERSION_1_0;
+       int feature;
+
+       feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
+
+       if (feature != PSCI_RET_NOT_SUPPORTED) {
+               u32 ret;
+               ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
+               if (ret == ARM_SMCCC_VERSION_1_1) {
+                       psci_ops.smccc_version = SMCCC_VERSION_1_1;
+                       ver = ret;
+               }
+       }
+
+       /*
+        * Conveniently, the SMCCC and PSCI versions are encoded the
+        * same way. No, this isn't accidental.
+        */
+       pr_info("SMC Calling Convention v%d.%d\n",
+               PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));
+
+}
+
 static void __init psci_0_2_set_functions(void)
 {
        pr_info("Using standard PSCI v0.2 function IDs\n");
@@ -559,6 +585,7 @@ static int __init psci_probe(void)
        psci_init_migrate();
 
        if (PSCI_VERSION_MAJOR(ver) >= 1) {
+               psci_init_smccc();
                psci_init_cpu_suspend();
                psci_init_system_suspend();
        }

diff --git a/include/linux/psci.h b/include/linux/psci.h
index f2679e5faa4fa705f62c8752ecce9b39524febcb..8b1b3b5935ab0fff113f7b270115461ceecd7e42 100644 (file)
--- 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;