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>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index e9493da2b111..c80ec1d03274 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 +512,31 @@ 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();
         }