firmware/psci: Expose SMCCC version through psci_ops

Web:        https://git.kernel.org/torvalds/c/e78eef554a912ef6c1e0bbf97619dafbeae3339f
Commit:     e78eef554a912ef6c1e0bbf97619dafbeae3339f
Parent:     09a8d6d48499f93e2abde691f5800081cd858726
Refname:    refs/heads/master
Author:     Marc Zyngier <[email protected]>
AuthorDate: Tue Feb 6 17:56:17 2018 +0000
Committer:  Catalin Marinas <[email protected]>
CommitDate: Tue Feb 6 22:54:11 2018 +0000

    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 <[email protected]>
    Reviewed-by: Robin Murphy <[email protected]>
    Tested-by: Ard Biesheuvel <[email protected]>
    Signed-off-by: Marc Zyngier <[email protected]>
    Signed-off-by: Catalin Marinas <[email protected]>
---
 drivers/firmware/psci.c | 27 +++++++++++++++++++++++++++
 include/linux/psci.h    |  6 ++++++
 2 files changed, 33 insertions(+)

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();
 	}
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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