linux-kernel - [PATCH 13/14] firmware/psci: Expose SMCCC version through psci

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Message-Id: <20180126142847.31240-14-marc.zyngier@arm.com>
Date:   Fri, 26 Jan 2018 14:28:46 +0000
From:   Marc Zyngier <marc.zyngier@....com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Peter Maydell <peter.maydell@...aro.org>,
        Christoffer Dall <christoffer.dall@...aro.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Mark Rutland <mark.rutland@....com>,
        Jon Masters <jcm@...hat.com>
Subject: [PATCH 13/14] 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.

Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 drivers/firmware/psci.c | 22 ++++++++++++++++++++++
 include/linux/psci.h    |  6 ++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 570187e5d084..b260bbf637a2 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -509,6 +509,27 @@ 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 ||
+	    (PSCI_VERSION_MAJOR(ver) == 1 && PSCI_VERSION_MINOR(ver) >= 0))
+		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");
@@ -555,6 +576,7 @@ static int __init psci_probe(void)
 	psci_0_2_set_functions();
 
 	psci_init_migrate();
+	psci_init_smccc(ver);
 
 	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;
 };
 
 extern struct psci_operations psci_ops;
-- 
2.14.2