linux-kernel - [PATCH v4 6/7] firmware: smccc: Add function to fetch SMCCC version

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Date:   Mon, 18 May 2020 10:12:21 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     Sudeep Holla <sudeep.holla@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Steven Price <steven.price@....com>,
        linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        harb@...erecomputing.com
Subject: [PATCH v4 6/7] firmware: smccc: Add function to fetch SMCCC version

For backward compatibility reasons, PSCI maintains SMCCC version as
SMCCC didn't provide ARM_SMCCC_VERSION_FUNC_ID until v1.1.

PSCI initialises both the SMCCC version and conduit. Similar to the
conduit, let us provide accessors to fetch the SMCCC version also so
that other SMCCC v1.1+ features can use it.

Tested-by: Etienne Carriere <etienne.carriere@...com>
Reviewed-by: Steven Price <steven.price@....com>
Reviewed-by: Etienne Carriere <etienne.carriere@...com>
Acked-by: Mark Rutland <mark.rutland@....com>
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/firmware/smccc/smccc.c |  5 +++++
 include/linux/arm-smccc.h      | 11 +++++++++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c
index de92a4b9f8f6..4e80921ee212 100644
--- a/drivers/firmware/smccc/smccc.c
+++ b/drivers/firmware/smccc/smccc.c
@@ -24,3 +24,8 @@ enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
 
 	return smccc_conduit;
 }
+
+u32 arm_smccc_get_version(void)
+{
+	return smccc_version;
+}
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index c3784ba8e2a4..c491d210e3c3 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -100,6 +100,17 @@ enum arm_smccc_conduit {
  */
 enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void);
 
+/**
+ * arm_smccc_get_version()
+ *
+ * Returns the version to be used for SMCCCv1.1 or later.
+ *
+ * When SMCCCv1.1 or above is not present, returns SMCCCv1.0, but this
+ * does not imply the presence of firmware or a valid conduit. Caller
+ * handling SMCCCv1.0 must determine the conduit by other means.
+ */
+u32 arm_smccc_get_version(void);
+
 /**
  * struct arm_smccc_res - Result from SMC/HVC call
  * @a0-a3 result values from registers 0 to 3
-- 
2.17.1