From 65397edfa1bba622a8159bed4c8efcc4ddb8ed16 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 11 Dec 2012 17:28:27 +0000 Subject: [PATCH] ARM: psci: add devicetree binding for describing PSCI firmware This patch adds a new devicetree binding for describing PSCI firmware to Linux. Acked-by: Arnd Bergmann Acked-by: Nicolas Pitre Signed-off-by: Will Deacon --- Documentation/devicetree/bindings/arm/psci.txt | 55 ++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/psci.txt diff --git a/Documentation/devicetree/bindings/arm/psci.txt b/Documentation/devicetree/bindings/arm/psci.txt new file mode 100644 index 0000000..433afe9 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/psci.txt @@ -0,0 +1,55 @@ +* Power State Coordination Interface (PSCI) + +Firmware implementing the PSCI functions described in ARM document number +ARM DEN 0022A ("Power State Coordination Interface System Software on ARM +processors") can be used by Linux to initiate various CPU-centric power +operations. + +Issue A of the specification describes functions for CPU suspend, hotplug +and migration of secure software. + +Functions are invoked by trapping to the privilege level of the PSCI +firmware (specified as part of the binding below) and passing arguments +in a manner similar to that specified by AAPCS: + + r0 => 32-bit Function ID / return value + {r1 - r3} => Parameters + +Note that the immediate field of the trapping instruction must be set +to #0. + + +Main node required properties: + + - compatible : Must be "arm,psci" + + - method : The method of calling the PSCI firmware. Permitted + values are: + + "smc" : SMC #0, with the register assignments specified + in this binding. + + "hvc" : HVC #0, with the register assignments specified + in this binding. + +Main node optional properties: + + - cpu_suspend : Function ID for CPU_SUSPEND operation + + - cpu_off : Function ID for CPU_OFF operation + + - cpu_on : Function ID for CPU_ON operation + + - migrate : Function ID for MIGRATE operation + + +Example: + + psci { + compatible = "arm,psci"; + method = "smc"; + cpu_suspend = <0x95c10000>; + cpu_off = <0x95c10001>; + cpu_on = <0x95c10002>; + migrate = <0x95c10003>; + }; -- 2.7.4