summaryrefslogtreecommitdiff
path: root/Documentation/devicetree/bindings/arm/psci.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/devicetree/bindings/arm/psci.txt')
-rw-r--r--Documentation/devicetree/bindings/arm/psci.txt55
1 files changed, 55 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/arm/psci.txt b/Documentation/devicetree/bindings/arm/psci.txt
new file mode 100644
index 000000000000..433afe9cb590
--- /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>;
+ };