Kernel-3.10.0-957.el7_psci

• 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>;
};