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Commit 65397edf authored by Will Deacon's avatar Will Deacon
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ARM: psci: add devicetree binding for describing PSCI firmware 



This patch adds a new devicetree binding for describing PSCI firmware
to Linux.

Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent af965acc

Documentation/devicetree/bindings/arm/psci.txt

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+55 −0
Original line number Diff line number Diff line 
* 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>;

	};