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Documentation: devicetree: Add new binding for PSCIv0.2

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The PSCI v0.2+ spec defines standard values for PSCI function IDs.
Add a new binding entry so that pre v0.2 implementations can
use DT entries for function IDs and v0.2+ implementations use
standard entries as defined by the PSCIv0.2 specification.

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ashwin Chaugule 2014-03-27 11:08:57 -04:00
parent e71246a23a
commit e1cd3b361a
1 changed files with 36 additions and 1 deletions
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37
Documentation/devicetree/bindings/arm/psci.txt
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@ -21,7 +21,15 @@ to #0.
Main node required properties:
- compatible : Must be "arm,psci"
- compatible : should contain at least one of:
* "arm,psci" : for implementations complying to PSCI versions prior to
0.2. For these cases function IDs must be provided.
* "arm,psci-0.2" : for implementations complying to PSCI 0.2. Function
IDs are not required and should be ignored by an OS with PSCI 0.2
support, but are permitted to be present for compatibility with
existing software when "arm,psci" is later in the compatible list.
- method : The method of calling the PSCI firmware. Permitted
values are:
@ -45,6 +53,8 @@ Main node optional properties:
Example:
Case 1: PSCI v0.1 only.
psci {
compatible = "arm,psci";
method = "smc";
@ -53,3 +63,28 @@ Example:
cpu_on = <0x95c10002>;
migrate = <0x95c10003>;
};
Case 2: PSCI v0.2 only
psci {
compatible = "arm,psci-0.2";
method = "smc";
};
Case 3: PSCI v0.2 and PSCI v0.1.
A DTB may provide IDs for use by kernels without PSCI 0.2 support,
enabling firmware and hypervisors to support existing and new kernels.
These IDs will be ignored by kernels with PSCI 0.2 support, which will
use the standard PSCI 0.2 IDs exclusively.
psci {
compatible = "arm,psci-0.2", "arm,psci";
method = "hvc";
cpu_on = < arbitrary value >;
cpu_off = < arbitrary value >;
...
};