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 --- Documentation/devicetree/bindings/arm/psci.txt | 37 +++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/arm/psci.txt b/Documentation/devicetree/bindings/arm/psci.txt index 433afe9..b4a58f3 100644 --- a/Documentation/devicetree/bindings/arm/psci.txt +++ b/Documentation/devicetree/bindings/arm/psci.txt @@ -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 >; + + ... + };