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dt-bindings: arm: Convert PSCI binding to json-schema

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Convert the PSCI binding to use DT schema format.

Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Rob Herring 2019-06-17 13:29:33 -06:00
parent c875a3f847
commit 5025ef8b7a
6 changed files with 167 additions and 115 deletions
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2
Documentation/arm64/booting.txt
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@ -257,7 +257,7 @@ following manner:
processors") to bring CPUs into the kernel.
The device tree should contain a 'psci' node, as described in
Documentation/devicetree/bindings/arm/psci.txt.
Documentation/devicetree/bindings/arm/psci.yaml.
- Secondary CPU general-purpose register settings
x0 = 0 (reserved for future use)

2
Documentation/devicetree/bindings/arm/arm-boards
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@ -197,7 +197,7 @@ Required nodes:
The description for the board must include:
- a "psci" node describing the boot method used for the secondary CPUs.
A detailed description of the bindings used for "psci" nodes is present
in the psci.txt file.
in the psci.yaml file.
- a "cpus" node describing the available cores and their associated
"enable-method"s. For more details see cpus.txt file.

2
Documentation/devicetree/bindings/arm/idle-states.txt
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@ -691,7 +691,7 @@ cpus {
Documentation/devicetree/bindings/arm/cpus.yaml
[2] ARM Linux Kernel documentation - PSCI bindings
Documentation/devicetree/bindings/arm/psci.txt
Documentation/devicetree/bindings/arm/psci.yaml
[3] ARM Server Base System Architecture (SBSA)
http://infocenter.arm.com/help/index.jsp

111
Documentation/devicetree/bindings/arm/psci.txt
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@ -1,111 +0,0 @@
* 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 : 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.
* "arm,psci-1.0" : For implementations complying to PSCI 1.0.
PSCI 1.0 is backward compatible with PSCI 0.2 with
minor specification updates, as defined in the PSCI
specification[2].
- 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
Device tree nodes that require usage of PSCI CPU_SUSPEND function (ie idle
state nodes, as per bindings in [1]) must specify the following properties:
- arm,psci-suspend-param
Usage: Required for state nodes[1] if the corresponding
idle-states node entry-method property is set
to "psci".
Value type: <u32>
Definition: power_state parameter to pass to the PSCI
suspend call.
Example:
Case 1: PSCI v0.1 only.
psci {
compatible = "arm,psci";
method = "smc";
cpu_suspend = <0x95c10000>;
cpu_off = <0x95c10001>;
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 >;
...
};
[1] Kernel documentation - ARM idle states bindings
Documentation/devicetree/bindings/arm/idle-states.txt
[2] Power State Coordination Interface (PSCI) specification
http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf

163
Documentation/devicetree/bindings/arm/psci.yaml Normal file
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@ -0,0 +1,163 @@
# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/arm/psci.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Power State Coordination Interface (PSCI)
maintainers:
- Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
description: |+
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.
[2] Power State Coordination Interface (PSCI) specification
http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf
properties:
compatible:
oneOf:
- description:
For implementations complying to PSCI versions prior to 0.2.
const: arm,psci
- description:
For implementations complying to PSCI 0.2.
const: arm,psci-0.2
- description:
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.
items:
- const: arm,psci-0.2
- const: arm,psci
- description:
For implementations complying to PSCI 1.0.
const: arm,psci-1.0
- description:
For implementations complying to PSCI 1.0.
PSCI 1.0 is backward compatible with PSCI 0.2 with minor
specification updates, as defined in the PSCI specification[2].
items:
- const: arm,psci-1.0
- const: arm,psci-0.2
method:
description: The method of calling the PSCI firmware.
allOf:
- $ref: /schemas/types.yaml#/definitions/string-array
- enum:
# SMC #0, with the register assignments specified in this binding.
- smc
# HVC #0, with the register assignments specified in this binding.
- hvc
cpu_suspend:
$ref: /schemas/types.yaml#/definitions/uint32
description: Function ID for CPU_SUSPEND operation
cpu_off:
$ref: /schemas/types.yaml#/definitions/uint32
description: Function ID for CPU_OFF operation
cpu_on:
$ref: /schemas/types.yaml#/definitions/uint32
description: Function ID for CPU_ON operation
migrate:
$ref: /schemas/types.yaml#/definitions/uint32
description: Function ID for MIGRATE operation
arm,psci-suspend-param:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
power_state parameter to pass to the PSCI suspend call.
Device tree nodes that require usage of PSCI CPU_SUSPEND function (ie
idle state nodes with entry-method property is set to "psci", as per
bindings in [1]) must specify this property.
[1] Kernel documentation - ARM idle states bindings
Documentation/devicetree/bindings/arm/idle-states.txt
required:
- compatible
- method
allOf:
- if:
properties:
compatible:
contains:
const: arm,psci
then:
required:
- cpu_off
- cpu_on
examples:
- |+
// Case 1: PSCI v0.1 only.
psci {
compatible = "arm,psci";
method = "smc";
cpu_suspend = <0x95c10000>;
cpu_off = <0x95c10001>;
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 = <0x95c10002>;
cpu_off = <0x95c10001>;
};
...

2
Documentation/translations/zh_CN/arm64/booting.txt
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@ -236,7 +236,7 @@ AArch64 内核当前没有提供自解压代码，因此如果使用了压缩内
*译者注: ARM DEN 0022A 已更新到 ARM DEN 0022C。
设备树必须包含一个 ‘psci’ 节点，请参考以下文档：
Documentation/devicetree/bindings/arm/psci.txt
Documentation/devicetree/bindings/arm/psci.yaml
- 辅助 CPU 通用寄存器设置