# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
# Copyright 2021 ARM Ltd.
%YAML 1.2
---
$id: http://devicetree.org/schemas/firmware/arm,scmi.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: System Control and Management Interface (SCMI) Message Protocol
maintainers:
- Sudeep Holla <sudeep.holla@arm.com>
description: |
The SCMI is intended to allow agents such as OSPM to manage various functions
that are provided by the hardware platform it is running on, including power
and performance functions.
This binding is intended to define the interface the firmware implementing
the SCMI as described in ARM document number ARM DEN 0056 ("ARM System Control
and Management Interface Platform Design Document")[0] provide for OSPM in
the device tree.
[0] https://developer.arm.com/documentation/den0056/latest
properties:
$nodename:
const: scmi
compatible:
oneOf:
- description: SCMI compliant firmware with mailbox transport
items:
- const: arm,scmi
- description: SCMI compliant firmware with ARM SMC/HVC transport
items:
- const: arm,scmi-smc
- description: SCMI compliant firmware with ARM SMC/HVC transport
with shmem address(4KB-page, offset) as parameters
items:
- const: arm,scmi-smc-param
- description: SCMI compliant firmware with SCMI Virtio transport.
The virtio transport only supports a single device.
items:
- const: arm,scmi-virtio
- description: SCMI compliant firmware with OP-TEE transport
items:
- const: linaro,scmi-optee
interrupts:
description:
The interrupt that indicates message completion by the platform
rather than by the return of the smc call. This should not be used
except when the platform requires such behavior.
maxItems: 1
interrupt-names:
const: a2p
mbox-names:
description:
Specifies the mailboxes used to communicate with SCMI compliant
firmware.
oneOf:
- items:
- const: tx
- const: rx
minItems: 1
- items:
- const: tx
- const: tx_reply
- const: rx
minItems: 2
mboxes:
description:
List of phandle and mailbox channel specifiers. It should contain
exactly one, two or three mailboxes; the first one or two for transmitting
messages ("tx") and another optional ("rx") for receiving notifications
and delayed responses, if supported by the platform.
The number of mailboxes needed for transmitting messages depends on the
type of channels exposed by the specific underlying mailbox controller;
one single channel descriptor is enough if such channel is bidirectional,
while two channel descriptors are needed to represent the SCMI ("tx")
channel if the underlying mailbox channels are of unidirectional type.
The effective combination in numbers of mboxes and shmem descriptors let
the SCMI subsystem determine unambiguosly which type of SCMI channels are
made available by the underlying mailbox controller and how to use them.
1 mbox / 1 shmem => SCMI TX over 1 mailbox bidirectional channel
2 mbox / 2 shmem => SCMI TX and RX over 2 mailbox bidirectional channels
2 mbox / 1 shmem => SCMI TX over 2 mailbox unidirectional channels
3 mbox / 2 shmem => SCMI TX and RX over 3 mailbox unidirectional channels
Any other combination of mboxes and shmem is invalid.
minItems: 1
maxItems: 3
shmem:
description:
List of phandle pointing to the shared memory(SHM) area, for each
transport channel specified.
minItems: 1
maxItems: 2
'#address-cells':
const: 1
'#size-cells':
const: 0
atomic-threshold-us:
description:
An optional time value, expressed in microseconds, representing, on this
platform, the threshold above which any SCMI command, advertised to have
an higher-than-threshold execution latency, should not be considered for
atomic mode of operation, even if requested.
default: 0
arm,smc-id:
$ref: /schemas/types.yaml#/definitions/uint32
description:
SMC id required when using smc or hvc transports
linaro,optee-channel-id:
$ref: /schemas/types.yaml#/definitions/uint32
description:
Channel specifier required when using OP-TEE transport.
protocol@11:
$ref: '#/$defs/protocol-node'
unevaluatedProperties: false
properties:
reg:
const: 0x11
'#power-domain-cells':
const: 1
required:
- '#power-domain-cells'
protocol@13:
$ref: '#/$defs/protocol-node'
unevaluatedProperties: false
properties:
reg:
const: 0x13
'#clock-cells':
const: 1
required:
- '#clock-cells'
protocol@14:
$ref: '#/$defs/protocol-node'
unevaluatedProperties: false
properties:
reg:
const: 0x14
'#clock-cells':
const: 1
required:
- '#clock-cells'
protocol@15:
$ref: '#/$defs/protocol-node'
unevaluatedProperties: false
properties:
reg:
const: 0x15
'#thermal-sensor-cells':
const: 1
required:
- '#thermal-sensor-cells'
protocol@16:
$ref: '#/$defs/protocol-node'
unevaluatedProperties: false
properties:
reg:
const: 0x16
'#reset-cells':
const: 1
required:
- '#reset-cells'
protocol@17:
$ref: '#/$defs/protocol-node'
unevaluatedProperties: false
properties:
reg:
const: 0x17
regulators:
type: object
additionalProperties: false
description:
The list of all regulators provided by this SCMI controller.
properties:
'#address-cells':
const: 1
'#size-cells':
const: 0
patternProperties:
'^regulator@[0-9a-f]+$':
type: object
$ref: /schemas/regulator/regulator.yaml#
unevaluatedProperties: false
properties:
reg:
maxItems: 1
description: Identifier for the voltage regulator.
required:
- reg
protocol@18:
$ref: '#/$defs/protocol-node'
unevaluatedProperties: false
properties:
reg:
const: 0x18
additionalProperties: false
$defs:
protocol-node:
type: object
description:
Each sub-node represents a protocol supported. If the platform
supports a dedicated communication channel for a particular protocol,
then the corresponding transport properties must be present.
The virtio transport does not support a dedicated communication channel.
properties:
reg:
maxItems: 1
mbox-names:
oneOf:
- items:
- const: tx
- const: rx
minItems: 1
- items:
- const: tx
- const: tx_reply
- const: rx
minItems: 2
mboxes:
minItems: 1
maxItems: 3
shmem:
minItems: 1
maxItems: 2
linaro,optee-channel-id:
$ref: /schemas/types.yaml#/definitions/uint32
description:
Channel specifier required when using OP-TEE transport and
protocol has a dedicated communication channel.
required:
- reg
required:
- compatible
if:
properties:
compatible:
contains:
const: arm,scmi
then:
properties:
interrupts: false
interrupt-names: false
required:
- mboxes
- shmem
else:
if:
properties:
compatible:
contains:
enum:
- arm,scmi-smc
- arm,scmi-smc-param
then:
required:
- arm,smc-id
- shmem
else:
if:
properties:
compatible:
contains:
const: linaro,scmi-optee
then:
required:
- linaro,optee-channel-id
examples:
- |
firmware {
scmi {
compatible = "arm,scmi";
mboxes = <&mhuB 0 0>,
<&mhuB 0 1>;
mbox-names = "tx", "rx";
shmem = <&cpu_scp_lpri0>,
<&cpu_scp_lpri1>;
#address-cells = <1>;
#size-cells = <0>;
atomic-threshold-us = <10000>;
scmi_devpd: protocol@11 {
reg = <0x11>;
#power-domain-cells = <1>;
};
scmi_dvfs: protocol@13 {
reg = <0x13>;
#clock-cells = <1>;
mboxes = <&mhuB 1 0>,
<&mhuB 1 1>;
mbox-names = "tx", "rx";
shmem = <&cpu_scp_hpri0>,
<&cpu_scp_hpri1>;
};
scmi_clk: protocol@14 {
reg = <0x14>;
#clock-cells = <1>;
};
scmi_sensors: protocol@15 {
reg = <0x15>;
#thermal-sensor-cells = <1>;
};
scmi_reset: protocol@16 {
reg = <0x16>;
#reset-cells = <1>;
};
scmi_voltage: protocol@17 {
reg = <0x17>;
regulators {
#address-cells = <1>;
#size-cells = <0>;
regulator_devX: regulator@0 {
reg = <0x0>;
regulator-max-microvolt = <3300000>;
};
regulator_devY: regulator@9 {
reg = <0x9>;
regulator-min-microvolt = <500000>;
regulator-max-microvolt = <4200000>;
};
};
};
scmi_powercap: protocol@18 {
reg = <0x18>;
};
};
};
soc {
#address-cells = <2>;
#size-cells = <2>;
sram@50000000 {
compatible = "mmio-sram";
reg = <0x0 0x50000000 0x0 0x10000>;
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x0 0x50000000 0x10000>;
cpu_scp_lpri0: scp-sram-section@0 {
compatible = "arm,scmi-shmem";
reg = <0x0 0x80>;
};
cpu_scp_lpri1: scp-sram-section@80 {
compatible = "arm,scmi-shmem";
reg = <0x80 0x80>;
};
cpu_scp_hpri0: scp-sram-section@100 {
compatible = "arm,scmi-shmem";
reg = <0x100 0x80>;
};
cpu_scp_hpri2: scp-sram-section@180 {
compatible = "arm,scmi-shmem";
reg = <0x180 0x80>;
};
};
};
- |
firmware {
scmi {
compatible = "arm,scmi-smc";
shmem = <&cpu_scp_lpri0>, <&cpu_scp_lpri1>;
arm,smc-id = <0xc3000001>;
#address-cells = <1>;
#size-cells = <0>;
scmi_devpd1: protocol@11 {
reg = <0x11>;
#power-domain-cells = <1>;
};
};
};
- |
firmware {
scmi {
compatible = "linaro,scmi-optee";
linaro,optee-channel-id = <0>;
#address-cells = <1>;
#size-cells = <0>;
scmi_dvfs1: protocol@13 {
reg = <0x13>;
linaro,optee-channel-id = <1>;
shmem = <&cpu_optee_lpri0>;
#clock-cells = <1>;
};
scmi_clk0: protocol@14 {
reg = <0x14>;
#clock-cells = <1>;
};
};
};
soc {
#address-cells = <2>;
#size-cells = <2>;
sram@51000000 {
compatible = "mmio-sram";
reg = <0x0 0x51000000 0x0 0x10000>;
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x0 0x51000000 0x10000>;
cpu_optee_lpri0: optee-sram-section@0 {
compatible = "arm,scmi-shmem";
reg = <0x0 0x80>;
};
};
};
...