-System Control and Management Interface (SCMI) Message Protocol
-----------------------------------------------------------
-
-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 0056A ("ARM System Control
-and Management Interface Platform Design Document")[0] provide for OSPM in
-the device tree.
-
-Required properties:
-
-The scmi node with the following properties shall be under the /firmware/ node.
-
-- compatible : shall be "arm,scmi" or "arm,scmi-smc" for smc/hvc transports,
- or "linaro,scmi-optee" for OP-TEE transport.
-- mboxes: List of phandle and mailbox channel specifiers. It should contain
- exactly one or two mailboxes, one for transmitting messages("tx")
- and another optional for receiving the notifications("rx") if
- supported.
-- shmem : List of phandle pointing to the shared memory(SHM) area as per
- generic mailbox client binding.
-- #address-cells : should be '1' if the device has sub-nodes, maps to
- protocol identifier for a given sub-node.
-- #size-cells : should be '0' as 'reg' property doesn't have any size
- associated with it.
-- arm,smc-id : SMC id required when using smc or hvc transports
-- linaro,optee-channel-id : Channel specifier required when using OP-TEE
- transport.
-
-Optional properties:
-
-- mbox-names: shall be "tx" or "rx" depending on mboxes entries.
-
-See Documentation/devicetree/bindings/mailbox/mailbox.txt for more details
-about the generic mailbox controller and client driver bindings.
-Mailbox doorbell is used as a mechanism to alert the presence of a
-messages and/or notification.
-
-Each protocol supported shall have a sub-node with corresponding compatible
-as described in the following sections. If the platform supports dedicated
-communication channel for a particular protocol, properties shall be present
-in the sub-node corresponding to that protocol. These properties are:
-- mboxes, mbox-names and shmem for mailbox transport
-- arm,smc-id and shmem for smc/hvc transport
-- linaro,optee-channel-id and possibly shmem for OP-TEE transport
-
-Clock/Performance bindings for the clocks/OPPs based on SCMI Message Protocol
-------------------------------------------------------------
-
-This binding uses the common clock binding[1].
-
-Required properties:
-- #clock-cells : Should be 1. Contains the Clock ID value used by SCMI commands.
-
-Power domain bindings for the power domains based on SCMI Message Protocol
-------------------------------------------------------------
-
-This binding for the SCMI power domain providers uses the generic power
-domain binding[2].
-
-Required properties:
- - #power-domain-cells : Should be 1. Contains the device or the power
- domain ID value used by SCMI commands.
-
-Regulator bindings for the SCMI Regulator based on SCMI Message Protocol
-------------------------------------------------------------
-An SCMI Regulator is permanently bound to a well defined SCMI Voltage Domain,
-and should be always positioned as a root regulator.
-It does not support any current operation.
-
-SCMI Regulators are grouped under a 'regulators' node which in turn is a child
-of the SCMI Voltage protocol node inside the desired SCMI instance node.
-
-This binding uses the common regulator binding[6].
-
-Required properties:
- - reg : shall identify an existent SCMI Voltage Domain.
-
-Sensor bindings for the sensors based on SCMI Message Protocol
---------------------------------------------------------------
-SCMI provides an API to access the various sensors on the SoC.
-
-Required properties:
-- #thermal-sensor-cells: should be set to 1. This property follows the
- thermal device tree bindings[3].
-
- Valid cell values are raw identifiers (Sensor ID)
- as used by the firmware. Refer to platform details
- for your implementation for the IDs to use.
-
-Reset signal bindings for the reset domains based on SCMI Message Protocol
-------------------------------------------------------------
-
-This binding for the SCMI reset domain providers uses the generic reset
-signal binding[5].
-
-Required properties:
- - #reset-cells : Should be 1. Contains the reset domain ID value used
- by SCMI commands.
-
-SRAM and Shared Memory for SCMI
--------------------------------
-
-A small area of SRAM is reserved for SCMI communication between application
-processors and SCP.
-
-The properties should follow the generic mmio-sram description found in [4]
-
-Each sub-node represents the reserved area for SCMI.
-
-Required sub-node properties:
-- reg : The base offset and size of the reserved area with the SRAM
-- compatible : should be "arm,scmi-shmem" for Non-secure SRAM based
- shared memory
-
-[0] http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/index.html
-[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
-[2] Documentation/devicetree/bindings/power/power-domain.yaml
-[3] Documentation/devicetree/bindings/thermal/thermal.txt
-[4] Documentation/devicetree/bindings/sram/sram.yaml
-[5] Documentation/devicetree/bindings/reset/reset.txt
-[6] Documentation/devicetree/bindings/regulator/regulator.yaml
-
-Example:
-
-sram@50000000 {
- compatible = "mmio-sram";
- reg = <0x0 0x50000000 0x0 0x10000>;
-
- #address-cells = <1>;
- #size-cells = <1>;
- ranges = <0 0x0 0x50000000 0x10000>;
-
- cpu_scp_lpri: scp-shmem@0 {
- compatible = "arm,scmi-shmem";
- reg = <0x0 0x200>;
- };
-
- cpu_scp_hpri: scp-shmem@200 {
- compatible = "arm,scmi-shmem";
- reg = <0x200 0x200>;
- };
-};
-
-mailbox@40000000 {
- ....
- #mbox-cells = <1>;
- reg = <0x0 0x40000000 0x0 0x10000>;
-};
-
-firmware {
-
- ...
-
- scmi {
- compatible = "arm,scmi";
- mboxes = <&mailbox 0 &mailbox 1>;
- mbox-names = "tx", "rx";
- shmem = <&cpu_scp_lpri &cpu_scp_hpri>;
- #address-cells = <1>;
- #size-cells = <0>;
-
- scmi_devpd: protocol@11 {
- reg = <0x11>;
- #power-domain-cells = <1>;
- };
-
- scmi_dvfs: protocol@13 {
- reg = <0x13>;
- #clock-cells = <1>;
- };
-
- scmi_clk: protocol@14 {
- reg = <0x14>;
- #clock-cells = <1>;
- };
-
- scmi_sensors0: protocol@15 {
- reg = <0x15>;
- #thermal-sensor-cells = <1>;
- };
-
- scmi_reset: protocol@16 {
- reg = <0x16>;
- #reset-cells = <1>;
- };
-
- scmi_voltage: protocol@17 {
- reg = <0x17>;
-
- regulators {
- regulator_devX: regulator@0 {
- reg = <0x0>;
- regulator-max-microvolt = <3300000>;
- };
-
- regulator_devY: regulator@9 {
- reg = <0x9>;
- regulator-min-microvolt = <500000>;
- regulator-max-microvolt = <4200000>;
- };
-
- ...
- };
- };
- };
-};
-
-cpu@0 {
- ...
- reg = <0 0>;
- clocks = <&scmi_dvfs 0>;
-};
-
-hdlcd@7ff60000 {
- ...
- reg = <0 0x7ff60000 0 0x1000>;
- clocks = <&scmi_clk 4>;
- power-domains = <&scmi_devpd 1>;
- resets = <&scmi_reset 10>;
-};
-
-thermal-zones {
- soc_thermal {
- polling-delay-passive = <100>;
- polling-delay = <1000>;
- /* sensor ID */
- thermal-sensors = <&scmi_sensors0 3>;
- ...
- };
-};
+See Binding in Linux documentation:
+Documentation/devicetree/bindings/firmware/arm,scmi.yaml
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