1 System Control and Management Interface (SCMI) Message Protocol
2 ----------------------------------------------------------
4 The SCMI is intended to allow agents such as OSPM to manage various functions
5 that are provided by the hardware platform it is running on, including power
6 and performance functions.
8 This binding is intended to define the interface the firmware implementing
9 the SCMI as described in ARM document number ARM DEN 0056A ("ARM System Control
10 and Management Interface Platform Design Document")[0] provide for OSPM in
15 The scmi node with the following properties shall be under the /firmware/ node.
17 - compatible : shall be "arm,scmi" or "arm,scmi-smc" for smc/hvc transports
18 - mboxes: List of phandle and mailbox channel specifiers. It should contain
19 exactly one or two mailboxes, one for transmitting messages("tx")
20 and another optional for receiving the notifications("rx") if
22 - shmem : List of phandle pointing to the shared memory(SHM) area as per
23 generic mailbox client binding.
24 - #address-cells : should be '1' if the device has sub-nodes, maps to
25 protocol identifier for a given sub-node.
26 - #size-cells : should be '0' as 'reg' property doesn't have any size
28 - arm,smc-id : SMC id required when using smc or hvc transports
32 - mbox-names: shall be "tx" or "rx" depending on mboxes entries.
34 - interrupts : when using smc or hvc transports, this optional
35 property indicates that msg completion by the platform is indicated
36 by an interrupt rather than by the return of the smc call. This
37 should not be used except when the platform requires such behavior.
39 - interrupt-names : if "interrupts" is present, interrupt-names must also
40 be present and have the value "a2p".
42 See Documentation/devicetree/bindings/mailbox/mailbox.txt for more details
43 about the generic mailbox controller and client driver bindings.
45 The mailbox is the only permitted method of calling the SCMI firmware.
46 Mailbox doorbell is used as a mechanism to alert the presence of a
47 messages and/or notification.
49 Each protocol supported shall have a sub-node with corresponding compatible
50 as described in the following sections. If the platform supports dedicated
51 communication channel for a particular protocol, the 3 properties namely:
52 mboxes, mbox-names and shmem shall be present in the sub-node corresponding
55 Clock/Performance bindings for the clocks/OPPs based on SCMI Message Protocol
56 ------------------------------------------------------------
58 This binding uses the common clock binding[1].
61 - #clock-cells : Should be 1. Contains the Clock ID value used by SCMI commands.
63 Power domain bindings for the power domains based on SCMI Message Protocol
64 ------------------------------------------------------------
66 This binding for the SCMI power domain providers uses the generic power
70 - #power-domain-cells : Should be 1. Contains the device or the power
71 domain ID value used by SCMI commands.
73 Regulator bindings for the SCMI Regulator based on SCMI Message Protocol
74 ------------------------------------------------------------
75 An SCMI Regulator is permanently bound to a well defined SCMI Voltage Domain,
76 and should be always positioned as a root regulator.
77 It does not support any current operation.
79 SCMI Regulators are grouped under a 'regulators' node which in turn is a child
80 of the SCMI Voltage protocol node inside the desired SCMI instance node.
82 This binding uses the common regulator binding[6].
85 - reg : shall identify an existent SCMI Voltage Domain.
87 Sensor bindings for the sensors based on SCMI Message Protocol
88 --------------------------------------------------------------
89 SCMI provides an API to access the various sensors on the SoC.
92 - #thermal-sensor-cells: should be set to 1. This property follows the
93 thermal device tree bindings[3].
95 Valid cell values are raw identifiers (Sensor ID)
96 as used by the firmware. Refer to platform details
97 for your implementation for the IDs to use.
99 Reset signal bindings for the reset domains based on SCMI Message Protocol
100 ------------------------------------------------------------
102 This binding for the SCMI reset domain providers uses the generic reset
106 - #reset-cells : Should be 1. Contains the reset domain ID value used
109 SRAM and Shared Memory for SCMI
110 -------------------------------
112 A small area of SRAM is reserved for SCMI communication between application
115 The properties should follow the generic mmio-sram description found in [4]
117 Each sub-node represents the reserved area for SCMI.
119 Required sub-node properties:
120 - reg : The base offset and size of the reserved area with the SRAM
121 - compatible : should be "arm,scmi-shmem" for Non-secure SRAM based
124 [0] http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/index.html
125 [1] Documentation/devicetree/bindings/clock/clock-bindings.txt
126 [2] Documentation/devicetree/bindings/power/power-domain.yaml
127 [3] Documentation/devicetree/bindings/thermal/thermal*.yaml
128 [4] Documentation/devicetree/bindings/sram/sram.yaml
129 [5] Documentation/devicetree/bindings/reset/reset.txt
130 [6] Documentation/devicetree/bindings/regulator/regulator.yaml
135 compatible = "mmio-sram";
136 reg = <0x0 0x50000000 0x0 0x10000>;
138 #address-cells = <1>;
140 ranges = <0 0x0 0x50000000 0x10000>;
142 cpu_scp_lpri: scp-shmem@0 {
143 compatible = "arm,scmi-shmem";
147 cpu_scp_hpri: scp-shmem@200 {
148 compatible = "arm,scmi-shmem";
156 reg = <0x0 0x40000000 0x0 0x10000>;
164 compatible = "arm,scmi";
165 mboxes = <&mailbox 0 &mailbox 1>;
166 mbox-names = "tx", "rx";
167 shmem = <&cpu_scp_lpri &cpu_scp_hpri>;
168 #address-cells = <1>;
171 scmi_devpd: protocol@11 {
173 #power-domain-cells = <1>;
176 scmi_dvfs: protocol@13 {
181 scmi_clk: protocol@14 {
186 scmi_sensors0: protocol@15 {
188 #thermal-sensor-cells = <1>;
191 scmi_reset: protocol@16 {
196 scmi_voltage: protocol@17 {
200 regulator_devX: regulator@0 {
202 regulator-max-microvolt = <3300000>;
205 regulator_devY: regulator@9 {
207 regulator-min-microvolt = <500000>;
208 regulator-max-microvolt = <4200000>;
220 clocks = <&scmi_dvfs 0>;
225 reg = <0 0x7ff60000 0 0x1000>;
226 clocks = <&scmi_clk 4>;
227 power-domains = <&scmi_devpd 1>;
228 resets = <&scmi_reset 10>;
233 polling-delay-passive = <100>;
234 polling-delay = <1000>;
236 thermal-sensors = <&scmi_sensors0 3>;