1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
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
- 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
Optional properties:
- mbox-names: shall be "tx" or "rx" depending on mboxes entries.
- interrupts : when using smc or hvc transports, this optional
property indicates that msg completion by the platform is indicated
by an interrupt rather than by the return of the smc call. This
should not be used except when the platform requires such behavior.
- interrupt-names : if "interrupts" is present, interrupt-names must also
be present and have the value "a2p".
See Documentation/devicetree/bindings/mailbox/mailbox.txt for more details
about the generic mailbox controller and client driver bindings.
The mailbox is the only permitted method of calling the SCMI firmware.
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, the 3 properties namely:
mboxes, mbox-names and shmem shall be present in the sub-node corresponding
to that protocol.
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*.yaml
[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>;
...
};
};
|
