[PATCH 2/4] dt-bindings: arm: SCMI bindings documentation

[Etienne Carriere <etienne.carriere@linaro.org>]

Hello Peng,

On Mon, 20 Jul 2020 at 04:01, Peng Fan <peng.fan@nxp.com> wrote:
>
> > Subject: [PATCH 2/4] dt-bindings: arm: SCMI bindings documentation
>
> Since kernel already has the binding doc, there is no need to add a U-Boot
> copy.
>

Ok. I'll remove this patch from the series in my v2.

Thanks,
Etienne


> Regards,
> Peng.
>
> >
> > Dump SCMI DT bindings documentation from Linux kernel source tree
> > v5.8-rc1.
> >
> > Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
> > ---
> >
> >  doc/device-tree-bindings/arm/arm,scmi.txt | 197
> > ++++++++++++++++++++++
> >  1 file changed, 197 insertions(+)
> >  create mode 100644 doc/device-tree-bindings/arm/arm,scmi.txt
> >
> > diff --git a/doc/device-tree-bindings/arm/arm,scmi.txt
> > b/doc/device-tree-bindings/arm/arm,scmi.txt
> > new file mode 100644
> > index 00000000000..1f293ea24cd
> > --- /dev/null
> > +++ b/doc/device-tree-bindings/arm/arm,scmi.txt
> > @@ -0,0 +1,197 @@
> > +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.
> > +
> > +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.
> > +
> > +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]
> > +https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Finfoce
> > +nter.arm.com%2Fhelp%2Ftopic%2Fcom.arm.doc.den0056a%2Findex.html&
> > amp;dat
> > +a=02%7C01%7Cpeng.fan%40nxp.com%7C94dcac2bc02346684bec08d82a67
> > 76b9%7C686
> > +ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C1%7C637305971145926287&a
> > mp;sdata=gS
> > +HhNqZ14iDSv0ws76jZox0JOzAL7Yrg%2BV%2ByH1Szkj4%3D&amp;reserved=
> > 0
> > +[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
> > +
> > +Example:
> > +
> > +sram at 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 at 0 {
> > +             compatible = "arm,scmi-shmem";
> > +             reg = <0x0 0x200>;
> > +     };
> > +
> > +     cpu_scp_hpri: scp-shmem at 200 {
> > +             compatible = "arm,scmi-shmem";
> > +             reg = <0x200 0x200>;
> > +     };
> > +};
> > +
> > +mailbox at 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 at 11 {
> > +                     reg = <0x11>;
> > +                     #power-domain-cells = <1>;
> > +             };
> > +
> > +             scmi_dvfs: protocol at 13 {
> > +                     reg = <0x13>;
> > +                     #clock-cells = <1>;
> > +             };
> > +
> > +             scmi_clk: protocol at 14 {
> > +                     reg = <0x14>;
> > +                     #clock-cells = <1>;
> > +             };
> > +
> > +             scmi_sensors0: protocol at 15 {
> > +                     reg = <0x15>;
> > +                     #thermal-sensor-cells = <1>;
> > +             };
> > +
> > +             scmi_reset: protocol at 16 {
> > +                     reg = <0x16>;
> > +                     #reset-cells = <1>;
> > +             };
> > +     };
> > +};
> > +
> > +cpu at 0 {
> > +     ...
> > +     reg = <0 0>;
> > +     clocks = <&scmi_dvfs 0>;
> > +};
> > +
> > +hdlcd at 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>;
> > +             ...
> > +     };
> > +};
> > --
> > 2.17.1
>