On 09/06/17 15:16, Rob Herring wrote:
> On Wed, Jun 07, 2017 at 05:10:05PM +0100, Sudeep Holla wrote:
>> This patch adds devicetree binding for System Control and Management
>> Interface (SCMI) Message Protocol used between the Application Cores(AP)
>> and the System Control Processor(SCP). The MHU peripheral provides a
>> mechanism for inter-processor communication between SCP's M3 processor
>> and AP.
>>
>> SCP offers control and management of the core/cluster power states,
>> various power domain DVFS including the core/cluster, certain system
>> clocks configuration, thermal sensors and many others.
>>
>> SCMI protocol is developed as better replacement to the existing SCPI
>> which is not flexible and easily extensible.
>>
>> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
>> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
>> ---
>> Documentation/devicetree/bindings/arm/arm,scmi.txt | 193 +++++++++++++++++++++
>> 1 file changed, 193 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/arm/arm,scmi.txt
>>
>> diff --git a/Documentation/devicetree/bindings/arm/arm,scmi.txt b/Documentation/devicetree/bindings/arm/arm,scmi.txt
>> new file mode 100644
>> index 000000000000..d6e4b7eff199
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/arm,scmi.txt
>> @@ -0,0 +1,193 @@
>> +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 DUI 0922B ("ARM System Control
>> +and Management Interface Platform Design Document")[0] provide for OSPM in
>> +the device tree.
>> +
>> +Required properties:
>> +
>> +- compatible : shall be "arm,scmi"
>
> Convince me that this genericish string is specific enough.
>
Now that you raised this point, I think we generate so many 4 letter
acronyms that it can collide. How about "arm,sys-ctl-mgmt-if"
>> +- method : The method of calling the SCMI firmware. Only permitted value
>> + currently is:
>> + "mailbox-doorbell" : When mailbox doorbell is used as a mechanism
>> + to alert the presence of a messages and/or
>> + notification
>> +- 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.
>> +- mbox-names: shall be "tx" or "rx"
>
> ...and optionally "rx"
>
OK
>> +- shmem : List of phandle pointing to the shared memory(SHM) area between the
>> + processors using these mailboxes for IPC, one for each mailbox
>> + SHM can be any memory reserved for the purpose of this communication
>> + between the processors.
>
> Maybe the mailbox binding should have a standard property for this?
>
Do you mean as part of it's client binding ? If so, agreed. I can come
up with that proposal.
--
Regards,
Sudeep
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