On 2020-02-07 11:00, Peng Fan wrote:
Subject: Re: [PATCH 1/2] dt-bindings: arm: arm,scmi: add smc/hvc
transports
On 2020-02-07 10:47, Sudeep Holla wrote:
> On Fri, Feb 07, 2020 at 10:08:36AM +0000, Marc Zyngier wrote:
>> On 2020-02-06 13:01, peng.fan@xxxxxxx wrote:
>> > From: Peng Fan <peng.fan@xxxxxxx>
>> >
>> > SCMI could use SMC/HVC as tranports, so add into devicetree binding
>> > doc.
>> >
>> > Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
>> > ---
>> > Documentation/devicetree/bindings/arm/arm,scmi.txt | 4 +++-
>> > 1 file changed, 3 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/Documentation/devicetree/bindings/arm/arm,scmi.txt
>> > b/Documentation/devicetree/bindings/arm/arm,scmi.txt
>> > index f493d69e6194..03cff8b55a93 100644
>> > --- a/Documentation/devicetree/bindings/arm/arm,scmi.txt
>> > +++ b/Documentation/devicetree/bindings/arm/arm,scmi.txt
>> > @@ -14,7 +14,7 @@ Required properties:
>> >
>> > The scmi node with the following properties shall be under the
>> > /firmware/ node.
>> >
>> > -- compatible : shall be "arm,scmi"
>> > +- compatible : shall be "arm,scmi" or "arm,scmi-smc"
>> > - 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
>> > @@ -25,6 +25,8 @@ The scmi node with the following properties shall
>> > be under the /firmware/ node.
>> > 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 transports
>> > +- arm,hvc-id : HVC id required when using hvc transports
>> >
>> > Optional properties:
>>
>> Not directly related to DT: Why do we need to distinguish between SMC
>> and HVC?
>
> IIUC you want just one property to get the function ID ? Does that
> align with what you are saying ? I wanted to ask the same question and
> I see no need for 2 different properties.
Exactly. Using SMC or HVC should come from the context, and there is
zero
value in having different different IDs, depending on the conduit.
We *really* want SMC and HVC to behave the same way. Any attempt to
make them different should just be NAKed.
ok. Then just like psci node,
Add a "method" property for each protocol, and add "arm,func-id" to
indicate the ID.
How about this?
Or rather just a function ID, full stop. the conduit *MUST* be inherited
from the PSCI context.
M.
--
Jazz is not dead. It just smells funny...
