Re: [RFC PATCH v3 5/8] firmware: Add legacy SCPI protocol driver

[Sudeep Holla]

Hi Neil,

On 16/08/16 10:41, Neil Armstrong wrote:
> On 08/15/2016 03:35 PM, Sudeep Holla wrote:
> > Hi Neil,
> >
> > On 09/08/16 11:29, Neil Armstrong wrote:
> > > Add legacy protocol driver for an early published SCPI implementation
> > > by supporting old command indexes and structure.
> > > This driver also supports vendor messages and rockchip specific
> > > mailbox data structure for message passing to SCP.
>
> Hi Sudeep,
>
> > Sorry for the delay but I expected some attempts to reduce the
> > duplication of code we have here. I really don't like the duplication of
> > the code. As I mentioned earlier it can be reduced. I see lot of scope
> > for that and I see that you made zero attempts since v2.
>
> Yes, this post is an intermediate RFC to show to rockchip guys how I
> could implement supportfor their vendor commands, the next RFC will
> certainly merge the two  drivers with minimal code duplication.

Ah sorry for the comment then, I didn't realize that. I missed those
discussions.

> > > +enum legacy_scpi_client_id {
> > > +    SCPI_CL_NONE,
> > > +    SCPI_CL_CLOCKS,
> > > +    SCPI_CL_DVFS,
> > > +    SCPI_CL_POWER,
> > > +    SCPI_CL_THERMAL,
> > > +    SCPI_MAX,
> > > +};
> > > +
> >
> > As I said before these values were introduced by me initially and I
> > reckon firmware doesn't depend on that. Have you really tested dropping
> > them ? This must go as they are useless and we now have tokens which are
> > much better.
>
> I am not sure, I'm currently waiting for Amlogic's SCPI FW specification to be sure
> these are not needed at all, in the meantime I will still implement them.

Just change and give it a spin on your board. The initial spec mentions
that the SCP should return this as is as sent by the requester. I
thought of this grouping initially and then found certain limitations
and went with token which is bit more useful compared to this after some
review.

> > I will stop here and ask why can't you start with simple change like
> > below ? Then we can add or re-define the structures/enums when
> > absolutely needed. Please don't just copy the entire driver and make
> > changes where-ever needed or please try to adapt to the new driver and
> > try to deviate as less as required by the firmware.
>
> It will be done in RFC v4.

Cool, thanks. I will try to review ASAP, so that we can target v4.9

--
Regards,
Sudeep