Re: [PATCH v2 1/2] PM / Domains: Add GENPD_FLAG_NO_SUSPEND/RESUME flags

[Sibi Sankar]

On 2020-08-25 23:23, Bjorn Andersson wrote:
> On Tue 25 Aug 02:20 CDT 2020, Stephen Boyd wrote:
> > Quoting Bjorn Andersson (2020-08-24 09:42:12)
> > > On Fri 21 Aug 14:41 PDT 2020, Stephen Boyd wrote:
> [..]
> > > > I find it odd that this is modeled as a power domain instead of some
> > > > Qualcomm specific message that the remoteproc driver sends to AOSS. Is
> > > > there some sort of benefit the driver gets from using the power domain
> > > > APIs for this vs. using a custom API?
> > >
> > > We need to send "up" and "down" notifications and this needs to happen
> > > at the same time as other standard resources are enabled/disabled.
> > >
> > > Further more, at the time the all resources handled by the downstream
> > > driver was either power-domains (per above understanding) or clocks, so
> > > it made sense to me not to spin up a custom API.
> > >
> >
> > So the benefit is not spinning up a custom API? I'm not Ulf, but it
> > looks like this is hard to rationalize about as a power domain. It
> > doesn't have any benefit to model it this way besides to make it
> > possible to turn on with other power domains.
> >
> > This modem remoteproc drivers isn't SoC agnostic anyway, it relies on
> > SMEM APIs, so standing up another small qmp_remoteproc_booted() and
> > qmp_remoteproc_shutdown() API would avoid adding a genpd flag here 
> > that
> > probably will never be used outside of this corner-case. There is also
> > some get/put EPROBE_DEFER sort of logic to implement, but otherwise it
> > would be possible to do this outside of power domains, and that seems
> > better given that this isn't really a power domain to start with.
>
> In later platforms a few new users of the AOSS communication interface
> is introduced that certainly doesn't fit any existing API/framework in
> the kernel. So the plan was to pretty much expose qmp_send() to these
> drivers.
>
> My worry with using this interface is that we'll probably have to come
> up with some DT binding pieces and probably we'll end up adding yet
> another piece of hard coded information in the remoteproc drivers.
>
> But I'm not against us doing this work in favor of not having to
> introduce a one-off for this corner case.

Bjorn/Stephen,

So the consensus is to stop modelling
aoss load_state as pds and expose qmp_send
to drivers?

> Regards,
> Bjorn




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