Clocks used by another OS/CPU (was: Re: [RFC PATCH] clk: renesas: cpg-mssr: Add interface for critical core clocks)

[Peter De Schrijver]

On Mon, Jul 03, 2017 at 10:17:22AM +0100, Sudeep Holla wrote:
> 
> 
> On 01/07/17 19:14, Uwe Kleine-König wrote:
> > Hello,
> > 
> > On Sat, Jul 01, 2017 at 07:02:48AM +0200, Dirk Behme wrote:
> 
> [...]
> 
> >>
> >>
> >> The other problem is security related. If, at all, you have to do it the
> >> other way around, then:
> >>
> >> Make Linux a consumer of the other CPU's (trusted/trustzone/whatever
> >> secured) OS clock driver.
> 
> Yes, that's better and is getting common on newer platforms. They have
> separate M-class(or even low A-class e.g. A5/A7) processors to handle
> all the system management.
> 
> The new ARM SCMI specification[0][1] is designed to standardize the
> interface. It covers the clocks in clock protocol.
> 

Yes, however this doesn't exist on older SoCs which still have multiple CPU's

Peter.