Re: [PATCH 1/3] arm64: dts: qcom: sdm845: Add Coresight support

[Sai Prakash Ranjan]

Hi Mathieu,

On 1/14/2019 9:05 PM, Mathieu Poirier wrote:
> On Sat, Jan 12, 2019 at 06:21:00PM +0530, saiprakash.ranjan@xxxxxxxxxxxxxx wrote:
> > Hi Mathieu,
> >
> > > > +
> > > > +	etm@7040000 {
> > > > +		compatible = "arm,coresight-etm4x", "arm,primecell";
> > > > +		arm,primecell-periphid = <0x000bb95d>;
> > >
> > > I'm a little curious as to why you need to bypass the normal AMBA bus
> > > discovery
> > > method by forcing the peripheral ID.  Tracers don't show up the way
> > > other
> > > coresight devices do at boot time?
> >
> > Yes on some Qcom SoC's like SDM845 and also on some previous ones, for
> > ETM(only) amba bus discovery method fails because of wrong pid read from the
> > registers. So we have to force this primecell peripheral ids to probe etm.
>
> Ok, if that is the case please add a comment to explain the situation.
> Otherwise someone will assuredly ask again in the future.

Sure, will add it in the next version.

Thanks,
Sai

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