How to trace PMU performance data by ETM?

Hi all,

I'm doubt that which document imply details of connections/architecture of PMU and ETM?

I read the core techinical reference manual, architecture reference manual and etm architecture spec.

But they only simply said the interaction that "The ETM trace unit uses four extended external input selectors to access the PMU events.".

I see PMU register can be accessed by APB interface, and the CP15 interface except PMU manager registers.

But ETM doc said the extended external input selector are used to enable oerformance monitoring events.

How to do that ? through which interface ?

And how can we finally get the PMU information from the ATB interface of ETM?

I'm confused, hope someone can help.

Thanks.

isc