Re: [PATCH 1/3] arm64: dts: juno: add coresight support

On 12/06/16 22:57, Mathieu Poirier wrote:

On 6 June 2016 at 09:59, Sudeep Holla [off-list ref] wrote:

quoted

Most of the debug-related components on Juno are located in the coreSight
subsystem while others are located in the Cortex-Axx clusters, the SCP
subsystem, and in the main system.

Each core in the two processor clusters contain an Embedded Trace
Macrocell(ETM) which generates real-time trace information that trace
tools can use and an ATB trace output that is sent to a funnel before
going to the CoreSight subsystem.

The trace output signals combine with two trace expansions using another
funnel and fed into the Embedded Trace FIFO(ETF0).

The output trace data stream of the funnel is then replicated before it
is sent to either the:
- Trace Port Interface Unit(TPIU), that sends it out using the trace port.
- ETR that can write the trace data to memory located in the application
   memory space

Hi Sudeep,

Did you try booting this on juno-r0?  On my side the system won't boot
unless I enable the debug power domain by externally connecting to the
system using DS-5.

As you have already realized that you need SCPI power domain patches for
the functionality. However, in absence of those patches or when it's
disabled, it shouldn't cause any boot or runtime issues. Only ETM or
coresight won't work. If it's causing any crash or hang, please do let
me know, that needs to be fixed. I have only tested with latest
firmware. Let me know the details of hang/crash and firmware version you
are using.

-- 
Regards,
Sudeep
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