Re: [PATCH v4 13/13] coresight: docs: Document etm4x timestamp interval option

[James Clark]

On 14/11/2025 5:02 am, Randy Dunlap wrote:
> On 11/12/25 7:22 AM, James Clark wrote:
> > Document how the new field is used, maximum value and the interaction
> > with SYNC timestamps.
> >
> > Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
> > ---
> >   Documentation/trace/coresight/coresight.rst | 15 +++++++++++++--
> >   1 file changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst
> > index 806699871b80..80b5ed09d69b 100644
> > --- a/Documentation/trace/coresight/coresight.rst
> > +++ b/Documentation/trace/coresight/coresight.rst
> > @@ -613,8 +613,19 @@ They are also listed in the folder /sys/bus/event_source/devices/cs_etm/format/
> >        - Session local version of the system wide setting: :ref:`ETM_MODE_RETURNSTACK
> >          <coresight-return-stack>`
> >      * - timestamp
> > -     - Session local version of the system wide setting: :ref:`ETMv4_MODE_TIMESTAMP
> > -       <coresight-timestamp>`
> > +     - Controls generation and interval of timestamps.
> > +
> > +       0 = off, 1 = maximum interval .. 15 = minimum interval.
> > +
> > +       Values 1 - 14 use a counter that decrements every cycle to generate a
> > +       timestamp on underflow. The reload value for the counter is 2 raised to
> > +       the power of timestamp interval - 1. If the value is 1 then the reload
> > +       value is 1, if the value is 11 then the reload value is 1024 etc.
>
> 	  value = 11: 2^11-1 = 2047
>
> Maybe add some parens?

Will do. I had them but I removed them because it was in a sentence so 
it made it look like a side note. I think I'll change from words to symbols:

  The reload value for the counter is 2 ^ (interval - 1).

Thanks
James