Re: [PATCH v2 5/5] Documentation: coresight: Update coresight configuration docs

[German Gomez <german.gomez@arm.com>]

Hi Mike,

Sorry if this is the wrong channel to report this, but is the section in
the coresight-config configuration, where it lists "configurations"
under the "/sys/devices/cs_etm/" directory still relevant?

    $ ls /sys/devices/cs_etm
    configurations  format  perf_event_mux_interval_ms  sinks  type
    events  nr_addr_filters  power

I think it may have been removed in a previous patchset [1]. I didn't
see it when trying the coresight-config patches.

    2) Dropped the 'configurations' sub dir in cs_etm perf directories as superfluous

Thanks,
German

[1] https://lore.kernel.org/linux-arm-kernel/20210707133003.5414-1-mike.leach@linaro.org/

On 19/10/2021 20:13, Mike Leach wrote:
> Update the CoreSight System Configuration document to cover the
> use of loadable modules to add configurations and features
> to the system.
>
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> ---
>  .../trace/coresight/coresight-config.rst      | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documentation/trace/coresight/coresight-config.rst
> index a4e3ef295240..911db4da7f99 100644
> --- a/Documentation/trace/coresight/coresight-config.rst
> +++ b/Documentation/trace/coresight/coresight-config.rst
> @@ -242,3 +242,22 @@ A preset to override the current parameter values can also be selected::
>  
>  When configurations are selected in this way, then the trace sink used is
>  automatically selected.
> +
> +Creating and Loading Custom Configurations
> +==========================================
> +
> +Custom configurations and / or features can be dynamically loaded into the
> +system by using a loadable module.
> +
> +An example of a custom configuration is found in ./samples/coresight.
> +
> +This creates a new configuration that uses the existing built in
> +strobing feature, but provides a different set of presets.
> +
> +When the module is loaded, then the configuration appears in the configfs
> +file system and is selectable in the same way as the built in configuration
> +described above.
> +
> +Configurations can use previously loaded features. The system will ensure
> +that it is not possible to unload a feature that is currently in use, by
> +enforcing the unload order as the strict reverse of the load order.

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