[PATCH 1/4] coresight/etm4x: disallow altering config via sysfs while enabled

[Yeoreum Yun]

Hi Suzuki,

> Is it not better to have separate "configs" for perf and sysfs ?
> And etmX driver can populate the "running" config, based on the
> mode specific config. That way, the configs can be updated
> independently without affecting the running config or the perf one.
>

That was i've tried but I've accepted Mike's opinion that
it's enough to check whether CS_MODE_DISABLED via coresight_get_mode()
in *_store().

"the .._store functions in sysfs should use coresight_get_mode() to ensure
this is set to CS_MODE_DISABLED before altering the config,
which ensures that the trace system is inactive.
We don't' really care about reading the config if trace is running."

Thanks.