tree cb436c839b890d04f589b49f75cb0df59315158e
parent f0dbe81f0e7c39783ad25d9084bbcda131508993
author Feng Tang <feng.tang@intel.com> 1358266187 +0800
committer John Stultz <john.stultz@linaro.org> 1358302567 -0800

timekeeping: Add persistent_clock_exist flag

In current kernel, there are several places which need to check
whether there is a persistent clock for the platform. Current check
is done by calling the read_persistent_clock() and validating its
return value.

So one optimization is to do the check only once in timekeeping_init(),
and use a flag persistent_clock_exist to record it.

v2: Add a has_persistent_clock() helper function, as suggested by John.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>