x86/tsc: Enumerate BXT tsc_khz via CPUID

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Hard code the BXT crystal clock (aka ART - Always Running Timer)
to 19.200 MHz, and use CPUID leaf 0x15 to determine the BXT TSC frequency.

Use tsc_khz to sanity check BXT cpu_khz,
which can be erroneous in some configurations.

(I simplified the original patch from Bin Gao.)

Original-From: Bin Gao <bin.gao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/bf4e7c175acd6d09719c47c319b10ff1f0627ff8.1466138954.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Len Brown 2016-06-17 01:22:52 -04:00 • committed by Ingo Molnar

parent aa297292d7

commit ff4c86635e

1 changed files with 15 additions and 1 deletions

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arch/x86/kernel/tsc.c

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