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| author |   Len Brown <len.brown@intel.com> | 2017-01-13 01:11:18 -0500 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2017-01-14 09:30:37 +0100 |
| commit | 695085b4bc7603551db0b3da897b8bf9893ca218 (patch) | |
| tree | 53f371f8f222c1cc8ee328115a112cadd9541aaa /arch/x86/kernel/tsc.c | |
| parent | x86/entry: Fix the end of the stack for newly forked tasks (diff) | |
| download | linux-dev-695085b4bc7603551db0b3da897b8bf9893ca218.tar.xz linux-dev-695085b4bc7603551db0b3da897b8bf9893ca218.zip | |
x86/tsc: Add the Intel Denverton Processor to native_calibrate_tsc()
The Intel Denverton microserver uses a 25 MHz TSC crystal,
so we can derive its exact [*] TSC frequency
using CPUID and some arithmetic, eg.:
TSC: 1800 MHz (25000000 Hz * 216 / 3 / 1000000)
[*] 'exact' is only as good as the crystal, which should be +/- 20ppm
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/306899f94804aece6d8fa8b4223ede3b48dbb59c.1484287748.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index be3a49ee0356..e41af597aed8 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -694,6 +694,7 @@ unsigned long native_calibrate_tsc(void) crystal_khz = 24000; /* 24.0 MHz */ break; case INTEL_FAM6_SKYLAKE_X: + case INTEL_FAM6_ATOM_DENVERTON: crystal_khz = 25000; /* 25.0 MHz */ break; case INTEL_FAM6_ATOM_GOLDMONT: |