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This patch ensures to follow Intel SDM Vol 3B Sec 18.7.3 to
calculate nominal TSC frequency.
As per SDM recommendation:
For any processor in which CPUID.15H is enumerated and
MSR_PLATFORM_INFO[15:8] (which gives the scalable bus frequency) is
available, a more accurate frequency can be obtained by using CPUID.15H
This patch also adds header file to capture Intel processor model number.
BUG=b:129839774
TEST=Boot ICL platform and calculate TSC frequency using below methods
1. TSC freq calculated based on MSR 0xCE
tsc: Detected 1600.000 MHz processor
2. TSC freq calculated based on CPUID 0x15
tsc: Detected 1612.800 MHz TSC
Method 2 actually reduce ~25ms of boot performance time.
Note: Method 2 is recommended from gen 6 processor onwards.
Change-Id: I9ff4b9159a94e61b7e634bd6095f7cc6d7df87c7
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32283
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-by: Aamir Bohra <aamir.bohra@intel.com>
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