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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2014-09-10 18:48:47 +0000
committeroliviermartin <oliviermartin@6f19259b-4bc3-4df7-8a09-765794883524>2014-09-10 18:48:47 +0000
commit7a1e861e2925b9c006bcf8f95bd0d720a8c48328 (patch)
tree033b8d4668b7d465db776eba9cb93e1e57f8b341 /ArmPlatformPkg
parentca3026d361970847d87a5c6ebb8108b28486e9ec (diff)
downloadedk2-platforms-7a1e861e2925b9c006bcf8f95bd0d720a8c48328.tar.xz
ArmPkg/TimerDxe: Read timer frequency from CPU
The PCD gArmTokenSpaceGuid.PcdArmArchTimerFreqInHz is used in the SEC phase (if applicable) to write the platform's counter frequency to the CNTFRQ system register, as this needs to be done by the highest exception level implemented. Under virtualization, we should be able to rely on the host to have initialized this register to a sane value, as we run at EL1 and only use the virtual timer, so the PcdArmArchTimerFreqInHz PCD has little meaning here. So in either case, by the time we enter the DXE phase, we can use the CNTFRQ system register to read the frequency instead of looking at the PCD. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Olivier Martin <olivier.martin@arm.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16090 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'ArmPlatformPkg')
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