Fix timer on all platforms

riscvarchive / riscv-edk2-platforms

Port of EDK2 implementation of UEFI to RISC-V. See documentation at:

https://github.com/riscv/riscv-uefi-edk2-docs

Other

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Fix timer on all platforms #19

Open JohnAZoidberg opened 3 years ago

JohnAZoidberg commented 3 years ago

The countdown in the shell to run autostart.nsh says it's counting down from 5s but it's much faster.

[ ] U540/U500 (works when setting the PCD to 10x the actual value, which is 1_000_000)
[ ] RiscvVirt
[ ] BeagleV (not tested but frequency is 6_250_000 according to datasheet)

JohnAZoidberg commented 3 years ago

Other platforms still use the SiFive timer, too. They shouldn't.

JohnAZoidberg commented 3 years ago

On U540 it seems to be off by a factor of 10. If I change PcdRiscVMachineTimerFrequencyInHerz from 1_000_000 to 10_000_000 the countdown to skip startup.sh seems to be roughly 5 seconds. However the device tree of the U540 indicates that the frequency is 1_000_000.

Maybe there's something wrong in Silicon/RISC-V/ProcessorPkg/Library/RiscVTimerLib/RiscVTimerLib.c?