ping Am Mo., 14. Mai 2018 um 11:32 Uhr schrieb Christian Gmeiner < [email protected]>:
> Starting with cpuid level 0x16 (Skylake-based processors) > it is possible to get CPU base freq via cpuid. > This fixes booting on a skylake based system. > Signed-off-by: Christian Gmeiner <[email protected]> > --- > drivers/timer/tsc_timer.c | 31 +++++++++++++++++++++++++------ > 1 file changed, 25 insertions(+), 6 deletions(-) > diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c > index c7fefd2031..96a3e55513 100644 > --- a/drivers/timer/tsc_timer.c > +++ b/drivers/timer/tsc_timer.c > @@ -21,6 +21,17 @@ > DECLARE_GLOBAL_DATA_PTR; > +static unsigned long cpu_mhz_from_cpuid(void) > +{ > + if (gd->arch.x86_vendor != X86_VENDOR_INTEL) > + return 0; > + > + if (cpuid_eax(0) < 0x16) > + return 0; > + > + return cpuid_eax(0x16); > +} > + > /* > * According to Intel 64 and IA-32 System Programming Guide, > * if MSR_PERF_STAT[31] is set, the maximum resolved bus ratio can be > @@ -343,14 +354,22 @@ static void tsc_timer_ensure_setup(void) > if (!gd->arch.clock_rate) { > unsigned long fast_calibrate; > + fast_calibrate = cpu_mhz_from_cpuid(); > + if (fast_calibrate) > + goto done; > + > fast_calibrate = cpu_mhz_from_msr(); > - if (!fast_calibrate) { > - fast_calibrate = quick_pit_calibrate(); > - if (!fast_calibrate) > - panic("TSC frequency is ZERO"); > - } > + if (fast_calibrate) > + goto done; > + > + fast_calibrate = quick_pit_calibrate(); > + if (fast_calibrate) > + goto done; > + > + panic("TSC frequency is ZERO"); > - gd->arch.clock_rate = fast_calibrate * 1000000; > + done: > + gd->arch.clock_rate = fast_calibrate * 1000000; > } > } > -- > 2.17.0 -- greets -- Christian Gmeiner, MSc https://christian-gmeiner.info _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
