[U-Boot] Antwort: Re: [PATCH] x86: tsc: Add support for APL soc

[Bernhard Messerklinger]

Hi Andy,

> Von: Bin Meng <bmeng.cn at gmail.com>
> An: Andy Shevchenko <andy.shevchenko at gmail.com>, 
> Kopie: Bernhard Messerklinger <bernhard.messerklinger at br-
> automation.com>, U-Boot Mailing List <u-boot at lists.denx.de>
> Datum: 25.11.2018 15:50
> Betreff: Re: [U-Boot] [PATCH] x86: tsc: Add support for APL soc
> 
> Hi Andy,
> 
> On Sun, Nov 25, 2018 at 10:43 PM Andy Shevchenko
> <andy.shevchenko at gmail.com> wrote:
> >
> > On Sun, Nov 25, 2018 at 4:31 PM Andy Shevchenko
> > <andy.shevchenko at gmail.com> wrote:
> > > On Sat, Nov 24, 2018 at 5:39 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> >
> > > > Are you saying that if doing cpu_mhz_from_cpuid() you can't get
> > > > correct frequency? Can you investigate why your core crystal clock 
is
> > > > always zero?
> > >
> > > Yes, this has to be investigated.
> > >
> > > > Can we do it something like VLV2?
> > >
> > > Please, don't. I see no evidence in the latest Linux kernel sources
> > > that Apollo Lake has such issue as Intel MID family of Atom SoCs.
> >
> > Sorry, I slipped one code in my consideration, i.e.
> >
> > unsigned long native_calibrate_tsc(void)
> > {
> > ...
> > if (crystal_khz == 0) {
> > switch (boot_cpu_data.x86_model) {
> > ...
> > case INTEL_FAM6_ATOM_GOLDMONT:
> > crystal_khz = 19200; /* 19.2 MHz */
> > break;
> > }
> > ...
> > if (boot_cpu_data.x86_model == INTEL_FAM6_ATOM_GOLDMONT)
> > setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
> > ...
> > }
> >
> > So, that's what we need to do in U-boot.
> >
> 
> Thanks for the investigation. Could you please send a proper patch?
do you want to take charge of this?
Otherwise I will post patch V2.
> 
> Regards,
> Bin

Regards,
Bernhard