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x86: tsc: Add support for native calibration of TSC freq

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Add native tsc calibration function. Calibrate the tsc timer the same
way as linux does in arch/x86/kernel/tsc.c.

Fixes booting for Apollo Lake processors.

Signed-off-by: Bernhard Messerklinger <bernhard.messerklinger@br-automation.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Bernhard Messerklinger 2019-01-07 12:14:40 +01:00 committed by Bin Meng
parent 2436396a11
commit ca7db866fe
1 changed files with 55 additions and 0 deletions
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55
drivers/timer/tsc_timer.c
View file

@ -19,8 +19,59 @@
#define MAX_NUM_FREQS 9
#define INTEL_FAM6_SKYLAKE_MOBILE 0x4E
#define INTEL_FAM6_ATOM_GOLDMONT 0x5C /* Apollo Lake */
#define INTEL_FAM6_SKYLAKE_DESKTOP 0x5E
#define INTEL_FAM6_ATOM_GOLDMONT_X 0x5F /* Denverton */
#define INTEL_FAM6_KABYLAKE_MOBILE 0x8E
#define INTEL_FAM6_KABYLAKE_DESKTOP 0x9E
DECLARE_GLOBAL_DATA_PTR;
/*
* native_calibrate_tsc
* Determine TSC frequency via CPUID, else return 0.
*/
static unsigned long native_calibrate_tsc(void)
{
struct cpuid_result tsc_info;
unsigned int crystal_freq;
if (gd->arch.x86_vendor != X86_VENDOR_INTEL)
return 0;
if (cpuid_eax(0) < 0x15)
return 0;
tsc_info = cpuid(0x15);
if (tsc_info.ebx == 0 || tsc_info.eax == 0)
return 0;
crystal_freq = tsc_info.ecx / 1000;
if (!crystal_freq) {
switch (gd->arch.x86_model) {
case INTEL_FAM6_SKYLAKE_MOBILE:
case INTEL_FAM6_SKYLAKE_DESKTOP:
case INTEL_FAM6_KABYLAKE_MOBILE:
case INTEL_FAM6_KABYLAKE_DESKTOP:
crystal_freq = 24000; /* 24.0 MHz */
break;
case INTEL_FAM6_ATOM_GOLDMONT_X:
crystal_freq = 25000; /* 25.0 MHz */
break;
case INTEL_FAM6_ATOM_GOLDMONT:
crystal_freq = 19200; /* 19.2 MHz */
break;
default:
return 0;
}
}
return (crystal_freq * tsc_info.ebx / tsc_info.eax) / 1000;
}
static unsigned long cpu_mhz_from_cpuid(void)
{
if (gd->arch.x86_vendor != X86_VENDOR_INTEL)
@ -350,6 +401,10 @@ static void tsc_timer_ensure_setup(bool early)
if (!gd->arch.clock_rate) {
unsigned long fast_calibrate;
fast_calibrate = native_calibrate_tsc();
if (fast_calibrate)
goto done;
fast_calibrate = cpu_mhz_from_cpuid();
if (fast_calibrate)
goto done;