diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2008-09-04 15:18:48 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-09-04 17:35:33 +0200 |
| commit | d683ef7afe8b6dbac6a3c681cef8a908357793ca (patch) | |
| tree | 1082814f6627a6fd7b0f11aa0f476e31bad701a3 /arch/x86/kernel/tsc.c | |
| parent | cce3e057242d3d46fea07b9eb3910b0076419be5 (diff) | |
x86: TSC: separate hpet/pmtimer calculation out
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 56 |
1 files changed, 41 insertions, 15 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index aa11413e7c1d..ebb9bf824a07 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -122,6 +122,43 @@ static u64 tsc_read_refs(u64 *pm, u64 *hpet) return ULLONG_MAX; } +/* + * Calculate the TSC frequency from HPET reference + */ +static unsigned long calc_hpet_ref(u64 deltatsc, u64 hpet1, u64 hpet2) +{ + u64 tmp; + + if (hpet2 < hpet1) + hpet2 += 0x100000000ULL; + hpet2 -= hpet1; + tmp = ((u64)hpet2 * hpet_readl(HPET_PERIOD)); + do_div(tmp, 1000000); + do_div(deltatsc, tmp); + + return (unsigned long) deltatsc; +} + +/* + * Calculate the TSC frequency from PMTimer reference + */ +static unsigned long calc_pmtimer_ref(u64 deltatsc, u64 pm1, u64 pm2) +{ + u64 tmp; + + if (!pm1 && !pm2) + return ULONG_MAX; + + if (pm2 < pm1) + pm2 += (u64)ACPI_PM_OVRRUN; + pm2 -= pm1; + tmp = pm2 * 1000000000LL; + do_div(tmp, PMTMR_TICKS_PER_SEC); + do_div(deltatsc, tmp); + + return (unsigned long) deltatsc; +} + #define CAL_MS 50 #define CAL_LATCH (CLOCK_TICK_RATE / (1000 / CAL_MS)) #define CAL_PIT_LOOPS 5000 @@ -247,22 +284,11 @@ unsigned long native_calibrate_tsc(void) continue; tsc2 = (tsc2 - tsc1) * 1000000LL; + if (hpet) + tsc2 = calc_hpet_ref(tsc2, hpet1, hpet2); + else + tsc2 = calc_pmtimer_ref(tsc2, pm1, pm2); - if (hpet) { - if (hpet2 < hpet1) - hpet2 += 0x100000000ULL; - hpet2 -= hpet1; - tsc1 = ((u64)hpet2 * hpet_readl(HPET_PERIOD)); - do_div(tsc1, 1000000); - } else { - if (pm2 < pm1) - pm2 += (u64)ACPI_PM_OVRRUN; - pm2 -= pm1; - tsc1 = pm2 * 1000000000LL; - do_div(tsc1, PMTMR_TICKS_PER_SEC); - } - - do_div(tsc2, tsc1); tsc_ref_min = min(tsc_ref_min, (unsigned long) tsc2); } |