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);
         }