1 files changed, 4 insertions, 56 deletions

diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c
index 51ef31a89be9..671d5aad7a0c 100644
--- a/arch/x86/kernel/apb_timer.c
+++ b/arch/x86/kernel/apb_timer.c
@@ -508,64 +508,12 @@ static int apbt_next_event(unsigned long delta,
         return 0;
 }
 
-/*
- * APB timer clock is not in sync with pclk on Langwell, which translates to
- * unreliable read value caused by sampling error. the error does not add up
- * overtime and only happens when sampling a 0 as a 1 by mistake. so the time
- * would go backwards. the following code is trying to prevent time traveling
- * backwards. little bit paranoid.
- */
 static cycle_t apbt_read_clocksource(struct clocksource *cs)
 {
-        unsigned long t0, t1, t2;
-        static unsigned long last_read;
-
-bad_count:
-        t1 = apbt_readl(phy_cs_timer_id,
-                        APBTMR_N_CURRENT_VALUE);
-        t2 = apbt_readl(phy_cs_timer_id,
-                        APBTMR_N_CURRENT_VALUE);
-        if (unlikely(t1 < t2)) {
-                pr_debug("APBT: read current count error %lx:%lx:%lx\n",
-                         t1, t2, t2 - t1);
-                goto bad_count;
-        }
-        /*
-         * check against cached last read, makes sure time does not go back.
-         * it could be a normal rollover but we will do tripple check anyway
-         */
-        if (unlikely(t2 > last_read)) {
-                /* check if we have a normal rollover */
-                unsigned long raw_intr_status =
-                        apbt_readl_reg(APBTMRS_RAW_INT_STATUS);
-                /*
-                 * cs timer interrupt is masked but raw intr bit is set if
-                 * rollover occurs. then we read EOI reg to clear it.
-                 */
-                if (raw_intr_status & (1 << phy_cs_timer_id)) {
-                        apbt_readl(phy_cs_timer_id, APBTMR_N_EOI);
-                        goto out;
-                }
-                pr_debug("APB CS going back %lx:%lx:%lx ",
-                         t2, last_read, t2 - last_read);
-bad_count_x3:
-                pr_debug("triple check enforced\n");
-                t0 = apbt_readl(phy_cs_timer_id,
-                                APBTMR_N_CURRENT_VALUE);
-                udelay(1);
-                t1 = apbt_readl(phy_cs_timer_id,
-                                APBTMR_N_CURRENT_VALUE);
-                udelay(1);
-                t2 = apbt_readl(phy_cs_timer_id,
-                                APBTMR_N_CURRENT_VALUE);
-                if ((t2 > t1) || (t1 > t0)) {
-                        printk(KERN_ERR "Error: APB CS tripple check failed\n");
-                        goto bad_count_x3;
-                }
-        }
-out:
-        last_read = t2;
-        return (cycle_t)~t2;
+        unsigned long current_count;
+
+        current_count = apbt_readl(phy_cs_timer_id, APBTMR_N_CURRENT_VALUE);
+        return (cycle_t)~current_count;
 }
 
 static int apbt_clocksource_register(void)