Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee13...

[pandora-kernel.git] / arch / i386 / kernel / time_hpet.c

diff --git a/arch/i386/kernel/time_hpet.c b/arch/i386/kernel/time_hpet.c
index cb1f313..1a2a979 100644 (file)
--- a/arch/i386/kernel/time_hpet.c
+++ b/arch/i386/kernel/time_hpet.c
@@ -18,7 +18,6 @@
 #include <asm/apic.h>
 
 #include <linux/timex.h>
-#include <linux/config.h>
 
 #include <asm/hpet.h>
 #include <linux/hpet.h>
@@ -259,8 +258,6 @@ __setup("hpet=", hpet_setup);
 #include <linux/mc146818rtc.h>
 #include <linux/rtc.h>
 
-extern irqreturn_t rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs);
-
 #define DEFAULT_RTC_INT_FREQ   64
 #define RTC_NUM_INTS           1
 
@@ -275,6 +272,7 @@ static unsigned long PIE_freq = DEFAULT_RTC_INT_FREQ;
 static unsigned long PIE_count;
 
 static unsigned long hpet_rtc_int_freq; /* RTC interrupt frequency */
+static unsigned int hpet_t1_cmp; /* cached comparator register */
 
 /*
  * Timer 1 for RTC, we do not use periodic interrupt feature,
@@ -303,22 +301,25 @@ int hpet_rtc_timer_init(void)
                hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ;
 
        local_irq_save(flags);
+
        cnt = hpet_readl(HPET_COUNTER);
        cnt += ((hpet_tick*HZ)/hpet_rtc_int_freq);
        hpet_writel(cnt, HPET_T1_CMP);
-       local_irq_restore(flags);
+       hpet_t1_cmp = cnt;
 
        cfg = hpet_readl(HPET_T1_CFG);
        cfg &= ~HPET_TN_PERIODIC;
        cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
        hpet_writel(cfg, HPET_T1_CFG);
 
+       local_irq_restore(flags);
+
        return 1;
 }
 
 static void hpet_rtc_timer_reinit(void)
 {
-       unsigned int cfg, cnt;
+       unsigned int cfg, cnt, ticks_per_int, lost_ints;
 
        if (unlikely(!(PIE_on | AIE_on | UIE_on))) {
                cfg = hpet_readl(HPET_T1_CFG);
@@ -333,9 +334,33 @@ static void hpet_rtc_timer_reinit(void)
                hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ;
 
        /* It is more accurate to use the comparator value than current count.*/
-       cnt = hpet_readl(HPET_T1_CMP);
-       cnt += hpet_tick*HZ/hpet_rtc_int_freq;
-       hpet_writel(cnt, HPET_T1_CMP);
+       ticks_per_int = hpet_tick * HZ / hpet_rtc_int_freq;
+       hpet_t1_cmp += ticks_per_int;
+       hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
+
+       /*
+        * If the interrupt handler was delayed too long, the write above tries
+        * to schedule the next interrupt in the past and the hardware would
+        * not interrupt until the counter had wrapped around.
+        * So we have to check that the comparator wasn't set to a past time.
+        */
+       cnt = hpet_readl(HPET_COUNTER);
+       if (unlikely((int)(cnt - hpet_t1_cmp) > 0)) {
+               lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1;
+               /* Make sure that, even with the time needed to execute
+                * this code, the next scheduled interrupt has been moved
+                * back to the future: */
+               lost_ints++;
+
+               hpet_t1_cmp += lost_ints * ticks_per_int;
+               hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
+
+               if (PIE_on)
+                       PIE_count += lost_ints;
+
+               printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
+                      hpet_rtc_int_freq);
+       }
 }
 
 /*
@@ -416,7 +441,7 @@ int hpet_rtc_dropped_irq(void)
        return 1;
 }
 
-irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
 {
        struct rtc_time curr_time;
        unsigned long rtc_int_flag = 0;
@@ -455,7 +480,7 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
        }
        if (call_rtc_interrupt) {
                rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
-               rtc_interrupt(rtc_int_flag, dev_id, regs);
+               rtc_interrupt(rtc_int_flag, dev_id);
        }
        return IRQ_HANDLED;
 }