VServer 1.9.2 (patch-2.6.8.1-vs1.9.2.diff)

[linux-2.6.git] / arch / i386 / kernel / timers / timer_pm.c

diff --git a/arch/i386/kernel/timers/timer_pm.c b/arch/i386/kernel/timers/timer_pm.c
index 7aa63c9..737a021 100644 (file)
--- a/arch/i386/kernel/timers/timer_pm.c
+++ b/arch/i386/kernel/timers/timer_pm.c
@@ -21,6 +21,14 @@
 #include <asm/io.h>
 #include <asm/arch_hooks.h>
 
+#include <linux/timex.h>
+#include "mach_timer.h"
+
+/* Number of PMTMR ticks expected during calibration run */
+#define PMTMR_TICKS_PER_SEC 3579545
+#define PMTMR_EXPECTED_RATE \
+  ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (CLOCK_TICK_RATE>>10))
+
 
 /* The I/O port the PMTMR resides at.
  * The location is detected during setup_arch(),
@@ -57,6 +65,33 @@ static inline u32 read_pmtmr(void)
        return v2 & ACPI_PM_MASK;
 }
 
+
+/*
+ * Some boards have the PMTMR running way too fast. We check
+ * the PMTMR rate against PIT channel 2 to catch these cases.
+ */
+static int verify_pmtmr_rate(void)
+{
+       u32 value1, value2;
+       unsigned long count, delta;
+
+       mach_prepare_counter();
+       value1 = read_pmtmr();
+       mach_countup(&count);
+       value2 = read_pmtmr();
+       delta = (value2 - value1) & ACPI_PM_MASK;
+
+       /* Check that the PMTMR delta is within 5% of what we expect */
+       if (delta < (PMTMR_EXPECTED_RATE * 19) / 20 ||
+           delta > (PMTMR_EXPECTED_RATE * 21) / 20) {
+               printk(KERN_INFO "PM-Timer running at invalid rate: %lu%% of normal - aborting.\n", 100UL * delta / PMTMR_EXPECTED_RATE);
+               return -1;
+       }
+
+       return 0;
+}
+
+
 static int init_pmtmr(char* override)
 {
        u32 value1, value2;
@@ -89,6 +124,9 @@ static int init_pmtmr(char* override)
        return -ENODEV;
 
 pm_good:
+       if (verify_pmtmr_rate() != 0)
+               return -ENODEV;
+
        init_cpu_khz();
        return 0;
 }