X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fia64%2Fsn%2Fkernel%2Fsn2%2Ftimer.c;h=56a88b6df4b41fbca0df635ab5fc23988b0298b4;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=85f7d215a35800de1447186fa75882493fbc4956;hpb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;p=linux-2.6.git

diff --git a/arch/ia64/sn/kernel/sn2/timer.c b/arch/ia64/sn/kernel/sn2/timer.c
index 85f7d215a..56a88b6df 100644
--- a/arch/ia64/sn/kernel/sn2/timer.c
+++ b/arch/ia64/sn/kernel/sn2/timer.c
@@ -14,22 +14,42 @@
 
 #include <asm/hw_irq.h>
 #include <asm/system.h>
+#include <asm/timex.h>
 
 #include <asm/sn/leds.h>
+#include <asm/sn/shub_mmr.h>
 #include <asm/sn/clksupport.h>
 
-
 extern unsigned long sn_rtc_cycles_per_second;
 
-static struct time_interpolator sn2_interpolator;
+static struct time_interpolator sn2_interpolator = {
+	.drift = -1,
+	.shift = 10,
+	.mask = (1LL << 55) - 1,
+	.source = TIME_SOURCE_MMIO64
+};
+
+/*
+ * sn udelay uses the RTC instead of the ITC because the ITC is not
+ * synchronized across all CPUs, and the thread may migrate to another CPU
+ * if preemption is enabled.
+ */
+static void
+ia64_sn_udelay (unsigned long usecs)
+{
+	unsigned long start = rtc_time();
+	unsigned long end = start +
+			usecs * sn_rtc_cycles_per_second / 1000000;
+
+	while (time_before((unsigned long)rtc_time(), end))
+		cpu_relax();
+}
 
-void __init
-sn_timer_init(void)
+void __init sn_timer_init(void)
 {
 	sn2_interpolator.frequency = sn_rtc_cycles_per_second;
-	sn2_interpolator.drift = -1;	/* unknown */
-	sn2_interpolator.shift = 10;	/* RTC is 54 bits maximum shift is 10 */
 	sn2_interpolator.addr = RTC_COUNTER_ADDR;
-	sn2_interpolator.source = TIME_SOURCE_MMIO64;
 	register_time_interpolator(&sn2_interpolator);
+
+	ia64_udelay = &ia64_sn_udelay;
 }