2 files changed, 14 insertions, 0 deletions

diff --git a/arch/s390/include/asm/delay.h b/arch/s390/include/asm/delay.h
index 78357314c450..a356c958e260 100644
--- a/arch/s390/include/asm/delay.h
+++ b/arch/s390/include/asm/delay.h
@@ -15,6 +15,7 @@
 #define _S390_DELAY_H
 
 extern void __udelay(unsigned long usecs);
+extern void udelay_simple(unsigned long usecs);
 extern void __delay(unsigned long loops);
 
 #define udelay(n) __udelay(n)
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 0953cee05efc..6ccb9fab055a 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -92,3 +92,16 @@ out:
         local_irq_restore(flags);
         preempt_enable();
 }
+
+/*
+ * Simple udelay variant. To be used on startup and reboot
+ * when the interrupt handler isn't working.
+ */
+void udelay_simple(unsigned long usecs)
+{
+        u64 end;
+
+        end = get_clock() + ((u64) usecs << 12);
+        while (get_clock() < end)
+                cpu_relax();
+}