3 files changed, 16 insertions, 15 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();
+}
diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index c0cb72547256..3db2c386546f 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -859,19 +859,6 @@ __disable_subchannel_easy(struct subchannel_id schid, struct schib *schib)
         return -EBUSY; /* uhm... */
 }
 
-/* we can't use the normal udelay here, since it enables external interrupts */
-
-static void udelay_reset(unsigned long usecs)
-{
-        uint64_t start_cc, end_cc;
-
-        asm volatile ("STCK %0" : "=m" (start_cc));
-        do {
-                cpu_relax();
-                asm volatile ("STCK %0" : "=m" (end_cc));
-        } while (((end_cc - start_cc)/4096) < usecs);
-}
-
 static int
 __clear_io_subchannel_easy(struct subchannel_id schid)
 {
@@ -887,7 +874,7 @@ __clear_io_subchannel_easy(struct subchannel_id schid)
                         if (schid_equal(&ti.schid, &schid))
                                 return 0;
                 }
-                udelay_reset(100);
+                udelay_simple(100);
         }
         return -EBUSY;
 }
@@ -895,7 +882,7 @@ __clear_io_subchannel_easy(struct subchannel_id schid)
 static void __clear_chsc_subchannel_easy(void)
 {
         /* It seems we can only wait for a bit here :/ */
-        udelay_reset(100);
+        udelay_simple(100);
 }
 
 static int pgm_check_occured;