1 files changed, 24 insertions, 7 deletions

diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 752b362bf651..a65229d91c92 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/irqflags.h>
 #include <linux/interrupt.h>
+#include <asm/div64.h>
 
 void __delay(unsigned long loops)
 {
@@ -29,21 +30,24 @@ static void __udelay_disabled(unsigned long long usecs)
 {
         unsigned long mask, cr0, cr0_saved;
         u64 clock_saved;
+        u64 end;
 
+        mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
+        end = get_clock() + (usecs << 12);
         clock_saved = local_tick_disable();
-        set_clock_comparator(get_clock() + (usecs << 12));
         __ctl_store(cr0_saved, 0, 0);
         cr0 = (cr0_saved & 0xffff00e0) | 0x00000800;
         __ctl_load(cr0 , 0, 0);
-        mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
         lockdep_off();
-        trace_hardirqs_on();
-        __load_psw_mask(mask);
-        local_irq_disable();
+        do {
+                set_clock_comparator(end);
+                trace_hardirqs_on();
+                __load_psw_mask(mask);
+                local_irq_disable();
+        } while (get_clock() < end);
         lockdep_on();
         __ctl_load(cr0_saved, 0, 0);
         local_tick_enable(clock_saved);
-        set_clock_comparator(S390_lowcore.clock_comparator);
 }
 
 static void __udelay_enabled(unsigned long long usecs)
@@ -66,7 +70,6 @@ static void __udelay_enabled(unsigned long long usecs)
                 if (clock_saved)
                         local_tick_enable(clock_saved);
         } while (get_clock() < end);
-        set_clock_comparator(S390_lowcore.clock_comparator);
 }
 
 /*
@@ -114,3 +117,17 @@ void udelay_simple(unsigned long long usecs)
         while (get_clock() < end)
                 cpu_relax();
 }
+
+void __ndelay(unsigned long long nsecs)
+{
+        u64 end;
+
+        nsecs <<= 9;
+        do_div(nsecs, 125);
+        end = get_clock() + nsecs;
+        if (nsecs & ~0xfffUL)
+                __udelay(nsecs >> 12);
+        while (get_clock() < end)
+                barrier();
+}
+EXPORT_SYMBOL(__ndelay);