diff --git a/arch/s390/include/asm/delay.h b/arch/s390/include/asm/delay.h
index b566be6f13f3..21a8fe18fe66 100644
--- a/arch/s390/include/asm/delay.h
+++ b/arch/s390/include/asm/delay.h
@@ -13,10 +13,8 @@
 #ifndef _S390_DELAY_H
 #define _S390_DELAY_H
 
-void udelay_enable(void);
 void __ndelay(unsigned long nsecs);
 void __udelay(unsigned long usecs);
-void udelay_simple(unsigned long usecs);
 void __delay(unsigned long loops);
 
 #define ndelay(n) __ndelay((unsigned long)(n))
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 98b3aca1de8e..7a21eca498aa 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1512,7 +1512,7 @@ static void diag308_dump(void *dump_block)
 	while (1) {
 		if (diag308(DIAG308_LOAD_NORMAL_DUMP, NULL) != 0x302)
 			break;
-		udelay_simple(USEC_PER_SEC);
+		udelay(USEC_PER_SEC);
 	}
 }
 
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 1f16a03be995..1fbed91c73bc 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -335,7 +335,6 @@ int __init arch_early_irq_init(void)
 	if (!stack)
 		panic("Couldn't allocate async stack");
 	S390_lowcore.async_stack = stack + STACK_INIT_OFFSET;
-	udelay_enable();
 	return 0;
 }
 
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 928b1dbe182c..f289afeb3f31 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -19,13 +19,6 @@
 #include <asm/div64.h>
 #include <asm/idle.h>
 
-static DEFINE_STATIC_KEY_FALSE(udelay_ready);
-
-void __init udelay_enable(void)
-{
-	static_branch_enable(&udelay_ready);
-}
-
 void __delay(unsigned long loops)
 {
         /*
@@ -39,40 +32,25 @@ void __delay(unsigned long loops)
 }
 EXPORT_SYMBOL(__delay);
 
-static void delay_loop(unsigned long delta, bool simple)
+static void delay_loop(unsigned long delta)
 {
 	unsigned long end;
 
-	if (static_branch_likely(&udelay_ready) && !simple) {
-		end = get_tod_clock_monotonic() + delta;
-		while (!tod_after(get_tod_clock_monotonic(), end))
-			cpu_relax();
-	} else {
-		end = get_tod_clock() + delta;
-		while (!tod_after(get_tod_clock(), end))
-			cpu_relax();
-	}
+	end = get_tod_clock_monotonic() + delta;
+	while (!tod_after(get_tod_clock_monotonic(), end))
+		cpu_relax();
 }
 
 void __udelay(unsigned long usecs)
 {
-	delay_loop(usecs << 12, 0);
+	delay_loop(usecs << 12);
 }
 EXPORT_SYMBOL(__udelay);
 
-/*
- * Simple udelay variant. To be used on startup and reboot
- * when the interrupt handler isn't working.
- */
-void udelay_simple(unsigned long usecs)
-{
-	delay_loop(usecs << 12, 1);
-}
-
 void __ndelay(unsigned long nsecs)
 {
 	nsecs <<= 9;
 	do_div(nsecs, 125);
-	delay_loop(nsecs, 0);
+	delay_loop(nsecs);
 }
 EXPORT_SYMBOL(__ndelay);
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index e0005a4fc978..9e3c8b4e7fa8 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -1668,7 +1668,7 @@ void ccw_device_wait_idle(struct ccw_device *cdev)
 		cio_tsch(sch);
 		if (sch->schib.scsw.cmd.actl == 0)
 			break;
-		udelay_simple(100);
+		udelay(100);
 	}
 }
 #endif