1 files changed, 9 insertions, 96 deletions

diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 68d61f2835df..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)
 {
         /*
@@ -39,105 +32,25 @@ void __delay(unsigned long loops)
 }
 EXPORT_SYMBOL(__delay);
 
-static void __udelay_disabled(unsigned long long usecs)
+static void delay_loop(unsigned long delta)
 {
-	unsigned long cr0, cr0_new, psw_mask;
-	struct s390_idle_data idle;
-	u64 end;
+	unsigned long end;
 
-	end = get_tod_clock() + (usecs << 12);
-	__ctl_store(cr0, 0, 0);
-	cr0_new = cr0 & ~CR0_IRQ_SUBCLASS_MASK;
-	cr0_new |= (1UL << (63 - 52)); /* enable clock comparator irq */
-	__ctl_load(cr0_new, 0, 0);
-	psw_mask = __extract_psw() | PSW_MASK_EXT | PSW_MASK_WAIT;
-	set_clock_comparator(end);
-	set_cpu_flag(CIF_IGNORE_IRQ);
-	psw_idle(&idle, psw_mask);
-	trace_hardirqs_off();
-	clear_cpu_flag(CIF_IGNORE_IRQ);
-	set_clock_comparator(S390_lowcore.clock_comparator);
-	__ctl_load(cr0, 0, 0);
+	end = get_tod_clock_monotonic() + delta;
+	while (!tod_after(get_tod_clock_monotonic(), end))
+		cpu_relax();
 }
 
-static void __udelay_enabled(unsigned long long usecs)
+void __udelay(unsigned long usecs)
 {
-	u64 clock_saved, end;
-
-	end = get_tod_clock_fast() + (usecs << 12);
-	do {
-		clock_saved = 0;
-		if (tod_after(S390_lowcore.clock_comparator, end)) {
-			clock_saved = local_tick_disable();
-			set_clock_comparator(end);
-		}
-		enabled_wait();
-		if (clock_saved)
-			local_tick_enable(clock_saved);
-	} while (get_tod_clock_fast() < end);
-}
-
-/*
- * Waits for 'usecs' microseconds using the TOD clock comparator.
- */
-void __udelay(unsigned long long usecs)
-{
-	unsigned long flags;
-
-	if (!static_branch_likely(&udelay_ready)) {
-		udelay_simple(usecs);
-		return;
-	}
-
-	preempt_disable();
-	local_irq_save(flags);
-	if (in_irq()) {
-		__udelay_disabled(usecs);
-		goto out;
-	}
-	if (in_softirq()) {
-		if (raw_irqs_disabled_flags(flags))
-			__udelay_disabled(usecs);
-		else
-			__udelay_enabled(usecs);
-		goto out;
-	}
-	if (raw_irqs_disabled_flags(flags)) {
-		local_bh_disable();
-		__udelay_disabled(usecs);
-		_local_bh_enable();
-		goto out;
-	}
-	__udelay_enabled(usecs);
-out:
-	local_irq_restore(flags);
-	preempt_enable();
+	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 long usecs)
-{
-	u64 end;
-
-	end = get_tod_clock_fast() + (usecs << 12);
-	while (get_tod_clock_fast() < end)
-		cpu_relax();
-}
-
-void __ndelay(unsigned long long nsecs)
+void __ndelay(unsigned long nsecs)
 {
-	u64 end;
-
 	nsecs <<= 9;
 	do_div(nsecs, 125);
-	end = get_tod_clock_fast() + nsecs;
-	if (nsecs & ~0xfffUL)
-		__udelay(nsecs >> 12);
-	while (get_tod_clock_fast() < end)
-		barrier();
+	delay_loop(nsecs);
 }
 EXPORT_SYMBOL(__ndelay);