1 files changed, 45 insertions, 0 deletions
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
new file mode 100644
index 0000000000..be14c58cb9
--- /dev/null
+++ b/arch/s390/lib/delay.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Precise Delay Loops for S390
+ *
+ *    Copyright IBM Corp. 1999, 2008
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ */
+
+#include <linux/processor.h>
+#include <linux/delay.h>
+#include <asm/div64.h>
+#include <asm/timex.h>
+
+void __delay(unsigned long loops)
+{
+	/*
+	 * Loop 'loops' times. Callers must not assume a specific
+	 * amount of time passes before this function returns.
+	 */
+	asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
+}
+EXPORT_SYMBOL(__delay);
+
+static void delay_loop(unsigned long delta)
+{
+	unsigned long end;
+
+	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);
+}
+EXPORT_SYMBOL(__udelay);
+
+void __ndelay(unsigned long nsecs)
+{
+	nsecs <<= 9;
+	do_div(nsecs, 125);
+	delay_loop(nsecs);
+}
+EXPORT_SYMBOL(__ndelay);