1 files changed, 54 insertions, 0 deletions
diff --git a/arch/sh/lib/delay.c b/arch/sh/lib/delay.c
new file mode 100644
index 000000000..dad8e6a54
--- /dev/null
+++ b/arch/sh/lib/delay.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *	Precise Delay Loops for SuperH
+ *
+ *	Copyright (C) 1999 Niibe Yutaka & Kaz Kojima
+ */
+
+#include <linux/sched.h>
+#include <linux/delay.h>
+
+void __delay(unsigned long loops)
+{
+	__asm__ __volatile__(
+		/*
+		 * ST40-300 appears to have an issue with this code,
+		 * normally taking two cycles each loop, as with all
+		 * other SH variants. If however the branch and the
+		 * delay slot straddle an 8 byte boundary, this increases
+		 * to 3 cycles.
+		 * This align directive ensures this doesn't occur.
+		 */
+		".balign 8\n\t"
+
+		"tst	%0, %0\n\t"
+		"1:\t"
+		"bf/s	1b\n\t"
+		" dt	%0"
+		: "=r" (loops)
+		: "0" (loops)
+		: "t");
+}
+
+inline void __const_udelay(unsigned long xloops)
+{
+	xloops *= 4;
+	__asm__("dmulu.l	%0, %2\n\t"
+		"sts	mach, %0"
+		: "=r" (xloops)
+		: "0" (xloops),
+		  "r" (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4))
+		: "macl", "mach");
+	__delay(++xloops);
+}
+
+void __udelay(unsigned long usecs)
+{
+	__const_udelay(usecs * 0x000010c6);  /* 2**32 / 1000000 */
+}
+
+void __ndelay(unsigned long nsecs)
+{
+	__const_udelay(nsecs * 0x00000005);
+}
+