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-rw-r--r--arch/sh/lib/delay.c54
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);
+}
+