1// SPDX-License-Identifier: GPL-2.0
2/*
3 *	Precise Delay Loops for SuperH
4 *
5 *	Copyright (C) 1999 Niibe Yutaka & Kaz Kojima
6 */
7
8#include <linux/sched.h>
9#include <linux/delay.h>
10
11void __delay(unsigned long loops)
12{
13	__asm__ __volatile__(
14		/*
15		 * ST40-300 appears to have an issue with this code,
16		 * normally taking two cycles each loop, as with all
17		 * other SH variants. If however the branch and the
18		 * delay slot straddle an 8 byte boundary, this increases
19		 * to 3 cycles.
20		 * This align directive ensures this doesn't occur.
21		 */
22		".balign 8\n\t"
23
24		"tst	%0, %0\n\t"
25		"1:\t"
26		"bf/s	1b\n\t"
27		" dt	%0"
28		: "=r" (loops)
29		: "0" (loops)
30		: "t");
31}
32
33inline void __const_udelay(unsigned long xloops)
34{
35	xloops *= 4;
36	__asm__("dmulu.l	%0, %2\n\t"
37		"sts	mach, %0"
38		: "=r" (xloops)
39		: "0" (xloops),
40		  "r" (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4))
41		: "macl", "mach");
42	__delay(++xloops);
43}
44
45void __udelay(unsigned long usecs)
46{
47	__const_udelay(usecs * 0x000010c6);  /* 2**32 / 1000000 */
48}
49
50void __ndelay(unsigned long nsecs)
51{
52	__const_udelay(nsecs * 0x00000005);
53}
54
55