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 
__delay(unsigned long loops)11 void __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 
__const_udelay(unsigned long xloops)33 inline 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 
__udelay(unsigned long usecs)45 void __udelay(unsigned long usecs)
46 {
47 	__const_udelay(usecs * 0x000010c6);  /* 2**32 / 1000000 */
48 }
49 
__ndelay(unsigned long nsecs)50 void __ndelay(unsigned long nsecs)
51 {
52 	__const_udelay(nsecs * 0x00000005);
53 }
54 
55