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