xref: /OK3568_Linux_fs/kernel/arch/nds32/include/asm/delay.h (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun // Copyright (C) 2005-2017 Andes Technology Corporation
3*4882a593Smuzhiyun 
4*4882a593Smuzhiyun #ifndef __NDS32_DELAY_H__
5*4882a593Smuzhiyun #define __NDS32_DELAY_H__
6*4882a593Smuzhiyun 
7*4882a593Smuzhiyun #include <asm/param.h>
8*4882a593Smuzhiyun 
9*4882a593Smuzhiyun /* There is no clocksource cycle counter in the CPU. */
__delay(unsigned long loops)10*4882a593Smuzhiyun static inline void __delay(unsigned long loops)
11*4882a593Smuzhiyun {
12*4882a593Smuzhiyun 	__asm__ __volatile__(".align 2\n"
13*4882a593Smuzhiyun 			     "1:\n"
14*4882a593Smuzhiyun 			     "\taddi\t%0, %0, -1\n"
15*4882a593Smuzhiyun 			     "\tbgtz\t%0, 1b\n"
16*4882a593Smuzhiyun 			     :"=r"(loops)
17*4882a593Smuzhiyun 			     :"0"(loops));
18*4882a593Smuzhiyun }
19*4882a593Smuzhiyun 
__udelay(unsigned long usecs,unsigned long lpj)20*4882a593Smuzhiyun static inline void __udelay(unsigned long usecs, unsigned long lpj)
21*4882a593Smuzhiyun {
22*4882a593Smuzhiyun 	usecs *= (unsigned long)(((0x8000000000000000ULL / (500000 / HZ)) +
23*4882a593Smuzhiyun 				  0x80000000ULL) >> 32);
24*4882a593Smuzhiyun 	usecs = (unsigned long)(((unsigned long long)usecs * lpj) >> 32);
25*4882a593Smuzhiyun 	__delay(usecs);
26*4882a593Smuzhiyun }
27*4882a593Smuzhiyun 
28*4882a593Smuzhiyun #define udelay(usecs) __udelay((usecs), loops_per_jiffy)
29*4882a593Smuzhiyun 
30*4882a593Smuzhiyun /* make sure "usecs *= ..." in udelay do not overflow. */
31*4882a593Smuzhiyun #if HZ >= 1000
32*4882a593Smuzhiyun #define MAX_UDELAY_MS	1
33*4882a593Smuzhiyun #elif HZ <= 200
34*4882a593Smuzhiyun #define MAX_UDELAY_MS	5
35*4882a593Smuzhiyun #else
36*4882a593Smuzhiyun #define MAX_UDELAY_MS	(1000 / HZ)
37*4882a593Smuzhiyun #endif
38*4882a593Smuzhiyun 
39*4882a593Smuzhiyun #endif
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