xref: /OK3568_Linux_fs/kernel/arch/c6x/include/asm/delay.h (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0-only */
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun  *  Port on Texas Instruments TMS320C6x architecture
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
6*4882a593Smuzhiyun  *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
7*4882a593Smuzhiyun  */
8*4882a593Smuzhiyun #ifndef _ASM_C6X_DELAY_H
9*4882a593Smuzhiyun #define _ASM_C6X_DELAY_H
10*4882a593Smuzhiyun 
11*4882a593Smuzhiyun #include <linux/kernel.h>
12*4882a593Smuzhiyun 
13*4882a593Smuzhiyun extern unsigned int ticks_per_ns_scaled;
14*4882a593Smuzhiyun 
__delay(unsigned long loops)15*4882a593Smuzhiyun static inline void __delay(unsigned long loops)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun 	uint32_t tmp;
18*4882a593Smuzhiyun 
19*4882a593Smuzhiyun 	/* 6 cycles per loop */
20*4882a593Smuzhiyun 	asm volatile ("        mv    .s1  %0,%1\n"
21*4882a593Smuzhiyun 		      "0: [%1] b     .s1  0b\n"
22*4882a593Smuzhiyun 		      "        add   .l1  -6,%0,%0\n"
23*4882a593Smuzhiyun 		      "        cmplt .l1  1,%0,%1\n"
24*4882a593Smuzhiyun 		      "        nop   3\n"
25*4882a593Smuzhiyun 		      : "+a"(loops), "=A"(tmp));
26*4882a593Smuzhiyun }
27*4882a593Smuzhiyun 
_c6x_tickdelay(unsigned int x)28*4882a593Smuzhiyun static inline void _c6x_tickdelay(unsigned int x)
29*4882a593Smuzhiyun {
30*4882a593Smuzhiyun 	uint32_t cnt, endcnt;
31*4882a593Smuzhiyun 
32*4882a593Smuzhiyun 	asm volatile ("        mvc   .s2   TSCL,%0\n"
33*4882a593Smuzhiyun 		      "        add   .s2x  %0,%1,%2\n"
34*4882a593Smuzhiyun 		      " ||     mvk   .l2   1,B0\n"
35*4882a593Smuzhiyun 		      "0: [B0] b     .s2   0b\n"
36*4882a593Smuzhiyun 		      "        mvc   .s2   TSCL,%0\n"
37*4882a593Smuzhiyun 		      "        sub   .s2   %0,%2,%0\n"
38*4882a593Smuzhiyun 		      "        cmpgt .l2   0,%0,B0\n"
39*4882a593Smuzhiyun 		      "        nop   2\n"
40*4882a593Smuzhiyun 		      : "=b"(cnt), "+a"(x), "=b"(endcnt) : : "B0");
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun 
43*4882a593Smuzhiyun /* use scaled math to avoid slow division */
44*4882a593Smuzhiyun #define C6X_NDELAY_SCALE 10
45*4882a593Smuzhiyun 
_ndelay(unsigned int n)46*4882a593Smuzhiyun static inline void _ndelay(unsigned int n)
47*4882a593Smuzhiyun {
48*4882a593Smuzhiyun 	_c6x_tickdelay((ticks_per_ns_scaled * n) >> C6X_NDELAY_SCALE);
49*4882a593Smuzhiyun }
50*4882a593Smuzhiyun 
_udelay(unsigned int n)51*4882a593Smuzhiyun static inline void _udelay(unsigned int n)
52*4882a593Smuzhiyun {
53*4882a593Smuzhiyun 	while (n >= 10) {
54*4882a593Smuzhiyun 		_ndelay(10000);
55*4882a593Smuzhiyun 		n -= 10;
56*4882a593Smuzhiyun 	}
57*4882a593Smuzhiyun 	while (n-- > 0)
58*4882a593Smuzhiyun 		_ndelay(1000);
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun 
61*4882a593Smuzhiyun #define udelay(x) _udelay((unsigned int)(x))
62*4882a593Smuzhiyun #define ndelay(x) _ndelay((unsigned int)(x))
63*4882a593Smuzhiyun 
64*4882a593Smuzhiyun #endif /* _ASM_C6X_DELAY_H */
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