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delay.h
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1 /*
2  * Port on Texas Instruments TMS320C6x architecture
3  *
4  * Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
5  * Author: Aurelien Jacquiot ([email protected])
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 #ifndef _ASM_C6X_DELAY_H
12 #define _ASM_C6X_DELAY_H
13 
14 #include <linux/kernel.h>
15 
16 extern unsigned int ticks_per_ns_scaled;
17 
18 static inline void __delay(unsigned long loops)
19 {
20  uint32_t tmp;
21 
22  /* 6 cycles per loop */
23  asm volatile (" mv .s1 %0,%1\n"
24  "0: [%1] b .s1 0b\n"
25  " add .l1 -6,%0,%0\n"
26  " cmplt .l1 1,%0,%1\n"
27  " nop 3\n"
28  : "+a"(loops), "=A"(tmp));
29 }
30 
31 static inline void _c6x_tickdelay(unsigned int x)
32 {
33  uint32_t cnt, endcnt;
34 
35  asm volatile (" mvc .s2 TSCL,%0\n"
36  " add .s2x %0,%1,%2\n"
37  " || mvk .l2 1,B0\n"
38  "0: [B0] b .s2 0b\n"
39  " mvc .s2 TSCL,%0\n"
40  " sub .s2 %0,%2,%0\n"
41  " cmpgt .l2 0,%0,B0\n"
42  " nop 2\n"
43  : "=b"(cnt), "+a"(x), "=b"(endcnt) : : "B0");
44 }
45 
46 /* use scaled math to avoid slow division */
47 #define C6X_NDELAY_SCALE 10
48 
49 static inline void _ndelay(unsigned int n)
50 {
51  _c6x_tickdelay((ticks_per_ns_scaled * n) >> C6X_NDELAY_SCALE);
52 }
53 
54 static inline void _udelay(unsigned int n)
55 {
56  while (n >= 10) {
57  _ndelay(10000);
58  n -= 10;
59  }
60  while (n-- > 0)
61  _ndelay(1000);
62 }
63 
64 #define udelay(x) _udelay((unsigned int)(x))
65 #define ndelay(x) _ndelay((unsigned int)(x))
66 
67 #endif /* _ASM_C6X_DELAY_H */