sh: Ensure ST40-300 BogoMIPS value is consistent
[linux-2.6.git] / arch / sh / lib / delay.c
1 /*
2  *      Precise Delay Loops for SuperH
3  *
4  *      Copyright (C) 1999 Niibe Yutaka & Kaz Kojima
5  */
6
7 #include <linux/sched.h>
8 #include <linux/delay.h>
9
10 void __delay(unsigned long loops)
11 {
12         __asm__ __volatile__(
13                 /*
14                  * ST40-300 appears to have an issue with this code,
15                  * normally taking two cycles each loop, as with all
16                  * other SH variants. If however the branch and the
17                  * delay slot straddle an 8 byte boundary, this increases
18                  * to 3 cycles.
19                  * This align directive ensures this doesn't occur.
20                  */
21                 ".balign 8\n\t"
22
23                 "tst    %0, %0\n\t"
24                 "1:\t"
25                 "bf/s   1b\n\t"
26                 " dt    %0"
27                 : "=r" (loops)
28                 : "0" (loops)
29                 : "t");
30 }
31
32 inline void __const_udelay(unsigned long xloops)
33 {
34         xloops *= 4;
35         __asm__("dmulu.l        %0, %2\n\t"
36                 "sts    mach, %0"
37                 : "=r" (xloops)
38                 : "0" (xloops),
39                   "r" (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4))
40                 : "macl", "mach");
41         __delay(++xloops);
42 }
43
44 void __udelay(unsigned long usecs)
45 {
46         __const_udelay(usecs * 0x000010c6);  /* 2**32 / 1000000 */
47 }
48
49 void __ndelay(unsigned long nsecs)
50 {
51         __const_udelay(nsecs * 0x00000005);
52 }
53