Merge branch 'upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/linville...
[linux-2.6] / arch / arm / lib / delay.S
1 /*
2  *  linux/arch/arm/lib/delay.S
3  *
4  *  Copyright (C) 1995, 1996 Russell King
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 #include <linux/linkage.h>
11 #include <asm/assembler.h>
12 #include <asm/param.h>
13                 .text
14
15 .LC0:           .word   loops_per_jiffy
16 .LC1:           .word   (2199023*HZ)>>11
17
18 /*
19  * r0  <= 2000
20  * lpj <= 0x01ffffff (max. 3355 bogomips)
21  * HZ  <= 1000
22  */
23
24 ENTRY(__udelay)
25                 ldr     r2, .LC1
26                 mul     r0, r2, r0
27 ENTRY(__const_udelay)                           @ 0 <= r0 <= 0x7fffff06
28                 ldr     r2, .LC0
29                 ldr     r2, [r2]                @ max = 0x01ffffff
30                 mov     r0, r0, lsr #14         @ max = 0x0001ffff
31                 mov     r2, r2, lsr #10         @ max = 0x00007fff
32                 mul     r0, r2, r0              @ max = 2^32-1
33                 movs    r0, r0, lsr #6
34                 RETINSTR(moveq,pc,lr)
35
36 /*
37  * loops = r0 * HZ * loops_per_jiffy / 1000000
38  *
39  * Oh, if only we had a cycle counter...
40  */
41
42 @ Delay routine
43 ENTRY(__delay)
44                 subs    r0, r0, #1
45 #if 0
46                 RETINSTR(movls,pc,lr)
47                 subs    r0, r0, #1
48                 RETINSTR(movls,pc,lr)
49                 subs    r0, r0, #1
50                 RETINSTR(movls,pc,lr)
51                 subs    r0, r0, #1
52                 RETINSTR(movls,pc,lr)
53                 subs    r0, r0, #1
54                 RETINSTR(movls,pc,lr)
55                 subs    r0, r0, #1
56                 RETINSTR(movls,pc,lr)
57                 subs    r0, r0, #1
58                 RETINSTR(movls,pc,lr)
59                 subs    r0, r0, #1
60 #endif
61                 bhi     __delay
62                 RETINSTR(mov,pc,lr)