| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
| Peter Teichmann | 6d4518d | 2006-03-20 17:10:09 +0000 | [diff] [blame^] | 12 | #include <asm/param.h> |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | .text |
| 14 | |
| Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 15 | .LC0: .word loops_per_jiffy |
| Peter Teichmann | 6d4518d | 2006-03-20 17:10:09 +0000 | [diff] [blame^] | 16 | .LC1: .word (2199023*HZ)>>11 |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | |
| 18 | /* |
| Peter Teichmann | 6d4518d | 2006-03-20 17:10:09 +0000 | [diff] [blame^] | 19 | * r0 <= 2000 |
| 20 | * lpj <= 0x01ffffff (max. 3355 bogomips) |
| 21 | * HZ <= 1000 |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | */ |
| Peter Teichmann | 6d4518d | 2006-03-20 17:10:09 +0000 | [diff] [blame^] | 23 | |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | ENTRY(__udelay) |
| Peter Teichmann | 6d4518d | 2006-03-20 17:10:09 +0000 | [diff] [blame^] | 25 | ldr r2, .LC1 |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | mul r0, r2, r0 |
| Peter Teichmann | 6d4518d | 2006-03-20 17:10:09 +0000 | [diff] [blame^] | 27 | ENTRY(__const_udelay) @ 0 <= r0 <= 0x7fffff06 |
| Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 28 | ldr r2, .LC0 |
| Peter Teichmann | 6d4518d | 2006-03-20 17:10:09 +0000 | [diff] [blame^] | 29 | ldr r2, [r2] @ max = 0x01ffffff |
| 30 | mov r0, r0, lsr #14 @ max = 0x0001ffff |
| 31 | mov r2, r2, lsr #10 @ max = 0x00007fff |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | mul r0, r2, r0 @ max = 2^32-1 |
| 33 | movs r0, r0, lsr #6 |
| 34 | RETINSTR(moveq,pc,lr) |
| 35 | |
| 36 | /* |
| Peter Teichmann | 6d4518d | 2006-03-20 17:10:09 +0000 | [diff] [blame^] | 37 | * loops = r0 * HZ * loops_per_jiffy / 1000000 |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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) |