diff options
Diffstat (limited to 'arch/arm/lib/delay-loop.S')
| -rw-r--r-- | arch/arm/lib/delay-loop.S | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/arch/arm/lib/delay-loop.S b/arch/arm/lib/delay-loop.S new file mode 100644 index 000000000000..36b668d8e121 --- /dev/null +++ b/arch/arm/lib/delay-loop.S | |||
| @@ -0,0 +1,67 @@ | |||
| 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/delay.h> | ||
| 13 | .text | ||
| 14 | |||
| 15 | .LC0: .word loops_per_jiffy | ||
| 16 | .LC1: .word UDELAY_MULT | ||
| 17 | |||
| 18 | /* | ||
| 19 | * r0 <= 2000 | ||
| 20 | * lpj <= 0x01ffffff (max. 3355 bogomips) | ||
| 21 | * HZ <= 1000 | ||
| 22 | */ | ||
| 23 | |||
| 24 | ENTRY(__loop_udelay) | ||
| 25 | ldr r2, .LC1 | ||
| 26 | mul r0, r2, r0 | ||
| 27 | ENTRY(__loop_const_udelay) @ 0 <= r0 <= 0x7fffff06 | ||
| 28 | mov r1, #-1 | ||
| 29 | ldr r2, .LC0 | ||
| 30 | ldr r2, [r2] @ max = 0x01ffffff | ||
| 31 | add r0, r0, r1, lsr #32-14 | ||
| 32 | mov r0, r0, lsr #14 @ max = 0x0001ffff | ||
| 33 | add r2, r2, r1, lsr #32-10 | ||
| 34 | mov r2, r2, lsr #10 @ max = 0x00007fff | ||
| 35 | mul r0, r2, r0 @ max = 2^32-1 | ||
| 36 | add r0, r0, r1, lsr #32-6 | ||
| 37 | movs r0, r0, lsr #6 | ||
| 38 | moveq pc, lr | ||
| 39 | |||
| 40 | /* | ||
| 41 | * loops = r0 * HZ * loops_per_jiffy / 1000000 | ||
| 42 | */ | ||
| 43 | |||
| 44 | @ Delay routine | ||
| 45 | ENTRY(__loop_delay) | ||
| 46 | subs r0, r0, #1 | ||
| 47 | #if 0 | ||
| 48 | movls pc, lr | ||
| 49 | subs r0, r0, #1 | ||
| 50 | movls pc, lr | ||
| 51 | subs r0, r0, #1 | ||
| 52 | movls pc, lr | ||
| 53 | subs r0, r0, #1 | ||
| 54 | movls pc, lr | ||
| 55 | subs r0, r0, #1 | ||
| 56 | movls pc, lr | ||
| 57 | subs r0, r0, #1 | ||
| 58 | movls pc, lr | ||
| 59 | subs r0, r0, #1 | ||
| 60 | movls pc, lr | ||
| 61 | subs r0, r0, #1 | ||
| 62 | #endif | ||
| 63 | bhi __loop_delay | ||
| 64 | mov pc, lr | ||
| 65 | ENDPROC(__loop_udelay) | ||
| 66 | ENDPROC(__loop_const_udelay) | ||
| 67 | ENDPROC(__loop_delay) | ||