b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | /* |
| 2 | * U-boot - delay.h Routines for introducing delays |
| 3 | * |
| 4 | * Copyright (c) 2005-2007 Analog Devices Inc. |
| 5 | * |
| 6 | * SPDX-License-Identifier: GPL-2.0+ |
| 7 | */ |
| 8 | |
| 9 | #ifndef _BLACKFIN_DELAY_H |
| 10 | #define _BLACKFIN_DELAY_H |
| 11 | |
| 12 | /* |
| 13 | * Changes made by akbar.hussain@Lineo.com, for BLACKFIN |
| 14 | * Copyright (C) 1994 Hamish Macdonald |
| 15 | * |
| 16 | * Delay routines, using a pre-computed "loops_per_second" value. |
| 17 | */ |
| 18 | |
| 19 | extern __inline__ void __delay(unsigned long loops) |
| 20 | { |
| 21 | __asm__ __volatile__("1:\t%0 += -1;\n\t" |
| 22 | "cc = %0 == 0;\n\t" |
| 23 | "if ! cc jump 1b;\n":"=d"(loops) |
| 24 | :"0"(loops)); |
| 25 | } |
| 26 | |
| 27 | /* |
| 28 | * Use only for very small delays ( < 1 msec). Should probably use a |
| 29 | * lookup table, really, as the multiplications take much too long with |
| 30 | * short delays. This is a "reasonable" implementation, though (and the |
| 31 | * first constant multiplications gets optimized away if the delay is |
| 32 | * a constant) |
| 33 | */ |
| 34 | extern __inline__ void __udelay(unsigned long usecs) |
| 35 | { |
| 36 | __delay(usecs); |
| 37 | } |
| 38 | |
| 39 | #endif |