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9a8fd558 CZ |
1 | /* |
2 | * include/asm-xtensa/delay.h | |
3 | * | |
4 | * This file is subject to the terms and conditions of the GNU General Public | |
5 | * License. See the file "COPYING" in the main directory of this archive | |
6 | * for more details. | |
7 | * | |
8 | * Copyright (C) 2001 - 2005 Tensilica Inc. | |
9 | * | |
10 | */ | |
11 | ||
12 | #ifndef _XTENSA_DELAY_H | |
13 | #define _XTENSA_DELAY_H | |
14 | ||
15 | #include <linux/config.h> | |
16 | #include <asm/processor.h> | |
17 | #include <asm/param.h> | |
18 | ||
19 | extern unsigned long loops_per_jiffy; | |
20 | ||
21 | extern __inline__ void __delay(unsigned long loops) | |
22 | { | |
23 | /* 2 cycles per loop. */ | |
9ec55a9b | 24 | __asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b" |
9a8fd558 CZ |
25 | : "=r" (loops) : "0" (loops)); |
26 | } | |
27 | ||
28 | static __inline__ u32 xtensa_get_ccount(void) | |
29 | { | |
30 | u32 ccount; | |
31 | asm volatile ("rsr %0, 234; # CCOUNT\n" : "=r" (ccount)); | |
32 | return ccount; | |
33 | } | |
34 | ||
35 | /* For SMP/NUMA systems, change boot_cpu_data to something like | |
36 | * local_cpu_data->... where local_cpu_data points to the current | |
37 | * cpu. */ | |
38 | ||
39 | static __inline__ void udelay (unsigned long usecs) | |
40 | { | |
41 | unsigned long start = xtensa_get_ccount(); | |
42 | unsigned long cycles = usecs * (loops_per_jiffy / (1000000UL / HZ)); | |
43 | ||
44 | /* Note: all variables are unsigned (can wrap around)! */ | |
45 | while (((unsigned long)xtensa_get_ccount()) - start < cycles) | |
46 | ; | |
47 | } | |
48 | ||
49 | #endif | |
50 |