ia64/linux-2.6.18-xen.hg

view arch/i386/lib/delay.c @ 647:a5bb490065f6

Fix the build after public header sync.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Wed Aug 13 14:01:49 2008 +0100 (2008-08-13)
parents 831230e53067
children
line source
1 /*
2 * Precise Delay Loops for i386
3 *
4 * Copyright (C) 1993 Linus Torvalds
5 * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
6 *
7 * The __delay function must _NOT_ be inlined as its execution time
8 * depends wildly on alignment on many x86 processors. The additional
9 * jump magic is needed to get the timing stable on all the CPU's
10 * we have to worry about.
11 */
13 #include <linux/module.h>
14 #include <linux/config.h>
15 #include <linux/sched.h>
16 #include <linux/delay.h>
18 #include <asm/processor.h>
19 #include <asm/delay.h>
20 #include <asm/timer.h>
22 #ifdef CONFIG_SMP
23 # include <asm/smp.h>
24 #endif
26 /* simple loop based delay: */
27 static void delay_loop(unsigned long loops)
28 {
29 int d0;
31 __asm__ __volatile__(
32 "\tjmp 1f\n"
33 ".align 16\n"
34 "1:\tjmp 2f\n"
35 ".align 16\n"
36 "2:\tdecl %0\n\tjns 2b"
37 :"=&a" (d0)
38 :"0" (loops));
39 }
41 /* TSC based delay: */
42 static void delay_tsc(unsigned long loops)
43 {
44 unsigned long bclock, now;
46 rdtscl(bclock);
47 do {
48 rep_nop();
49 rdtscl(now);
50 } while ((now-bclock) < loops);
51 }
53 /*
54 * Since we calibrate only once at boot, this
55 * function should be set once at boot and not changed
56 */
57 static void (*delay_fn)(unsigned long) = delay_loop;
59 void use_tsc_delay(void)
60 {
61 delay_fn = delay_tsc;
62 }
64 int read_current_timer(unsigned long *timer_val)
65 {
66 if (delay_fn == delay_tsc) {
67 rdtscl(*timer_val);
68 return 0;
69 }
70 return -1;
71 }
73 void __delay(unsigned long loops)
74 {
75 delay_fn(loops);
76 }
78 inline void __const_udelay(unsigned long xloops)
79 {
80 int d0;
82 xloops *= 4;
83 __asm__("mull %0"
84 :"=d" (xloops), "=&a" (d0)
85 :"1" (xloops), "0"
86 (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4)));
88 __delay(++xloops);
89 }
91 void __udelay(unsigned long usecs)
92 {
93 __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
94 }
96 void __ndelay(unsigned long nsecs)
97 {
98 __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
99 }
101 EXPORT_SYMBOL(__delay);
102 EXPORT_SYMBOL(__const_udelay);
103 EXPORT_SYMBOL(__udelay);
104 EXPORT_SYMBOL(__ndelay);