ia64/linux-2.6.18-xen.hg

view arch/xtensa/kernel/time.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 * arch/xtensa/kernel/time.c
3 *
4 * Timer and clock support.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 *
10 * Copyright (C) 2005 Tensilica Inc.
11 *
12 * Chris Zankel <chris@zankel.net>
13 */
15 #include <linux/errno.h>
16 #include <linux/time.h>
17 #include <linux/timex.h>
18 #include <linux/interrupt.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/irq.h>
22 #include <linux/profile.h>
23 #include <linux/delay.h>
25 #include <asm/timex.h>
26 #include <asm/platform.h>
29 extern volatile unsigned long wall_jiffies;
31 DEFINE_SPINLOCK(rtc_lock);
32 EXPORT_SYMBOL(rtc_lock);
35 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
36 unsigned long ccount_per_jiffy; /* per 1/HZ */
37 unsigned long ccount_nsec; /* nsec per ccount increment */
38 #endif
40 unsigned int last_ccount_stamp;
41 static long last_rtc_update = 0;
43 /*
44 * Scheduler clock - returns current tim in nanosec units.
45 */
47 unsigned long long sched_clock(void)
48 {
49 return (unsigned long long)jiffies * (1000000000 / HZ);
50 }
52 static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs);
53 static struct irqaction timer_irqaction = {
54 .handler = timer_interrupt,
55 .flags = IRQF_DISABLED,
56 .name = "timer",
57 };
59 void __init time_init(void)
60 {
61 time_t sec_o, sec_n = 0;
63 /* The platform must provide a function to calibrate the processor
64 * speed for the CALIBRATE.
65 */
67 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
68 printk("Calibrating CPU frequency ");
69 platform_calibrate_ccount();
70 printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ),
71 (int)(ccount_per_jiffy/(10000/HZ))%100);
72 #endif
74 /* Set time from RTC (if provided) */
76 if (platform_get_rtc_time(&sec_o) == 0)
77 while (platform_get_rtc_time(&sec_n))
78 if (sec_o != sec_n)
79 break;
81 xtime.tv_nsec = 0;
82 last_rtc_update = xtime.tv_sec = sec_n;
83 last_ccount_stamp = get_ccount();
85 set_normalized_timespec(&wall_to_monotonic,
86 -xtime.tv_sec, -xtime.tv_nsec);
88 /* Initialize the linux timer interrupt. */
90 setup_irq(LINUX_TIMER_INT, &timer_irqaction);
91 set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY);
92 }
95 int do_settimeofday(struct timespec *tv)
96 {
97 time_t wtm_sec, sec = tv->tv_sec;
98 long wtm_nsec, nsec = tv->tv_nsec;
99 unsigned long ccount;
101 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
102 return -EINVAL;
104 write_seqlock_irq(&xtime_lock);
106 /* This is revolting. We need to set "xtime" correctly. However, the
107 * value in this location is the value at the most recent update of
108 * wall time. Discover what correction gettimeofday() would have
109 * made, and then undo it!
110 */
111 ccount = get_ccount();
112 nsec -= (ccount - last_ccount_stamp) * CCOUNT_NSEC;
113 nsec -= (jiffies - wall_jiffies) * CCOUNT_PER_JIFFY * CCOUNT_NSEC;
115 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
116 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
118 set_normalized_timespec(&xtime, sec, nsec);
119 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
121 ntp_clear();
122 write_sequnlock_irq(&xtime_lock);
123 return 0;
124 }
126 EXPORT_SYMBOL(do_settimeofday);
129 void do_gettimeofday(struct timeval *tv)
130 {
131 unsigned long flags;
132 unsigned long sec, usec, delta, lost, seq;
134 do {
135 seq = read_seqbegin_irqsave(&xtime_lock, flags);
137 delta = get_ccount() - last_ccount_stamp;
138 sec = xtime.tv_sec;
139 usec = (xtime.tv_nsec / NSEC_PER_USEC);
141 lost = jiffies - wall_jiffies;
143 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
145 usec += lost * (1000000UL/HZ) + (delta * CCOUNT_NSEC) / NSEC_PER_USEC;
146 for (; usec >= 1000000; sec++, usec -= 1000000)
147 ;
149 tv->tv_sec = sec;
150 tv->tv_usec = usec;
151 }
153 EXPORT_SYMBOL(do_gettimeofday);
155 /*
156 * The timer interrupt is called HZ times per second.
157 */
159 irqreturn_t timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
160 {
162 unsigned long next;
164 next = get_linux_timer();
166 again:
167 while ((signed long)(get_ccount() - next) > 0) {
169 profile_tick(CPU_PROFILING, regs);
170 #ifndef CONFIG_SMP
171 update_process_times(user_mode(regs));
172 #endif
174 write_seqlock(&xtime_lock);
176 last_ccount_stamp = next;
177 next += CCOUNT_PER_JIFFY;
178 do_timer (regs); /* Linux handler in kernel/timer.c */
180 if (ntp_synced() &&
181 xtime.tv_sec - last_rtc_update >= 659 &&
182 abs((xtime.tv_nsec/1000)-(1000000-1000000/HZ))<5000000/HZ &&
183 jiffies - wall_jiffies == 1) {
185 if (platform_set_rtc_time(xtime.tv_sec+1) == 0)
186 last_rtc_update = xtime.tv_sec+1;
187 else
188 /* Do it again in 60 s */
189 last_rtc_update += 60;
190 }
191 write_sequnlock(&xtime_lock);
192 }
194 /* NOTE: writing CCOMPAREn clears the interrupt. */
196 set_linux_timer (next);
198 /* Make sure we didn't miss any tick... */
200 if ((signed long)(get_ccount() - next) > 0)
201 goto again;
203 /* Allow platform to do something useful (Wdog). */
205 platform_heartbeat();
207 return IRQ_HANDLED;
208 }
210 #ifndef CONFIG_GENERIC_CALIBRATE_DELAY
211 void __devinit calibrate_delay(void)
212 {
213 loops_per_jiffy = CCOUNT_PER_JIFFY;
214 printk("Calibrating delay loop (skipped)... "
215 "%lu.%02lu BogoMIPS preset\n",
216 loops_per_jiffy/(1000000/HZ),
217 (loops_per_jiffy/(10000/HZ)) % 100);
218 }
219 #endif