1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
/*
* arch/xtensa/kernel/time.c
*
* Timer and clock support.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2005 Tensilica Inc.
*
* Chris Zankel <chris@zankel.net>
*/
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/profile.h>
#include <linux/delay.h>
#include <asm/timex.h>
#include <asm/platform.h>
extern volatile unsigned long wall_jiffies;
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
unsigned long ccount_per_jiffy; /* per 1/HZ */
unsigned long ccount_nsec; /* nsec per ccount increment */
#endif
unsigned int last_ccount_stamp;
static long last_rtc_update = 0;
/*
* Scheduler clock - returns current tim in nanosec units.
*/
unsigned long long sched_clock(void)
{
return (unsigned long long)jiffies * (1000000000 / HZ);
}
static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs);
static struct irqaction timer_irqaction = {
.handler = timer_interrupt,
.flags = IRQF_DISABLED,
.name = "timer",
};
void __init time_init(void)
{
time_t sec_o, sec_n = 0;
/* The platform must provide a function to calibrate the processor
* speed for the CALIBRATE.
*/
#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
printk("Calibrating CPU frequency ");
platform_calibrate_ccount();
printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ),
(int)(ccount_per_jiffy/(10000/HZ))%100);
#endif
/* Set time from RTC (if provided) */
if (platform_get_rtc_time(&sec_o) == 0)
while (platform_get_rtc_time(&sec_n))
if (sec_o != sec_n)
break;
xtime.tv_nsec = 0;
last_rtc_update = xtime.tv_sec = sec_n;
last_ccount_stamp = get_ccount();
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
/* Initialize the linux timer interrupt. */
setup_irq(LINUX_TIMER_INT, &timer_irqaction);
set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY);
}
int do_settimeofday(struct timespec *tv)
{
time_t wtm_sec, sec = tv->tv_sec;
long wtm_nsec, nsec = tv->tv_nsec;
unsigned long ccount;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irq(&xtime_lock);
/* This is revolting. We need to set "xtime" correctly. However, the
* value in this location is the value at the most recent update of
* wall time. Discover what correction gettimeofday() would have
* made, and then undo it!
*/
ccount = get_ccount();
nsec -= (ccount - last_ccount_stamp) * CCOUNT_NSEC;
nsec -= (jiffies - wall_jiffies) * CCOUNT_PER_JIFFY * CCOUNT_NSEC;
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
set_normalized_timespec(&xtime, sec, nsec);
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
ntp_clear();
write_sequnlock_irq(&xtime_lock);
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
void do_gettimeofday(struct timeval *tv)
{
unsigned long flags;
unsigned long sec, usec, delta, lost, seq;
do {
seq = read_seqbegin_irqsave(&xtime_lock, flags);
delta = get_ccount() - last_ccount_stamp;
sec = xtime.tv_sec;
usec = (xtime.tv_nsec / NSEC_PER_USEC);
lost = jiffies - wall_jiffies;
} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
usec += lost * (1000000UL/HZ) + (delta * CCOUNT_NSEC) / NSEC_PER_USEC;
for (; usec >= 1000000; sec++, usec -= 1000000)
;
tv->tv_sec = sec;
tv->tv_usec = usec;
}
EXPORT_SYMBOL(do_gettimeofday);
/*
* The timer interrupt is called HZ times per second.
*/
irqreturn_t timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
{
unsigned long next;
next = get_linux_timer();
again:
while ((signed long)(get_ccount() - next) > 0) {
profile_tick(CPU_PROFILING, regs);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
write_seqlock(&xtime_lock);
last_ccount_stamp = next;
next += CCOUNT_PER_JIFFY;
do_timer (1); /* Linux handler in kernel/timer.c */
if (ntp_synced() &&
xtime.tv_sec - last_rtc_update >= 659 &&
abs((xtime.tv_nsec/1000)-(1000000-1000000/HZ))<5000000/HZ &&
jiffies - wall_jiffies == 1) {
if (platform_set_rtc_time(xtime.tv_sec+1) == 0)
last_rtc_update = xtime.tv_sec+1;
else
/* Do it again in 60 s */
last_rtc_update += 60;
}
write_sequnlock(&xtime_lock);
}
/* NOTE: writing CCOMPAREn clears the interrupt. */
set_linux_timer (next);
/* Make sure we didn't miss any tick... */
if ((signed long)(get_ccount() - next) > 0)
goto again;
/* Allow platform to do something useful (Wdog). */
platform_heartbeat();
return IRQ_HANDLED;
}
#ifndef CONFIG_GENERIC_CALIBRATE_DELAY
void __devinit calibrate_delay(void)
{
loops_per_jiffy = CCOUNT_PER_JIFFY;
printk("Calibrating delay loop (skipped)... "
"%lu.%02lu BogoMIPS preset\n",
loops_per_jiffy/(1000000/HZ),
(loops_per_jiffy/(10000/HZ)) % 100);
}
#endif
|
