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
221
222
223
224
225
226
227
228
229
230
231
232
|
/* time.c: FRV arch-specific time handling
*
* Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from arch/m68k/kernel/time.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/config.h> /* CONFIG_HEARTBEAT */
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/profile.h>
#include <linux/irq.h>
#include <linux/mm.h>
#include <asm/io.h>
#include <asm/timer-regs.h>
#include <asm/mb-regs.h>
#include <asm/mb86943a.h>
#include <asm/irq-routing.h>
#include <linux/timex.h>
#define TICK_SIZE (tick_nsec / 1000)
extern unsigned long wall_jiffies;
unsigned long __nongprelbss __clkin_clock_speed_HZ;
unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
unsigned long __nongprelbss __res_bus_clock_speed_HZ;
unsigned long __nongprelbss __sdram_clock_speed_HZ;
unsigned long __nongprelbss __core_bus_clock_speed_HZ;
unsigned long __nongprelbss __core_clock_speed_HZ;
unsigned long __nongprelbss __dsu_clock_speed_HZ;
unsigned long __nongprelbss __serial_clock_speed_HZ;
unsigned long __delay_loops_MHz;
static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs *regs);
static struct irqaction timer_irq = {
timer_interrupt, IRQF_DISABLED, CPU_MASK_NONE, "timer", NULL, NULL
};
static inline int set_rtc_mmss(unsigned long nowtime)
{
return -1;
}
/*
* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick
*/
static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
{
/* last time the cmos clock got updated */
static long last_rtc_update = 0;
/*
* Here we are in the timer irq handler. We just have irqs locally
* disabled but we don't know if the timer_bh is running on the other
* CPU. We need to avoid to SMP race with it. NOTE: we don' t need
* the irq version of write_lock because as just said we have irq
* locally disabled. -arca
*/
write_seqlock(&xtime_lock);
do_timer(regs);
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING, regs);
/*
* If we have an externally synchronized Linux clock, then update
* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
* called as close as possible to 500 ms before the new second starts.
*/
if (ntp_synced() &&
xtime.tv_sec > last_rtc_update + 660 &&
(xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
(xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2
) {
if (set_rtc_mmss(xtime.tv_sec) == 0)
last_rtc_update = xtime.tv_sec;
else
last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
}
#ifdef CONFIG_HEARTBEAT
static unsigned short n;
n++;
__set_LEDS(n);
#endif /* CONFIG_HEARTBEAT */
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
void time_divisor_init(void)
{
unsigned short base, pre, prediv;
/* set the scheduling timer going */
pre = 1;
prediv = 4;
base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
__set_TPRV(pre);
__set_TxCKSL_DATA(0, prediv);
__set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
__set_TCSR_DATA(0, base & 0xff);
__set_TCSR_DATA(0, base >> 8);
}
void time_init(void)
{
unsigned int year, mon, day, hour, min, sec;
extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
/* FIX by dqg : Set to zero for platforms that don't have tod */
/* without this time is undefined and can overflow time_t, causing */
/* very stange errors */
year = 1980;
mon = day = 1;
hour = min = sec = 0;
arch_gettod (&year, &mon, &day, &hour, &min, &sec);
if ((year += 1900) < 1970)
year += 100;
xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
xtime.tv_nsec = 0;
/* install scheduling interrupt handler */
setup_irq(IRQ_CPU_TIMER0, &timer_irq);
time_divisor_init();
}
/*
* This version of gettimeofday has near microsecond resolution.
*/
void do_gettimeofday(struct timeval *tv)
{
unsigned long seq;
unsigned long usec, sec;
unsigned long max_ntp_tick;
do {
unsigned long lost;
seq = read_seqbegin(&xtime_lock);
usec = 0;
lost = jiffies - wall_jiffies;
/*
* If time_adjust is negative then NTP is slowing the clock
* so make sure not to go into next possible interval.
* Better to lose some accuracy than have time go backwards..
*/
if (unlikely(time_adjust < 0)) {
max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
usec = min(usec, max_ntp_tick);
if (lost)
usec += lost * max_ntp_tick;
}
else if (unlikely(lost))
usec += lost * (USEC_PER_SEC / HZ);
sec = xtime.tv_sec;
usec += (xtime.tv_nsec / 1000);
} while (read_seqretry(&xtime_lock, seq));
while (usec >= 1000000) {
usec -= 1000000;
sec++;
}
tv->tv_sec = sec;
tv->tv_usec = usec;
}
EXPORT_SYMBOL(do_gettimeofday);
int do_settimeofday(struct timespec *tv)
{
time_t wtm_sec, sec = tv->tv_sec;
long wtm_nsec, nsec = tv->tv_nsec;
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!
*/
nsec -= 0 * NSEC_PER_USEC;
nsec -= (jiffies - wall_jiffies) * TICK_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);
clock_was_set();
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
return jiffies_64 * (1000000000 / HZ);
}
|
