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1 /* time.c: FRV arch-specific time handling
2 *
3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * - Derived from arch/m68k/kernel/time.c
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13 #include <linux/config.h> /* CONFIG_HEARTBEAT */
14 #include <linux/module.h>
15 #include <linux/errno.h>
16 #include <linux/sched.h>
17 #include <linux/kernel.h>
18 #include <linux/param.h>
19 #include <linux/string.h>
20 #include <linux/interrupt.h>
21 #include <linux/profile.h>
22 #include <linux/irq.h>
23 #include <linux/mm.h>
24
25 #include <asm/io.h>
26 #include <asm/timer-regs.h>
27 #include <asm/mb-regs.h>
28 #include <asm/mb86943a.h>
29 #include <asm/irq-routing.h>
30
31 #include <linux/timex.h>
32
33 #define TICK_SIZE (tick_nsec / 1000)
34
35 extern unsigned long wall_jiffies;
36
37 unsigned long __nongprelbss __clkin_clock_speed_HZ;
38 unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
39 unsigned long __nongprelbss __res_bus_clock_speed_HZ;
40 unsigned long __nongprelbss __sdram_clock_speed_HZ;
41 unsigned long __nongprelbss __core_bus_clock_speed_HZ;
42 unsigned long __nongprelbss __core_clock_speed_HZ;
43 unsigned long __nongprelbss __dsu_clock_speed_HZ;
44 unsigned long __nongprelbss __serial_clock_speed_HZ;
45 unsigned long __delay_loops_MHz;
46
47 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs *regs);
48
49 static struct irqaction timer_irq = {
50 timer_interrupt, IRQF_DISABLED, CPU_MASK_NONE, "timer", NULL, NULL
51 };
52
53 static inline int set_rtc_mmss(unsigned long nowtime)
54 {
55 return -1;
56 }
57
58 /*
59 * timer_interrupt() needs to keep up the real-time clock,
60 * as well as call the "do_timer()" routine every clocktick
61 */
62 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
63 {
64 /* last time the cmos clock got updated */
65 static long last_rtc_update = 0;
66
67 /*
68 * Here we are in the timer irq handler. We just have irqs locally
69 * disabled but we don't know if the timer_bh is running on the other
70 * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
71 * the irq version of write_lock because as just said we have irq
72 * locally disabled. -arca
73 */
74 write_seqlock(&xtime_lock);
75
76 do_timer(regs);
77 update_process_times(user_mode(regs));
78 profile_tick(CPU_PROFILING, regs);
79
80 /*
81 * If we have an externally synchronized Linux clock, then update
82 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
83 * called as close as possible to 500 ms before the new second starts.
84 */
85 if (ntp_synced() &&
86 xtime.tv_sec > last_rtc_update + 660 &&
87 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
88 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2
89 ) {
90 if (set_rtc_mmss(xtime.tv_sec) == 0)
91 last_rtc_update = xtime.tv_sec;
92 else
93 last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
94 }
95
96 #ifdef CONFIG_HEARTBEAT
97 static unsigned short n;
98 n++;
99 __set_LEDS(n);
100 #endif /* CONFIG_HEARTBEAT */
101
102 write_sequnlock(&xtime_lock);
103 return IRQ_HANDLED;
104 }
105
106 void time_divisor_init(void)
107 {
108 unsigned short base, pre, prediv;
109
110 /* set the scheduling timer going */
111 pre = 1;
112 prediv = 4;
113 base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
114
115 __set_TPRV(pre);
116 __set_TxCKSL_DATA(0, prediv);
117 __set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
118 __set_TCSR_DATA(0, base & 0xff);
119 __set_TCSR_DATA(0, base >> 8);
120 }
121
122 void time_init(void)
123 {
124 unsigned int year, mon, day, hour, min, sec;
125
126 extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
127
128 /* FIX by dqg : Set to zero for platforms that don't have tod */
129 /* without this time is undefined and can overflow time_t, causing */
130 /* very stange errors */
131 year = 1980;
132 mon = day = 1;
133 hour = min = sec = 0;
134 arch_gettod (&year, &mon, &day, &hour, &min, &sec);
135
136 if ((year += 1900) < 1970)
137 year += 100;
138 xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
139 xtime.tv_nsec = 0;
140
141 /* install scheduling interrupt handler */
142 setup_irq(IRQ_CPU_TIMER0, &timer_irq);
143
144 time_divisor_init();
145 }
146
147 /*
148 * This version of gettimeofday has near microsecond resolution.
149 */
150 void do_gettimeofday(struct timeval *tv)
151 {
152 unsigned long seq;
153 unsigned long usec, sec;
154 unsigned long max_ntp_tick;
155
156 do {
157 unsigned long lost;
158
159 seq = read_seqbegin(&xtime_lock);
160
161 usec = 0;
162 lost = jiffies - wall_jiffies;
163
164 /*
165 * If time_adjust is negative then NTP is slowing the clock
166 * so make sure not to go into next possible interval.
167 * Better to lose some accuracy than have time go backwards..
168 */
169 if (unlikely(time_adjust < 0)) {
170 max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
171 usec = min(usec, max_ntp_tick);
172
173 if (lost)
174 usec += lost * max_ntp_tick;
175 }
176 else if (unlikely(lost))
177 usec += lost * (USEC_PER_SEC / HZ);
178
179 sec = xtime.tv_sec;
180 usec += (xtime.tv_nsec / 1000);
181 } while (read_seqretry(&xtime_lock, seq));
182
183 while (usec >= 1000000) {
184 usec -= 1000000;
185 sec++;
186 }
187
188 tv->tv_sec = sec;
189 tv->tv_usec = usec;
190 }
191
192 EXPORT_SYMBOL(do_gettimeofday);
193
194 int do_settimeofday(struct timespec *tv)
195 {
196 time_t wtm_sec, sec = tv->tv_sec;
197 long wtm_nsec, nsec = tv->tv_nsec;
198
199 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
200 return -EINVAL;
201
202 write_seqlock_irq(&xtime_lock);
203 /*
204 * This is revolting. We need to set "xtime" correctly. However, the
205 * value in this location is the value at the most recent update of
206 * wall time. Discover what correction gettimeofday() would have
207 * made, and then undo it!
208 */
209 nsec -= 0 * NSEC_PER_USEC;
210 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
211
212 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
213 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
214
215 set_normalized_timespec(&xtime, sec, nsec);
216 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
217
218 ntp_clear();
219 write_sequnlock_irq(&xtime_lock);
220 clock_was_set();
221 return 0;
222 }
223
224 EXPORT_SYMBOL(do_settimeofday);
225
226 /*
227 * Scheduler clock - returns current time in nanosec units.
228 */
229 unsigned long long sched_clock(void)
230 {
231 return jiffies_64 * (1000000000 / HZ);
232 }