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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/module.h>
14 #include <linux/errno.h>
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/param.h>
18 #include <linux/string.h>
19 #include <linux/interrupt.h>
20 #include <linux/profile.h>
21 #include <linux/irq.h>
22 #include <linux/mm.h>
23
24 #include <asm/io.h>
25 #include <asm/timer-regs.h>
26 #include <asm/mb-regs.h>
27 #include <asm/mb86943a.h>
28
29 #include <linux/timex.h>
30
31 #define TICK_SIZE (tick_nsec / 1000)
32
33 unsigned long __nongprelbss __clkin_clock_speed_HZ;
34 unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
35 unsigned long __nongprelbss __res_bus_clock_speed_HZ;
36 unsigned long __nongprelbss __sdram_clock_speed_HZ;
37 unsigned long __nongprelbss __core_bus_clock_speed_HZ;
38 unsigned long __nongprelbss __core_clock_speed_HZ;
39 unsigned long __nongprelbss __dsu_clock_speed_HZ;
40 unsigned long __nongprelbss __serial_clock_speed_HZ;
41 unsigned long __delay_loops_MHz;
42
43 static irqreturn_t timer_interrupt(int irq, void *dummy);
44
45 static struct irqaction timer_irq = {
46 timer_interrupt, IRQF_DISABLED, CPU_MASK_NONE, "timer", NULL, NULL
47 };
48
49 static inline int set_rtc_mmss(unsigned long nowtime)
50 {
51 return -1;
52 }
53
54 /*
55 * timer_interrupt() needs to keep up the real-time clock,
56 * as well as call the "do_timer()" routine every clocktick
57 */
58 static irqreturn_t timer_interrupt(int irq, void *dummy)
59 {
60 /* last time the cmos clock got updated */
61 static long last_rtc_update = 0;
62
63 /*
64 * Here we are in the timer irq handler. We just have irqs locally
65 * disabled but we don't know if the timer_bh is running on the other
66 * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
67 * the irq version of write_lock because as just said we have irq
68 * locally disabled. -arca
69 */
70 write_seqlock(&xtime_lock);
71
72 do_timer(1);
73 update_process_times(user_mode(get_irq_regs()));
74 profile_tick(CPU_PROFILING);
75
76 /*
77 * If we have an externally synchronized Linux clock, then update
78 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
79 * called as close as possible to 500 ms before the new second starts.
80 */
81 if (ntp_synced() &&
82 xtime.tv_sec > last_rtc_update + 660 &&
83 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
84 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2
85 ) {
86 if (set_rtc_mmss(xtime.tv_sec) == 0)
87 last_rtc_update = xtime.tv_sec;
88 else
89 last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
90 }
91
92 #ifdef CONFIG_HEARTBEAT
93 static unsigned short n;
94 n++;
95 __set_LEDS(n);
96 #endif /* CONFIG_HEARTBEAT */
97
98 write_sequnlock(&xtime_lock);
99 return IRQ_HANDLED;
100 }
101
102 void time_divisor_init(void)
103 {
104 unsigned short base, pre, prediv;
105
106 /* set the scheduling timer going */
107 pre = 1;
108 prediv = 4;
109 base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
110
111 __set_TPRV(pre);
112 __set_TxCKSL_DATA(0, prediv);
113 __set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
114 __set_TCSR_DATA(0, base & 0xff);
115 __set_TCSR_DATA(0, base >> 8);
116 }
117
118 void time_init(void)
119 {
120 unsigned int year, mon, day, hour, min, sec;
121
122 extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
123
124 /* FIX by dqg : Set to zero for platforms that don't have tod */
125 /* without this time is undefined and can overflow time_t, causing */
126 /* very stange errors */
127 year = 1980;
128 mon = day = 1;
129 hour = min = sec = 0;
130 arch_gettod (&year, &mon, &day, &hour, &min, &sec);
131
132 if ((year += 1900) < 1970)
133 year += 100;
134 xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
135 xtime.tv_nsec = 0;
136
137 /* install scheduling interrupt handler */
138 setup_irq(IRQ_CPU_TIMER0, &timer_irq);
139
140 time_divisor_init();
141 }
142
143 /*
144 * Scheduler clock - returns current time in nanosec units.
145 */
146 unsigned long long sched_clock(void)
147 {
148 return jiffies_64 * (1000000000 / HZ);
149 }