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 .handler = timer_interrupt,
47 .flags = IRQF_DISABLED,
48 .mask = CPU_MASK_NONE,
49 .name = "timer",
50 };
51
set_rtc_mmss(unsigned long nowtime)52 static inline int set_rtc_mmss(unsigned long nowtime)
53 {
54 return -1;
55 }
56
57 /*
58 * timer_interrupt() needs to keep up the real-time clock,
59 * as well as call the "do_timer()" routine every clocktick
60 */
timer_interrupt(int irq,void * dummy)61 static irqreturn_t timer_interrupt(int irq, void *dummy)
62 {
63 /* last time the cmos clock got updated */
64 static long last_rtc_update = 0;
65
66 profile_tick(CPU_PROFILING);
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(1);
77
78 /*
79 * If we have an externally synchronized Linux clock, then update
80 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
81 * called as close as possible to 500 ms before the new second starts.
82 */
83 if (ntp_synced() &&
84 xtime.tv_sec > last_rtc_update + 660 &&
85 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
86 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2
87 ) {
88 if (set_rtc_mmss(xtime.tv_sec) == 0)
89 last_rtc_update = xtime.tv_sec;
90 else
91 last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
92 }
93
94 #ifdef CONFIG_HEARTBEAT
95 static unsigned short n;
96 n++;
97 __set_LEDS(n);
98 #endif /* CONFIG_HEARTBEAT */
99
100 write_sequnlock(&xtime_lock);
101
102 update_process_times(user_mode(get_irq_regs()));
103
104 return IRQ_HANDLED;
105 }
106
time_divisor_init(void)107 void time_divisor_init(void)
108 {
109 unsigned short base, pre, prediv;
110
111 /* set the scheduling timer going */
112 pre = 1;
113 prediv = 4;
114 base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
115
116 __set_TPRV(pre);
117 __set_TxCKSL_DATA(0, prediv);
118 __set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
119 __set_TCSR_DATA(0, base & 0xff);
120 __set_TCSR_DATA(0, base >> 8);
121 }
122
time_init(void)123 void time_init(void)
124 {
125 unsigned int year, mon, day, hour, min, sec;
126
127 extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
128
129 /* FIX by dqg : Set to zero for platforms that don't have tod */
130 /* without this time is undefined and can overflow time_t, causing */
131 /* very strange errors */
132 year = 1980;
133 mon = day = 1;
134 hour = min = sec = 0;
135 arch_gettod (&year, &mon, &day, &hour, &min, &sec);
136
137 if ((year += 1900) < 1970)
138 year += 100;
139 xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
140 xtime.tv_nsec = 0;
141
142 /* install scheduling interrupt handler */
143 setup_irq(IRQ_CPU_TIMER0, &timer_irq);
144
145 time_divisor_init();
146 }
147
148 /*
149 * Scheduler clock - returns current time in nanosec units.
150 */
sched_clock(void)151 unsigned long long sched_clock(void)
152 {
153 return jiffies_64 * (1000000000 / HZ);
154 }
155