2 * linux/arch/m32r/kernel/time.c
4 * Copyright (c) 2001, 2002 Hiroyuki Kondo, Hirokazu Takata,
6 * Taken from i386 version.
7 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
8 * Copyright (C) 1996, 1997, 1998 Ralf Baechle
10 * This file contains the time handling details for PC-style clocks as
11 * found in some MIPS systems.
13 * Some code taken from sh version.
14 * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
15 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
20 #include <linux/errno.h>
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/sched.h>
24 #include <linux/kernel.h>
25 #include <linux/param.h>
26 #include <linux/string.h>
28 #include <linux/interrupt.h>
29 #include <linux/profile.h>
34 #include <asm/hw_irq.h>
37 extern void smp_local_timer_interrupt(void);
40 #define TICK_SIZE (tick_nsec / 1000)
43 * Change this if you have some constant time drift
46 /* This is for machines which generate the exact clock. */
47 #define USECS_PER_JIFFY (1000000/HZ)
49 static unsigned long latch;
51 u32 arch_gettimeoffset(void)
53 unsigned long elapsed_time = 0; /* [us] */
55 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
56 || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
57 || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
62 /* timer count may underflow right here */
63 count = inl(M32R_MFT2CUT_PORTL);
65 if (inl(M32R_ICU_CR18_PORTL) & 0x00000100) /* underflow check */
68 count = (latch - count) * TICK_SIZE;
69 elapsed_time = (count + latch / 2) / latch;
70 /* NOTE: LATCH is equal to the "interval" value (= reload count). */
72 #else /* CONFIG_SMP */
74 static unsigned long p_jiffies = -1;
75 static unsigned long p_count = 0;
77 /* timer count may underflow right here */
78 count = inl(M32R_MFT2CUT_PORTL);
80 if (jiffies == p_jiffies && count > p_count)
86 count = (latch - count) * TICK_SIZE;
87 elapsed_time = (count + latch / 2) / latch;
88 /* NOTE: LATCH is equal to the "interval" value (= reload count). */
89 #endif /* CONFIG_SMP */
90 #elif defined(CONFIG_CHIP_M32310)
91 #warning do_gettimeoffse not implemented
93 #error no chip configuration
96 return elapsed_time * 1000;
100 * In order to set the CMOS clock precisely, set_rtc_mmss has to be
101 * called 500 ms after the second nowtime has started, because when
102 * nowtime is written into the registers of the CMOS clock, it will
103 * jump to the next second precisely 500 ms later. Check the Motorola
104 * MC146818A or Dallas DS12887 data sheet for details.
106 * BUG: This routine does not handle hour overflow properly; it just
107 * sets the minutes. Usually you won't notice until after reboot!
109 static inline int set_rtc_mmss(unsigned long nowtime)
114 /* last time the cmos clock got updated */
115 static long last_rtc_update = 0;
118 * timer_interrupt() needs to keep up the real-time clock,
119 * as well as call the "do_timer()" routine every clocktick
121 static irqreturn_t timer_interrupt(int irq, void *dev_id)
124 profile_tick(CPU_PROFILING);
126 /* XXX FIXME. Uh, the xtime_lock should be held here, no? */
130 update_process_times(user_mode(get_irq_regs()));
133 * If we have an externally synchronized Linux clock, then update
134 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
135 * called as close as possible to 500 ms before the new second starts.
137 write_seqlock(&xtime_lock);
139 && xtime.tv_sec > last_rtc_update + 660
140 && (xtime.tv_nsec / 1000) >= 500000 - ((unsigned)TICK_SIZE) / 2
141 && (xtime.tv_nsec / 1000) <= 500000 + ((unsigned)TICK_SIZE) / 2)
143 if (set_rtc_mmss(xtime.tv_sec) == 0)
144 last_rtc_update = xtime.tv_sec;
145 else /* do it again in 60 s */
146 last_rtc_update = xtime.tv_sec - 600;
148 write_sequnlock(&xtime_lock);
149 /* As we return to user mode fire off the other CPU schedulers..
150 this is basically because we don't yet share IRQ's around.
151 This message is rigged to be safe on the 386 - basically it's
152 a hack, so don't look closely for now.. */
155 smp_local_timer_interrupt();
162 static struct irqaction irq0 = {
163 .handler = timer_interrupt,
164 .flags = IRQF_DISABLED,
168 void __init time_init(void)
170 unsigned int epoch, year, mon, day, hour, min, sec;
172 sec = min = hour = day = mon = year = 0;
179 /* Attempt to guess the epoch. This is the same heuristic as in rtc.c
180 so no stupid things will happen to timekeeping. Who knows, maybe
181 Ultrix also uses 1952 as epoch ... */
182 if (year > 10 && year < 44)
188 xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
189 xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
190 set_normalized_timespec(&wall_to_monotonic,
191 -xtime.tv_sec, -xtime.tv_nsec);
193 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
194 || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
195 || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
197 /* M32102 MFT setup */
198 setup_irq(M32R_IRQ_MFT2, &irq0);
200 unsigned long bus_clock;
201 unsigned short divide;
203 bus_clock = boot_cpu_data.bus_clock;
204 divide = boot_cpu_data.timer_divide;
205 latch = (bus_clock/divide + HZ / 2) / HZ;
207 printk("Timer start : latch = %ld\n", latch);
209 outl((M32R_MFTMOD_CC_MASK | M32R_MFTMOD_TCCR \
210 |M32R_MFTMOD_CSSEL011), M32R_MFT2MOD_PORTL);
211 outl(latch, M32R_MFT2RLD_PORTL);
212 outl(latch, M32R_MFT2CUT_PORTL);
213 outl(0, M32R_MFT2CMPRLD_PORTL);
214 outl((M32R_MFTCR_MFT2MSK|M32R_MFTCR_MFT2EN), M32R_MFTCR_PORTL);
217 #elif defined(CONFIG_CHIP_M32310)
218 #warning time_init not implemented
220 #error no chip configuration