1/*
2 *  linux/arch/m32r/kernel/time.c
3 *
4 *  Copyright (c) 2001, 2002  Hiroyuki Kondo, Hirokazu Takata,
5 *                            Hitoshi Yamamoto
6 *  Taken from i386 version.
7 *    Copyright (C) 1991, 1992, 1995  Linus Torvalds
8 *    Copyright (C) 1996, 1997, 1998  Ralf Baechle
9 *
10 *  This file contains the time handling details for PC-style clocks as
11 *  found in some MIPS systems.
12 *
13 *  Some code taken from sh version.
14 *    Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
15 *    Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
16 */
17
18#undef  DEBUG_TIMER
19
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>
27#include <linux/mm.h>
28#include <linux/interrupt.h>
29#include <linux/profile.h>
30
31#include <asm/io.h>
32#include <asm/m32r.h>
33
34#include <asm/hw_irq.h>
35
36#ifdef CONFIG_SMP
37extern void send_IPI_allbutself(int, int);
38extern void smp_local_timer_interrupt(void);
39#endif
40
41#define TICK_SIZE	(tick_nsec / 1000)
42
43/*
44 * Change this if you have some constant time drift
45 */
46
47/* This is for machines which generate the exact clock. */
48#define USECS_PER_JIFFY (1000000/HZ)
49
50static unsigned long latch;
51
52static unsigned long do_gettimeoffset(void)
53{
54	unsigned long  elapsed_time = 0;  /* [us] */
55
56#if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) || \
57	defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP) \
58	|| defined(CONFIG_CHIP_M32104)
59#ifndef CONFIG_SMP
60
61	unsigned long count;
62
63	/* timer count may underflow right here */
64	count = inl(M32R_MFT2CUT_PORTL);
65
66	if (inl(M32R_ICU_CR18_PORTL) & 0x00000100)	/* underflow check */
67		count = 0;
68
69	count = (latch - count) * TICK_SIZE;
70	elapsed_time = (count + latch / 2) / latch;
71	/* NOTE: LATCH is equal to the "interval" value (= reload count). */
72
73#else /* CONFIG_SMP */
74	unsigned long count;
75	static unsigned long p_jiffies = -1;
76	static unsigned long p_count = 0;
77
78	/* timer count may underflow right here */
79	count = inl(M32R_MFT2CUT_PORTL);
80
81	if (jiffies == p_jiffies && count > p_count)
82		count = 0;
83
84	p_jiffies = jiffies;
85	p_count = count;
86
87	count = (latch - count) * TICK_SIZE;
88	elapsed_time = (count + latch / 2) / latch;
89	/* NOTE: LATCH is equal to the "interval" value (= reload count). */
90#endif /* CONFIG_SMP */
91#elif defined(CONFIG_CHIP_M32310)
92#warning do_gettimeoffse not implemented
93#else
94#error no chip configuration
95#endif
96
97	return elapsed_time;
98}
99
100/*
101 * This version of gettimeofday has near microsecond resolution.
102 */
103void do_gettimeofday(struct timeval *tv)
104{
105	unsigned long seq;
106	unsigned long usec, sec;
107	unsigned long max_ntp_tick = tick_usec - tickadj;
108
109	do {
110		seq = read_seqbegin(&xtime_lock);
111
112		usec = do_gettimeoffset();
113
114		/*
115		 * If time_adjust is negative then NTP is slowing the clock
116		 * so make sure not to go into next possible interval.
117		 * Better to lose some accuracy than have time go backwards..
118		 */
119		if (unlikely(time_adjust < 0))
120			usec = min(usec, max_ntp_tick);
121
122		sec = xtime.tv_sec;
123		usec += (xtime.tv_nsec / 1000);
124	} while (read_seqretry(&xtime_lock, seq));
125
126	while (usec >= 1000000) {
127		usec -= 1000000;
128		sec++;
129	}
130
131	tv->tv_sec = sec;
132	tv->tv_usec = usec;
133}
134
135EXPORT_SYMBOL(do_gettimeofday);
136
137int do_settimeofday(struct timespec *tv)
138{
139	time_t wtm_sec, sec = tv->tv_sec;
140 	long wtm_nsec, nsec = tv->tv_nsec;
141
142	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
143		return -EINVAL;
144
145	write_seqlock_irq(&xtime_lock);
146	/*
147	 * This is revolting. We need to set "xtime" correctly. However, the
148	 * value in this location is the value at the most recent update of
149	 * wall time.  Discover what correction gettimeofday() would have
150	 * made, and then undo it!
151	 */
152	nsec -= do_gettimeoffset() * NSEC_PER_USEC;
153
154	wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
155	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
156
157	set_normalized_timespec(&xtime, sec, nsec);
158	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
159
160	ntp_clear();
161	write_sequnlock_irq(&xtime_lock);
162	clock_was_set();
163
164	return 0;
165}
166
167EXPORT_SYMBOL(do_settimeofday);
168
169/*
170 * In order to set the CMOS clock precisely, set_rtc_mmss has to be
171 * called 500 ms after the second nowtime has started, because when
172 * nowtime is written into the registers of the CMOS clock, it will
173 * jump to the next second precisely 500 ms later. Check the Motorola
174 * MC146818A or Dallas DS12887 data sheet for details.
175 *
176 * BUG: This routine does not handle hour overflow properly; it just
177 *      sets the minutes. Usually you won't notice until after reboot!
178 */
179static inline int set_rtc_mmss(unsigned long nowtime)
180{
181	return 0;
182}
183
184/* last time the cmos clock got updated */
185static long last_rtc_update = 0;
186
187/*
188 * timer_interrupt() needs to keep up the real-time clock,
189 * as well as call the "do_timer()" routine every clocktick
190 */
191irqreturn_t timer_interrupt(int irq, void *dev_id)
192{
193#ifndef CONFIG_SMP
194	profile_tick(CPU_PROFILING);
195#endif
196	do_timer(1);
197
198#ifndef CONFIG_SMP
199	update_process_times(user_mode(get_irq_regs()));
200#endif
201	/*
202	 * If we have an externally synchronized Linux clock, then update
203	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
204	 * called as close as possible to 500 ms before the new second starts.
205	 */
206	write_seqlock(&xtime_lock);
207	if (ntp_synced()
208		&& xtime.tv_sec > last_rtc_update + 660
209		&& (xtime.tv_nsec / 1000) >= 500000 - ((unsigned)TICK_SIZE) / 2
210		&& (xtime.tv_nsec / 1000) <= 500000 + ((unsigned)TICK_SIZE) / 2)
211	{
212		if (set_rtc_mmss(xtime.tv_sec) == 0)
213			last_rtc_update = xtime.tv_sec;
214		else	/* do it again in 60 s */
215			last_rtc_update = xtime.tv_sec - 600;
216	}
217	write_sequnlock(&xtime_lock);
218	/* As we return to user mode fire off the other CPU schedulers..
219	   this is basically because we don't yet share IRQ's around.
220	   This message is rigged to be safe on the 386 - basically it's
221	   a hack, so don't look closely for now.. */
222
223#ifdef CONFIG_SMP
224	smp_local_timer_interrupt();
225	smp_send_timer();
226#endif
227
228	return IRQ_HANDLED;
229}
230
231struct irqaction irq0 = { timer_interrupt, IRQF_DISABLED, CPU_MASK_NONE,
232			  "MFT2", NULL, NULL };
233
234void __init time_init(void)
235{
236	unsigned int epoch, year, mon, day, hour, min, sec;
237
238	sec = min = hour = day = mon = year = 0;
239	epoch = 0;
240
241	year = 23;
242	mon = 4;
243	day = 17;
244
245	/* Attempt to guess the epoch.  This is the same heuristic as in rtc.c
246	   so no stupid things will happen to timekeeping.  Who knows, maybe
247	   Ultrix also uses 1952 as epoch ...  */
248	if (year > 10 && year < 44)
249		epoch = 1980;
250	else if (year < 96)
251		epoch = 1952;
252	year += epoch;
253
254	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
255	xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
256	set_normalized_timespec(&wall_to_monotonic,
257		-xtime.tv_sec, -xtime.tv_nsec);
258
259#if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) || \
260	defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP) \
261	|| defined(CONFIG_CHIP_M32104)
262
263	/* M32102 MFT setup */
264	setup_irq(M32R_IRQ_MFT2, &irq0);
265	{
266		unsigned long bus_clock;
267		unsigned short divide;
268
269		bus_clock = boot_cpu_data.bus_clock;
270		divide = boot_cpu_data.timer_divide;
271		latch = (bus_clock/divide + HZ / 2) / HZ;
272
273		printk("Timer start : latch = %ld\n", latch);
274
275		outl((M32R_MFTMOD_CC_MASK | M32R_MFTMOD_TCCR \
276			|M32R_MFTMOD_CSSEL011), M32R_MFT2MOD_PORTL);
277		outl(latch, M32R_MFT2RLD_PORTL);
278		outl(latch, M32R_MFT2CUT_PORTL);
279		outl(0, M32R_MFT2CMPRLD_PORTL);
280		outl((M32R_MFTCR_MFT2MSK|M32R_MFTCR_MFT2EN), M32R_MFTCR_PORTL);
281	}
282
283#elif defined(CONFIG_CHIP_M32310)
284#warning time_init not implemented
285#else
286#error no chip configuration
287#endif
288}
289