1/*
2 * linux/arch/m68k/atari/time.c
3 *
4 * Atari time and real time clock stuff
5 *
6 * Assembled of parts of former atari/config.c 97-12-18 by Roman Hodek
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License.  See the file COPYING in the main directory of this archive
10 * for more details.
11 */
12
13#include <linux/types.h>
14#include <linux/mc146818rtc.h>
15#include <linux/interrupt.h>
16#include <linux/init.h>
17#include <linux/rtc.h>
18#include <linux/bcd.h>
19#include <linux/clocksource.h>
20#include <linux/delay.h>
21#include <linux/export.h>
22
23#include <asm/atariints.h>
24#include <asm/machdep.h>
25
26#include "atari.h"
27
28DEFINE_SPINLOCK(rtc_lock);
29EXPORT_SYMBOL_GPL(rtc_lock);
30
31static u64 atari_read_clk(struct clocksource *cs);
32
33static struct clocksource atari_clk = {
34	.name   = "mfp",
35	.rating = 100,
36	.read   = atari_read_clk,
37	.mask   = CLOCKSOURCE_MASK(32),
38	.flags  = CLOCK_SOURCE_IS_CONTINUOUS,
39};
40
41static u32 clk_total;
42static u8 last_timer_count;
43
44static irqreturn_t mfp_timer_c_handler(int irq, void *dev_id)
45{
46	unsigned long flags;
47
48	local_irq_save(flags);
49	do {
50		last_timer_count = st_mfp.tim_dt_c;
51	} while (last_timer_count == 1);
52	clk_total += INT_TICKS;
53	legacy_timer_tick(1);
54	timer_heartbeat();
55	local_irq_restore(flags);
56
57	return IRQ_HANDLED;
58}
59
60void __init
61atari_sched_init(void)
62{
63    /* set Timer C data Register */
64    st_mfp.tim_dt_c = INT_TICKS;
65    /* start timer C, div = 1:100 */
66    st_mfp.tim_ct_cd = (st_mfp.tim_ct_cd & 15) | 0x60;
67    /* install interrupt service routine for MFP Timer C */
68    if (request_irq(IRQ_MFP_TIMC, mfp_timer_c_handler, IRQF_TIMER, "timer",
69                    NULL))
70	pr_err("Couldn't register timer interrupt\n");
71
72    clocksource_register_hz(&atari_clk, INT_CLK);
73}
74
75/* ++andreas: gettimeoffset fixed to check for pending interrupt */
76
77static u64 atari_read_clk(struct clocksource *cs)
78{
79	unsigned long flags;
80	u8 count;
81	u32 ticks;
82
83	local_irq_save(flags);
84	/* Ensure that the count is monotonically decreasing, even though
85	 * the result may briefly stop changing after counter wrap-around.
86	 */
87	count = min(st_mfp.tim_dt_c, last_timer_count);
88	last_timer_count = count;
89
90	ticks = INT_TICKS - count;
91	ticks += clk_total;
92	local_irq_restore(flags);
93
94	return ticks;
95}
96
97
98static void mste_read(struct MSTE_RTC *val)
99{
100#define COPY(v) val->v=(mste_rtc.v & 0xf)
101	do {
102		COPY(sec_ones) ; COPY(sec_tens) ; COPY(min_ones) ;
103		COPY(min_tens) ; COPY(hr_ones) ; COPY(hr_tens) ;
104		COPY(weekday) ; COPY(day_ones) ; COPY(day_tens) ;
105		COPY(mon_ones) ; COPY(mon_tens) ; COPY(year_ones) ;
106		COPY(year_tens) ;
107	/* prevent from reading the clock while it changed */
108	} while (val->sec_ones != (mste_rtc.sec_ones & 0xf));
109#undef COPY
110}
111
112static void mste_write(struct MSTE_RTC *val)
113{
114#define COPY(v) mste_rtc.v=val->v
115	do {
116		COPY(sec_ones) ; COPY(sec_tens) ; COPY(min_ones) ;
117		COPY(min_tens) ; COPY(hr_ones) ; COPY(hr_tens) ;
118		COPY(weekday) ; COPY(day_ones) ; COPY(day_tens) ;
119		COPY(mon_ones) ; COPY(mon_tens) ; COPY(year_ones) ;
120		COPY(year_tens) ;
121	/* prevent from writing the clock while it changed */
122	} while (val->sec_ones != (mste_rtc.sec_ones & 0xf));
123#undef COPY
124}
125
126#define	RTC_READ(reg)				\
127    ({	unsigned char	__val;			\
128		(void) atari_writeb(reg,&tt_rtc.regsel);	\
129		__val = tt_rtc.data;		\
130		__val;				\
131	})
132
133#define	RTC_WRITE(reg,val)			\
134    do {					\
135		atari_writeb(reg,&tt_rtc.regsel);	\
136		tt_rtc.data = (val);		\
137	} while(0)
138
139
140#define HWCLK_POLL_INTERVAL	5
141
142int atari_mste_hwclk( int op, struct rtc_time *t )
143{
144    int hour, year;
145    int hr24=0;
146    struct MSTE_RTC val;
147
148    mste_rtc.mode=(mste_rtc.mode | 1);
149    hr24=mste_rtc.mon_tens & 1;
150    mste_rtc.mode=(mste_rtc.mode & ~1);
151
152    if (op) {
153        /* write: prepare values */
154
155        val.sec_ones = t->tm_sec % 10;
156        val.sec_tens = t->tm_sec / 10;
157        val.min_ones = t->tm_min % 10;
158        val.min_tens = t->tm_min / 10;
159        hour = t->tm_hour;
160        if (!hr24) {
161	    if (hour > 11)
162		hour += 20 - 12;
163	    if (hour == 0 || hour == 20)
164		hour += 12;
165        }
166        val.hr_ones = hour % 10;
167        val.hr_tens = hour / 10;
168        val.day_ones = t->tm_mday % 10;
169        val.day_tens = t->tm_mday / 10;
170        val.mon_ones = (t->tm_mon+1) % 10;
171        val.mon_tens = (t->tm_mon+1) / 10;
172        year = t->tm_year - 80;
173        val.year_ones = year % 10;
174        val.year_tens = year / 10;
175        val.weekday = t->tm_wday;
176        mste_write(&val);
177        mste_rtc.mode=(mste_rtc.mode | 1);
178        val.year_ones = (year % 4);	/* leap year register */
179        mste_rtc.mode=(mste_rtc.mode & ~1);
180    }
181    else {
182        mste_read(&val);
183        t->tm_sec = val.sec_ones + val.sec_tens * 10;
184        t->tm_min = val.min_ones + val.min_tens * 10;
185        hour = val.hr_ones + val.hr_tens * 10;
186	if (!hr24) {
187	    if (hour == 12 || hour == 12 + 20)
188		hour -= 12;
189	    if (hour >= 20)
190                hour += 12 - 20;
191        }
192	t->tm_hour = hour;
193	t->tm_mday = val.day_ones + val.day_tens * 10;
194        t->tm_mon  = val.mon_ones + val.mon_tens * 10 - 1;
195        t->tm_year = val.year_ones + val.year_tens * 10 + 80;
196        t->tm_wday = val.weekday;
197    }
198    return 0;
199}
200
201int atari_tt_hwclk( int op, struct rtc_time *t )
202{
203    int sec=0, min=0, hour=0, day=0, mon=0, year=0, wday=0;
204    unsigned long	flags;
205    unsigned char	ctrl;
206    int pm = 0;
207
208    ctrl = RTC_READ(RTC_CONTROL); /* control registers are
209                                   * independent from the UIP */
210
211    if (op) {
212        /* write: prepare values */
213
214        sec  = t->tm_sec;
215        min  = t->tm_min;
216        hour = t->tm_hour;
217        day  = t->tm_mday;
218        mon  = t->tm_mon + 1;
219        year = t->tm_year - atari_rtc_year_offset;
220        wday = t->tm_wday + (t->tm_wday >= 0);
221
222        if (!(ctrl & RTC_24H)) {
223	    if (hour > 11) {
224		pm = 0x80;
225		if (hour != 12)
226		    hour -= 12;
227	    }
228	    else if (hour == 0)
229		hour = 12;
230        }
231
232        if (!(ctrl & RTC_DM_BINARY)) {
233	    sec = bin2bcd(sec);
234	    min = bin2bcd(min);
235	    hour = bin2bcd(hour);
236	    day = bin2bcd(day);
237	    mon = bin2bcd(mon);
238	    year = bin2bcd(year);
239	    if (wday >= 0)
240		wday = bin2bcd(wday);
241        }
242    }
243
244    /* Reading/writing the clock registers is a bit critical due to
245     * the regular update cycle of the RTC. While an update is in
246     * progress, registers 0..9 shouldn't be touched.
247     * The problem is solved like that: If an update is currently in
248     * progress (the UIP bit is set), the process sleeps for a while
249     * (50ms). This really should be enough, since the update cycle
250     * normally needs 2 ms.
251     * If the UIP bit reads as 0, we have at least 244 usecs until the
252     * update starts. This should be enough... But to be sure,
253     * additionally the RTC_SET bit is set to prevent an update cycle.
254     */
255
256    while( RTC_READ(RTC_FREQ_SELECT) & RTC_UIP ) {
257	if (in_atomic() || irqs_disabled())
258	    mdelay(1);
259	else
260	    schedule_timeout_interruptible(HWCLK_POLL_INTERVAL);
261    }
262
263    local_irq_save(flags);
264    RTC_WRITE( RTC_CONTROL, ctrl | RTC_SET );
265    if (!op) {
266        sec  = RTC_READ( RTC_SECONDS );
267        min  = RTC_READ( RTC_MINUTES );
268        hour = RTC_READ( RTC_HOURS );
269        day  = RTC_READ( RTC_DAY_OF_MONTH );
270        mon  = RTC_READ( RTC_MONTH );
271        year = RTC_READ( RTC_YEAR );
272        wday = RTC_READ( RTC_DAY_OF_WEEK );
273    }
274    else {
275        RTC_WRITE( RTC_SECONDS, sec );
276        RTC_WRITE( RTC_MINUTES, min );
277        RTC_WRITE( RTC_HOURS, hour + pm);
278        RTC_WRITE( RTC_DAY_OF_MONTH, day );
279        RTC_WRITE( RTC_MONTH, mon );
280        RTC_WRITE( RTC_YEAR, year );
281        if (wday >= 0) RTC_WRITE( RTC_DAY_OF_WEEK, wday );
282    }
283    RTC_WRITE( RTC_CONTROL, ctrl & ~RTC_SET );
284    local_irq_restore(flags);
285
286    if (!op) {
287        /* read: adjust values */
288
289        if (hour & 0x80) {
290	    hour &= ~0x80;
291	    pm = 1;
292	}
293
294	if (!(ctrl & RTC_DM_BINARY)) {
295	    sec = bcd2bin(sec);
296	    min = bcd2bin(min);
297	    hour = bcd2bin(hour);
298	    day = bcd2bin(day);
299	    mon = bcd2bin(mon);
300	    year = bcd2bin(year);
301	    wday = bcd2bin(wday);
302        }
303
304        if (!(ctrl & RTC_24H)) {
305	    if (!pm && hour == 12)
306		hour = 0;
307	    else if (pm && hour != 12)
308		hour += 12;
309        }
310
311        t->tm_sec  = sec;
312        t->tm_min  = min;
313        t->tm_hour = hour;
314        t->tm_mday = day;
315        t->tm_mon  = mon - 1;
316        t->tm_year = year + atari_rtc_year_offset;
317        t->tm_wday = wday - 1;
318    }
319
320    return( 0 );
321}
322