summaryrefslogtreecommitdiffstats
path: root/board/mousse/m48t59y.c
blob: 9a70dbeab16fa81f2ddf30f3641506212f3fed99 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
/*
 * SGS M48-T59Y TOD/NVRAM Driver
 *
 * (C) Copyright 2000
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * (C) Copyright 1999, by Curt McDowell, 08-06-99, Broadcom Corp.
 *
 * (C) Copyright 2001, James Dougherty, 07/18/01, Broadcom Corp.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

/*
 * SGS M48-T59Y TOD/NVRAM Driver
 *
 * The SGS M48 an 8K NVRAM starting at offset M48_BASE_ADDR and
 * continuing for 8176 bytes. After that starts the Time-Of-Day (TOD)
 * registers which are used to set/get the internal date/time functions.
 *
 * This module implements Y2K compliance by taking full year numbers
 * and translating back and forth from the TOD 2-digit year.
 *
 * NOTE: for proper interaction with an operating system, the TOD should
 * be used to store Universal Coordinated Time (GMT) and timezone
 * conversions should be used.
 *
 * Here is a diagram of the memory layout:
 *
 * +---------------------------------------------+ 0xffe0a000
 * | Non-volatile memory                         | .
 * |                                             | .
 * | (8176 bytes of Non-volatile memory)         | .
 * |                                             | .
 * +---------------------------------------------+ 0xffe0bff0
 * | Flags                                       |
 * +---------------------------------------------+ 0xffe0bff1
 * | Unused                                      |
 * +---------------------------------------------+ 0xffe0bff2
 * | Alarm Seconds                               |
 * +---------------------------------------------+ 0xffe0bff3
 * | Alarm Minutes                               |
 * +---------------------------------------------+ 0xffe0bff4
 * | Alarm Date                                  |
 * +---------------------------------------------+ 0xffe0bff5
 * | Interrupts                                  |
 * +---------------------------------------------+ 0xffe0bff6
 * | WatchDog                                    |
 * +---------------------------------------------+ 0xffe0bff7
 * | Calibration                                 |
 * +---------------------------------------------+ 0xffe0bff8
 * | Seconds                                     |
 * +---------------------------------------------+ 0xffe0bff9
 * | Minutes                                     |
 * +---------------------------------------------+ 0xffe0bffa
 * | Hours                                       |
 * +---------------------------------------------+ 0xffe0bffb
 * | Day                                         |
 * +---------------------------------------------+ 0xffe0bffc
 * | Date                                        |
 * +---------------------------------------------+ 0xffe0bffd
 * | Month                                       |
 * +---------------------------------------------+ 0xffe0bffe
 * | Year (2 digits only)                        |
 * +---------------------------------------------+ 0xffe0bfff
 */
#include <common.h>
#include <rtc.h>
#include "mousse.h"

/*
 * Imported from mousse.h:
 *
 *   TOD_REG_BASE		Base of m48t59y TOD registers
 *   SYS_TOD_UNPROTECT()	Disable NVRAM write protect
 *   SYS_TOD_PROTECT()		Re-enable NVRAM write protect
 */

#define YEAR		0xf
#define MONTH		0xe
#define DAY		0xd
#define DAY_OF_WEEK	0xc
#define HOUR		0xb
#define MINUTE		0xa
#define SECOND		0x9
#define CONTROL		0x8
#define WATCH		0x7
#define INTCTL		0x6
#define WD_DATE		0x5
#define WD_HOUR		0x4
#define WD_MIN		0x3
#define WD_SEC		0x2
#define _UNUSED		0x1
#define FLAGS		0x0

#define M48_ADDR	((volatile unsigned char *) TOD_REG_BASE)

int m48_tod_init(void)
{
    SYS_TOD_UNPROTECT();

    M48_ADDR[CONTROL] = 0;
    M48_ADDR[WATCH] = 0;
    M48_ADDR[INTCTL] = 0;

    /*
     * If the oscillator is currently stopped (as on a new part shipped
     * from the factory), start it running.
     *
     * Here is an example of the TOD bytes on a brand new M48T59Y part:
     *		00 00 00 00 00 00 00 00 00 88 8c c3 bf c8 f5 01
     */

    if (M48_ADDR[SECOND] & 0x80)
	M48_ADDR[SECOND] = 0;

    /* Is battery low */
    if ( M48_ADDR[FLAGS] & 0x10) {
	 printf("NOTICE: Battery low on Real-Time Clock (replace SNAPHAT).\n");
    }

    SYS_TOD_PROTECT();

    return 0;
}

/*
 * m48_tod_set
 */

static int to_bcd(int value)
{
    return value / 10 * 16 + value % 10;
}

static int from_bcd(int value)
{
    return value / 16 * 10 + value % 16;
}

static int day_of_week(int y, int m, int d)	/* 0-6 ==> Sun-Sat */
{
    static int t[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
    y -= m < 3;
    return (y + y/4 - y/100 + y/400 + t[m-1] + d) % 7;
}

/*
 * Note: the TOD should store the current GMT
 */

int m48_tod_set(int year,		/* 1980-2079 */
		int month,		/* 01-12 */
		int day,		/* 01-31 */
		int hour,		/* 00-23 */
		int minute,		/* 00-59 */
		int second)		/* 00-59 */

{
    SYS_TOD_UNPROTECT();

    M48_ADDR[CONTROL] |= 0x80;	/* Set WRITE bit */

    M48_ADDR[YEAR] = to_bcd(year % 100);
    M48_ADDR[MONTH] = to_bcd(month);
    M48_ADDR[DAY] = to_bcd(day);
    M48_ADDR[DAY_OF_WEEK] = day_of_week(year, month, day) + 1;
    M48_ADDR[HOUR] = to_bcd(hour);
    M48_ADDR[MINUTE] = to_bcd(minute);
    M48_ADDR[SECOND] = to_bcd(second);

    M48_ADDR[CONTROL] &= ~0x80;	/* Clear WRITE bit */

    SYS_TOD_PROTECT();

    return 0;
}

/*
 * Note: the TOD should store the current GMT
 */

int m48_tod_get(int *year,		/* 1980-2079 */
		int *month,		/* 01-12 */
		int *day,		/* 01-31 */
		int *hour,		/* 00-23 */
		int *minute,		/* 00-59 */
		int *second)		/* 00-59 */
{
    int y;

    SYS_TOD_UNPROTECT();

    M48_ADDR[CONTROL] |= 0x40;	/* Set READ bit */

    y = from_bcd(M48_ADDR[YEAR]);
    *year = y < 80 ? 2000 + y : 1900 + y;
    *month = from_bcd(M48_ADDR[MONTH]);
    *day = from_bcd(M48_ADDR[DAY]);
    /* day_of_week = M48_ADDR[DAY_OF_WEEK] & 0xf; */
    *hour = from_bcd(M48_ADDR[HOUR]);
    *minute = from_bcd(M48_ADDR[MINUTE]);
    *second = from_bcd(M48_ADDR[SECOND] & 0x7f);

    M48_ADDR[CONTROL] &= ~0x40;	/* Clear READ bit */

    SYS_TOD_PROTECT();

    return 0;
}

int m48_tod_get_second(void)
{
    return from_bcd(M48_ADDR[SECOND] & 0x7f);
}

/*
 * Watchdog function
 *
 *  If usec is 0, the watchdog timer is disarmed.
 *
 *  If usec is non-zero, the watchdog timer is armed (or re-armed) for
 *    approximately usec microseconds (if the exact requested usec is
 *    not supported by the chip, the next higher available value is used).
 *
 *  Minimum watchdog timeout = 62500 usec
 *  Maximum watchdog timeout = 124 sec (124000000 usec)
 */

void m48_watchdog_arm(int usec)
{
    int		mpy, res;

    SYS_TOD_UNPROTECT();

    if (usec == 0) {
	res = 0;
	mpy = 0;
    } else if (usec < 2000000) {	/* Resolution: 1/16s if below 2s */
	res = 0;
	mpy = (usec + 62499) / 62500;
    } else if (usec < 8000000) {	/* Resolution: 1/4s if below 8s */
	res = 1;
	mpy = (usec + 249999) / 250000;
    } else if (usec < 32000000) {	/* Resolution: 1s if below 32s */
	res = 2;
	mpy = (usec + 999999) / 1000000;
    } else {				/* Resolution: 4s up to 124s */
	res = 3;
	mpy = (usec + 3999999) / 4000000;
	if (mpy > 31)
	    mpy = 31;
    }

    M48_ADDR[WATCH] = (0x80 |		/* Steer to RST signal (IRQ = N/C) */
		       mpy << 2 |
		       res);

    SYS_TOD_PROTECT();
}

/*
 * U-Boot RTC support.
 */
int
rtc_get( struct rtc_time *tmp )
{
	m48_tod_get(&tmp->tm_year,
		    &tmp->tm_mon,
		    &tmp->tm_mday,
		    &tmp->tm_hour,
		    &tmp->tm_min,
		    &tmp->tm_sec);
	tmp->tm_yday = 0;
	tmp->tm_isdst= 0;

#ifdef RTC_DEBUG
	printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
		tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
#endif

	return 0;
}

int rtc_set( struct rtc_time *tmp )
{
	m48_tod_set(tmp->tm_year,		/* 1980-2079 */
		    tmp->tm_mon,		/* 01-12 */
		    tmp->tm_mday,              /* 01-31 */
		    tmp->tm_hour,		/* 00-23 */
		    tmp->tm_min,		/* 00-59 */
		    tmp->tm_sec);		/* 00-59 */

#ifdef RTC_DEBUG
	printf( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
#endif

	return 0;
}

void
rtc_reset (void)
{
  m48_tod_init();
}
OpenPOWER on IntegriCloud