source: SVN/rincon/u-boot/board/bmw/m48t59y.c @ 55

Last change on this file since 55 was 55, checked in by Tim Harvey, 22 months ago

rincon: added latest u-boot source

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Signed-off-by: Tim Harvey <tharvey@…>

File size: 8.7 KB
Line 
1/*
2 * SGS M48-T59Y TOD/NVRAM Driver
3 *
4 * (C) Copyright 2000
5 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
6 *
7 * (C) Copyright 1999, by Curt McDowell, 08-06-99, Broadcom Corp.
8 *
9 * (C) Copyright 2001, James Dougherty, 07/18/01, Broadcom Corp.
10 *
11 * See file CREDITS for list of people who contributed to this
12 * project.
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License as
16 * published by the Free Software Foundation; either version 2 of
17 * the License, or (at your option) any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 * MA 02111-1307 USA
28 */
29
30/*
31 * SGS M48-T59Y TOD/NVRAM Driver
32 *
33 * The SGS M48 an 8K NVRAM starting at offset M48_BASE_ADDR and
34 * continuing for 8176 bytes. After that starts the Time-Of-Day (TOD)
35 * registers which are used to set/get the internal date/time functions.
36 *
37 * This module implements Y2K compliance by taking full year numbers
38 * and translating back and forth from the TOD 2-digit year.
39 *
40 * NOTE: for proper interaction with an operating system, the TOD should
41 * be used to store Universal Coordinated Time (GMT) and timezone
42 * conversions should be used.
43 *
44 * Here is a diagram of the memory layout:
45 *
46 * +---------------------------------------------+ 0xffe0a000
47 * | Non-volatile memory                         | .
48 * |                                             | .
49 * | (8176 bytes of Non-volatile memory)         | .
50 * |                                             | .
51 * +---------------------------------------------+ 0xffe0bff0
52 * | Flags                                       |
53 * +---------------------------------------------+ 0xffe0bff1
54 * | Unused                                      |
55 * +---------------------------------------------+ 0xffe0bff2
56 * | Alarm Seconds                               |
57 * +---------------------------------------------+ 0xffe0bff3
58 * | Alarm Minutes                               |
59 * +---------------------------------------------+ 0xffe0bff4
60 * | Alarm Date                                  |
61 * +---------------------------------------------+ 0xffe0bff5
62 * | Interrupts                                  |
63 * +---------------------------------------------+ 0xffe0bff6
64 * | WatchDog                                    |
65 * +---------------------------------------------+ 0xffe0bff7
66 * | Calibration                                 |
67 * +---------------------------------------------+ 0xffe0bff8
68 * | Seconds                                     |
69 * +---------------------------------------------+ 0xffe0bff9
70 * | Minutes                                     |
71 * +---------------------------------------------+ 0xffe0bffa
72 * | Hours                                       |
73 * +---------------------------------------------+ 0xffe0bffb
74 * | Day                                         |
75 * +---------------------------------------------+ 0xffe0bffc
76 * | Date                                        |
77 * +---------------------------------------------+ 0xffe0bffd
78 * | Month                                       |
79 * +---------------------------------------------+ 0xffe0bffe
80 * | Year (2 digits only)                        |
81 * +---------------------------------------------+ 0xffe0bfff
82 */
83#include <common.h>
84#include <rtc.h>
85#include "bmw.h"
86
87/*
88 * Imported from mousse.h:
89 *
90 *   TOD_REG_BASE               Base of m48t59y TOD registers
91 *   SYS_TOD_UNPROTECT()        Disable NVRAM write protect
92 *   SYS_TOD_PROTECT()          Re-enable NVRAM write protect
93 */
94
95#define YEAR            0xf
96#define MONTH           0xe
97#define DAY             0xd
98#define DAY_OF_WEEK     0xc
99#define HOUR            0xb
100#define MINUTE          0xa
101#define SECOND          0x9
102#define CONTROL         0x8
103#define WATCH           0x7
104#define INTCTL          0x6
105#define WD_DATE         0x5
106#define WD_HOUR         0x4
107#define WD_MIN          0x3
108#define WD_SEC          0x2
109#define _UNUSED         0x1
110#define FLAGS           0x0
111
112#define M48_ADDR        ((volatile unsigned char *) TOD_REG_BASE)
113
114int m48_tod_init(void)
115{
116    SYS_TOD_UNPROTECT();
117
118    M48_ADDR[CONTROL] = 0;
119    M48_ADDR[WATCH] = 0;
120    M48_ADDR[INTCTL] = 0;
121
122    /*
123     * If the oscillator is currently stopped (as on a new part shipped
124     * from the factory), start it running.
125     *
126     * Here is an example of the TOD bytes on a brand new M48T59Y part:
127     *          00 00 00 00 00 00 00 00 00 88 8c c3 bf c8 f5 01
128     */
129
130    if (M48_ADDR[SECOND] & 0x80)
131        M48_ADDR[SECOND] = 0;
132
133    /* Is battery low */
134    if ( M48_ADDR[FLAGS] & 0x10) {
135         printf("NOTICE: Battery low on Real-Time Clock (replace SNAPHAT).\n");
136    }
137
138    SYS_TOD_PROTECT();
139
140    return 0;
141}
142
143/*
144 * m48_tod_set
145 */
146
147static int to_bcd(int value)
148{
149    return value / 10 * 16 + value % 10;
150}
151
152static int from_bcd(int value)
153{
154    return value / 16 * 10 + value % 16;
155}
156
157static int day_of_week(int y, int m, int d)     /* 0-6 ==> Sun-Sat */
158{
159    static int t[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
160    y -= m < 3;
161    return (y + y/4 - y/100 + y/400 + t[m-1] + d) % 7;
162}
163
164/*
165 * Note: the TOD should store the current GMT
166 */
167
168int m48_tod_set(int year,               /* 1980-2079 */
169                int month,              /* 01-12 */
170                int day,                /* 01-31 */
171                int hour,               /* 00-23 */
172                int minute,             /* 00-59 */
173                int second)             /* 00-59 */
174
175{
176    SYS_TOD_UNPROTECT();
177
178    M48_ADDR[CONTROL] |= 0x80;  /* Set WRITE bit */
179
180    M48_ADDR[YEAR] = to_bcd(year % 100);
181    M48_ADDR[MONTH] = to_bcd(month);
182    M48_ADDR[DAY] = to_bcd(day);
183    M48_ADDR[DAY_OF_WEEK] = day_of_week(year, month, day) + 1;
184    M48_ADDR[HOUR] = to_bcd(hour);
185    M48_ADDR[MINUTE] = to_bcd(minute);
186    M48_ADDR[SECOND] = to_bcd(second);
187
188    M48_ADDR[CONTROL] &= ~0x80; /* Clear WRITE bit */
189
190    SYS_TOD_PROTECT();
191
192    return 0;
193}
194
195/*
196 * Note: the TOD should store the current GMT
197 */
198
199int m48_tod_get(int *year,              /* 1980-2079 */
200                int *month,             /* 01-12 */
201                int *day,               /* 01-31 */
202                int *hour,              /* 00-23 */
203                int *minute,            /* 00-59 */
204                int *second)            /* 00-59 */
205{
206    int y;
207
208    SYS_TOD_UNPROTECT();
209
210    M48_ADDR[CONTROL] |= 0x40;  /* Set READ bit */
211
212    y = from_bcd(M48_ADDR[YEAR]);
213    *year = y < 80 ? 2000 + y : 1900 + y;
214    *month = from_bcd(M48_ADDR[MONTH]);
215    *day = from_bcd(M48_ADDR[DAY]);
216    /* day_of_week = M48_ADDR[DAY_OF_WEEK] & 0xf; */
217    *hour = from_bcd(M48_ADDR[HOUR]);
218    *minute = from_bcd(M48_ADDR[MINUTE]);
219    *second = from_bcd(M48_ADDR[SECOND] & 0x7f);
220
221    M48_ADDR[CONTROL] &= ~0x40; /* Clear READ bit */
222
223    SYS_TOD_PROTECT();
224
225    return 0;
226}
227
228int m48_tod_get_second(void)
229{
230    return from_bcd(M48_ADDR[SECOND] & 0x7f);
231}
232
233/*
234 * Watchdog function
235 *
236 *  If usec is 0, the watchdog timer is disarmed.
237 *
238 *  If usec is non-zero, the watchdog timer is armed (or re-armed) for
239 *    approximately usec microseconds (if the exact requested usec is
240 *    not supported by the chip, the next higher available value is used).
241 *
242 *  Minimum watchdog timeout = 62500 usec
243 *  Maximum watchdog timeout = 124 sec (124000000 usec)
244 */
245
246void m48_watchdog_arm(int usec)
247{
248    int         mpy, res;
249
250    SYS_TOD_UNPROTECT();
251
252    if (usec == 0) {
253        res = 0;
254        mpy = 0;
255    } else if (usec < 2000000) {        /* Resolution: 1/16s if below 2s */
256        res = 0;
257        mpy = (usec + 62499) / 62500;
258    } else if (usec < 8000000) {        /* Resolution: 1/4s if below 8s */
259        res = 1;
260        mpy = (usec + 249999) / 250000;
261    } else if (usec < 32000000) {       /* Resolution: 1s if below 32s */
262        res = 2;
263        mpy = (usec + 999999) / 1000000;
264    } else {                            /* Resolution: 4s up to 124s */
265        res = 3;
266        mpy = (usec + 3999999) / 4000000;
267        if (mpy > 31)
268            mpy = 31;
269    }
270
271    M48_ADDR[WATCH] = (0x80 |           /* Steer to RST signal (IRQ = N/C) */
272                       mpy << 2 |
273                       res);
274
275    SYS_TOD_PROTECT();
276}
277
278/*
279 * U-Boot RTC support.
280 */
281int
282rtc_get( struct rtc_time *tmp )
283{
284        m48_tod_get(&tmp->tm_year,
285                    &tmp->tm_mon,
286                    &tmp->tm_mday,
287                    &tmp->tm_hour,
288                    &tmp->tm_min,
289                    &tmp->tm_sec);
290        tmp->tm_yday = 0;
291        tmp->tm_isdst= 0;
292
293#ifdef RTC_DEBUG
294        printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
295                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
296                tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
297#endif
298
299        return 0;
300}
301
302int rtc_set( struct rtc_time *tmp )
303{
304        m48_tod_set(tmp->tm_year,               /* 1980-2079 */
305                    tmp->tm_mon,                /* 01-12 */
306                    tmp->tm_mday,              /* 01-31 */
307                    tmp->tm_hour,               /* 00-23 */
308                    tmp->tm_min,                /* 00-59 */
309                    tmp->tm_sec);               /* 00-59 */
310
311#ifdef RTC_DEBUG
312        printf( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
313                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
314                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
315#endif
316
317        return 0;
318}
319
320void
321rtc_reset (void)
322{
323  m48_tod_init();
324}
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