OpenCores
URL https://opencores.org/ocsvn/or1k/or1k/trunk

Subversion Repositories or1k

[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [include/] [asm-arm/] [arch-riscstation/] [time.h] - Blame information for rev 1276

Go to most recent revision | Details | Compare with Previous | View Log

Line No. Rev Author Line
1 1276 phoenix
/*
2
 *  linux/include/asm-arm/arch-rs/time.h
3
 *
4
 * This program is free software; you can redistribute it and/or modify
5
 * it under the terms of the GNU General Public License version 2 as
6
 * published by the Free Software Foundation.
7
 *
8
 * (c) 2002 Simtec Electronics / Ben Dooks
9
 *
10
 * Bits taken from linux/include/asm-arm/arch-rpc/time.h
11
 *
12
 * (c) 1996-2002 Russell King
13
 *
14
 * Bits taken from linux/include/asm-arm/arch-ebsa285/time.h
15
 *
16
 * Copyright (C) 1998 Russell King.
17
 * Copyright (C) 1998 Phil Blundell
18
*/
19
 
20
#define RTC_PORT(x)    (0x70 + (x))
21
#define RTC_ALWAYS_BCD (0)
22
 
23
#include <linux/mc146818rtc.h>
24
#include <asm/mach-types.h>
25
 
26
extern void ioctime_init(void);
27
 
28
/* timer interrut - update things like profiling information and our
29
 * copy of the RTC's time
30
*/
31
 
32
static void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
33
{
34
        do_timer(regs);
35
        do_set_rtc();
36
        do_profile(regs);
37
}
38
 
39
/* get_isa_cmos_time()
40
 *
41
 * get the time from the CMOS RTC
42
 *
43
 * from linux/include/asm-arm/arch-ebsa285/time.h
44
*/
45
 
46
static unsigned long get_isa_cmos_time(void)
47
{
48
        unsigned int year, mon, day, hour, min, sec;
49
        int i;
50
 
51
        // check to see if the RTC makes sense.....
52
        if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0)
53
                return mktime(1970, 1, 1, 0, 0, 0);
54
 
55
        /* The Linux interpretation of the CMOS clock register contents:
56
         * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
57
         * RTC registers show the second which has precisely just started.
58
         * Let's hope other operating systems interpret the RTC the same way.
59
         */
60
        /* read RTC exactly on falling edge of update flag */
61
        for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
62
                if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
63
                        break;
64
 
65
        for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
66
                if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
67
                        break;
68
 
69
        do { /* Isn't this overkill ? UIP above should guarantee consistency */
70
                sec  = CMOS_READ(RTC_SECONDS);
71
                min  = CMOS_READ(RTC_MINUTES);
72
                hour = CMOS_READ(RTC_HOURS);
73
                day  = CMOS_READ(RTC_DAY_OF_MONTH);
74
                mon  = CMOS_READ(RTC_MONTH);
75
                year = CMOS_READ(RTC_YEAR);
76
        } while (sec != CMOS_READ(RTC_SECONDS));
77
 
78
        if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
79
                BCD_TO_BIN(sec);
80
                BCD_TO_BIN(min);
81
                BCD_TO_BIN(hour);
82
                BCD_TO_BIN(day);
83
                BCD_TO_BIN(mon);
84
                BCD_TO_BIN(year);
85
        }
86
        if ((year += 1900) < 1970)
87
                year += 100;
88
        return mktime(year, mon, day, hour, min, sec);
89
}
90
 
91
/* set_isa_cmos_time()
92
 *
93
 * set the CMOS RTC time
94
 *
95
 * from linux/include/asm-arm/arch-ebsa285/time.h
96
*/
97
 
98
static int
99
set_isa_cmos_time(void)
100
{
101
        int retval = 0;
102
        int real_seconds, real_minutes, cmos_minutes;
103
        unsigned char save_control, save_freq_select;
104
        unsigned long nowtime = xtime.tv_sec;
105
 
106
        save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
107
        CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
108
 
109
        save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
110
        CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
111
 
112
        cmos_minutes = CMOS_READ(RTC_MINUTES);
113
        if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
114
                BCD_TO_BIN(cmos_minutes);
115
 
116
        /*
117
         * since we're only adjusting minutes and seconds,
118
         * don't interfere with hour overflow. This avoids
119
         * messing with unknown time zones but requires your
120
         * RTC not to be off by more than 15 minutes
121
         */
122
        real_seconds = nowtime % 60;
123
        real_minutes = nowtime / 60;
124
        if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
125
                real_minutes += 30;             /* correct for half hour time zone */
126
        real_minutes %= 60;
127
 
128
        if (abs(real_minutes - cmos_minutes) < 30) {
129
                if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
130
                        BIN_TO_BCD(real_seconds);
131
                        BIN_TO_BCD(real_minutes);
132
                }
133
                CMOS_WRITE(real_seconds,RTC_SECONDS);
134
                CMOS_WRITE(real_minutes,RTC_MINUTES);
135
        } else
136
                retval = -1;
137
 
138
        /* The following flags have to be released exactly in this order,
139
         * otherwise the DS12887 (popular MC146818A clone with integrated
140
         * battery and quartz) will not reset the oscillator and will not
141
         * update precisely 500 ms later. You won't find this mentioned in
142
         * the Dallas Semiconductor data sheets, but who believes data
143
         * sheets anyway ...                           -- Markus Kuhn
144
         */
145
        CMOS_WRITE(save_control, RTC_CONTROL);
146
        CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
147
 
148
        return retval;
149
}
150
 
151
 
152
/*
153
 * Set up timer interrupt.
154
 */
155
static inline void setup_timer(void)
156
{
157
        int reg_b, reg_d;
158
 
159
        ioctime_init();
160
 
161
        /* ensure we have an RTC chip, and initialise it... */
162
 
163
        reg_d = CMOS_READ(RTC_REG_D);
164
 
165
        CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A);
166
 
167
        /*
168
         * Set control reg B
169
         *   (24 hour mode, update enabled)
170
         */
171
        reg_b = CMOS_READ(RTC_REG_B) & 0x7f;
172
        reg_b |= 2;
173
        CMOS_WRITE(reg_b, RTC_REG_B);
174
 
175
        if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ &&
176
            CMOS_READ(RTC_REG_B) == reg_b) {
177
 
178
                /*
179
                 * We have a RTC.  Check the battery
180
                 */
181
                if ((reg_d & 0x80) == 0)
182
                        printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n");
183
 
184
                printk("RTC: detected\n");
185
 
186
                xtime.tv_sec = get_isa_cmos_time();
187
                set_rtc = set_isa_cmos_time;
188
        } else {
189
                printk("RTC: Warning: No RTC detected\n");
190
        }
191
 
192
        /* ensure we have the IOC time interrupt setup */
193
 
194
        timer_irq.handler = timer_interrupt;
195
 
196
        setup_arm_irq(IRQ_TIMER, &timer_irq);
197
}
198
 

powered by: WebSVN 2.1.0

© copyright 1999-2025 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.