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[/] [test_project/] [trunk/] [linux_sd_driver/] [drivers/] [char/] [ip27-rtc.c] - Blame information for rev 62

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1 62 marcus.erl
/*
2
 *      Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
3
 *
4
 *      Real Time Clock interface for Linux
5
 *
6
 *      TODO: Implement periodic interrupts.
7
 *
8
 *      Copyright (C) 2000 Silicon Graphics, Inc.
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 *      Written by Ulf Carlsson (ulfc@engr.sgi.com)
10
 *
11
 *      Based on code written by Paul Gortmaker.
12
 *
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 *      This driver allows use of the real time clock (built into
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 *      nearly all computers) from user space. It exports the /dev/rtc
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 *      interface supporting various ioctl() and also the /proc/rtc
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 *      pseudo-file for status information.
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 *
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 *      This program is free software; you can redistribute it and/or
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 *      modify it under the terms of the GNU General Public License
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 *      as published by the Free Software Foundation; either version
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 *      2 of the License, or (at your option) any later version.
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 *
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 */
24
 
25
#define RTC_VERSION             "1.09b"
26
 
27
#include <linux/bcd.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/miscdevice.h>
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#include <linux/ioport.h>
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#include <linux/fcntl.h>
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#include <linux/rtc.h>
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#include <linux/init.h>
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#include <linux/poll.h>
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#include <linux/proc_fs.h>
38
 
39
#include <asm/m48t35.h>
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#include <asm/sn/ioc3.h>
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#include <asm/io.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <asm/sn/klconfig.h>
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#include <asm/sn/sn0/ip27.h>
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#include <asm/sn/sn0/hub.h>
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#include <asm/sn/sn_private.h>
48
 
49
static int rtc_ioctl(struct inode *inode, struct file *file,
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                     unsigned int cmd, unsigned long arg);
51
 
52
static int rtc_read_proc(char *page, char **start, off_t off,
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                         int count, int *eof, void *data);
54
 
55
static void get_rtc_time(struct rtc_time *rtc_tm);
56
 
57
/*
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 *      Bits in rtc_status. (6 bits of room for future expansion)
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 */
60
 
61
#define RTC_IS_OPEN             0x01    /* means /dev/rtc is in use     */
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#define RTC_TIMER_ON            0x02    /* missed irq timer active      */
63
 
64
static unsigned char rtc_status;        /* bitmapped status byte.       */
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static unsigned long rtc_freq;  /* Current periodic IRQ rate    */
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static struct m48t35_rtc *rtc;
67
 
68
/*
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 *      If this driver ever becomes modularised, it will be really nice
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 *      to make the epoch retain its value across module reload...
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 */
72
 
73
static unsigned long epoch = 1970;      /* year corresponding to 0x00   */
74
 
75
static const unsigned char days_in_mo[] =
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{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
77
 
78
static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
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                     unsigned long arg)
80
{
81
 
82
        struct rtc_time wtime;
83
 
84
        switch (cmd) {
85
        case RTC_RD_TIME:       /* Read the time/date from RTC  */
86
        {
87
                get_rtc_time(&wtime);
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                break;
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        }
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        case RTC_SET_TIME:      /* Set the RTC */
91
        {
92
                struct rtc_time rtc_tm;
93
                unsigned char mon, day, hrs, min, sec, leap_yr;
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                unsigned int yrs;
95
 
96
                if (!capable(CAP_SYS_TIME))
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                        return -EACCES;
98
 
99
                if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
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                                   sizeof(struct rtc_time)))
101
                        return -EFAULT;
102
 
103
                yrs = rtc_tm.tm_year + 1900;
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                mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
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                day = rtc_tm.tm_mday;
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                hrs = rtc_tm.tm_hour;
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                min = rtc_tm.tm_min;
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                sec = rtc_tm.tm_sec;
109
 
110
                if (yrs < 1970)
111
                        return -EINVAL;
112
 
113
                leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
114
 
115
                if ((mon > 12) || (day == 0))
116
                        return -EINVAL;
117
 
118
                if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
119
                        return -EINVAL;
120
 
121
                if ((hrs >= 24) || (min >= 60) || (sec >= 60))
122
                        return -EINVAL;
123
 
124
                if ((yrs -= epoch) > 255)    /* They are unsigned */
125
                        return -EINVAL;
126
 
127
                if (yrs > 169)
128
                        return -EINVAL;
129
 
130
                if (yrs >= 100)
131
                        yrs -= 100;
132
 
133
                sec = BIN2BCD(sec);
134
                min = BIN2BCD(min);
135
                hrs = BIN2BCD(hrs);
136
                day = BIN2BCD(day);
137
                mon = BIN2BCD(mon);
138
                yrs = BIN2BCD(yrs);
139
 
140
                spin_lock_irq(&rtc_lock);
141
                rtc->control |= M48T35_RTC_SET;
142
                rtc->year = yrs;
143
                rtc->month = mon;
144
                rtc->date = day;
145
                rtc->hour = hrs;
146
                rtc->min = min;
147
                rtc->sec = sec;
148
                rtc->control &= ~M48T35_RTC_SET;
149
                spin_unlock_irq(&rtc_lock);
150
 
151
                return 0;
152
        }
153
        default:
154
                return -EINVAL;
155
        }
156
        return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
157
}
158
 
159
/*
160
 *      We enforce only one user at a time here with the open/close.
161
 *      Also clear the previous interrupt data on an open, and clean
162
 *      up things on a close.
163
 */
164
 
165
static int rtc_open(struct inode *inode, struct file *file)
166
{
167
        spin_lock_irq(&rtc_lock);
168
 
169
        if (rtc_status & RTC_IS_OPEN) {
170
                spin_unlock_irq(&rtc_lock);
171
                return -EBUSY;
172
        }
173
 
174
        rtc_status |= RTC_IS_OPEN;
175
        spin_unlock_irq(&rtc_lock);
176
 
177
        return 0;
178
}
179
 
180
static int rtc_release(struct inode *inode, struct file *file)
181
{
182
        /*
183
         * Turn off all interrupts once the device is no longer
184
         * in use, and clear the data.
185
         */
186
 
187
        spin_lock_irq(&rtc_lock);
188
        rtc_status &= ~RTC_IS_OPEN;
189
        spin_unlock_irq(&rtc_lock);
190
 
191
        return 0;
192
}
193
 
194
/*
195
 *      The various file operations we support.
196
 */
197
 
198
static const struct file_operations rtc_fops = {
199
        .owner          = THIS_MODULE,
200
        .ioctl          = rtc_ioctl,
201
        .open           = rtc_open,
202
        .release        = rtc_release,
203
};
204
 
205
static struct miscdevice rtc_dev=
206
{
207
        RTC_MINOR,
208
        "rtc",
209
        &rtc_fops
210
};
211
 
212
static int __init rtc_init(void)
213
{
214
        rtc = (struct m48t35_rtc *)
215
        (KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base + IOC3_BYTEBUS_DEV0);
216
 
217
        printk(KERN_INFO "Real Time Clock Driver v%s\n", RTC_VERSION);
218
        if (misc_register(&rtc_dev)) {
219
                printk(KERN_ERR "rtc: cannot register misc device.\n");
220
                return -ENODEV;
221
        }
222
        if (!create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)) {
223
                printk(KERN_ERR "rtc: cannot create /proc/rtc.\n");
224
                misc_deregister(&rtc_dev);
225
                return -ENOENT;
226
        }
227
 
228
        rtc_freq = 1024;
229
 
230
        return 0;
231
}
232
 
233
static void __exit rtc_exit (void)
234
{
235
        /* interrupts and timer disabled at this point by rtc_release */
236
 
237
        remove_proc_entry ("rtc", NULL);
238
        misc_deregister(&rtc_dev);
239
}
240
 
241
module_init(rtc_init);
242
module_exit(rtc_exit);
243
 
244
/*
245
 *      Info exported via "/proc/rtc".
246
 */
247
 
248
static int rtc_get_status(char *buf)
249
{
250
        char *p;
251
        struct rtc_time tm;
252
 
253
        /*
254
         * Just emulate the standard /proc/rtc
255
         */
256
 
257
        p = buf;
258
 
259
        get_rtc_time(&tm);
260
 
261
        /*
262
         * There is no way to tell if the luser has the RTC set for local
263
         * time or for Universal Standard Time (GMT). Probably local though.
264
         */
265
        p += sprintf(p,
266
                     "rtc_time\t: %02d:%02d:%02d\n"
267
                     "rtc_date\t: %04d-%02d-%02d\n"
268
                     "rtc_epoch\t: %04lu\n"
269
                     "24hr\t\t: yes\n",
270
                     tm.tm_hour, tm.tm_min, tm.tm_sec,
271
                     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
272
 
273
        return  p - buf;
274
}
275
 
276
static int rtc_read_proc(char *page, char **start, off_t off,
277
                                 int count, int *eof, void *data)
278
{
279
        int len = rtc_get_status(page);
280
        if (len <= off+count) *eof = 1;
281
        *start = page + off;
282
        len -= off;
283
        if (len>count) len = count;
284
        if (len<0) len = 0;
285
        return len;
286
}
287
 
288
static void get_rtc_time(struct rtc_time *rtc_tm)
289
{
290
        /*
291
         * Do we need to wait for the last update to finish?
292
         */
293
 
294
        /*
295
         * Only the values that we read from the RTC are set. We leave
296
         * tm_wday, tm_yday and tm_isdst untouched. Even though the
297
         * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
298
         * by the RTC when initially set to a non-zero value.
299
         */
300
        spin_lock_irq(&rtc_lock);
301
        rtc->control |= M48T35_RTC_READ;
302
        rtc_tm->tm_sec = rtc->sec;
303
        rtc_tm->tm_min = rtc->min;
304
        rtc_tm->tm_hour = rtc->hour;
305
        rtc_tm->tm_mday = rtc->date;
306
        rtc_tm->tm_mon = rtc->month;
307
        rtc_tm->tm_year = rtc->year;
308
        rtc->control &= ~M48T35_RTC_READ;
309
        spin_unlock_irq(&rtc_lock);
310
 
311
        rtc_tm->tm_sec = BCD2BIN(rtc_tm->tm_sec);
312
        rtc_tm->tm_min = BCD2BIN(rtc_tm->tm_min);
313
        rtc_tm->tm_hour = BCD2BIN(rtc_tm->tm_hour);
314
        rtc_tm->tm_mday = BCD2BIN(rtc_tm->tm_mday);
315
        rtc_tm->tm_mon = BCD2BIN(rtc_tm->tm_mon);
316
        rtc_tm->tm_year = BCD2BIN(rtc_tm->tm_year);
317
 
318
        /*
319
         * Account for differences between how the RTC uses the values
320
         * and how they are defined in a struct rtc_time;
321
         */
322
        if ((rtc_tm->tm_year += (epoch - 1900)) <= 69)
323
                rtc_tm->tm_year += 100;
324
 
325
        rtc_tm->tm_mon--;
326
}

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