aboutsummaryrefslogtreecommitdiff
path: root/arch/ppc64/kernel/rtc.c
blob: 79e7ed2858dde6f399f4c708d8a9bf41e4341e6c (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
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
/*
 *	Real Time Clock interface for PPC64.
 *
 *	Based on rtc.c by Paul Gortmaker
 *
 *	This driver allows use of the real time clock
 *	from user space. It exports the /dev/rtc
 *	interface supporting various ioctl() and also the
 *	/proc/driver/rtc pseudo-file for status information.
 *
 * 	Interface does not support RTC interrupts nor an alarm.
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 *      1.0	Mike Corrigan:    IBM iSeries rtc support
 *      1.1	Dave Engebretsen: IBM pSeries rtc support
 */

#define RTC_VERSION		"1.1"

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/bcd.h>
#include <linux/interrupt.h>
#include <linux/delay.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/time.h>
#include <asm/rtas.h>

#include <asm/machdep.h>

/*
 *	We sponge a minor off of the misc major. No need slurping
 *	up another valuable major dev number for this. If you add
 *	an ioctl, make sure you don't conflict with SPARC's RTC
 *	ioctls.
 */

static ssize_t rtc_read(struct file *file, char __user *buf,
			size_t count, loff_t *ppos);

static int rtc_ioctl(struct inode *inode, struct file *file,
		     unsigned int cmd, unsigned long arg);

static int rtc_read_proc(char *page, char **start, off_t off,
                         int count, int *eof, void *data);

/*
 *	If this driver ever becomes modularised, it will be really nice
 *	to make the epoch retain its value across module reload...
 */

static unsigned long epoch = 1900;	/* year corresponding to 0x00	*/

static const unsigned char days_in_mo[] = 
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

/*
 *	Now all the various file operations that we export.
 */

static ssize_t rtc_read(struct file *file, char __user *buf,
			size_t count, loff_t *ppos)
{
	return -EIO;
}

static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
		     unsigned long arg)
{
	struct rtc_time wtime; 

	switch (cmd) {
	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
	{
		memset(&wtime, 0, sizeof(struct rtc_time));
		ppc_md.get_rtc_time(&wtime);
		break;
	}
	case RTC_SET_TIME:	/* Set the RTC */
	{
		struct rtc_time rtc_tm;
		unsigned char mon, day, hrs, min, sec, leap_yr;
		unsigned int yrs;

		if (!capable(CAP_SYS_TIME))
			return -EACCES;

		if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
				   sizeof(struct rtc_time)))
			return -EFAULT;

		yrs = rtc_tm.tm_year;
		mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
		day = rtc_tm.tm_mday;
		hrs = rtc_tm.tm_hour;
		min = rtc_tm.tm_min;
		sec = rtc_tm.tm_sec;

		if (yrs < 70)
			return -EINVAL;

		leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));

		if ((mon > 12) || (day == 0))
			return -EINVAL;

		if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
			return -EINVAL;
			
		if ((hrs >= 24) || (min >= 60) || (sec >= 60))
			return -EINVAL;

		if ( yrs > 169 )
			return -EINVAL;

		ppc_md.set_rtc_time(&rtc_tm);
		
		return 0;
	}
	case RTC_EPOCH_READ:	/* Read the epoch.	*/
	{
		return put_user (epoch, (unsigned long __user *)arg);
	}
	case RTC_EPOCH_SET:	/* Set the epoch.	*/
	{
		/* 
		 * There were no RTC clocks before 1900.
		 */
		if (arg < 1900)
			return -EINVAL;

		if (!capable(CAP_SYS_TIME))
			return -EACCES;

		epoch = arg;
		return 0;
	}
	default:
		return -EINVAL;
	}
	return copy_to_user((void __user *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
}

static int rtc_open(struct inode *inode, struct file *file)
{
	nonseekable_open(inode, file);
	return 0;
}

static int rtc_release(struct inode *inode, struct file *file)
{
	return 0;
}

/*
 *	The various file operations we support.
 */
static struct file_operations rtc_fops = {
	.owner =	THIS_MODULE,
	.llseek =	no_llseek,
	.read =		rtc_read,
	.ioctl =	rtc_ioctl,
	.open =		rtc_open,
	.release =	rtc_release,
};

static struct miscdevice rtc_dev = {
	.minor =	RTC_MINOR,
	.name =		"rtc",
	.fops =		&rtc_fops
};

static int __init rtc_init(void)
{
	int retval;

	retval = misc_register(&rtc_dev);
	if(retval < 0)
		return retval;

#ifdef CONFIG_PROC_FS
	if (create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)
			== NULL) {
		misc_deregister(&rtc_dev);
		return -ENOMEM;
	}
#endif

	printk(KERN_INFO "i/pSeries Real Time Clock Driver v" RTC_VERSION "\n");

	return 0;
}

static void __exit rtc_exit (void)
{
	remove_proc_entry ("driver/rtc", NULL);
	misc_deregister(&rtc_dev);
}

module_init(rtc_init);
module_exit(rtc_exit);

/*
 *	Info exported via "/proc/driver/rtc".
 */

static int rtc_proc_output (char *buf)
{
	
	char *p;
	struct rtc_time tm;
	
	p = buf;

	ppc_md.get_rtc_time(&tm);

	/*
	 * There is no way to tell if the luser has the RTC set for local
	 * time or for Universal Standard Time (GMT). Probably local though.
	 */
	p += sprintf(p,
		     "rtc_time\t: %02d:%02d:%02d\n"
		     "rtc_date\t: %04d-%02d-%02d\n"
	 	     "rtc_epoch\t: %04lu\n",
		     tm.tm_hour, tm.tm_min, tm.tm_sec,
		     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);

	p += sprintf(p,
		     "DST_enable\t: no\n"
		     "BCD\t\t: yes\n"
		     "24hr\t\t: yes\n" );

	return  p - buf;
}

static int rtc_read_proc(char *page, char **start, off_t off,
                         int count, int *eof, void *data)
{
        int len = rtc_proc_output (page);
        if (len <= off+count) *eof = 1;
        *start = page + off;
        len -= off;
        if (len>count) len = count;
        if (len<0) len = 0;
        return len;
}

#ifdef CONFIG_PPC_RTAS
#define MAX_RTC_WAIT 5000	/* 5 sec */
#define RTAS_CLOCK_BUSY (-2)
unsigned long rtas_get_boot_time(void)
{
	int ret[8];
	int error, wait_time;
	unsigned long max_wait_tb;

	max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
	do {
		error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
		if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
			wait_time = rtas_extended_busy_delay_time(error);
			/* This is boot time so we spin. */
			udelay(wait_time*1000);
			error = RTAS_CLOCK_BUSY;
		}
	} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));

	if (error != 0 && printk_ratelimit()) {
		printk(KERN_WARNING "error: reading the clock failed (%d)\n",
			error);
		return 0;
	}

	return mktime(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
}

/* NOTE: get_rtc_time will get an error if executed in interrupt context
 * and if a delay is needed to read the clock.  In this case we just
 * silently return without updating rtc_tm.
 */
void rtas_get_rtc_time(struct rtc_time *rtc_tm)
{
        int ret[8];
	int error, wait_time;
	unsigned long max_wait_tb;

	max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
	do {
		error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
		if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
			if (in_interrupt() && printk_ratelimit()) {
				printk(KERN_WARNING "error: reading clock would delay interrupt\n");
				return;	/* delay not allowed */
			}
			wait_time = rtas_extended_busy_delay_time(error);
			msleep_interruptible(wait_time);
			error = RTAS_CLOCK_BUSY;
		}
	} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));

        if (error != 0 && printk_ratelimit()) {
                printk(KERN_WARNING "error: reading the clock failed (%d)\n",
		       error);
		return;
        }

	rtc_tm->tm_sec = ret[5];
	rtc_tm->tm_min = ret[4];
	rtc_tm->tm_hour = ret[3];
	rtc_tm->tm_mday = ret[2];
	rtc_tm->tm_mon = ret[1] - 1;
	rtc_tm->tm_year = ret[0] - 1900;
}

int rtas_set_rtc_time(struct rtc_time *tm)
{
	int error, wait_time;
	unsigned long max_wait_tb;

	max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
	do {
	        error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
				  tm->tm_year + 1900, tm->tm_mon + 1, 
				  tm->tm_mday, tm->tm_hour, tm->tm_min, 
				  tm->tm_sec, 0);
		if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
			if (in_interrupt())
				return 1;	/* probably decrementer */
			wait_time = rtas_extended_busy_delay_time(error);
			msleep_interruptible(wait_time);
			error = RTAS_CLOCK_BUSY;
		}
	} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));

        if (error != 0 && printk_ratelimit())
                printk(KERN_WARNING "error: setting the clock failed (%d)\n",
		       error); 

        return 0;
}
#endif