summaryrefslogtreecommitdiffstats
path: root/drivers/char/efirtc.c
blob: ea54a6e3f5adfa5311eaccb03d09571961beeee9 (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
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
/*
 * EFI Time Services Driver for Linux
 *
 * Copyright (C) 1999 Hewlett-Packard Co
 * Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
 *
 * Based on skeleton from the drivers/char/rtc.c driver by P. Gortmaker
 *
 * This code provides an architected & portable interface to the real time
 * clock by using EFI instead of direct bit fiddling. The functionalities are 
 * quite different from the rtc.c driver. The only way to talk to the device 
 * is by using ioctl(). There is a /proc interface which provides the raw 
 * information.
 *
 * Please note that we have kept the API as close as possible to the
 * legacy RTC. The standard /sbin/hwclock program should work normally 
 * when used to get/set the time.
 *
 * NOTES:
 *	- Locking is required for safe execution of EFI calls with regards
 *	  to interrupts and SMP.
 *
 * TODO (December 1999):
 * 	- provide the API to set/get the WakeUp Alarm (different from the
 *	  rtc.c alarm).
 *	- SMP testing
 * 	- Add module support
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtc.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/efi.h>
#include <linux/uaccess.h>


#define EFI_RTC_VERSION		"0.4"

#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
/*
 * EFI Epoch is 1/1/1998
 */
#define EFI_RTC_EPOCH		1998

static DEFINE_SPINLOCK(efi_rtc_lock);

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

#define is_leap(year) \
          ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))

static const unsigned short int __mon_yday[2][13] =
{
	/* Normal years.  */
	{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
	/* Leap years.  */  
	{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
};

/*
 * returns day of the year [0-365]
 */
static inline int
compute_yday(efi_time_t *eft)
{
	/* efi_time_t.month is in the [1-12] so, we need -1 */
	return  __mon_yday[is_leap(eft->year)][eft->month-1]+ eft->day -1;
}
/*
 * returns day of the week [0-6] 0=Sunday
 *
 * Don't try to provide a year that's before 1998, please !
 */
static int
compute_wday(efi_time_t *eft)
{
	int y;
	int ndays = 0;

	if ( eft->year < 1998 ) {
		printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n");
		return -1;
	}

	for(y=EFI_RTC_EPOCH; y < eft->year; y++ ) {
		ndays += 365 + (is_leap(y) ? 1 : 0);
	}
	ndays += compute_yday(eft);

	/*
	 * 4=1/1/1998 was a Thursday
	 */
	return (ndays + 4) % 7;
}

static void
convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
{

	eft->year	= wtime->tm_year + 1900;
	eft->month	= wtime->tm_mon + 1; 
	eft->day	= wtime->tm_mday;
	eft->hour	= wtime->tm_hour;
	eft->minute	= wtime->tm_min;
	eft->second 	= wtime->tm_sec;
	eft->nanosecond = 0; 
	eft->daylight	= wtime->tm_isdst ? EFI_ISDST: 0;
	eft->timezone	= EFI_UNSPECIFIED_TIMEZONE;
}

static void
convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
{
	memset(wtime, 0, sizeof(*wtime));
	wtime->tm_sec  = eft->second;
	wtime->tm_min  = eft->minute;
	wtime->tm_hour = eft->hour;
	wtime->tm_mday = eft->day;
	wtime->tm_mon  = eft->month - 1;
	wtime->tm_year = eft->year - 1900;

	/* day of the week [0-6], Sunday=0 */
	wtime->tm_wday = compute_wday(eft);

	/* day in the year [1-365]*/
	wtime->tm_yday = compute_yday(eft);


	switch (eft->daylight & EFI_ISDST) {
		case EFI_ISDST:
			wtime->tm_isdst = 1;
			break;
		case EFI_TIME_ADJUST_DAYLIGHT:
			wtime->tm_isdst = 0;
			break;
		default:
			wtime->tm_isdst = -1;
	}
}

static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{

	efi_status_t	status;
	unsigned long	flags;
	efi_time_t	eft;
	efi_time_cap_t	cap;
	struct rtc_time	wtime;
	struct rtc_wkalrm __user *ewp;
	unsigned char	enabled, pending;

	switch (cmd) {
		case RTC_UIE_ON:
		case RTC_UIE_OFF:
		case RTC_PIE_ON:
		case RTC_PIE_OFF:
		case RTC_AIE_ON:
		case RTC_AIE_OFF:
		case RTC_ALM_SET:
		case RTC_ALM_READ:
		case RTC_IRQP_READ:
		case RTC_IRQP_SET:
		case RTC_EPOCH_READ:
		case RTC_EPOCH_SET:
			return -EINVAL;

		case RTC_RD_TIME:
			spin_lock_irqsave(&efi_rtc_lock, flags);

			status = efi.get_time(&eft, &cap);

			spin_unlock_irqrestore(&efi_rtc_lock,flags);

			if (status != EFI_SUCCESS) {
				/* should never happen */
				printk(KERN_ERR "efitime: can't read time\n");
				return -EINVAL;
			}

			convert_from_efi_time(&eft, &wtime);

 			return copy_to_user((void __user *)arg, &wtime,
					    sizeof (struct rtc_time)) ? - EFAULT : 0;

		case RTC_SET_TIME:

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

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

			convert_to_efi_time(&wtime, &eft);

			spin_lock_irqsave(&efi_rtc_lock, flags);

			status = efi.set_time(&eft);

			spin_unlock_irqrestore(&efi_rtc_lock,flags);

			return status == EFI_SUCCESS ? 0 : -EINVAL;

		case RTC_WKALM_SET:

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

			ewp = (struct rtc_wkalrm __user *)arg;

			if (  get_user(enabled, &ewp->enabled)
			   || copy_from_user(&wtime, &ewp->time, sizeof(struct rtc_time)) )
				return -EFAULT;

			convert_to_efi_time(&wtime, &eft);

			spin_lock_irqsave(&efi_rtc_lock, flags);
			/*
			 * XXX Fixme:
			 * As of EFI 0.92 with the firmware I have on my
			 * machine this call does not seem to work quite
			 * right
			 */
			status = efi.set_wakeup_time((efi_bool_t)enabled, &eft);

			spin_unlock_irqrestore(&efi_rtc_lock,flags);

			return status == EFI_SUCCESS ? 0 : -EINVAL;

		case RTC_WKALM_RD:

			spin_lock_irqsave(&efi_rtc_lock, flags);

			status = efi.get_wakeup_time((efi_bool_t *)&enabled, (efi_bool_t *)&pending, &eft);

			spin_unlock_irqrestore(&efi_rtc_lock,flags);

			if (status != EFI_SUCCESS) return -EINVAL;

			ewp = (struct rtc_wkalrm __user *)arg;

			if (  put_user(enabled, &ewp->enabled)
			   || put_user(pending, &ewp->pending)) return -EFAULT;

			convert_from_efi_time(&eft, &wtime);

			return copy_to_user(&ewp->time, &wtime,
					    sizeof(struct rtc_time)) ? -EFAULT : 0;
	}
	return -ENOTTY;
}

/*
 *	We enforce only one user at a time here with the open/close.
 *	Also clear the previous interrupt data on an open, and clean
 *	up things on a close.
 */

static int efi_rtc_open(struct inode *inode, struct file *file)
{
	/*
	 * nothing special to do here
	 * We do accept multiple open files at the same time as we
	 * synchronize on the per call operation.
	 */
	return 0;
}

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

/*
 *	The various file operations we support.
 */

static const struct file_operations efi_rtc_fops = {
	.owner		= THIS_MODULE,
	.unlocked_ioctl	= efi_rtc_ioctl,
	.open		= efi_rtc_open,
	.release	= efi_rtc_close,
	.llseek		= no_llseek,
};

static struct miscdevice efi_rtc_dev= {
	EFI_RTC_MINOR,
	"efirtc",
	&efi_rtc_fops
};

/*
 *	We export RAW EFI information to /proc/driver/efirtc
 */
static int efi_rtc_proc_show(struct seq_file *m, void *v)
{
	efi_time_t 	eft, alm;
	efi_time_cap_t	cap;
	efi_bool_t	enabled, pending;	
	unsigned long	flags;

	memset(&eft, 0, sizeof(eft));
	memset(&alm, 0, sizeof(alm));
	memset(&cap, 0, sizeof(cap));

	spin_lock_irqsave(&efi_rtc_lock, flags);

	efi.get_time(&eft, &cap);
	efi.get_wakeup_time(&enabled, &pending, &alm);

	spin_unlock_irqrestore(&efi_rtc_lock,flags);

	seq_printf(m,
		   "Time           : %u:%u:%u.%09u\n"
		   "Date           : %u-%u-%u\n"
		   "Daylight       : %u\n",
		   eft.hour, eft.minute, eft.second, eft.nanosecond, 
		   eft.year, eft.month, eft.day,
		   eft.daylight);

	if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
		seq_puts(m, "Timezone       : unspecified\n");
	else
		/* XXX fixme: convert to string? */
		seq_printf(m, "Timezone       : %u\n", eft.timezone);
		

	seq_printf(m,
		   "Alarm Time     : %u:%u:%u.%09u\n"
		   "Alarm Date     : %u-%u-%u\n"
		   "Alarm Daylight : %u\n"
		   "Enabled        : %s\n"
		   "Pending        : %s\n",
		   alm.hour, alm.minute, alm.second, alm.nanosecond, 
		   alm.year, alm.month, alm.day, 
		   alm.daylight,
		   enabled == 1 ? "yes" : "no",
		   pending == 1 ? "yes" : "no");

	if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
		seq_puts(m, "Timezone       : unspecified\n");
	else
		/* XXX fixme: convert to string? */
		seq_printf(m, "Timezone       : %u\n", alm.timezone);

	/*
	 * now prints the capabilities
	 */
	seq_printf(m,
		   "Resolution     : %u\n"
		   "Accuracy       : %u\n"
		   "SetstoZero     : %u\n",
		   cap.resolution, cap.accuracy, cap.sets_to_zero);

	return 0;
}

static int efi_rtc_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, efi_rtc_proc_show, NULL);
}

static const struct file_operations efi_rtc_proc_fops = {
	.open		= efi_rtc_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int __init 
efi_rtc_init(void)
{
	int ret;
	struct proc_dir_entry *dir;

	printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);

	ret = misc_register(&efi_rtc_dev);
	if (ret) {
		printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
				EFI_RTC_MINOR);
		return ret;
	}

	dir = proc_create("driver/efirtc", 0, NULL, &efi_rtc_proc_fops);
	if (dir == NULL) {
		printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
		misc_deregister(&efi_rtc_dev);
		return -1;
	}
	return 0;
}

static void __exit
efi_rtc_exit(void)
{
	/* not yet used */
}

module_init(efi_rtc_init);
module_exit(efi_rtc_exit);

MODULE_LICENSE("GPL");