summaryrefslogtreecommitdiff
path: root/drivers/char/genrtc.c
blob: bc9b84d56ee4aed6f8e83ede52039f6f5ffa0def (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
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
/*
 *	Real Time Clock interface for
 *		- q40 and other m68k machines,
 *		- HP PARISC machines
 *		- PowerPC machines
 *      emulate some RTC irq capabilities in software
 *
 *      Copyright (C) 1999 Richard Zidlicky
 *
 *	based on Paul Gortmaker's rtc.c device and
 *           Sam Creasey Generic rtc driver
 *
 *	This driver allows use of the real time clock (built into
 *	nearly all computers) from user space. It exports the /dev/rtc
 *	interface supporting various ioctl() and also the /proc/driver/rtc
 *	pseudo-file for status information.
 *
 *	The ioctls can be used to set the interrupt behaviour where
 *	supported.
 *
 *	The /dev/rtc interface will block on reads until an interrupt
 *	has been received. If a RTC interrupt has already happened,
 *	it will output an unsigned long and then block. The output value
 *	contains the interrupt status in the low byte and the number of
 *	interrupts since the last read in the remaining high bytes. The
 *	/dev/rtc interface can also be used with the select(2) call.
 *
 *	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.
 *

 *      1.01 fix for 2.3.X                    rz@linux-m68k.org
 *      1.02 merged with code from genrtc.c   rz@linux-m68k.org
 *      1.03 make it more portable            zippel@linux-m68k.org
 *      1.04 removed useless timer code       rz@linux-m68k.org
 *      1.05 portable RTC_UIE emulation       rz@linux-m68k.org
 *      1.06 set_rtc_time can return an error trini@kernel.crashing.org
 *      1.07 ported to HP PARISC (hppa)	      Helge Deller <deller@gmx.de>
 */

#define RTC_VERSION	"1.07"

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/fcntl.h>

#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>

#include <asm/uaccess.h>
#include <asm/rtc.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 DEFINE_MUTEX(gen_rtc_mutex);
static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait);

/*
 *	Bits in gen_rtc_status.
 */

#define RTC_IS_OPEN		0x01	/* means /dev/rtc is in use	*/

static unsigned char gen_rtc_status;	/* bitmapped status byte.	*/
static unsigned long gen_rtc_irq_data;	/* our output to the world	*/

/* months start at 0 now */
static unsigned char days_in_mo[] =
{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

static int irq_active;

#ifdef CONFIG_GEN_RTC_X
static struct work_struct genrtc_task;
static struct timer_list timer_task;

static unsigned int oldsecs;
static int lostint;
static unsigned long tt_exp;

static void gen_rtc_timer(unsigned long data);

static volatile int stask_active;              /* schedule_work */
static volatile int ttask_active;              /* timer_task */
static int stop_rtc_timers;                    /* don't requeue tasks */
static DEFINE_SPINLOCK(gen_rtc_lock);

static void gen_rtc_interrupt(unsigned long arg);

/*
 * Routine to poll RTC seconds field for change as often as possible,
 * after first RTC_UIE use timer to reduce polling
 */
static void genrtc_troutine(struct work_struct *work)
{
	unsigned int tmp = get_rtc_ss();
	
	if (stop_rtc_timers) {
		stask_active = 0;
		return;
	}

	if (oldsecs != tmp){
		oldsecs = tmp;

		timer_task.function = gen_rtc_timer;
		timer_task.expires = jiffies + HZ - (HZ/10);
		tt_exp=timer_task.expires;
		ttask_active=1;
		stask_active=0;
		add_timer(&timer_task);

		gen_rtc_interrupt(0);
	} else if (schedule_work(&genrtc_task) == 0)
		stask_active = 0;
}

static void gen_rtc_timer(unsigned long data)
{
	lostint = get_rtc_ss() - oldsecs ;
	if (lostint<0) 
		lostint = 60 - lostint;
	if (time_after(jiffies, tt_exp))
		printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n",
		       jiffies-tt_exp);
	ttask_active=0;
	stask_active=1;
	if ((schedule_work(&genrtc_task) == 0))
		stask_active = 0;
}

/* 
 * call gen_rtc_interrupt function to signal an RTC_UIE,
 * arg is unused.
 * Could be invoked either from a real interrupt handler or
 * from some routine that periodically (eg 100HZ) monitors
 * whether RTC_SECS changed
 */
static void gen_rtc_interrupt(unsigned long arg)
{
	/*  We store the status in the low byte and the number of
	 *	interrupts received since the last read in the remainder
	 *	of rtc_irq_data.  */

	gen_rtc_irq_data += 0x100;
	gen_rtc_irq_data &= ~0xff;
	gen_rtc_irq_data |= RTC_UIE;

	if (lostint){
		printk("genrtc: system delaying clock ticks?\n");
		/* increment count so that userspace knows something is wrong */
		gen_rtc_irq_data += ((lostint-1)<<8);
		lostint = 0;
	}

	wake_up_interruptible(&gen_rtc_wait);
}

/*
 *	Now all the various file operations that we export.
 */
static ssize_t gen_rtc_read(struct file *file, char __user *buf,
			size_t count, loff_t *ppos)
{
	unsigned long data;
	ssize_t retval;

	if (count != sizeof (unsigned int) && count != sizeof (unsigned long))
		return -EINVAL;

	if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data)
		return -EAGAIN;

	retval = wait_event_interruptible(gen_rtc_wait,
			(data = xchg(&gen_rtc_irq_data, 0)));
	if (retval)
		goto out;

	/* first test allows optimizer to nuke this case for 32-bit machines */
	if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) {
		unsigned int uidata = data;
		retval = put_user(uidata, (unsigned int __user *)buf) ?:
			sizeof(unsigned int);
	}
	else {
		retval = put_user(data, (unsigned long __user *)buf) ?:
			sizeof(unsigned long);
	}
out:
	return retval;
}

static unsigned int gen_rtc_poll(struct file *file,
				 struct poll_table_struct *wait)
{
	poll_wait(file, &gen_rtc_wait, wait);
	if (gen_rtc_irq_data != 0)
		return POLLIN | POLLRDNORM;
	return 0;
}

#endif

/*
 * Used to disable/enable interrupts, only RTC_UIE supported
 * We also clear out any old irq data after an ioctl() that
 * meddles with the interrupt enable/disable bits.
 */

static inline void gen_clear_rtc_irq_bit(unsigned char bit)
{
#ifdef CONFIG_GEN_RTC_X
	stop_rtc_timers = 1;
	if (ttask_active){
		del_timer_sync(&timer_task);
		ttask_active = 0;
	}
	while (stask_active)
		schedule();

	spin_lock(&gen_rtc_lock);
	irq_active = 0;
	spin_unlock(&gen_rtc_lock);
#endif
}

static inline int gen_set_rtc_irq_bit(unsigned char bit)
{
#ifdef CONFIG_GEN_RTC_X
	spin_lock(&gen_rtc_lock);
	if ( !irq_active ) {
		irq_active = 1;
		stop_rtc_timers = 0;
		lostint = 0;
		INIT_WORK(&genrtc_task, genrtc_troutine);
		oldsecs = get_rtc_ss();
		init_timer(&timer_task);

		stask_active = 1;
		if (schedule_work(&genrtc_task) == 0){
			stask_active = 0;
		}
	}
	spin_unlock(&gen_rtc_lock);
	gen_rtc_irq_data = 0;
	return 0;
#else
	return -EINVAL;
#endif
}

static int gen_rtc_ioctl(struct file *file,
			 unsigned int cmd, unsigned long arg)
{
	struct rtc_time wtime;
	struct rtc_pll_info pll;
	void __user *argp = (void __user *)arg;

	switch (cmd) {

	case RTC_PLL_GET:
	    if (get_rtc_pll(&pll))
	 	    return -EINVAL;
	    else
		    return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;

	case RTC_PLL_SET:
		if (!capable(CAP_SYS_TIME))
			return -EACCES;
		if (copy_from_user(&pll, argp, sizeof(pll)))
			return -EFAULT;
	    return set_rtc_pll(&pll);

	case RTC_UIE_OFF:	/* disable ints from RTC updates.	*/
		gen_clear_rtc_irq_bit(RTC_UIE);
		return 0;

	case RTC_UIE_ON:	/* enable ints for RTC updates.	*/
	        return gen_set_rtc_irq_bit(RTC_UIE);

	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
		/* this doesn't get week-day, who cares */
		memset(&wtime, 0, sizeof(wtime));
		get_rtc_time(&wtime);

		return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0;

	case RTC_SET_TIME:	/* Set the RTC */
	    {
		int year;
		unsigned char leap_yr;

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

		if (copy_from_user(&wtime, argp, sizeof(wtime)))
			return -EFAULT;

		year = wtime.tm_year + 1900;
		leap_yr = ((!(year % 4) && (year % 100)) ||
			   !(year % 400));

		if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1))
			return -EINVAL;

		if (wtime.tm_mday < 0 || wtime.tm_mday >
		    (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr)))
			return -EINVAL;

		if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 ||
		    wtime.tm_min < 0 || wtime.tm_min >= 60 ||
		    wtime.tm_sec < 0 || wtime.tm_sec >= 60)
			return -EINVAL;

		return set_rtc_time(&wtime);
	    }
	}

	return -EINVAL;
}

static long gen_rtc_unlocked_ioctl(struct file *file, unsigned int cmd,
				   unsigned long arg)
{
	int ret;

	mutex_lock(&gen_rtc_mutex);
	ret = gen_rtc_ioctl(file, cmd, arg);
	mutex_unlock(&gen_rtc_mutex);

	return ret;
}

/*
 *	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 gen_rtc_open(struct inode *inode, struct file *file)
{
	mutex_lock(&gen_rtc_mutex);
	if (gen_rtc_status & RTC_IS_OPEN) {
		mutex_unlock(&gen_rtc_mutex);
		return -EBUSY;
	}

	gen_rtc_status |= RTC_IS_OPEN;
	gen_rtc_irq_data = 0;
	irq_active = 0;
	mutex_unlock(&gen_rtc_mutex);

	return 0;
}

static int gen_rtc_release(struct inode *inode, struct file *file)
{
	/*
	 * Turn off all interrupts once the device is no longer
	 * in use and clear the data.
	 */

	gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);

	gen_rtc_status &= ~RTC_IS_OPEN;
	return 0;
}


#ifdef CONFIG_PROC_FS

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

static int gen_rtc_proc_show(struct seq_file *m, void *v)
{
	struct rtc_time tm;
	unsigned int flags;
	struct rtc_pll_info pll;

	flags = get_rtc_time(&tm);

	seq_printf(m,
		     "rtc_time\t: %02d:%02d:%02d\n"
		     "rtc_date\t: %04d-%02d-%02d\n"
		     "rtc_epoch\t: %04u\n",
		     tm.tm_hour, tm.tm_min, tm.tm_sec,
		     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900);

	tm.tm_hour = tm.tm_min = tm.tm_sec = 0;

	seq_puts(m, "alarm\t\t: ");
	if (tm.tm_hour <= 24)
		seq_printf(m, "%02d:", tm.tm_hour);
	else
		seq_puts(m, "**:");

	if (tm.tm_min <= 59)
		seq_printf(m, "%02d:", tm.tm_min);
	else
		seq_puts(m, "**:");

	if (tm.tm_sec <= 59)
		seq_printf(m, "%02d\n", tm.tm_sec);
	else
		seq_puts(m, "**\n");

	seq_printf(m,
		     "DST_enable\t: %s\n"
		     "BCD\t\t: %s\n"
		     "24hr\t\t: %s\n"
		     "square_wave\t: %s\n"
		     "alarm_IRQ\t: %s\n"
		     "update_IRQ\t: %s\n"
		     "periodic_IRQ\t: %s\n"
		     "periodic_freq\t: %ld\n"
		     "batt_status\t: %s\n",
		     (flags & RTC_DST_EN) ? "yes" : "no",
		     (flags & RTC_DM_BINARY) ? "no" : "yes",
		     (flags & RTC_24H) ? "yes" : "no",
		     (flags & RTC_SQWE) ? "yes" : "no",
		     (flags & RTC_AIE) ? "yes" : "no",
		     irq_active ? "yes" : "no",
		     (flags & RTC_PIE) ? "yes" : "no",
		     0L /* freq */,
		     (flags & RTC_BATT_BAD) ? "bad" : "okay");
	if (!get_rtc_pll(&pll))
	    seq_printf(m,
			 "PLL adjustment\t: %d\n"
			 "PLL max +ve adjustment\t: %d\n"
			 "PLL max -ve adjustment\t: %d\n"
			 "PLL +ve adjustment factor\t: %d\n"
			 "PLL -ve adjustment factor\t: %d\n"
			 "PLL frequency\t: %ld\n",
			 pll.pll_value,
			 pll.pll_max,
			 pll.pll_min,
			 pll.pll_posmult,
			 pll.pll_negmult,
			 pll.pll_clock);
	return 0;
}

static int gen_rtc_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, gen_rtc_proc_show, NULL);
}

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

static int __init gen_rtc_proc_init(void)
{
	struct proc_dir_entry *r;

	r = proc_create("driver/rtc", 0, NULL, &gen_rtc_proc_fops);
	if (!r)
		return -ENOMEM;
	return 0;
}
#else
static inline int gen_rtc_proc_init(void) { return 0; }
#endif /* CONFIG_PROC_FS */


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

static const struct file_operations gen_rtc_fops = {
	.owner		= THIS_MODULE,
#ifdef CONFIG_GEN_RTC_X
	.read		= gen_rtc_read,
	.poll		= gen_rtc_poll,
#endif
	.unlocked_ioctl	= gen_rtc_unlocked_ioctl,
	.open		= gen_rtc_open,
	.release	= gen_rtc_release,
	.llseek		= noop_llseek,
};

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

static int __init rtc_generic_init(void)
{
	int retval;

	printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION);

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

	retval = gen_rtc_proc_init();
	if (retval) {
		misc_deregister(&rtc_gen_dev);
		return retval;
	}

	return 0;
}

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


module_init(rtc_generic_init);
module_exit(rtc_generic_exit);

MODULE_AUTHOR("Richard Zidlicky");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(RTC_MINOR);