1/*
2 *	Real Time Clock interface for
3 *		- q40 and other m68k machines,
4 *		- HP PARISC machines
5 *		- PowerPC machines
6 *      emulate some RTC irq capabilities in software
7 *
8 *      Copyright (C) 1999 Richard Zidlicky
9 *
10 *	based on Paul Gortmaker's rtc.c device and
11 *           Sam Creasey Generic rtc driver
12 *
13 *	This driver allows use of the real time clock (built into
14 *	nearly all computers) from user space. It exports the /dev/rtc
15 *	interface supporting various ioctl() and also the /proc/driver/rtc
16 *	pseudo-file for status information.
17 *
18 *	The ioctls can be used to set the interrupt behaviour where
19 *	supported.
20 *
21 *	The /dev/rtc interface will block on reads until an interrupt
22 *	has been received. If a RTC interrupt has already happened,
23 *	it will output an unsigned long and then block. The output value
24 *	contains the interrupt status in the low byte and the number of
25 *	interrupts since the last read in the remaining high bytes. The
26 *	/dev/rtc interface can also be used with the select(2) call.
27 *
28 *	This program is free software; you can redistribute it and/or
29 *	modify it under the terms of the GNU General Public License
30 *	as published by the Free Software Foundation; either version
31 *	2 of the License, or (at your option) any later version.
32 *
33
34 *      1.01 fix for 2.3.X                    rz@linux-m68k.org
35 *      1.02 merged with code from genrtc.c   rz@linux-m68k.org
36 *      1.03 make it more portable            zippel@linux-m68k.org
37 *      1.04 removed useless timer code       rz@linux-m68k.org
38 *      1.05 portable RTC_UIE emulation       rz@linux-m68k.org
39 *      1.06 set_rtc_time can return an error trini@kernel.crashing.org
40 *      1.07 ported to HP PARISC (hppa)	      Helge Deller <deller@gmx.de>
41 */
42
43#define RTC_VERSION	"1.07"
44
45#include <linux/module.h>
46#include <linux/errno.h>
47#include <linux/miscdevice.h>
48#include <linux/fcntl.h>
49
50#include <linux/rtc.h>
51#include <linux/init.h>
52#include <linux/poll.h>
53#include <linux/proc_fs.h>
54#include <linux/workqueue.h>
55
56#include <asm/uaccess.h>
57#include <asm/system.h>
58#include <asm/rtc.h>
59
60/*
61 *	We sponge a minor off of the misc major. No need slurping
62 *	up another valuable major dev number for this. If you add
63 *	an ioctl, make sure you don't conflict with SPARC's RTC
64 *	ioctls.
65 */
66
67static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait);
68
69/*
70 *	Bits in gen_rtc_status.
71 */
72
73#define RTC_IS_OPEN		0x01	/* means /dev/rtc is in use	*/
74
75static unsigned char gen_rtc_status;	/* bitmapped status byte.	*/
76static unsigned long gen_rtc_irq_data;	/* our output to the world	*/
77
78/* months start at 0 now */
79static unsigned char days_in_mo[] =
80{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
81
82static int irq_active;
83
84#ifdef CONFIG_GEN_RTC_X
85static struct work_struct genrtc_task;
86static struct timer_list timer_task;
87
88static unsigned int oldsecs;
89static int lostint;
90static unsigned long tt_exp;
91
92static void gen_rtc_timer(unsigned long data);
93
94static volatile int stask_active;              /* schedule_work */
95static volatile int ttask_active;              /* timer_task */
96static int stop_rtc_timers;                    /* don't requeue tasks */
97static DEFINE_SPINLOCK(gen_rtc_lock);
98
99static void gen_rtc_interrupt(unsigned long arg);
100
101/*
102 * Routine to poll RTC seconds field for change as often as possible,
103 * after first RTC_UIE use timer to reduce polling
104 */
105static void genrtc_troutine(struct work_struct *work)
106{
107	unsigned int tmp = get_rtc_ss();
108
109	if (stop_rtc_timers) {
110		stask_active = 0;
111		return;
112	}
113
114	if (oldsecs != tmp){
115		oldsecs = tmp;
116
117		timer_task.function = gen_rtc_timer;
118		timer_task.expires = jiffies + HZ - (HZ/10);
119		tt_exp=timer_task.expires;
120		ttask_active=1;
121		stask_active=0;
122		add_timer(&timer_task);
123
124		gen_rtc_interrupt(0);
125	} else if (schedule_work(&genrtc_task) == 0)
126		stask_active = 0;
127}
128
129static void gen_rtc_timer(unsigned long data)
130{
131	lostint = get_rtc_ss() - oldsecs ;
132	if (lostint<0)
133		lostint = 60 - lostint;
134	if (time_after(jiffies, tt_exp))
135		printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n",
136		       jiffies-tt_exp);
137	ttask_active=0;
138	stask_active=1;
139	if ((schedule_work(&genrtc_task) == 0))
140		stask_active = 0;
141}
142
143/*
144 * call gen_rtc_interrupt function to signal an RTC_UIE,
145 * arg is unused.
146 * Could be invoked either from a real interrupt handler or
147 * from some routine that periodically (eg 100HZ) monitors
148 * whether RTC_SECS changed
149 */
150static void gen_rtc_interrupt(unsigned long arg)
151{
152	/*  We store the status in the low byte and the number of
153	 *	interrupts received since the last read in the remainder
154	 *	of rtc_irq_data.  */
155
156	gen_rtc_irq_data += 0x100;
157	gen_rtc_irq_data &= ~0xff;
158	gen_rtc_irq_data |= RTC_UIE;
159
160	if (lostint){
161		printk("genrtc: system delaying clock ticks?\n");
162		/* increment count so that userspace knows something is wrong */
163		gen_rtc_irq_data += ((lostint-1)<<8);
164		lostint = 0;
165	}
166
167	wake_up_interruptible(&gen_rtc_wait);
168}
169
170/*
171 *	Now all the various file operations that we export.
172 */
173static ssize_t gen_rtc_read(struct file *file, char __user *buf,
174			size_t count, loff_t *ppos)
175{
176	DECLARE_WAITQUEUE(wait, current);
177	unsigned long data;
178	ssize_t retval;
179
180	if (count != sizeof (unsigned int) && count != sizeof (unsigned long))
181		return -EINVAL;
182
183	if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data)
184		return -EAGAIN;
185
186	add_wait_queue(&gen_rtc_wait, &wait);
187	retval = -ERESTARTSYS;
188
189	while (1) {
190		set_current_state(TASK_INTERRUPTIBLE);
191		data = xchg(&gen_rtc_irq_data, 0);
192		if (data)
193			break;
194		if (signal_pending(current))
195			goto out;
196		schedule();
197	}
198
199	/* first test allows optimizer to nuke this case for 32-bit machines */
200	if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) {
201		unsigned int uidata = data;
202		retval = put_user(uidata, (unsigned int __user *)buf) ?:
203			sizeof(unsigned int);
204	}
205	else {
206		retval = put_user(data, (unsigned long __user *)buf) ?:
207			sizeof(unsigned long);
208	}
209 out:
210	__set_current_state(TASK_RUNNING);
211	remove_wait_queue(&gen_rtc_wait, &wait);
212
213	return retval;
214}
215
216static unsigned int gen_rtc_poll(struct file *file,
217				 struct poll_table_struct *wait)
218{
219	poll_wait(file, &gen_rtc_wait, wait);
220	if (gen_rtc_irq_data != 0)
221		return POLLIN | POLLRDNORM;
222	return 0;
223}
224
225#endif
226
227/*
228 * Used to disable/enable interrupts, only RTC_UIE supported
229 * We also clear out any old irq data after an ioctl() that
230 * meddles with the interrupt enable/disable bits.
231 */
232
233static inline void gen_clear_rtc_irq_bit(unsigned char bit)
234{
235#ifdef CONFIG_GEN_RTC_X
236	stop_rtc_timers = 1;
237	if (ttask_active){
238		del_timer_sync(&timer_task);
239		ttask_active = 0;
240	}
241	while (stask_active)
242		schedule();
243
244	spin_lock(&gen_rtc_lock);
245	irq_active = 0;
246	spin_unlock(&gen_rtc_lock);
247#endif
248}
249
250static inline int gen_set_rtc_irq_bit(unsigned char bit)
251{
252#ifdef CONFIG_GEN_RTC_X
253	spin_lock(&gen_rtc_lock);
254	if ( !irq_active ) {
255		irq_active = 1;
256		stop_rtc_timers = 0;
257		lostint = 0;
258		INIT_WORK(&genrtc_task, genrtc_troutine);
259		oldsecs = get_rtc_ss();
260		init_timer(&timer_task);
261
262		stask_active = 1;
263		if (schedule_work(&genrtc_task) == 0){
264			stask_active = 0;
265		}
266	}
267	spin_unlock(&gen_rtc_lock);
268	gen_rtc_irq_data = 0;
269	return 0;
270#else
271	return -EINVAL;
272#endif
273}
274
275static int gen_rtc_ioctl(struct inode *inode, struct file *file,
276			 unsigned int cmd, unsigned long arg)
277{
278	struct rtc_time wtime;
279	struct rtc_pll_info pll;
280	void __user *argp = (void __user *)arg;
281
282	switch (cmd) {
283
284	case RTC_PLL_GET:
285	    if (get_rtc_pll(&pll))
286	 	    return -EINVAL;
287	    else
288		    return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;
289
290	case RTC_PLL_SET:
291		if (!capable(CAP_SYS_TIME))
292			return -EACCES;
293		if (copy_from_user(&pll, argp, sizeof(pll)))
294			return -EFAULT;
295	    return set_rtc_pll(&pll);
296
297	case RTC_UIE_OFF:	/* disable ints from RTC updates.	*/
298		gen_clear_rtc_irq_bit(RTC_UIE);
299		return 0;
300
301	case RTC_UIE_ON:	/* enable ints for RTC updates.	*/
302	        return gen_set_rtc_irq_bit(RTC_UIE);
303
304	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
305		/* this doesn't get week-day, who cares */
306		memset(&wtime, 0, sizeof(wtime));
307		get_rtc_time(&wtime);
308
309		return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0;
310
311	case RTC_SET_TIME:	/* Set the RTC */
312	    {
313		int year;
314		unsigned char leap_yr;
315
316		if (!capable(CAP_SYS_TIME))
317			return -EACCES;
318
319		if (copy_from_user(&wtime, argp, sizeof(wtime)))
320			return -EFAULT;
321
322		year = wtime.tm_year + 1900;
323		leap_yr = ((!(year % 4) && (year % 100)) ||
324			   !(year % 400));
325
326		if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1))
327			return -EINVAL;
328
329		if (wtime.tm_mday < 0 || wtime.tm_mday >
330		    (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr)))
331			return -EINVAL;
332
333		if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 ||
334		    wtime.tm_min < 0 || wtime.tm_min >= 60 ||
335		    wtime.tm_sec < 0 || wtime.tm_sec >= 60)
336			return -EINVAL;
337
338		return set_rtc_time(&wtime);
339	    }
340	}
341
342	return -EINVAL;
343}
344
345/*
346 *	We enforce only one user at a time here with the open/close.
347 *	Also clear the previous interrupt data on an open, and clean
348 *	up things on a close.
349 */
350
351static int gen_rtc_open(struct inode *inode, struct file *file)
352{
353	if (gen_rtc_status & RTC_IS_OPEN)
354		return -EBUSY;
355
356	gen_rtc_status |= RTC_IS_OPEN;
357	gen_rtc_irq_data = 0;
358	irq_active = 0;
359
360	return 0;
361}
362
363static int gen_rtc_release(struct inode *inode, struct file *file)
364{
365	/*
366	 * Turn off all interrupts once the device is no longer
367	 * in use and clear the data.
368	 */
369
370	gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
371
372	gen_rtc_status &= ~RTC_IS_OPEN;
373	return 0;
374}
375
376
377#ifdef CONFIG_PROC_FS
378
379/*
380 *	Info exported via "/proc/driver/rtc".
381 */
382
383static int gen_rtc_proc_output(char *buf)
384{
385	char *p;
386	struct rtc_time tm;
387	unsigned int flags;
388	struct rtc_pll_info pll;
389
390	p = buf;
391
392	flags = get_rtc_time(&tm);
393
394	p += sprintf(p,
395		     "rtc_time\t: %02d:%02d:%02d\n"
396		     "rtc_date\t: %04d-%02d-%02d\n"
397		     "rtc_epoch\t: %04u\n",
398		     tm.tm_hour, tm.tm_min, tm.tm_sec,
399		     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900);
400
401	tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
402
403	p += sprintf(p, "alarm\t\t: ");
404	if (tm.tm_hour <= 24)
405		p += sprintf(p, "%02d:", tm.tm_hour);
406	else
407		p += sprintf(p, "**:");
408
409	if (tm.tm_min <= 59)
410		p += sprintf(p, "%02d:", tm.tm_min);
411	else
412		p += sprintf(p, "**:");
413
414	if (tm.tm_sec <= 59)
415		p += sprintf(p, "%02d\n", tm.tm_sec);
416	else
417		p += sprintf(p, "**\n");
418
419	p += sprintf(p,
420		     "DST_enable\t: %s\n"
421		     "BCD\t\t: %s\n"
422		     "24hr\t\t: %s\n"
423		     "square_wave\t: %s\n"
424		     "alarm_IRQ\t: %s\n"
425		     "update_IRQ\t: %s\n"
426		     "periodic_IRQ\t: %s\n"
427		     "periodic_freq\t: %ld\n"
428		     "batt_status\t: %s\n",
429		     (flags & RTC_DST_EN) ? "yes" : "no",
430		     (flags & RTC_DM_BINARY) ? "no" : "yes",
431		     (flags & RTC_24H) ? "yes" : "no",
432		     (flags & RTC_SQWE) ? "yes" : "no",
433		     (flags & RTC_AIE) ? "yes" : "no",
434		     irq_active ? "yes" : "no",
435		     (flags & RTC_PIE) ? "yes" : "no",
436		     0L /* freq */,
437		     (flags & RTC_BATT_BAD) ? "bad" : "okay");
438	if (!get_rtc_pll(&pll))
439	    p += sprintf(p,
440			 "PLL adjustment\t: %d\n"
441			 "PLL max +ve adjustment\t: %d\n"
442			 "PLL max -ve adjustment\t: %d\n"
443			 "PLL +ve adjustment factor\t: %d\n"
444			 "PLL -ve adjustment factor\t: %d\n"
445			 "PLL frequency\t: %ld\n",
446			 pll.pll_value,
447			 pll.pll_max,
448			 pll.pll_min,
449			 pll.pll_posmult,
450			 pll.pll_negmult,
451			 pll.pll_clock);
452	return p - buf;
453}
454
455static int gen_rtc_read_proc(char *page, char **start, off_t off,
456			     int count, int *eof, void *data)
457{
458	int len = gen_rtc_proc_output (page);
459        if (len <= off+count) *eof = 1;
460	*start = page + off;
461	len -= off;
462        if (len>count) len = count;
463        if (len<0) len = 0;
464	return len;
465}
466
467static int __init gen_rtc_proc_init(void)
468{
469	struct proc_dir_entry *r;
470
471	r = create_proc_read_entry("driver/rtc", 0, NULL, gen_rtc_read_proc, NULL);
472	if (!r)
473		return -ENOMEM;
474	return 0;
475}
476#else
477static inline int gen_rtc_proc_init(void) { return 0; }
478#endif /* CONFIG_PROC_FS */
479
480
481/*
482 *	The various file operations we support.
483 */
484
485static const struct file_operations gen_rtc_fops = {
486	.owner		= THIS_MODULE,
487#ifdef CONFIG_GEN_RTC_X
488	.read		= gen_rtc_read,
489	.poll		= gen_rtc_poll,
490#endif
491	.ioctl		= gen_rtc_ioctl,
492	.open		= gen_rtc_open,
493	.release	= gen_rtc_release,
494};
495
496static struct miscdevice rtc_gen_dev =
497{
498	.minor		= RTC_MINOR,
499	.name		= "rtc",
500	.fops		= &gen_rtc_fops,
501};
502
503static int __init rtc_generic_init(void)
504{
505	int retval;
506
507	printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION);
508
509	retval = misc_register(&rtc_gen_dev);
510	if (retval < 0)
511		return retval;
512
513	retval = gen_rtc_proc_init();
514	if (retval) {
515		misc_deregister(&rtc_gen_dev);
516		return retval;
517	}
518
519	return 0;
520}
521
522static void __exit rtc_generic_exit(void)
523{
524	remove_proc_entry ("driver/rtc", NULL);
525	misc_deregister(&rtc_gen_dev);
526}
527
528
529module_init(rtc_generic_init);
530module_exit(rtc_generic_exit);
531
532MODULE_AUTHOR("Richard Zidlicky");
533MODULE_LICENSE("GPL");
534MODULE_ALIAS_MISCDEV(RTC_MINOR);
535