blob: 31e7c91c2d9d25679a63b2b792bfbbd534e6166a [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Robert P. J. Dayc685ce02007-05-09 07:21:11 +020015 * interface supporting various ioctl() and also the /proc/driver/rtc
Linus Torvalds1da177e2005-04-16 15:20:36 -070016 * 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>
Ingo Molnar86ae13b2009-10-12 16:22:46 +020046#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/errno.h>
48#include <linux/miscdevice.h>
49#include <linux/fcntl.h>
50
51#include <linux/rtc.h>
52#include <linux/init.h>
53#include <linux/poll.h>
54#include <linux/proc_fs.h>
Arnd Bergmann742a2fe2008-05-20 19:15:55 +020055#include <linux/smp_lock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070056#include <linux/workqueue.h>
57
58#include <asm/uaccess.h>
59#include <asm/system.h>
60#include <asm/rtc.h>
61
62/*
63 * We sponge a minor off of the misc major. No need slurping
64 * up another valuable major dev number for this. If you add
65 * an ioctl, make sure you don't conflict with SPARC's RTC
66 * ioctls.
67 */
68
69static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait);
70
71/*
72 * Bits in gen_rtc_status.
73 */
74
75#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
76
77static unsigned char gen_rtc_status; /* bitmapped status byte. */
78static unsigned long gen_rtc_irq_data; /* our output to the world */
79
80/* months start at 0 now */
81static unsigned char days_in_mo[] =
82{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
83
84static int irq_active;
85
86#ifdef CONFIG_GEN_RTC_X
87static struct work_struct genrtc_task;
88static struct timer_list timer_task;
89
90static unsigned int oldsecs;
91static int lostint;
92static unsigned long tt_exp;
93
94static void gen_rtc_timer(unsigned long data);
95
96static volatile int stask_active; /* schedule_work */
97static volatile int ttask_active; /* timer_task */
98static int stop_rtc_timers; /* don't requeue tasks */
99static DEFINE_SPINLOCK(gen_rtc_lock);
100
101static void gen_rtc_interrupt(unsigned long arg);
102
103/*
104 * Routine to poll RTC seconds field for change as often as possible,
105 * after first RTC_UIE use timer to reduce polling
106 */
David Howellsc4028952006-11-22 14:57:56 +0000107static void genrtc_troutine(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
109 unsigned int tmp = get_rtc_ss();
110
111 if (stop_rtc_timers) {
112 stask_active = 0;
113 return;
114 }
115
116 if (oldsecs != tmp){
117 oldsecs = tmp;
118
119 timer_task.function = gen_rtc_timer;
120 timer_task.expires = jiffies + HZ - (HZ/10);
121 tt_exp=timer_task.expires;
122 ttask_active=1;
123 stask_active=0;
124 add_timer(&timer_task);
125
126 gen_rtc_interrupt(0);
127 } else if (schedule_work(&genrtc_task) == 0)
128 stask_active = 0;
129}
130
131static void gen_rtc_timer(unsigned long data)
132{
133 lostint = get_rtc_ss() - oldsecs ;
134 if (lostint<0)
135 lostint = 60 - lostint;
136 if (time_after(jiffies, tt_exp))
137 printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n",
138 jiffies-tt_exp);
139 ttask_active=0;
140 stask_active=1;
141 if ((schedule_work(&genrtc_task) == 0))
142 stask_active = 0;
143}
144
145/*
146 * call gen_rtc_interrupt function to signal an RTC_UIE,
147 * arg is unused.
148 * Could be invoked either from a real interrupt handler or
149 * from some routine that periodically (eg 100HZ) monitors
150 * whether RTC_SECS changed
151 */
152static void gen_rtc_interrupt(unsigned long arg)
153{
154 /* We store the status in the low byte and the number of
155 * interrupts received since the last read in the remainder
156 * of rtc_irq_data. */
157
158 gen_rtc_irq_data += 0x100;
159 gen_rtc_irq_data &= ~0xff;
160 gen_rtc_irq_data |= RTC_UIE;
161
162 if (lostint){
163 printk("genrtc: system delaying clock ticks?\n");
164 /* increment count so that userspace knows something is wrong */
165 gen_rtc_irq_data += ((lostint-1)<<8);
166 lostint = 0;
167 }
168
169 wake_up_interruptible(&gen_rtc_wait);
170}
171
172/*
173 * Now all the various file operations that we export.
174 */
175static ssize_t gen_rtc_read(struct file *file, char __user *buf,
176 size_t count, loff_t *ppos)
177{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 unsigned long data;
179 ssize_t retval;
180
181 if (count != sizeof (unsigned int) && count != sizeof (unsigned long))
182 return -EINVAL;
183
184 if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data)
185 return -EAGAIN;
186
Jiri Slabye0955e12007-07-15 23:40:19 -0700187 retval = wait_event_interruptible(gen_rtc_wait,
188 (data = xchg(&gen_rtc_irq_data, 0)));
189 if (retval)
190 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191
192 /* first test allows optimizer to nuke this case for 32-bit machines */
193 if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) {
194 unsigned int uidata = data;
Atsushi Nemotof3537ea2006-05-01 12:16:17 -0700195 retval = put_user(uidata, (unsigned int __user *)buf) ?:
196 sizeof(unsigned int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 }
198 else {
Atsushi Nemotof3537ea2006-05-01 12:16:17 -0700199 retval = put_user(data, (unsigned long __user *)buf) ?:
200 sizeof(unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 }
Jiri Slabye0955e12007-07-15 23:40:19 -0700202out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 return retval;
204}
205
206static unsigned int gen_rtc_poll(struct file *file,
207 struct poll_table_struct *wait)
208{
209 poll_wait(file, &gen_rtc_wait, wait);
210 if (gen_rtc_irq_data != 0)
211 return POLLIN | POLLRDNORM;
212 return 0;
213}
214
215#endif
216
217/*
218 * Used to disable/enable interrupts, only RTC_UIE supported
219 * We also clear out any old irq data after an ioctl() that
220 * meddles with the interrupt enable/disable bits.
221 */
222
223static inline void gen_clear_rtc_irq_bit(unsigned char bit)
224{
225#ifdef CONFIG_GEN_RTC_X
226 stop_rtc_timers = 1;
227 if (ttask_active){
228 del_timer_sync(&timer_task);
229 ttask_active = 0;
230 }
231 while (stask_active)
232 schedule();
233
234 spin_lock(&gen_rtc_lock);
235 irq_active = 0;
236 spin_unlock(&gen_rtc_lock);
237#endif
238}
239
240static inline int gen_set_rtc_irq_bit(unsigned char bit)
241{
242#ifdef CONFIG_GEN_RTC_X
243 spin_lock(&gen_rtc_lock);
244 if ( !irq_active ) {
245 irq_active = 1;
246 stop_rtc_timers = 0;
247 lostint = 0;
David Howellsc4028952006-11-22 14:57:56 +0000248 INIT_WORK(&genrtc_task, genrtc_troutine);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 oldsecs = get_rtc_ss();
250 init_timer(&timer_task);
251
252 stask_active = 1;
253 if (schedule_work(&genrtc_task) == 0){
254 stask_active = 0;
255 }
256 }
257 spin_unlock(&gen_rtc_lock);
258 gen_rtc_irq_data = 0;
259 return 0;
260#else
261 return -EINVAL;
262#endif
263}
264
265static int gen_rtc_ioctl(struct inode *inode, struct file *file,
266 unsigned int cmd, unsigned long arg)
267{
268 struct rtc_time wtime;
269 struct rtc_pll_info pll;
270 void __user *argp = (void __user *)arg;
271
272 switch (cmd) {
273
274 case RTC_PLL_GET:
275 if (get_rtc_pll(&pll))
276 return -EINVAL;
277 else
278 return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;
279
280 case RTC_PLL_SET:
281 if (!capable(CAP_SYS_TIME))
282 return -EACCES;
283 if (copy_from_user(&pll, argp, sizeof(pll)))
284 return -EFAULT;
285 return set_rtc_pll(&pll);
286
287 case RTC_UIE_OFF: /* disable ints from RTC updates. */
288 gen_clear_rtc_irq_bit(RTC_UIE);
289 return 0;
290
291 case RTC_UIE_ON: /* enable ints for RTC updates. */
292 return gen_set_rtc_irq_bit(RTC_UIE);
293
294 case RTC_RD_TIME: /* Read the time/date from RTC */
295 /* this doesn't get week-day, who cares */
296 memset(&wtime, 0, sizeof(wtime));
297 get_rtc_time(&wtime);
298
299 return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0;
300
301 case RTC_SET_TIME: /* Set the RTC */
302 {
303 int year;
304 unsigned char leap_yr;
305
306 if (!capable(CAP_SYS_TIME))
307 return -EACCES;
308
309 if (copy_from_user(&wtime, argp, sizeof(wtime)))
310 return -EFAULT;
311
312 year = wtime.tm_year + 1900;
313 leap_yr = ((!(year % 4) && (year % 100)) ||
314 !(year % 400));
315
316 if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1))
317 return -EINVAL;
318
319 if (wtime.tm_mday < 0 || wtime.tm_mday >
320 (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr)))
321 return -EINVAL;
322
323 if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 ||
324 wtime.tm_min < 0 || wtime.tm_min >= 60 ||
325 wtime.tm_sec < 0 || wtime.tm_sec >= 60)
326 return -EINVAL;
327
328 return set_rtc_time(&wtime);
329 }
330 }
331
332 return -EINVAL;
333}
334
335/*
336 * We enforce only one user at a time here with the open/close.
337 * Also clear the previous interrupt data on an open, and clean
338 * up things on a close.
339 */
340
341static int gen_rtc_open(struct inode *inode, struct file *file)
342{
Arnd Bergmann742a2fe2008-05-20 19:15:55 +0200343 lock_kernel();
344 if (gen_rtc_status & RTC_IS_OPEN) {
345 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 return -EBUSY;
Arnd Bergmann742a2fe2008-05-20 19:15:55 +0200347 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
349 gen_rtc_status |= RTC_IS_OPEN;
350 gen_rtc_irq_data = 0;
351 irq_active = 0;
Arnd Bergmann742a2fe2008-05-20 19:15:55 +0200352 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353
354 return 0;
355}
356
357static int gen_rtc_release(struct inode *inode, struct file *file)
358{
359 /*
360 * Turn off all interrupts once the device is no longer
361 * in use and clear the data.
362 */
363
364 gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
365
366 gen_rtc_status &= ~RTC_IS_OPEN;
367 return 0;
368}
369
370
371#ifdef CONFIG_PROC_FS
372
373/*
Robert P. J. Dayc685ce02007-05-09 07:21:11 +0200374 * Info exported via "/proc/driver/rtc".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 */
376
377static int gen_rtc_proc_output(char *buf)
378{
379 char *p;
380 struct rtc_time tm;
381 unsigned int flags;
382 struct rtc_pll_info pll;
383
384 p = buf;
385
386 flags = get_rtc_time(&tm);
387
388 p += sprintf(p,
389 "rtc_time\t: %02d:%02d:%02d\n"
390 "rtc_date\t: %04d-%02d-%02d\n"
391 "rtc_epoch\t: %04u\n",
392 tm.tm_hour, tm.tm_min, tm.tm_sec,
393 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900);
394
395 tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
396
397 p += sprintf(p, "alarm\t\t: ");
398 if (tm.tm_hour <= 24)
399 p += sprintf(p, "%02d:", tm.tm_hour);
400 else
401 p += sprintf(p, "**:");
402
403 if (tm.tm_min <= 59)
404 p += sprintf(p, "%02d:", tm.tm_min);
405 else
406 p += sprintf(p, "**:");
407
408 if (tm.tm_sec <= 59)
409 p += sprintf(p, "%02d\n", tm.tm_sec);
410 else
411 p += sprintf(p, "**\n");
412
413 p += sprintf(p,
414 "DST_enable\t: %s\n"
415 "BCD\t\t: %s\n"
416 "24hr\t\t: %s\n"
417 "square_wave\t: %s\n"
418 "alarm_IRQ\t: %s\n"
419 "update_IRQ\t: %s\n"
420 "periodic_IRQ\t: %s\n"
421 "periodic_freq\t: %ld\n"
422 "batt_status\t: %s\n",
423 (flags & RTC_DST_EN) ? "yes" : "no",
424 (flags & RTC_DM_BINARY) ? "no" : "yes",
425 (flags & RTC_24H) ? "yes" : "no",
426 (flags & RTC_SQWE) ? "yes" : "no",
427 (flags & RTC_AIE) ? "yes" : "no",
428 irq_active ? "yes" : "no",
429 (flags & RTC_PIE) ? "yes" : "no",
430 0L /* freq */,
431 (flags & RTC_BATT_BAD) ? "bad" : "okay");
432 if (!get_rtc_pll(&pll))
433 p += sprintf(p,
434 "PLL adjustment\t: %d\n"
435 "PLL max +ve adjustment\t: %d\n"
436 "PLL max -ve adjustment\t: %d\n"
437 "PLL +ve adjustment factor\t: %d\n"
438 "PLL -ve adjustment factor\t: %d\n"
439 "PLL frequency\t: %ld\n",
440 pll.pll_value,
441 pll.pll_max,
442 pll.pll_min,
443 pll.pll_posmult,
444 pll.pll_negmult,
445 pll.pll_clock);
446 return p - buf;
447}
448
449static int gen_rtc_read_proc(char *page, char **start, off_t off,
450 int count, int *eof, void *data)
451{
452 int len = gen_rtc_proc_output (page);
453 if (len <= off+count) *eof = 1;
454 *start = page + off;
455 len -= off;
456 if (len>count) len = count;
457 if (len<0) len = 0;
458 return len;
459}
460
461static int __init gen_rtc_proc_init(void)
462{
463 struct proc_dir_entry *r;
464
465 r = create_proc_read_entry("driver/rtc", 0, NULL, gen_rtc_read_proc, NULL);
466 if (!r)
467 return -ENOMEM;
468 return 0;
469}
470#else
471static inline int gen_rtc_proc_init(void) { return 0; }
472#endif /* CONFIG_PROC_FS */
473
474
475/*
476 * The various file operations we support.
477 */
478
Arjan van de Ven62322d22006-07-03 00:24:21 -0700479static const struct file_operations gen_rtc_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 .owner = THIS_MODULE,
481#ifdef CONFIG_GEN_RTC_X
482 .read = gen_rtc_read,
483 .poll = gen_rtc_poll,
484#endif
485 .ioctl = gen_rtc_ioctl,
486 .open = gen_rtc_open,
487 .release = gen_rtc_release,
488};
489
490static struct miscdevice rtc_gen_dev =
491{
492 .minor = RTC_MINOR,
493 .name = "rtc",
494 .fops = &gen_rtc_fops,
495};
496
497static int __init rtc_generic_init(void)
498{
499 int retval;
500
501 printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION);
502
503 retval = misc_register(&rtc_gen_dev);
504 if (retval < 0)
505 return retval;
506
507 retval = gen_rtc_proc_init();
508 if (retval) {
509 misc_deregister(&rtc_gen_dev);
510 return retval;
511 }
512
513 return 0;
514}
515
516static void __exit rtc_generic_exit(void)
517{
518 remove_proc_entry ("driver/rtc", NULL);
519 misc_deregister(&rtc_gen_dev);
520}
521
522
523module_init(rtc_generic_init);
524module_exit(rtc_generic_exit);
525
526MODULE_AUTHOR("Richard Zidlicky");
527MODULE_LICENSE("GPL");
528MODULE_ALIAS_MISCDEV(RTC_MINOR);