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/sched.h>
47 #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>
55 #include <linux/mutex.h>
56 #include <linux/workqueue.h>
57
58 #include <asm/uaccess.h>
59 #include <asm/rtc.h>
60
61 /*
62 * We sponge a minor off of the misc major. No need slurping
63 * up another valuable major dev number for this. If you add
64 * an ioctl, make sure you don't conflict with SPARC's RTC
65 * ioctls.
66 */
67
68 static DEFINE_MUTEX(gen_rtc_mutex);
69 static 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
77 static unsigned char gen_rtc_status; /* bitmapped status byte. */
78 static unsigned long gen_rtc_irq_data; /* our output to the world */
79
80 /* months start at 0 now */
81 static unsigned char days_in_mo[] =
82 {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
83
84 static int irq_active;
85
86 #ifdef CONFIG_GEN_RTC_X
87 static struct work_struct genrtc_task;
88 static struct timer_list timer_task;
89
90 static unsigned int oldsecs;
91 static int lostint;
92 static unsigned long tt_exp;
93
94 static void gen_rtc_timer(unsigned long data);
95
96 static volatile int stask_active; /* schedule_work */
97 static volatile int ttask_active; /* timer_task */
98 static int stop_rtc_timers; /* don't requeue tasks */
99 static DEFINE_SPINLOCK(gen_rtc_lock);
100
101 static 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 */
genrtc_troutine(struct work_struct * work)107 static void genrtc_troutine(struct work_struct *work)
108 {
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
gen_rtc_timer(unsigned long data)131 static 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 */
gen_rtc_interrupt(unsigned long arg)152 static 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 */
gen_rtc_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)175 static ssize_t gen_rtc_read(struct file *file, char __user *buf,
176 size_t count, loff_t *ppos)
177 {
178 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
187 retval = wait_event_interruptible(gen_rtc_wait,
188 (data = xchg(&gen_rtc_irq_data, 0)));
189 if (retval)
190 goto out;
191
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;
195 retval = put_user(uidata, (unsigned int __user *)buf) ?:
196 sizeof(unsigned int);
197 }
198 else {
199 retval = put_user(data, (unsigned long __user *)buf) ?:
200 sizeof(unsigned long);
201 }
202 out:
203 return retval;
204 }
205
gen_rtc_poll(struct file * file,struct poll_table_struct * wait)206 static 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
gen_clear_rtc_irq_bit(unsigned char bit)223 static 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
gen_set_rtc_irq_bit(unsigned char bit)240 static 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;
248 INIT_WORK(&genrtc_task, genrtc_troutine);
249 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
gen_rtc_ioctl(struct file * file,unsigned int cmd,unsigned long arg)265 static int gen_rtc_ioctl(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
gen_rtc_unlocked_ioctl(struct file * file,unsigned int cmd,unsigned long arg)335 static long gen_rtc_unlocked_ioctl(struct file *file, unsigned int cmd,
336 unsigned long arg)
337 {
338 int ret;
339
340 mutex_lock(&gen_rtc_mutex);
341 ret = gen_rtc_ioctl(file, cmd, arg);
342 mutex_unlock(&gen_rtc_mutex);
343
344 return ret;
345 }
346
347 /*
348 * We enforce only one user at a time here with the open/close.
349 * Also clear the previous interrupt data on an open, and clean
350 * up things on a close.
351 */
352
gen_rtc_open(struct inode * inode,struct file * file)353 static int gen_rtc_open(struct inode *inode, struct file *file)
354 {
355 mutex_lock(&gen_rtc_mutex);
356 if (gen_rtc_status & RTC_IS_OPEN) {
357 mutex_unlock(&gen_rtc_mutex);
358 return -EBUSY;
359 }
360
361 gen_rtc_status |= RTC_IS_OPEN;
362 gen_rtc_irq_data = 0;
363 irq_active = 0;
364 mutex_unlock(&gen_rtc_mutex);
365
366 return 0;
367 }
368
gen_rtc_release(struct inode * inode,struct file * file)369 static int gen_rtc_release(struct inode *inode, struct file *file)
370 {
371 /*
372 * Turn off all interrupts once the device is no longer
373 * in use and clear the data.
374 */
375
376 gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
377
378 gen_rtc_status &= ~RTC_IS_OPEN;
379 return 0;
380 }
381
382
383 #ifdef CONFIG_PROC_FS
384
385 /*
386 * Info exported via "/proc/driver/rtc".
387 */
388
gen_rtc_proc_output(char * buf)389 static int gen_rtc_proc_output(char *buf)
390 {
391 char *p;
392 struct rtc_time tm;
393 unsigned int flags;
394 struct rtc_pll_info pll;
395
396 p = buf;
397
398 flags = get_rtc_time(&tm);
399
400 p += sprintf(p,
401 "rtc_time\t: %02d:%02d:%02d\n"
402 "rtc_date\t: %04d-%02d-%02d\n"
403 "rtc_epoch\t: %04u\n",
404 tm.tm_hour, tm.tm_min, tm.tm_sec,
405 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900);
406
407 tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
408
409 p += sprintf(p, "alarm\t\t: ");
410 if (tm.tm_hour <= 24)
411 p += sprintf(p, "%02d:", tm.tm_hour);
412 else
413 p += sprintf(p, "**:");
414
415 if (tm.tm_min <= 59)
416 p += sprintf(p, "%02d:", tm.tm_min);
417 else
418 p += sprintf(p, "**:");
419
420 if (tm.tm_sec <= 59)
421 p += sprintf(p, "%02d\n", tm.tm_sec);
422 else
423 p += sprintf(p, "**\n");
424
425 p += sprintf(p,
426 "DST_enable\t: %s\n"
427 "BCD\t\t: %s\n"
428 "24hr\t\t: %s\n"
429 "square_wave\t: %s\n"
430 "alarm_IRQ\t: %s\n"
431 "update_IRQ\t: %s\n"
432 "periodic_IRQ\t: %s\n"
433 "periodic_freq\t: %ld\n"
434 "batt_status\t: %s\n",
435 (flags & RTC_DST_EN) ? "yes" : "no",
436 (flags & RTC_DM_BINARY) ? "no" : "yes",
437 (flags & RTC_24H) ? "yes" : "no",
438 (flags & RTC_SQWE) ? "yes" : "no",
439 (flags & RTC_AIE) ? "yes" : "no",
440 irq_active ? "yes" : "no",
441 (flags & RTC_PIE) ? "yes" : "no",
442 0L /* freq */,
443 (flags & RTC_BATT_BAD) ? "bad" : "okay");
444 if (!get_rtc_pll(&pll))
445 p += sprintf(p,
446 "PLL adjustment\t: %d\n"
447 "PLL max +ve adjustment\t: %d\n"
448 "PLL max -ve adjustment\t: %d\n"
449 "PLL +ve adjustment factor\t: %d\n"
450 "PLL -ve adjustment factor\t: %d\n"
451 "PLL frequency\t: %ld\n",
452 pll.pll_value,
453 pll.pll_max,
454 pll.pll_min,
455 pll.pll_posmult,
456 pll.pll_negmult,
457 pll.pll_clock);
458 return p - buf;
459 }
460
gen_rtc_read_proc(char * page,char ** start,off_t off,int count,int * eof,void * data)461 static int gen_rtc_read_proc(char *page, char **start, off_t off,
462 int count, int *eof, void *data)
463 {
464 int len = gen_rtc_proc_output (page);
465 if (len <= off+count) *eof = 1;
466 *start = page + off;
467 len -= off;
468 if (len>count) len = count;
469 if (len<0) len = 0;
470 return len;
471 }
472
gen_rtc_proc_init(void)473 static int __init gen_rtc_proc_init(void)
474 {
475 struct proc_dir_entry *r;
476
477 r = create_proc_read_entry("driver/rtc", 0, NULL, gen_rtc_read_proc, NULL);
478 if (!r)
479 return -ENOMEM;
480 return 0;
481 }
482 #else
gen_rtc_proc_init(void)483 static inline int gen_rtc_proc_init(void) { return 0; }
484 #endif /* CONFIG_PROC_FS */
485
486
487 /*
488 * The various file operations we support.
489 */
490
491 static const struct file_operations gen_rtc_fops = {
492 .owner = THIS_MODULE,
493 #ifdef CONFIG_GEN_RTC_X
494 .read = gen_rtc_read,
495 .poll = gen_rtc_poll,
496 #endif
497 .unlocked_ioctl = gen_rtc_unlocked_ioctl,
498 .open = gen_rtc_open,
499 .release = gen_rtc_release,
500 .llseek = noop_llseek,
501 };
502
503 static struct miscdevice rtc_gen_dev =
504 {
505 .minor = RTC_MINOR,
506 .name = "rtc",
507 .fops = &gen_rtc_fops,
508 };
509
rtc_generic_init(void)510 static int __init rtc_generic_init(void)
511 {
512 int retval;
513
514 printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION);
515
516 retval = misc_register(&rtc_gen_dev);
517 if (retval < 0)
518 return retval;
519
520 retval = gen_rtc_proc_init();
521 if (retval) {
522 misc_deregister(&rtc_gen_dev);
523 return retval;
524 }
525
526 return 0;
527 }
528
rtc_generic_exit(void)529 static void __exit rtc_generic_exit(void)
530 {
531 remove_proc_entry ("driver/rtc", NULL);
532 misc_deregister(&rtc_gen_dev);
533 }
534
535
536 module_init(rtc_generic_init);
537 module_exit(rtc_generic_exit);
538
539 MODULE_AUTHOR("Richard Zidlicky");
540 MODULE_LICENSE("GPL");
541 MODULE_ALIAS_MISCDEV(RTC_MINOR);
542