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/dev/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/config.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/workqueue.h>
56
57 #include <asm/uaccess.h>
58 #include <asm/system.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 DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait);
69
70 /*
71 * Bits in gen_rtc_status.
72 */
73
74 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
75
76 static unsigned char gen_rtc_status; /* bitmapped status byte. */
77 static unsigned long gen_rtc_irq_data; /* our output to the world */
78
79 /* months start at 0 now */
80 static unsigned char days_in_mo[] =
81 {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
82
83 static int irq_active;
84
85 #ifdef CONFIG_GEN_RTC_X
86 static struct work_struct genrtc_task;
87 static struct timer_list timer_task;
88
89 static unsigned int oldsecs;
90 static int lostint;
91 static unsigned long tt_exp;
92
93 static void gen_rtc_timer(unsigned long data);
94
95 static volatile int stask_active; /* schedule_work */
96 static volatile int ttask_active; /* timer_task */
97 static int stop_rtc_timers; /* don't requeue tasks */
98 static DEFINE_SPINLOCK(gen_rtc_lock);
99
100 static void gen_rtc_interrupt(unsigned long arg);
101
102 /*
103 * Routine to poll RTC seconds field for change as often as possible,
104 * after first RTC_UIE use timer to reduce polling
105 */
106 static void genrtc_troutine(void *data)
107 {
108 unsigned int tmp = get_rtc_ss();
109
110 if (stop_rtc_timers) {
111 stask_active = 0;
112 return;
113 }
114
115 if (oldsecs != tmp){
116 oldsecs = tmp;
117
118 timer_task.function = gen_rtc_timer;
119 timer_task.expires = jiffies + HZ - (HZ/10);
120 tt_exp=timer_task.expires;
121 ttask_active=1;
122 stask_active=0;
123 add_timer(&timer_task);
124
125 gen_rtc_interrupt(0);
126 } else if (schedule_work(&genrtc_task) == 0)
127 stask_active = 0;
128 }
129
130 static void gen_rtc_timer(unsigned long data)
131 {
132 lostint = get_rtc_ss() - oldsecs ;
133 if (lostint<0)
134 lostint = 60 - lostint;
135 if (time_after(jiffies, tt_exp))
136 printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n",
137 jiffies-tt_exp);
138 ttask_active=0;
139 stask_active=1;
140 if ((schedule_work(&genrtc_task) == 0))
141 stask_active = 0;
142 }
143
144 /*
145 * call gen_rtc_interrupt function to signal an RTC_UIE,
146 * arg is unused.
147 * Could be invoked either from a real interrupt handler or
148 * from some routine that periodically (eg 100HZ) monitors
149 * whether RTC_SECS changed
150 */
151 static void gen_rtc_interrupt(unsigned long arg)
152 {
153 /* We store the status in the low byte and the number of
154 * interrupts received since the last read in the remainder
155 * of rtc_irq_data. */
156
157 gen_rtc_irq_data += 0x100;
158 gen_rtc_irq_data &= ~0xff;
159 gen_rtc_irq_data |= RTC_UIE;
160
161 if (lostint){
162 printk("genrtc: system delaying clock ticks?\n");
163 /* increment count so that userspace knows something is wrong */
164 gen_rtc_irq_data += ((lostint-1)<<8);
165 lostint = 0;
166 }
167
168 wake_up_interruptible(&gen_rtc_wait);
169 }
170
171 /*
172 * Now all the various file operations that we export.
173 */
174 static ssize_t gen_rtc_read(struct file *file, char __user *buf,
175 size_t count, loff_t *ppos)
176 {
177 DECLARE_WAITQUEUE(wait, current);
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 add_wait_queue(&gen_rtc_wait, &wait);
188 retval = -ERESTARTSYS;
189
190 while (1) {
191 set_current_state(TASK_INTERRUPTIBLE);
192 data = xchg(&gen_rtc_irq_data, 0);
193 if (data)
194 break;
195 if (signal_pending(current))
196 goto out;
197 schedule();
198 }
199
200 /* first test allows optimizer to nuke this case for 32-bit machines */
201 if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) {
202 unsigned int uidata = data;
203 retval = put_user(uidata, (unsigned long __user *)buf);
204 }
205 else {
206 retval = put_user(data, (unsigned long __user *)buf);
207 }
208 if (!retval)
209 retval = sizeof(unsigned long);
210 out:
211 current->state = TASK_RUNNING;
212 remove_wait_queue(&gen_rtc_wait, &wait);
213
214 return retval;
215 }
216
217 static unsigned int gen_rtc_poll(struct file *file,
218 struct poll_table_struct *wait)
219 {
220 poll_wait(file, &gen_rtc_wait, wait);
221 if (gen_rtc_irq_data != 0)
222 return POLLIN | POLLRDNORM;
223 return 0;
224 }
225
226 #endif
227
228 /*
229 * Used to disable/enable interrupts, only RTC_UIE supported
230 * We also clear out any old irq data after an ioctl() that
231 * meddles with the interrupt enable/disable bits.
232 */
233
234 static inline void gen_clear_rtc_irq_bit(unsigned char bit)
235 {
236 #ifdef CONFIG_GEN_RTC_X
237 stop_rtc_timers = 1;
238 if (ttask_active){
239 del_timer_sync(&timer_task);
240 ttask_active = 0;
241 }
242 while (stask_active)
243 schedule();
244
245 spin_lock(&gen_rtc_lock);
246 irq_active = 0;
247 spin_unlock(&gen_rtc_lock);
248 #endif
249 }
250
251 static inline int gen_set_rtc_irq_bit(unsigned char bit)
252 {
253 #ifdef CONFIG_GEN_RTC_X
254 spin_lock(&gen_rtc_lock);
255 if ( !irq_active ) {
256 irq_active = 1;
257 stop_rtc_timers = 0;
258 lostint = 0;
259 INIT_WORK(&genrtc_task, genrtc_troutine, NULL);
260 oldsecs = get_rtc_ss();
261 init_timer(&timer_task);
262
263 stask_active = 1;
264 if (schedule_work(&genrtc_task) == 0){
265 stask_active = 0;
266 }
267 }
268 spin_unlock(&gen_rtc_lock);
269 gen_rtc_irq_data = 0;
270 return 0;
271 #else
272 return -EINVAL;
273 #endif
274 }
275
276 static int gen_rtc_ioctl(struct inode *inode, struct file *file,
277 unsigned int cmd, unsigned long arg)
278 {
279 struct rtc_time wtime;
280 struct rtc_pll_info pll;
281 void __user *argp = (void __user *)arg;
282
283 switch (cmd) {
284
285 case RTC_PLL_GET:
286 if (get_rtc_pll(&pll))
287 return -EINVAL;
288 else
289 return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;
290
291 case RTC_PLL_SET:
292 if (!capable(CAP_SYS_TIME))
293 return -EACCES;
294 if (copy_from_user(&pll, argp, sizeof(pll)))
295 return -EFAULT;
296 return set_rtc_pll(&pll);
297
298 case RTC_UIE_OFF: /* disable ints from RTC updates. */
299 gen_clear_rtc_irq_bit(RTC_UIE);
300 return 0;
301
302 case RTC_UIE_ON: /* enable ints for RTC updates. */
303 return gen_set_rtc_irq_bit(RTC_UIE);
304
305 case RTC_RD_TIME: /* Read the time/date from RTC */
306 /* this doesn't get week-day, who cares */
307 memset(&wtime, 0, sizeof(wtime));
308 get_rtc_time(&wtime);
309
310 return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0;
311
312 case RTC_SET_TIME: /* Set the RTC */
313 {
314 int year;
315 unsigned char leap_yr;
316
317 if (!capable(CAP_SYS_TIME))
318 return -EACCES;
319
320 if (copy_from_user(&wtime, argp, sizeof(wtime)))
321 return -EFAULT;
322
323 year = wtime.tm_year + 1900;
324 leap_yr = ((!(year % 4) && (year % 100)) ||
325 !(year % 400));
326
327 if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1))
328 return -EINVAL;
329
330 if (wtime.tm_mday < 0 || wtime.tm_mday >
331 (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr)))
332 return -EINVAL;
333
334 if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 ||
335 wtime.tm_min < 0 || wtime.tm_min >= 60 ||
336 wtime.tm_sec < 0 || wtime.tm_sec >= 60)
337 return -EINVAL;
338
339 return set_rtc_time(&wtime);
340 }
341 }
342
343 return -EINVAL;
344 }
345
346 /*
347 * We enforce only one user at a time here with the open/close.
348 * Also clear the previous interrupt data on an open, and clean
349 * up things on a close.
350 */
351
352 static int gen_rtc_open(struct inode *inode, struct file *file)
353 {
354 if (gen_rtc_status & RTC_IS_OPEN)
355 return -EBUSY;
356
357 gen_rtc_status |= RTC_IS_OPEN;
358 gen_rtc_irq_data = 0;
359 irq_active = 0;
360
361 return 0;
362 }
363
364 static int gen_rtc_release(struct inode *inode, struct file *file)
365 {
366 /*
367 * Turn off all interrupts once the device is no longer
368 * in use and clear the data.
369 */
370
371 gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
372
373 gen_rtc_status &= ~RTC_IS_OPEN;
374 return 0;
375 }
376
377
378 #ifdef CONFIG_PROC_FS
379
380 /*
381 * Info exported via "/proc/rtc".
382 */
383
384 static int gen_rtc_proc_output(char *buf)
385 {
386 char *p;
387 struct rtc_time tm;
388 unsigned int flags;
389 struct rtc_pll_info pll;
390
391 p = buf;
392
393 flags = get_rtc_time(&tm);
394
395 p += sprintf(p,
396 "rtc_time\t: %02d:%02d:%02d\n"
397 "rtc_date\t: %04d-%02d-%02d\n"
398 "rtc_epoch\t: %04u\n",
399 tm.tm_hour, tm.tm_min, tm.tm_sec,
400 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900);
401
402 tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
403
404 p += sprintf(p, "alarm\t\t: ");
405 if (tm.tm_hour <= 24)
406 p += sprintf(p, "%02d:", tm.tm_hour);
407 else
408 p += sprintf(p, "**:");
409
410 if (tm.tm_min <= 59)
411 p += sprintf(p, "%02d:", tm.tm_min);
412 else
413 p += sprintf(p, "**:");
414
415 if (tm.tm_sec <= 59)
416 p += sprintf(p, "%02d\n", tm.tm_sec);
417 else
418 p += sprintf(p, "**\n");
419
420 p += sprintf(p,
421 "DST_enable\t: %s\n"
422 "BCD\t\t: %s\n"
423 "24hr\t\t: %s\n"
424 "square_wave\t: %s\n"
425 "alarm_IRQ\t: %s\n"
426 "update_IRQ\t: %s\n"
427 "periodic_IRQ\t: %s\n"
428 "periodic_freq\t: %ld\n"
429 "batt_status\t: %s\n",
430 (flags & RTC_DST_EN) ? "yes" : "no",
431 (flags & RTC_DM_BINARY) ? "no" : "yes",
432 (flags & RTC_24H) ? "yes" : "no",
433 (flags & RTC_SQWE) ? "yes" : "no",
434 (flags & RTC_AIE) ? "yes" : "no",
435 irq_active ? "yes" : "no",
436 (flags & RTC_PIE) ? "yes" : "no",
437 0L /* freq */,
438 (flags & RTC_BATT_BAD) ? "bad" : "okay");
439 if (!get_rtc_pll(&pll))
440 p += sprintf(p,
441 "PLL adjustment\t: %d\n"
442 "PLL max +ve adjustment\t: %d\n"
443 "PLL max -ve adjustment\t: %d\n"
444 "PLL +ve adjustment factor\t: %d\n"
445 "PLL -ve adjustment factor\t: %d\n"
446 "PLL frequency\t: %ld\n",
447 pll.pll_value,
448 pll.pll_max,
449 pll.pll_min,
450 pll.pll_posmult,
451 pll.pll_negmult,
452 pll.pll_clock);
453 return p - buf;
454 }
455
456 static int gen_rtc_read_proc(char *page, char **start, off_t off,
457 int count, int *eof, void *data)
458 {
459 int len = gen_rtc_proc_output (page);
460 if (len <= off+count) *eof = 1;
461 *start = page + off;
462 len -= off;
463 if (len>count) len = count;
464 if (len<0) len = 0;
465 return len;
466 }
467
468 static int __init gen_rtc_proc_init(void)
469 {
470 struct proc_dir_entry *r;
471
472 r = create_proc_read_entry("driver/rtc", 0, NULL, gen_rtc_read_proc, NULL);
473 if (!r)
474 return -ENOMEM;
475 return 0;
476 }
477 #else
478 static inline int gen_rtc_proc_init(void) { return 0; }
479 #endif /* CONFIG_PROC_FS */
480
481
482 /*
483 * The various file operations we support.
484 */
485
486 static struct file_operations gen_rtc_fops = {
487 .owner = THIS_MODULE,
488 #ifdef CONFIG_GEN_RTC_X
489 .read = gen_rtc_read,
490 .poll = gen_rtc_poll,
491 #endif
492 .ioctl = gen_rtc_ioctl,
493 .open = gen_rtc_open,
494 .release = gen_rtc_release,
495 };
496
497 static struct miscdevice rtc_gen_dev =
498 {
499 .minor = RTC_MINOR,
500 .name = "rtc",
501 .fops = &gen_rtc_fops,
502 };
503
504 static int __init rtc_generic_init(void)
505 {
506 int retval;
507
508 printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION);
509
510 retval = misc_register(&rtc_gen_dev);
511 if (retval < 0)
512 return retval;
513
514 retval = gen_rtc_proc_init();
515 if (retval) {
516 misc_deregister(&rtc_gen_dev);
517 return retval;
518 }
519
520 return 0;
521 }
522
523 static void __exit rtc_generic_exit(void)
524 {
525 remove_proc_entry ("driver/rtc", NULL);
526 misc_deregister(&rtc_gen_dev);
527 }
528
529
530 module_init(rtc_generic_init);
531 module_exit(rtc_generic_exit);
532
533 MODULE_AUTHOR("Richard Zidlicky");
534 MODULE_LICENSE("GPL");
535 MODULE_ALIAS_MISCDEV(RTC_MINOR);
536
|
This page was automatically generated by the
LXR engine.
|