ext4: fix possible use-after-free in ext4_remove_li_request()
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / rtc / rtc-sa1100.c
blob5dfe5ffcb0d332700eb98027f91775e3541c58d3
1 /*
2 * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx
4 * Copyright (c) 2000 Nils Faerber
6 * Based on rtc.c by Paul Gortmaker
8 * Original Driver by Nils Faerber <nils@kernelconcepts.de>
10 * Modifications from:
11 * CIH <cih@coventive.com>
12 * Nicolas Pitre <nico@fluxnic.net>
13 * Andrew Christian <andrew.christian@hp.com>
15 * Converted to the RTC subsystem and Driver Model
16 * by Richard Purdie <rpurdie@rpsys.net>
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
24 #include <linux/platform_device.h>
25 #include <linux/module.h>
26 #include <linux/rtc.h>
27 #include <linux/init.h>
28 #include <linux/fs.h>
29 #include <linux/interrupt.h>
30 #include <linux/string.h>
31 #include <linux/pm.h>
32 #include <linux/bitops.h>
34 #include <mach/hardware.h>
35 #include <asm/irq.h>
37 #ifdef CONFIG_ARCH_PXA
38 #include <mach/regs-rtc.h>
39 #include <mach/regs-ost.h>
40 #endif
42 #define RTC_DEF_DIVIDER (32768 - 1)
43 #define RTC_DEF_TRIM 0
45 static const unsigned long RTC_FREQ = 1024;
46 static unsigned long timer_freq;
47 static struct rtc_time rtc_alarm;
48 static DEFINE_SPINLOCK(sa1100_rtc_lock);
50 static inline int rtc_periodic_alarm(struct rtc_time *tm)
52 return (tm->tm_year == -1) ||
53 ((unsigned)tm->tm_mon >= 12) ||
54 ((unsigned)(tm->tm_mday - 1) >= 31) ||
55 ((unsigned)tm->tm_hour > 23) ||
56 ((unsigned)tm->tm_min > 59) ||
57 ((unsigned)tm->tm_sec > 59);
61 * Calculate the next alarm time given the requested alarm time mask
62 * and the current time.
64 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
65 struct rtc_time *alrm)
67 unsigned long next_time;
68 unsigned long now_time;
70 next->tm_year = now->tm_year;
71 next->tm_mon = now->tm_mon;
72 next->tm_mday = now->tm_mday;
73 next->tm_hour = alrm->tm_hour;
74 next->tm_min = alrm->tm_min;
75 next->tm_sec = alrm->tm_sec;
77 rtc_tm_to_time(now, &now_time);
78 rtc_tm_to_time(next, &next_time);
80 if (next_time < now_time) {
81 /* Advance one day */
82 next_time += 60 * 60 * 24;
83 rtc_time_to_tm(next_time, next);
87 static int rtc_update_alarm(struct rtc_time *alrm)
89 struct rtc_time alarm_tm, now_tm;
90 unsigned long now, time;
91 int ret;
93 do {
94 now = RCNR;
95 rtc_time_to_tm(now, &now_tm);
96 rtc_next_alarm_time(&alarm_tm, &now_tm, alrm);
97 ret = rtc_tm_to_time(&alarm_tm, &time);
98 if (ret != 0)
99 break;
101 RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL);
102 RTAR = time;
103 } while (now != RCNR);
105 return ret;
108 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
110 struct platform_device *pdev = to_platform_device(dev_id);
111 struct rtc_device *rtc = platform_get_drvdata(pdev);
112 unsigned int rtsr;
113 unsigned long events = 0;
115 spin_lock(&sa1100_rtc_lock);
117 rtsr = RTSR;
118 /* clear interrupt sources */
119 RTSR = 0;
120 /* Fix for a nasty initialization problem the in SA11xx RTSR register.
121 * See also the comments in sa1100_rtc_probe(). */
122 if (rtsr & (RTSR_ALE | RTSR_HZE)) {
123 /* This is the original code, before there was the if test
124 * above. This code does not clear interrupts that were not
125 * enabled. */
126 RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2);
127 } else {
128 /* For some reason, it is possible to enter this routine
129 * without interruptions enabled, it has been tested with
130 * several units (Bug in SA11xx chip?).
132 * This situation leads to an infinite "loop" of interrupt
133 * routine calling and as a result the processor seems to
134 * lock on its first call to open(). */
135 RTSR = RTSR_AL | RTSR_HZ;
138 /* clear alarm interrupt if it has occurred */
139 if (rtsr & RTSR_AL)
140 rtsr &= ~RTSR_ALE;
141 RTSR = rtsr & (RTSR_ALE | RTSR_HZE);
143 /* update irq data & counter */
144 if (rtsr & RTSR_AL)
145 events |= RTC_AF | RTC_IRQF;
146 if (rtsr & RTSR_HZ)
147 events |= RTC_UF | RTC_IRQF;
149 rtc_update_irq(rtc, 1, events);
151 if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm))
152 rtc_update_alarm(&rtc_alarm);
154 spin_unlock(&sa1100_rtc_lock);
156 return IRQ_HANDLED;
159 static int sa1100_irq_set_freq(struct device *dev, int freq)
161 if (freq < 1 || freq > timer_freq) {
162 return -EINVAL;
163 } else {
164 struct rtc_device *rtc = (struct rtc_device *)dev;
166 rtc->irq_freq = freq;
168 return 0;
172 static int rtc_timer1_count;
174 static int sa1100_irq_set_state(struct device *dev, int enabled)
176 spin_lock_irq(&sa1100_rtc_lock);
177 if (enabled) {
178 struct rtc_device *rtc = (struct rtc_device *)dev;
180 OSMR1 = timer_freq / rtc->irq_freq + OSCR;
181 OIER |= OIER_E1;
182 rtc_timer1_count = 1;
183 } else {
184 OIER &= ~OIER_E1;
186 spin_unlock_irq(&sa1100_rtc_lock);
188 return 0;
191 static inline int sa1100_timer1_retrigger(struct rtc_device *rtc)
193 unsigned long diff;
194 unsigned long period = timer_freq / rtc->irq_freq;
196 spin_lock_irq(&sa1100_rtc_lock);
198 do {
199 OSMR1 += period;
200 diff = OSMR1 - OSCR;
201 /* If OSCR > OSMR1, diff is a very large number (unsigned
202 * math). This means we have a lost interrupt. */
203 } while (diff > period);
204 OIER |= OIER_E1;
206 spin_unlock_irq(&sa1100_rtc_lock);
208 return 0;
211 static irqreturn_t timer1_interrupt(int irq, void *dev_id)
213 struct platform_device *pdev = to_platform_device(dev_id);
214 struct rtc_device *rtc = platform_get_drvdata(pdev);
217 * If we match for the first time, rtc_timer1_count will be 1.
218 * Otherwise, we wrapped around (very unlikely but
219 * still possible) so compute the amount of missed periods.
220 * The match reg is updated only when the data is actually retrieved
221 * to avoid unnecessary interrupts.
223 OSSR = OSSR_M1; /* clear match on timer1 */
225 rtc_update_irq(rtc, rtc_timer1_count, RTC_PF | RTC_IRQF);
227 if (rtc_timer1_count == 1)
228 rtc_timer1_count =
229 (rtc->irq_freq * ((1 << 30) / (timer_freq >> 2)));
231 /* retrigger. */
232 sa1100_timer1_retrigger(rtc);
234 return IRQ_HANDLED;
237 static int sa1100_rtc_read_callback(struct device *dev, int data)
239 if (data & RTC_PF) {
240 struct rtc_device *rtc = (struct rtc_device *)dev;
242 /* interpolate missed periods and set match for the next */
243 unsigned long period = timer_freq / rtc->irq_freq;
244 unsigned long oscr = OSCR;
245 unsigned long osmr1 = OSMR1;
246 unsigned long missed = (oscr - osmr1)/period;
247 data += missed << 8;
248 OSSR = OSSR_M1; /* clear match on timer 1 */
249 OSMR1 = osmr1 + (missed + 1)*period;
250 /* Ensure we didn't miss another match in the mean time.
251 * Here we compare (match - OSCR) 8 instead of 0 --
252 * see comment in pxa_timer_interrupt() for explanation.
254 while ((signed long)((osmr1 = OSMR1) - OSCR) <= 8) {
255 data += 0x100;
256 OSSR = OSSR_M1; /* clear match on timer 1 */
257 OSMR1 = osmr1 + period;
260 return data;
263 static int sa1100_rtc_open(struct device *dev)
265 int ret;
266 struct rtc_device *rtc = (struct rtc_device *)dev;
268 ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED,
269 "rtc 1Hz", dev);
270 if (ret) {
271 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz);
272 goto fail_ui;
274 ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, IRQF_DISABLED,
275 "rtc Alrm", dev);
276 if (ret) {
277 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm);
278 goto fail_ai;
280 ret = request_irq(IRQ_OST1, timer1_interrupt, IRQF_DISABLED,
281 "rtc timer", dev);
282 if (ret) {
283 dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1);
284 goto fail_pi;
286 rtc->max_user_freq = RTC_FREQ;
287 sa1100_irq_set_freq(dev, RTC_FREQ);
289 return 0;
291 fail_pi:
292 free_irq(IRQ_RTCAlrm, dev);
293 fail_ai:
294 free_irq(IRQ_RTC1Hz, dev);
295 fail_ui:
296 return ret;
299 static void sa1100_rtc_release(struct device *dev)
301 spin_lock_irq(&sa1100_rtc_lock);
302 RTSR = 0;
303 OIER &= ~OIER_E1;
304 OSSR = OSSR_M1;
305 spin_unlock_irq(&sa1100_rtc_lock);
307 free_irq(IRQ_OST1, dev);
308 free_irq(IRQ_RTCAlrm, dev);
309 free_irq(IRQ_RTC1Hz, dev);
313 static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd,
314 unsigned long arg)
316 switch (cmd) {
317 case RTC_UIE_OFF:
318 spin_lock_irq(&sa1100_rtc_lock);
319 RTSR &= ~RTSR_HZE;
320 spin_unlock_irq(&sa1100_rtc_lock);
321 return 0;
322 case RTC_UIE_ON:
323 spin_lock_irq(&sa1100_rtc_lock);
324 RTSR |= RTSR_HZE;
325 spin_unlock_irq(&sa1100_rtc_lock);
326 return 0;
328 return -ENOIOCTLCMD;
331 static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
333 spin_lock_irq(&sa1100_rtc_lock);
334 if (enabled)
335 RTSR |= RTSR_ALE;
336 else
337 RTSR &= ~RTSR_ALE;
338 spin_unlock_irq(&sa1100_rtc_lock);
339 return 0;
342 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
344 rtc_time_to_tm(RCNR, tm);
345 return 0;
348 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
350 unsigned long time;
351 int ret;
353 ret = rtc_tm_to_time(tm, &time);
354 if (ret == 0)
355 RCNR = time;
356 return ret;
359 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
361 u32 rtsr;
363 memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time));
364 rtsr = RTSR;
365 alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
366 alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
367 return 0;
370 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
372 int ret;
374 spin_lock_irq(&sa1100_rtc_lock);
375 ret = rtc_update_alarm(&alrm->time);
376 if (ret == 0) {
377 if (alrm->enabled)
378 RTSR |= RTSR_ALE;
379 else
380 RTSR &= ~RTSR_ALE;
382 spin_unlock_irq(&sa1100_rtc_lock);
384 return ret;
387 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
389 struct rtc_device *rtc = (struct rtc_device *)dev;
391 seq_printf(seq, "trim/divider\t: 0x%08x\n", (u32) RTTR);
392 seq_printf(seq, "update_IRQ\t: %s\n",
393 (RTSR & RTSR_HZE) ? "yes" : "no");
394 seq_printf(seq, "periodic_IRQ\t: %s\n",
395 (OIER & OIER_E1) ? "yes" : "no");
396 seq_printf(seq, "periodic_freq\t: %d\n", rtc->irq_freq);
397 seq_printf(seq, "RTSR\t\t: 0x%08x\n", (u32)RTSR);
399 return 0;
402 static const struct rtc_class_ops sa1100_rtc_ops = {
403 .open = sa1100_rtc_open,
404 .read_callback = sa1100_rtc_read_callback,
405 .release = sa1100_rtc_release,
406 .ioctl = sa1100_rtc_ioctl,
407 .read_time = sa1100_rtc_read_time,
408 .set_time = sa1100_rtc_set_time,
409 .read_alarm = sa1100_rtc_read_alarm,
410 .set_alarm = sa1100_rtc_set_alarm,
411 .proc = sa1100_rtc_proc,
412 .irq_set_freq = sa1100_irq_set_freq,
413 .irq_set_state = sa1100_irq_set_state,
414 .alarm_irq_enable = sa1100_rtc_alarm_irq_enable,
417 static int sa1100_rtc_probe(struct platform_device *pdev)
419 struct rtc_device *rtc;
421 timer_freq = get_clock_tick_rate();
424 * According to the manual we should be able to let RTTR be zero
425 * and then a default diviser for a 32.768KHz clock is used.
426 * Apparently this doesn't work, at least for my SA1110 rev 5.
427 * If the clock divider is uninitialized then reset it to the
428 * default value to get the 1Hz clock.
430 if (RTTR == 0) {
431 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
432 dev_warn(&pdev->dev, "warning: "
433 "initializing default clock divider/trim value\n");
434 /* The current RTC value probably doesn't make sense either */
435 RCNR = 0;
438 device_init_wakeup(&pdev->dev, 1);
440 rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops,
441 THIS_MODULE);
443 if (IS_ERR(rtc))
444 return PTR_ERR(rtc);
446 platform_set_drvdata(pdev, rtc);
448 /* Set the irq_freq */
449 /*TODO: Find out who is messing with this value after we initialize
450 * it here.*/
451 rtc->irq_freq = RTC_FREQ;
453 /* Fix for a nasty initialization problem the in SA11xx RTSR register.
454 * See also the comments in sa1100_rtc_interrupt().
456 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an
457 * interrupt pending, even though interrupts were never enabled.
458 * In this case, this bit it must be reset before enabling
459 * interruptions to avoid a nonexistent interrupt to occur.
461 * In principle, the same problem would apply to bit 0, although it has
462 * never been observed to happen.
464 * This issue is addressed both here and in sa1100_rtc_interrupt().
465 * If the issue is not addressed here, in the times when the processor
466 * wakes up with the bit set there will be one spurious interrupt.
468 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the
469 * safe side, once the condition that lead to this strange
470 * initialization is unknown and could in principle happen during
471 * normal processing.
473 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to
474 * the corresponding bits in RTSR. */
475 RTSR = RTSR_AL | RTSR_HZ;
477 return 0;
480 static int sa1100_rtc_remove(struct platform_device *pdev)
482 struct rtc_device *rtc = platform_get_drvdata(pdev);
484 if (rtc)
485 rtc_device_unregister(rtc);
487 return 0;
490 #ifdef CONFIG_PM
491 static int sa1100_rtc_suspend(struct device *dev)
493 if (device_may_wakeup(dev))
494 enable_irq_wake(IRQ_RTCAlrm);
495 return 0;
498 static int sa1100_rtc_resume(struct device *dev)
500 if (device_may_wakeup(dev))
501 disable_irq_wake(IRQ_RTCAlrm);
502 return 0;
505 static const struct dev_pm_ops sa1100_rtc_pm_ops = {
506 .suspend = sa1100_rtc_suspend,
507 .resume = sa1100_rtc_resume,
509 #endif
511 static struct platform_driver sa1100_rtc_driver = {
512 .probe = sa1100_rtc_probe,
513 .remove = sa1100_rtc_remove,
514 .driver = {
515 .name = "sa1100-rtc",
516 #ifdef CONFIG_PM
517 .pm = &sa1100_rtc_pm_ops,
518 #endif
522 static int __init sa1100_rtc_init(void)
524 return platform_driver_register(&sa1100_rtc_driver);
527 static void __exit sa1100_rtc_exit(void)
529 platform_driver_unregister(&sa1100_rtc_driver);
532 module_init(sa1100_rtc_init);
533 module_exit(sa1100_rtc_exit);
535 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
536 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
537 MODULE_LICENSE("GPL");
538 MODULE_ALIAS("platform:sa1100-rtc");