rtc, x86/mrst/vrtc: Fix boot crash in rtc_read_alarm()
[linux-2.6.git] / drivers / rtc / rtc-mrst.c
1 /*
2  * rtc-mrst.c: Driver for Moorestown virtual RTC
3  *
4  * (C) Copyright 2009 Intel Corporation
5  * Author: Jacob Pan (jacob.jun.pan@intel.com)
6  *         Feng Tang (feng.tang@intel.com)
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * as published by the Free Software Foundation; version 2
11  * of the License.
12  *
13  * Note:
14  * VRTC is emulated by system controller firmware, the real HW
15  * RTC is located in the PMIC device. SCU FW shadows PMIC RTC
16  * in a memory mapped IO space that is visible to the host IA
17  * processor.
18  *
19  * This driver is based upon drivers/rtc/rtc-cmos.c
20  */
21
22 /*
23  * Note:
24  *  * vRTC only supports binary mode and 24H mode
25  *  * vRTC only support PIE and AIE, no UIE, and its PIE only happens
26  *    at 23:59:59pm everyday, no support for adjustable frequency
27  *  * Alarm function is also limited to hr/min/sec.
28  */
29
30 #include <linux/mod_devicetable.h>
31 #include <linux/platform_device.h>
32 #include <linux/interrupt.h>
33 #include <linux/spinlock.h>
34 #include <linux/kernel.h>
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/sfi.h>
38
39 #include <asm-generic/rtc.h>
40 #include <asm/intel_scu_ipc.h>
41 #include <asm/mrst.h>
42 #include <asm/mrst-vrtc.h>
43
44 struct mrst_rtc {
45         struct rtc_device       *rtc;
46         struct device           *dev;
47         int                     irq;
48         struct resource         *iomem;
49
50         u8                      enabled_wake;
51         u8                      suspend_ctrl;
52 };
53
54 static const char driver_name[] = "rtc_mrst";
55
56 #define RTC_IRQMASK     (RTC_PF | RTC_AF)
57
58 static inline int is_intr(u8 rtc_intr)
59 {
60         if (!(rtc_intr & RTC_IRQF))
61                 return 0;
62         return rtc_intr & RTC_IRQMASK;
63 }
64
65 static inline unsigned char vrtc_is_updating(void)
66 {
67         unsigned char uip;
68         unsigned long flags;
69
70         spin_lock_irqsave(&rtc_lock, flags);
71         uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
72         spin_unlock_irqrestore(&rtc_lock, flags);
73         return uip;
74 }
75
76 /*
77  * rtc_time's year contains the increment over 1900, but vRTC's YEAR
78  * register can't be programmed to value larger than 0x64, so vRTC
79  * driver chose to use 1960 (1970 is UNIX time start point) as the base,
80  * and does the translation at read/write time.
81  *
82  * Why not just use 1970 as the offset? it's because using 1960 will
83  * make it consistent in leap year setting for both vrtc and low-level
84  * physical rtc devices.
85  */
86 static int mrst_read_time(struct device *dev, struct rtc_time *time)
87 {
88         unsigned long flags;
89
90         if (vrtc_is_updating())
91                 mdelay(20);
92
93         spin_lock_irqsave(&rtc_lock, flags);
94         time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
95         time->tm_min = vrtc_cmos_read(RTC_MINUTES);
96         time->tm_hour = vrtc_cmos_read(RTC_HOURS);
97         time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
98         time->tm_mon = vrtc_cmos_read(RTC_MONTH);
99         time->tm_year = vrtc_cmos_read(RTC_YEAR);
100         spin_unlock_irqrestore(&rtc_lock, flags);
101
102         /* Adjust for the 1960/1900 */
103         time->tm_year += 60;
104         time->tm_mon--;
105         return RTC_24H;
106 }
107
108 static int mrst_set_time(struct device *dev, struct rtc_time *time)
109 {
110         int ret;
111         unsigned long flags;
112         unsigned char mon, day, hrs, min, sec;
113         unsigned int yrs;
114
115         yrs = time->tm_year;
116         mon = time->tm_mon + 1;   /* tm_mon starts at zero */
117         day = time->tm_mday;
118         hrs = time->tm_hour;
119         min = time->tm_min;
120         sec = time->tm_sec;
121
122         if (yrs < 70 || yrs > 138)
123                 return -EINVAL;
124         yrs -= 60;
125
126         spin_lock_irqsave(&rtc_lock, flags);
127
128         vrtc_cmos_write(yrs, RTC_YEAR);
129         vrtc_cmos_write(mon, RTC_MONTH);
130         vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
131         vrtc_cmos_write(hrs, RTC_HOURS);
132         vrtc_cmos_write(min, RTC_MINUTES);
133         vrtc_cmos_write(sec, RTC_SECONDS);
134
135         spin_unlock_irqrestore(&rtc_lock, flags);
136
137         ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
138         return ret;
139 }
140
141 static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
142 {
143         struct mrst_rtc *mrst = dev_get_drvdata(dev);
144         unsigned char rtc_control;
145
146         if (mrst->irq <= 0)
147                 return -EIO;
148
149         /* Basic alarms only support hour, minute, and seconds fields.
150          * Some also support day and month, for alarms up to a year in
151          * the future.
152          */
153         t->time.tm_mday = -1;
154         t->time.tm_mon = -1;
155         t->time.tm_year = -1;
156
157         /* vRTC only supports binary mode */
158         spin_lock_irq(&rtc_lock);
159         t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
160         t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
161         t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
162
163         rtc_control = vrtc_cmos_read(RTC_CONTROL);
164         spin_unlock_irq(&rtc_lock);
165
166         t->enabled = !!(rtc_control & RTC_AIE);
167         t->pending = 0;
168
169         return 0;
170 }
171
172 static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
173 {
174         unsigned char   rtc_intr;
175
176         /*
177          * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
178          * allegedly some older rtcs need that to handle irqs properly
179          */
180         rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
181         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
182         if (is_intr(rtc_intr))
183                 rtc_update_irq(mrst->rtc, 1, rtc_intr);
184 }
185
186 static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
187 {
188         unsigned char   rtc_control;
189
190         /*
191          * Flush any pending IRQ status, notably for update irqs,
192          * before we enable new IRQs
193          */
194         rtc_control = vrtc_cmos_read(RTC_CONTROL);
195         mrst_checkintr(mrst, rtc_control);
196
197         rtc_control |= mask;
198         vrtc_cmos_write(rtc_control, RTC_CONTROL);
199
200         mrst_checkintr(mrst, rtc_control);
201 }
202
203 static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
204 {
205         unsigned char   rtc_control;
206
207         rtc_control = vrtc_cmos_read(RTC_CONTROL);
208         rtc_control &= ~mask;
209         vrtc_cmos_write(rtc_control, RTC_CONTROL);
210         mrst_checkintr(mrst, rtc_control);
211 }
212
213 static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
214 {
215         struct mrst_rtc *mrst = dev_get_drvdata(dev);
216         unsigned char hrs, min, sec;
217         int ret = 0;
218
219         if (!mrst->irq)
220                 return -EIO;
221
222         hrs = t->time.tm_hour;
223         min = t->time.tm_min;
224         sec = t->time.tm_sec;
225
226         spin_lock_irq(&rtc_lock);
227         /* Next rtc irq must not be from previous alarm setting */
228         mrst_irq_disable(mrst, RTC_AIE);
229
230         /* Update alarm */
231         vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
232         vrtc_cmos_write(min, RTC_MINUTES_ALARM);
233         vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
234
235         spin_unlock_irq(&rtc_lock);
236
237         ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
238         if (ret)
239                 return ret;
240
241         spin_lock_irq(&rtc_lock);
242         if (t->enabled)
243                 mrst_irq_enable(mrst, RTC_AIE);
244
245         spin_unlock_irq(&rtc_lock);
246
247         return 0;
248 }
249
250 /* Currently, the vRTC doesn't support UIE ON/OFF */
251 static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
252 {
253         struct mrst_rtc *mrst = dev_get_drvdata(dev);
254         unsigned long   flags;
255
256         spin_lock_irqsave(&rtc_lock, flags);
257         if (enabled)
258                 mrst_irq_enable(mrst, RTC_AIE);
259         else
260                 mrst_irq_disable(mrst, RTC_AIE);
261         spin_unlock_irqrestore(&rtc_lock, flags);
262         return 0;
263 }
264
265
266 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
267
268 static int mrst_procfs(struct device *dev, struct seq_file *seq)
269 {
270         unsigned char   rtc_control, valid;
271
272         spin_lock_irq(&rtc_lock);
273         rtc_control = vrtc_cmos_read(RTC_CONTROL);
274         valid = vrtc_cmos_read(RTC_VALID);
275         spin_unlock_irq(&rtc_lock);
276
277         return seq_printf(seq,
278                         "periodic_IRQ\t: %s\n"
279                         "alarm\t\t: %s\n"
280                         "BCD\t\t: no\n"
281                         "periodic_freq\t: daily (not adjustable)\n",
282                         (rtc_control & RTC_PIE) ? "on" : "off",
283                         (rtc_control & RTC_AIE) ? "on" : "off");
284 }
285
286 #else
287 #define mrst_procfs     NULL
288 #endif
289
290 static const struct rtc_class_ops mrst_rtc_ops = {
291         .read_time      = mrst_read_time,
292         .set_time       = mrst_set_time,
293         .read_alarm     = mrst_read_alarm,
294         .set_alarm      = mrst_set_alarm,
295         .proc           = mrst_procfs,
296         .alarm_irq_enable = mrst_rtc_alarm_irq_enable,
297 };
298
299 static struct mrst_rtc  mrst_rtc;
300
301 /*
302  * When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
303  * Reg B, so no need for this driver to clear it
304  */
305 static irqreturn_t mrst_rtc_irq(int irq, void *p)
306 {
307         u8 irqstat;
308
309         spin_lock(&rtc_lock);
310         /* This read will clear all IRQ flags inside Reg C */
311         irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
312         spin_unlock(&rtc_lock);
313
314         irqstat &= RTC_IRQMASK | RTC_IRQF;
315         if (is_intr(irqstat)) {
316                 rtc_update_irq(p, 1, irqstat);
317                 return IRQ_HANDLED;
318         }
319         return IRQ_NONE;
320 }
321
322 static int __devinit
323 vrtc_mrst_do_probe(struct device *dev, struct resource *iomem, int rtc_irq)
324 {
325         int retval = 0;
326         unsigned char rtc_control;
327
328         /* There can be only one ... */
329         if (mrst_rtc.dev)
330                 return -EBUSY;
331
332         if (!iomem)
333                 return -ENODEV;
334
335         iomem = request_mem_region(iomem->start,
336                         iomem->end + 1 - iomem->start,
337                         driver_name);
338         if (!iomem) {
339                 dev_dbg(dev, "i/o mem already in use.\n");
340                 return -EBUSY;
341         }
342
343         mrst_rtc.irq = rtc_irq;
344         mrst_rtc.iomem = iomem;
345         mrst_rtc.dev = dev;
346         dev_set_drvdata(dev, &mrst_rtc);
347
348         mrst_rtc.rtc = rtc_device_register(driver_name, dev,
349                                 &mrst_rtc_ops, THIS_MODULE);
350         if (IS_ERR(mrst_rtc.rtc)) {
351                 retval = PTR_ERR(mrst_rtc.rtc);
352                 goto cleanup0;
353         }
354
355         rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
356
357         spin_lock_irq(&rtc_lock);
358         mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
359         rtc_control = vrtc_cmos_read(RTC_CONTROL);
360         spin_unlock_irq(&rtc_lock);
361
362         if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
363                 dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
364
365         if (rtc_irq) {
366                 retval = request_irq(rtc_irq, mrst_rtc_irq,
367                                 IRQF_DISABLED, dev_name(&mrst_rtc.rtc->dev),
368                                 mrst_rtc.rtc);
369                 if (retval < 0) {
370                         dev_dbg(dev, "IRQ %d is already in use, err %d\n",
371                                 rtc_irq, retval);
372                         goto cleanup1;
373                 }
374         }
375         dev_dbg(dev, "initialised\n");
376         return 0;
377
378 cleanup1:
379         rtc_device_unregister(mrst_rtc.rtc);
380 cleanup0:
381         dev_set_drvdata(dev, NULL);
382         mrst_rtc.dev = NULL;
383         release_region(iomem->start, iomem->end + 1 - iomem->start);
384         dev_err(dev, "rtc-mrst: unable to initialise\n");
385         return retval;
386 }
387
388 static void rtc_mrst_do_shutdown(void)
389 {
390         spin_lock_irq(&rtc_lock);
391         mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
392         spin_unlock_irq(&rtc_lock);
393 }
394
395 static void __devexit rtc_mrst_do_remove(struct device *dev)
396 {
397         struct mrst_rtc *mrst = dev_get_drvdata(dev);
398         struct resource *iomem;
399
400         rtc_mrst_do_shutdown();
401
402         if (mrst->irq)
403                 free_irq(mrst->irq, mrst->rtc);
404
405         rtc_device_unregister(mrst->rtc);
406         mrst->rtc = NULL;
407
408         iomem = mrst->iomem;
409         release_region(iomem->start, iomem->end + 1 - iomem->start);
410         mrst->iomem = NULL;
411
412         mrst->dev = NULL;
413         dev_set_drvdata(dev, NULL);
414 }
415
416 #ifdef  CONFIG_PM
417 static int mrst_suspend(struct device *dev, pm_message_t mesg)
418 {
419         struct mrst_rtc *mrst = dev_get_drvdata(dev);
420         unsigned char   tmp;
421
422         /* Only the alarm might be a wakeup event source */
423         spin_lock_irq(&rtc_lock);
424         mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
425         if (tmp & (RTC_PIE | RTC_AIE)) {
426                 unsigned char   mask;
427
428                 if (device_may_wakeup(dev))
429                         mask = RTC_IRQMASK & ~RTC_AIE;
430                 else
431                         mask = RTC_IRQMASK;
432                 tmp &= ~mask;
433                 vrtc_cmos_write(tmp, RTC_CONTROL);
434
435                 mrst_checkintr(mrst, tmp);
436         }
437         spin_unlock_irq(&rtc_lock);
438
439         if (tmp & RTC_AIE) {
440                 mrst->enabled_wake = 1;
441                 enable_irq_wake(mrst->irq);
442         }
443
444         dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
445                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
446                         tmp);
447
448         return 0;
449 }
450
451 /*
452  * We want RTC alarms to wake us from the deep power saving state
453  */
454 static inline int mrst_poweroff(struct device *dev)
455 {
456         return mrst_suspend(dev, PMSG_HIBERNATE);
457 }
458
459 static int mrst_resume(struct device *dev)
460 {
461         struct mrst_rtc *mrst = dev_get_drvdata(dev);
462         unsigned char tmp = mrst->suspend_ctrl;
463
464         /* Re-enable any irqs previously active */
465         if (tmp & RTC_IRQMASK) {
466                 unsigned char   mask;
467
468                 if (mrst->enabled_wake) {
469                         disable_irq_wake(mrst->irq);
470                         mrst->enabled_wake = 0;
471                 }
472
473                 spin_lock_irq(&rtc_lock);
474                 do {
475                         vrtc_cmos_write(tmp, RTC_CONTROL);
476
477                         mask = vrtc_cmos_read(RTC_INTR_FLAGS);
478                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
479                         if (!is_intr(mask))
480                                 break;
481
482                         rtc_update_irq(mrst->rtc, 1, mask);
483                         tmp &= ~RTC_AIE;
484                 } while (mask & RTC_AIE);
485                 spin_unlock_irq(&rtc_lock);
486         }
487
488         dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
489
490         return 0;
491 }
492
493 #else
494 #define mrst_suspend    NULL
495 #define mrst_resume     NULL
496
497 static inline int mrst_poweroff(struct device *dev)
498 {
499         return -ENOSYS;
500 }
501
502 #endif
503
504 static int __devinit vrtc_mrst_platform_probe(struct platform_device *pdev)
505 {
506         return vrtc_mrst_do_probe(&pdev->dev,
507                         platform_get_resource(pdev, IORESOURCE_MEM, 0),
508                         platform_get_irq(pdev, 0));
509 }
510
511 static int __devexit vrtc_mrst_platform_remove(struct platform_device *pdev)
512 {
513         rtc_mrst_do_remove(&pdev->dev);
514         return 0;
515 }
516
517 static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
518 {
519         if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
520                 return;
521
522         rtc_mrst_do_shutdown();
523 }
524
525 MODULE_ALIAS("platform:vrtc_mrst");
526
527 static struct platform_driver vrtc_mrst_platform_driver = {
528         .probe          = vrtc_mrst_platform_probe,
529         .remove         = __devexit_p(vrtc_mrst_platform_remove),
530         .shutdown       = vrtc_mrst_platform_shutdown,
531         .driver = {
532                 .name           = (char *) driver_name,
533                 .suspend        = mrst_suspend,
534                 .resume         = mrst_resume,
535         }
536 };
537
538 static int __init vrtc_mrst_init(void)
539 {
540         return platform_driver_register(&vrtc_mrst_platform_driver);
541 }
542
543 static void __exit vrtc_mrst_exit(void)
544 {
545         platform_driver_unregister(&vrtc_mrst_platform_driver);
546 }
547
548 module_init(vrtc_mrst_init);
549 module_exit(vrtc_mrst_exit);
550
551 MODULE_AUTHOR("Jacob Pan; Feng Tang");
552 MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
553 MODULE_LICENSE("GPL");