vrtc: change its year offset from 1960 to 1972
[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 1972 (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 1972 will
83  * make it consistent in leap year setting for both vrtc and low-level
84  * physical rtc devices. Then why not use 1960 as the offset? If we use
85  * 1960, for a device's first use, its YEAR register is 0 and the system
86  * year will be parsed as 1960 which is not a valid UNIX time and will
87  * cause many applications to fail mysteriously.
88  */
89 static int mrst_read_time(struct device *dev, struct rtc_time *time)
90 {
91         unsigned long flags;
92
93         if (vrtc_is_updating())
94                 mdelay(20);
95
96         spin_lock_irqsave(&rtc_lock, flags);
97         time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
98         time->tm_min = vrtc_cmos_read(RTC_MINUTES);
99         time->tm_hour = vrtc_cmos_read(RTC_HOURS);
100         time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
101         time->tm_mon = vrtc_cmos_read(RTC_MONTH);
102         time->tm_year = vrtc_cmos_read(RTC_YEAR);
103         spin_unlock_irqrestore(&rtc_lock, flags);
104
105         /* Adjust for the 1972/1900 */
106         time->tm_year += 72;
107         time->tm_mon--;
108         return rtc_valid_tm(time);
109 }
110
111 static int mrst_set_time(struct device *dev, struct rtc_time *time)
112 {
113         int ret;
114         unsigned long flags;
115         unsigned char mon, day, hrs, min, sec;
116         unsigned int yrs;
117
118         yrs = time->tm_year;
119         mon = time->tm_mon + 1;   /* tm_mon starts at zero */
120         day = time->tm_mday;
121         hrs = time->tm_hour;
122         min = time->tm_min;
123         sec = time->tm_sec;
124
125         if (yrs < 72 || yrs > 138)
126                 return -EINVAL;
127         yrs -= 72;
128
129         spin_lock_irqsave(&rtc_lock, flags);
130
131         vrtc_cmos_write(yrs, RTC_YEAR);
132         vrtc_cmos_write(mon, RTC_MONTH);
133         vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
134         vrtc_cmos_write(hrs, RTC_HOURS);
135         vrtc_cmos_write(min, RTC_MINUTES);
136         vrtc_cmos_write(sec, RTC_SECONDS);
137
138         spin_unlock_irqrestore(&rtc_lock, flags);
139
140         ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
141         return ret;
142 }
143
144 static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
145 {
146         struct mrst_rtc *mrst = dev_get_drvdata(dev);
147         unsigned char rtc_control;
148
149         if (mrst->irq <= 0)
150                 return -EIO;
151
152         /* Basic alarms only support hour, minute, and seconds fields.
153          * Some also support day and month, for alarms up to a year in
154          * the future.
155          */
156         t->time.tm_mday = -1;
157         t->time.tm_mon = -1;
158         t->time.tm_year = -1;
159
160         /* vRTC only supports binary mode */
161         spin_lock_irq(&rtc_lock);
162         t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
163         t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
164         t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
165
166         rtc_control = vrtc_cmos_read(RTC_CONTROL);
167         spin_unlock_irq(&rtc_lock);
168
169         t->enabled = !!(rtc_control & RTC_AIE);
170         t->pending = 0;
171
172         return 0;
173 }
174
175 static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
176 {
177         unsigned char   rtc_intr;
178
179         /*
180          * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
181          * allegedly some older rtcs need that to handle irqs properly
182          */
183         rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
184         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
185         if (is_intr(rtc_intr))
186                 rtc_update_irq(mrst->rtc, 1, rtc_intr);
187 }
188
189 static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
190 {
191         unsigned char   rtc_control;
192
193         /*
194          * Flush any pending IRQ status, notably for update irqs,
195          * before we enable new IRQs
196          */
197         rtc_control = vrtc_cmos_read(RTC_CONTROL);
198         mrst_checkintr(mrst, rtc_control);
199
200         rtc_control |= mask;
201         vrtc_cmos_write(rtc_control, RTC_CONTROL);
202
203         mrst_checkintr(mrst, rtc_control);
204 }
205
206 static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
207 {
208         unsigned char   rtc_control;
209
210         rtc_control = vrtc_cmos_read(RTC_CONTROL);
211         rtc_control &= ~mask;
212         vrtc_cmos_write(rtc_control, RTC_CONTROL);
213         mrst_checkintr(mrst, rtc_control);
214 }
215
216 static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
217 {
218         struct mrst_rtc *mrst = dev_get_drvdata(dev);
219         unsigned char hrs, min, sec;
220         int ret = 0;
221
222         if (!mrst->irq)
223                 return -EIO;
224
225         hrs = t->time.tm_hour;
226         min = t->time.tm_min;
227         sec = t->time.tm_sec;
228
229         spin_lock_irq(&rtc_lock);
230         /* Next rtc irq must not be from previous alarm setting */
231         mrst_irq_disable(mrst, RTC_AIE);
232
233         /* Update alarm */
234         vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
235         vrtc_cmos_write(min, RTC_MINUTES_ALARM);
236         vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
237
238         spin_unlock_irq(&rtc_lock);
239
240         ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
241         if (ret)
242                 return ret;
243
244         spin_lock_irq(&rtc_lock);
245         if (t->enabled)
246                 mrst_irq_enable(mrst, RTC_AIE);
247
248         spin_unlock_irq(&rtc_lock);
249
250         return 0;
251 }
252
253 /* Currently, the vRTC doesn't support UIE ON/OFF */
254 static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
255 {
256         struct mrst_rtc *mrst = dev_get_drvdata(dev);
257         unsigned long   flags;
258
259         spin_lock_irqsave(&rtc_lock, flags);
260         if (enabled)
261                 mrst_irq_enable(mrst, RTC_AIE);
262         else
263                 mrst_irq_disable(mrst, RTC_AIE);
264         spin_unlock_irqrestore(&rtc_lock, flags);
265         return 0;
266 }
267
268
269 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
270
271 static int mrst_procfs(struct device *dev, struct seq_file *seq)
272 {
273         unsigned char   rtc_control, valid;
274
275         spin_lock_irq(&rtc_lock);
276         rtc_control = vrtc_cmos_read(RTC_CONTROL);
277         valid = vrtc_cmos_read(RTC_VALID);
278         spin_unlock_irq(&rtc_lock);
279
280         return seq_printf(seq,
281                         "periodic_IRQ\t: %s\n"
282                         "alarm\t\t: %s\n"
283                         "BCD\t\t: no\n"
284                         "periodic_freq\t: daily (not adjustable)\n",
285                         (rtc_control & RTC_PIE) ? "on" : "off",
286                         (rtc_control & RTC_AIE) ? "on" : "off");
287 }
288
289 #else
290 #define mrst_procfs     NULL
291 #endif
292
293 static const struct rtc_class_ops mrst_rtc_ops = {
294         .read_time      = mrst_read_time,
295         .set_time       = mrst_set_time,
296         .read_alarm     = mrst_read_alarm,
297         .set_alarm      = mrst_set_alarm,
298         .proc           = mrst_procfs,
299         .alarm_irq_enable = mrst_rtc_alarm_irq_enable,
300 };
301
302 static struct mrst_rtc  mrst_rtc;
303
304 /*
305  * When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
306  * Reg B, so no need for this driver to clear it
307  */
308 static irqreturn_t mrst_rtc_irq(int irq, void *p)
309 {
310         u8 irqstat;
311
312         spin_lock(&rtc_lock);
313         /* This read will clear all IRQ flags inside Reg C */
314         irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
315         spin_unlock(&rtc_lock);
316
317         irqstat &= RTC_IRQMASK | RTC_IRQF;
318         if (is_intr(irqstat)) {
319                 rtc_update_irq(p, 1, irqstat);
320                 return IRQ_HANDLED;
321         }
322         return IRQ_NONE;
323 }
324
325 static int __devinit
326 vrtc_mrst_do_probe(struct device *dev, struct resource *iomem, int rtc_irq)
327 {
328         int retval = 0;
329         unsigned char rtc_control;
330
331         /* There can be only one ... */
332         if (mrst_rtc.dev)
333                 return -EBUSY;
334
335         if (!iomem)
336                 return -ENODEV;
337
338         iomem = request_mem_region(iomem->start, resource_size(iomem),
339                                    driver_name);
340         if (!iomem) {
341                 dev_dbg(dev, "i/o mem already in use.\n");
342                 return -EBUSY;
343         }
344
345         mrst_rtc.irq = rtc_irq;
346         mrst_rtc.iomem = iomem;
347         mrst_rtc.dev = dev;
348         dev_set_drvdata(dev, &mrst_rtc);
349
350         mrst_rtc.rtc = rtc_device_register(driver_name, dev,
351                                 &mrst_rtc_ops, THIS_MODULE);
352         if (IS_ERR(mrst_rtc.rtc)) {
353                 retval = PTR_ERR(mrst_rtc.rtc);
354                 goto cleanup0;
355         }
356
357         rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
358
359         spin_lock_irq(&rtc_lock);
360         mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
361         rtc_control = vrtc_cmos_read(RTC_CONTROL);
362         spin_unlock_irq(&rtc_lock);
363
364         if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
365                 dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
366
367         if (rtc_irq) {
368                 retval = request_irq(rtc_irq, mrst_rtc_irq,
369                                 IRQF_DISABLED, dev_name(&mrst_rtc.rtc->dev),
370                                 mrst_rtc.rtc);
371                 if (retval < 0) {
372                         dev_dbg(dev, "IRQ %d is already in use, err %d\n",
373                                 rtc_irq, retval);
374                         goto cleanup1;
375                 }
376         }
377         dev_dbg(dev, "initialised\n");
378         return 0;
379
380 cleanup1:
381         rtc_device_unregister(mrst_rtc.rtc);
382 cleanup0:
383         dev_set_drvdata(dev, NULL);
384         mrst_rtc.dev = NULL;
385         release_mem_region(iomem->start, resource_size(iomem));
386         dev_err(dev, "rtc-mrst: unable to initialise\n");
387         return retval;
388 }
389
390 static void rtc_mrst_do_shutdown(void)
391 {
392         spin_lock_irq(&rtc_lock);
393         mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
394         spin_unlock_irq(&rtc_lock);
395 }
396
397 static void __devexit rtc_mrst_do_remove(struct device *dev)
398 {
399         struct mrst_rtc *mrst = dev_get_drvdata(dev);
400         struct resource *iomem;
401
402         rtc_mrst_do_shutdown();
403
404         if (mrst->irq)
405                 free_irq(mrst->irq, mrst->rtc);
406
407         rtc_device_unregister(mrst->rtc);
408         mrst->rtc = NULL;
409
410         iomem = mrst->iomem;
411         release_mem_region(iomem->start, resource_size(iomem));
412         mrst->iomem = NULL;
413
414         mrst->dev = NULL;
415         dev_set_drvdata(dev, NULL);
416 }
417
418 #ifdef  CONFIG_PM
419 static int mrst_suspend(struct device *dev, pm_message_t mesg)
420 {
421         struct mrst_rtc *mrst = dev_get_drvdata(dev);
422         unsigned char   tmp;
423
424         /* Only the alarm might be a wakeup event source */
425         spin_lock_irq(&rtc_lock);
426         mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
427         if (tmp & (RTC_PIE | RTC_AIE)) {
428                 unsigned char   mask;
429
430                 if (device_may_wakeup(dev))
431                         mask = RTC_IRQMASK & ~RTC_AIE;
432                 else
433                         mask = RTC_IRQMASK;
434                 tmp &= ~mask;
435                 vrtc_cmos_write(tmp, RTC_CONTROL);
436
437                 mrst_checkintr(mrst, tmp);
438         }
439         spin_unlock_irq(&rtc_lock);
440
441         if (tmp & RTC_AIE) {
442                 mrst->enabled_wake = 1;
443                 enable_irq_wake(mrst->irq);
444         }
445
446         dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
447                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
448                         tmp);
449
450         return 0;
451 }
452
453 /*
454  * We want RTC alarms to wake us from the deep power saving state
455  */
456 static inline int mrst_poweroff(struct device *dev)
457 {
458         return mrst_suspend(dev, PMSG_HIBERNATE);
459 }
460
461 static int mrst_resume(struct device *dev)
462 {
463         struct mrst_rtc *mrst = dev_get_drvdata(dev);
464         unsigned char tmp = mrst->suspend_ctrl;
465
466         /* Re-enable any irqs previously active */
467         if (tmp & RTC_IRQMASK) {
468                 unsigned char   mask;
469
470                 if (mrst->enabled_wake) {
471                         disable_irq_wake(mrst->irq);
472                         mrst->enabled_wake = 0;
473                 }
474
475                 spin_lock_irq(&rtc_lock);
476                 do {
477                         vrtc_cmos_write(tmp, RTC_CONTROL);
478
479                         mask = vrtc_cmos_read(RTC_INTR_FLAGS);
480                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
481                         if (!is_intr(mask))
482                                 break;
483
484                         rtc_update_irq(mrst->rtc, 1, mask);
485                         tmp &= ~RTC_AIE;
486                 } while (mask & RTC_AIE);
487                 spin_unlock_irq(&rtc_lock);
488         }
489
490         dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
491
492         return 0;
493 }
494
495 #else
496 #define mrst_suspend    NULL
497 #define mrst_resume     NULL
498
499 static inline int mrst_poweroff(struct device *dev)
500 {
501         return -ENOSYS;
502 }
503
504 #endif
505
506 static int __devinit vrtc_mrst_platform_probe(struct platform_device *pdev)
507 {
508         return vrtc_mrst_do_probe(&pdev->dev,
509                         platform_get_resource(pdev, IORESOURCE_MEM, 0),
510                         platform_get_irq(pdev, 0));
511 }
512
513 static int __devexit vrtc_mrst_platform_remove(struct platform_device *pdev)
514 {
515         rtc_mrst_do_remove(&pdev->dev);
516         return 0;
517 }
518
519 static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
520 {
521         if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
522                 return;
523
524         rtc_mrst_do_shutdown();
525 }
526
527 MODULE_ALIAS("platform:vrtc_mrst");
528
529 static struct platform_driver vrtc_mrst_platform_driver = {
530         .probe          = vrtc_mrst_platform_probe,
531         .remove         = __devexit_p(vrtc_mrst_platform_remove),
532         .shutdown       = vrtc_mrst_platform_shutdown,
533         .driver = {
534                 .name           = (char *) driver_name,
535                 .suspend        = mrst_suspend,
536                 .resume         = mrst_resume,
537         }
538 };
539
540 static int __init vrtc_mrst_init(void)
541 {
542         return platform_driver_register(&vrtc_mrst_platform_driver);
543 }
544
545 static void __exit vrtc_mrst_exit(void)
546 {
547         platform_driver_unregister(&vrtc_mrst_platform_driver);
548 }
549
550 module_init(vrtc_mrst_init);
551 module_exit(vrtc_mrst_exit);
552
553 MODULE_AUTHOR("Jacob Pan; Feng Tang");
554 MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
555 MODULE_LICENSE("GPL");