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Linux/drivers/rtc/rtc-cmos.c

  1 /*
  2  * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
  3  *
  4  * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
  5  * Copyright (C) 2006 David Brownell (convert to new framework)
  6  *
  7  * This program is free software; you can redistribute it and/or
  8  * modify it under the terms of the GNU General Public License
  9  * as published by the Free Software Foundation; either version
 10  * 2 of the License, or (at your option) any later version.
 11  */
 12 
 13 /*
 14  * The original "cmos clock" chip was an MC146818 chip, now obsolete.
 15  * That defined the register interface now provided by all PCs, some
 16  * non-PC systems, and incorporated into ACPI.  Modern PC chipsets
 17  * integrate an MC146818 clone in their southbridge, and boards use
 18  * that instead of discrete clones like the DS12887 or M48T86.  There
 19  * are also clones that connect using the LPC bus.
 20  *
 21  * That register API is also used directly by various other drivers
 22  * (notably for integrated NVRAM), infrastructure (x86 has code to
 23  * bypass the RTC framework, directly reading the RTC during boot
 24  * and updating minutes/seconds for systems using NTP synch) and
 25  * utilities (like userspace 'hwclock', if no /dev node exists).
 26  *
 27  * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
 28  * interrupts disabled, holding the global rtc_lock, to exclude those
 29  * other drivers and utilities on correctly configured systems.
 30  */
 31 
 32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 33 
 34 #include <linux/kernel.h>
 35 #include <linux/module.h>
 36 #include <linux/init.h>
 37 #include <linux/interrupt.h>
 38 #include <linux/spinlock.h>
 39 #include <linux/platform_device.h>
 40 #include <linux/log2.h>
 41 #include <linux/pm.h>
 42 #include <linux/of.h>
 43 #include <linux/of_platform.h>
 44 #include <linux/dmi.h>
 45 
 46 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
 47 #include <asm-generic/rtc.h>
 48 
 49 struct cmos_rtc {
 50         struct rtc_device       *rtc;
 51         struct device           *dev;
 52         int                     irq;
 53         struct resource         *iomem;
 54 
 55         void                    (*wake_on)(struct device *);
 56         void                    (*wake_off)(struct device *);
 57 
 58         u8                      enabled_wake;
 59         u8                      suspend_ctrl;
 60 
 61         /* newer hardware extends the original register set */
 62         u8                      day_alrm;
 63         u8                      mon_alrm;
 64         u8                      century;
 65 };
 66 
 67 /* both platform and pnp busses use negative numbers for invalid irqs */
 68 #define is_valid_irq(n)         ((n) > 0)
 69 
 70 static const char driver_name[] = "rtc_cmos";
 71 
 72 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
 73  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
 74  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
 75  */
 76 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
 77 
 78 static inline int is_intr(u8 rtc_intr)
 79 {
 80         if (!(rtc_intr & RTC_IRQF))
 81                 return 0;
 82         return rtc_intr & RTC_IRQMASK;
 83 }
 84 
 85 /*----------------------------------------------------------------*/
 86 
 87 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
 88  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
 89  * used in a broken "legacy replacement" mode.  The breakage includes
 90  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
 91  * other (better) use.
 92  *
 93  * When that broken mode is in use, platform glue provides a partial
 94  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
 95  * want to use HPET for anything except those IRQs though...
 96  */
 97 #ifdef CONFIG_HPET_EMULATE_RTC
 98 #include <asm/hpet.h>
 99 #else
100 
101 static inline int is_hpet_enabled(void)
102 {
103         return 0;
104 }
105 
106 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
107 {
108         return 0;
109 }
110 
111 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
112 {
113         return 0;
114 }
115 
116 static inline int
117 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
118 {
119         return 0;
120 }
121 
122 static inline int hpet_set_periodic_freq(unsigned long freq)
123 {
124         return 0;
125 }
126 
127 static inline int hpet_rtc_dropped_irq(void)
128 {
129         return 0;
130 }
131 
132 static inline int hpet_rtc_timer_init(void)
133 {
134         return 0;
135 }
136 
137 extern irq_handler_t hpet_rtc_interrupt;
138 
139 static inline int hpet_register_irq_handler(irq_handler_t handler)
140 {
141         return 0;
142 }
143 
144 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
145 {
146         return 0;
147 }
148 
149 #endif
150 
151 /*----------------------------------------------------------------*/
152 
153 #ifdef RTC_PORT
154 
155 /* Most newer x86 systems have two register banks, the first used
156  * for RTC and NVRAM and the second only for NVRAM.  Caller must
157  * own rtc_lock ... and we won't worry about access during NMI.
158  */
159 #define can_bank2       true
160 
161 static inline unsigned char cmos_read_bank2(unsigned char addr)
162 {
163         outb(addr, RTC_PORT(2));
164         return inb(RTC_PORT(3));
165 }
166 
167 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
168 {
169         outb(addr, RTC_PORT(2));
170         outb(val, RTC_PORT(3));
171 }
172 
173 #else
174 
175 #define can_bank2       false
176 
177 static inline unsigned char cmos_read_bank2(unsigned char addr)
178 {
179         return 0;
180 }
181 
182 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
183 {
184 }
185 
186 #endif
187 
188 /*----------------------------------------------------------------*/
189 
190 static int cmos_read_time(struct device *dev, struct rtc_time *t)
191 {
192         /* REVISIT:  if the clock has a "century" register, use
193          * that instead of the heuristic in get_rtc_time().
194          * That'll make Y3K compatility (year > 2070) easy!
195          */
196         get_rtc_time(t);
197         return 0;
198 }
199 
200 static int cmos_set_time(struct device *dev, struct rtc_time *t)
201 {
202         /* REVISIT:  set the "century" register if available
203          *
204          * NOTE: this ignores the issue whereby updating the seconds
205          * takes effect exactly 500ms after we write the register.
206          * (Also queueing and other delays before we get this far.)
207          */
208         return set_rtc_time(t);
209 }
210 
211 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
212 {
213         struct cmos_rtc *cmos = dev_get_drvdata(dev);
214         unsigned char   rtc_control;
215 
216         if (!is_valid_irq(cmos->irq))
217                 return -EIO;
218 
219         /* Basic alarms only support hour, minute, and seconds fields.
220          * Some also support day and month, for alarms up to a year in
221          * the future.
222          */
223         t->time.tm_mday = -1;
224         t->time.tm_mon = -1;
225 
226         spin_lock_irq(&rtc_lock);
227         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
228         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
229         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
230 
231         if (cmos->day_alrm) {
232                 /* ignore upper bits on readback per ACPI spec */
233                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
234                 if (!t->time.tm_mday)
235                         t->time.tm_mday = -1;
236 
237                 if (cmos->mon_alrm) {
238                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
239                         if (!t->time.tm_mon)
240                                 t->time.tm_mon = -1;
241                 }
242         }
243 
244         rtc_control = CMOS_READ(RTC_CONTROL);
245         spin_unlock_irq(&rtc_lock);
246 
247         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
248                 if (((unsigned)t->time.tm_sec) < 0x60)
249                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
250                 else
251                         t->time.tm_sec = -1;
252                 if (((unsigned)t->time.tm_min) < 0x60)
253                         t->time.tm_min = bcd2bin(t->time.tm_min);
254                 else
255                         t->time.tm_min = -1;
256                 if (((unsigned)t->time.tm_hour) < 0x24)
257                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
258                 else
259                         t->time.tm_hour = -1;
260 
261                 if (cmos->day_alrm) {
262                         if (((unsigned)t->time.tm_mday) <= 0x31)
263                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
264                         else
265                                 t->time.tm_mday = -1;
266 
267                         if (cmos->mon_alrm) {
268                                 if (((unsigned)t->time.tm_mon) <= 0x12)
269                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
270                                 else
271                                         t->time.tm_mon = -1;
272                         }
273                 }
274         }
275         t->time.tm_year = -1;
276 
277         t->enabled = !!(rtc_control & RTC_AIE);
278         t->pending = 0;
279 
280         return 0;
281 }
282 
283 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
284 {
285         unsigned char   rtc_intr;
286 
287         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
288          * allegedly some older rtcs need that to handle irqs properly
289          */
290         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
291 
292         if (is_hpet_enabled())
293                 return;
294 
295         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
296         if (is_intr(rtc_intr))
297                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
298 }
299 
300 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
301 {
302         unsigned char   rtc_control;
303 
304         /* flush any pending IRQ status, notably for update irqs,
305          * before we enable new IRQs
306          */
307         rtc_control = CMOS_READ(RTC_CONTROL);
308         cmos_checkintr(cmos, rtc_control);
309 
310         rtc_control |= mask;
311         CMOS_WRITE(rtc_control, RTC_CONTROL);
312         hpet_set_rtc_irq_bit(mask);
313 
314         cmos_checkintr(cmos, rtc_control);
315 }
316 
317 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
318 {
319         unsigned char   rtc_control;
320 
321         rtc_control = CMOS_READ(RTC_CONTROL);
322         rtc_control &= ~mask;
323         CMOS_WRITE(rtc_control, RTC_CONTROL);
324         hpet_mask_rtc_irq_bit(mask);
325 
326         cmos_checkintr(cmos, rtc_control);
327 }
328 
329 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
330 {
331         struct cmos_rtc *cmos = dev_get_drvdata(dev);
332         unsigned char mon, mday, hrs, min, sec, rtc_control;
333 
334         if (!is_valid_irq(cmos->irq))
335                 return -EIO;
336 
337         mon = t->time.tm_mon + 1;
338         mday = t->time.tm_mday;
339         hrs = t->time.tm_hour;
340         min = t->time.tm_min;
341         sec = t->time.tm_sec;
342 
343         rtc_control = CMOS_READ(RTC_CONTROL);
344         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
345                 /* Writing 0xff means "don't care" or "match all".  */
346                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
347                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
348                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
349                 min = (min < 60) ? bin2bcd(min) : 0xff;
350                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
351         }
352 
353         spin_lock_irq(&rtc_lock);
354 
355         /* next rtc irq must not be from previous alarm setting */
356         cmos_irq_disable(cmos, RTC_AIE);
357 
358         /* update alarm */
359         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
360         CMOS_WRITE(min, RTC_MINUTES_ALARM);
361         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
362 
363         /* the system may support an "enhanced" alarm */
364         if (cmos->day_alrm) {
365                 CMOS_WRITE(mday, cmos->day_alrm);
366                 if (cmos->mon_alrm)
367                         CMOS_WRITE(mon, cmos->mon_alrm);
368         }
369 
370         /* FIXME the HPET alarm glue currently ignores day_alrm
371          * and mon_alrm ...
372          */
373         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
374 
375         if (t->enabled)
376                 cmos_irq_enable(cmos, RTC_AIE);
377 
378         spin_unlock_irq(&rtc_lock);
379 
380         return 0;
381 }
382 
383 /*
384  * Do not disable RTC alarm on shutdown - workaround for b0rked BIOSes.
385  */
386 static bool alarm_disable_quirk;
387 
388 static int __init set_alarm_disable_quirk(const struct dmi_system_id *id)
389 {
390         alarm_disable_quirk = true;
391         pr_info("BIOS has alarm-disable quirk - RTC alarms disabled\n");
392         return 0;
393 }
394 
395 static const struct dmi_system_id rtc_quirks[] __initconst = {
396         /* https://bugzilla.novell.com/show_bug.cgi?id=805740 */
397         {
398                 .callback = set_alarm_disable_quirk,
399                 .ident    = "IBM Truman",
400                 .matches  = {
401                         DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
402                         DMI_MATCH(DMI_PRODUCT_NAME, "4852570"),
403                 },
404         },
405         /* https://bugzilla.novell.com/show_bug.cgi?id=812592 */
406         {
407                 .callback = set_alarm_disable_quirk,
408                 .ident    = "Gigabyte GA-990XA-UD3",
409                 .matches  = {
410                         DMI_MATCH(DMI_SYS_VENDOR,
411                                         "Gigabyte Technology Co., Ltd."),
412                         DMI_MATCH(DMI_PRODUCT_NAME, "GA-990XA-UD3"),
413                 },
414         },
415         /* http://permalink.gmane.org/gmane.linux.kernel/1604474 */
416         {
417                 .callback = set_alarm_disable_quirk,
418                 .ident    = "Toshiba Satellite L300",
419                 .matches  = {
420                         DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
421                         DMI_MATCH(DMI_PRODUCT_NAME, "Satellite L300"),
422                 },
423         },
424         {}
425 };
426 
427 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
428 {
429         struct cmos_rtc *cmos = dev_get_drvdata(dev);
430         unsigned long   flags;
431 
432         if (!is_valid_irq(cmos->irq))
433                 return -EINVAL;
434 
435         if (alarm_disable_quirk)
436                 return 0;
437 
438         spin_lock_irqsave(&rtc_lock, flags);
439 
440         if (enabled)
441                 cmos_irq_enable(cmos, RTC_AIE);
442         else
443                 cmos_irq_disable(cmos, RTC_AIE);
444 
445         spin_unlock_irqrestore(&rtc_lock, flags);
446         return 0;
447 }
448 
449 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
450 
451 static int cmos_procfs(struct device *dev, struct seq_file *seq)
452 {
453         struct cmos_rtc *cmos = dev_get_drvdata(dev);
454         unsigned char   rtc_control, valid;
455 
456         spin_lock_irq(&rtc_lock);
457         rtc_control = CMOS_READ(RTC_CONTROL);
458         valid = CMOS_READ(RTC_VALID);
459         spin_unlock_irq(&rtc_lock);
460 
461         /* NOTE:  at least ICH6 reports battery status using a different
462          * (non-RTC) bit; and SQWE is ignored on many current systems.
463          */
464         seq_printf(seq,
465                    "periodic_IRQ\t: %s\n"
466                    "update_IRQ\t: %s\n"
467                    "HPET_emulated\t: %s\n"
468                    // "square_wave\t: %s\n"
469                    "BCD\t\t: %s\n"
470                    "DST_enable\t: %s\n"
471                    "periodic_freq\t: %d\n"
472                    "batt_status\t: %s\n",
473                    (rtc_control & RTC_PIE) ? "yes" : "no",
474                    (rtc_control & RTC_UIE) ? "yes" : "no",
475                    is_hpet_enabled() ? "yes" : "no",
476                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
477                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
478                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
479                    cmos->rtc->irq_freq,
480                    (valid & RTC_VRT) ? "okay" : "dead");
481 
482         return 0;
483 }
484 
485 #else
486 #define cmos_procfs     NULL
487 #endif
488 
489 static const struct rtc_class_ops cmos_rtc_ops = {
490         .read_time              = cmos_read_time,
491         .set_time               = cmos_set_time,
492         .read_alarm             = cmos_read_alarm,
493         .set_alarm              = cmos_set_alarm,
494         .proc                   = cmos_procfs,
495         .alarm_irq_enable       = cmos_alarm_irq_enable,
496 };
497 
498 /*----------------------------------------------------------------*/
499 
500 /*
501  * All these chips have at least 64 bytes of address space, shared by
502  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
503  * by boot firmware.  Modern chips have 128 or 256 bytes.
504  */
505 
506 #define NVRAM_OFFSET    (RTC_REG_D + 1)
507 
508 static ssize_t
509 cmos_nvram_read(struct file *filp, struct kobject *kobj,
510                 struct bin_attribute *attr,
511                 char *buf, loff_t off, size_t count)
512 {
513         int     retval;
514 
515         if (unlikely(off >= attr->size))
516                 return 0;
517         if (unlikely(off < 0))
518                 return -EINVAL;
519         if ((off + count) > attr->size)
520                 count = attr->size - off;
521 
522         off += NVRAM_OFFSET;
523         spin_lock_irq(&rtc_lock);
524         for (retval = 0; count; count--, off++, retval++) {
525                 if (off < 128)
526                         *buf++ = CMOS_READ(off);
527                 else if (can_bank2)
528                         *buf++ = cmos_read_bank2(off);
529                 else
530                         break;
531         }
532         spin_unlock_irq(&rtc_lock);
533 
534         return retval;
535 }
536 
537 static ssize_t
538 cmos_nvram_write(struct file *filp, struct kobject *kobj,
539                 struct bin_attribute *attr,
540                 char *buf, loff_t off, size_t count)
541 {
542         struct cmos_rtc *cmos;
543         int             retval;
544 
545         cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
546         if (unlikely(off >= attr->size))
547                 return -EFBIG;
548         if (unlikely(off < 0))
549                 return -EINVAL;
550         if ((off + count) > attr->size)
551                 count = attr->size - off;
552 
553         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
554          * checksum on part of the NVRAM data.  That's currently ignored
555          * here.  If userspace is smart enough to know what fields of
556          * NVRAM to update, updating checksums is also part of its job.
557          */
558         off += NVRAM_OFFSET;
559         spin_lock_irq(&rtc_lock);
560         for (retval = 0; count; count--, off++, retval++) {
561                 /* don't trash RTC registers */
562                 if (off == cmos->day_alrm
563                                 || off == cmos->mon_alrm
564                                 || off == cmos->century)
565                         buf++;
566                 else if (off < 128)
567                         CMOS_WRITE(*buf++, off);
568                 else if (can_bank2)
569                         cmos_write_bank2(*buf++, off);
570                 else
571                         break;
572         }
573         spin_unlock_irq(&rtc_lock);
574 
575         return retval;
576 }
577 
578 static struct bin_attribute nvram = {
579         .attr = {
580                 .name   = "nvram",
581                 .mode   = S_IRUGO | S_IWUSR,
582         },
583 
584         .read   = cmos_nvram_read,
585         .write  = cmos_nvram_write,
586         /* size gets set up later */
587 };
588 
589 /*----------------------------------------------------------------*/
590 
591 static struct cmos_rtc  cmos_rtc;
592 
593 static irqreturn_t cmos_interrupt(int irq, void *p)
594 {
595         u8              irqstat;
596         u8              rtc_control;
597 
598         spin_lock(&rtc_lock);
599 
600         /* When the HPET interrupt handler calls us, the interrupt
601          * status is passed as arg1 instead of the irq number.  But
602          * always clear irq status, even when HPET is in the way.
603          *
604          * Note that HPET and RTC are almost certainly out of phase,
605          * giving different IRQ status ...
606          */
607         irqstat = CMOS_READ(RTC_INTR_FLAGS);
608         rtc_control = CMOS_READ(RTC_CONTROL);
609         if (is_hpet_enabled())
610                 irqstat = (unsigned long)irq & 0xF0;
611 
612         /* If we were suspended, RTC_CONTROL may not be accurate since the
613          * bios may have cleared it.
614          */
615         if (!cmos_rtc.suspend_ctrl)
616                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
617         else
618                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
619 
620         /* All Linux RTC alarms should be treated as if they were oneshot.
621          * Similar code may be needed in system wakeup paths, in case the
622          * alarm woke the system.
623          */
624         if (irqstat & RTC_AIE) {
625                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
626                 rtc_control &= ~RTC_AIE;
627                 CMOS_WRITE(rtc_control, RTC_CONTROL);
628                 hpet_mask_rtc_irq_bit(RTC_AIE);
629                 CMOS_READ(RTC_INTR_FLAGS);
630         }
631         spin_unlock(&rtc_lock);
632 
633         if (is_intr(irqstat)) {
634                 rtc_update_irq(p, 1, irqstat);
635                 return IRQ_HANDLED;
636         } else
637                 return IRQ_NONE;
638 }
639 
640 #ifdef  CONFIG_PNP
641 #define INITSECTION
642 
643 #else
644 #define INITSECTION     __init
645 #endif
646 
647 static int INITSECTION
648 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
649 {
650         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
651         int                             retval = 0;
652         unsigned char                   rtc_control;
653         unsigned                        address_space;
654         u32                             flags = 0;
655 
656         /* there can be only one ... */
657         if (cmos_rtc.dev)
658                 return -EBUSY;
659 
660         if (!ports)
661                 return -ENODEV;
662 
663         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
664          *
665          * REVISIT non-x86 systems may instead use memory space resources
666          * (needing ioremap etc), not i/o space resources like this ...
667          */
668         if (RTC_IOMAPPED)
669                 ports = request_region(ports->start, resource_size(ports),
670                                        driver_name);
671         else
672                 ports = request_mem_region(ports->start, resource_size(ports),
673                                            driver_name);
674         if (!ports) {
675                 dev_dbg(dev, "i/o registers already in use\n");
676                 return -EBUSY;
677         }
678 
679         cmos_rtc.irq = rtc_irq;
680         cmos_rtc.iomem = ports;
681 
682         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
683          * driver did, but don't reject unknown configs.   Old hardware
684          * won't address 128 bytes.  Newer chips have multiple banks,
685          * though they may not be listed in one I/O resource.
686          */
687 #if     defined(CONFIG_ATARI)
688         address_space = 64;
689 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
690                         || defined(__sparc__) || defined(__mips__) \
691                         || defined(__powerpc__)
692         address_space = 128;
693 #else
694 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
695         address_space = 128;
696 #endif
697         if (can_bank2 && ports->end > (ports->start + 1))
698                 address_space = 256;
699 
700         /* For ACPI systems extension info comes from the FADT.  On others,
701          * board specific setup provides it as appropriate.  Systems where
702          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
703          * some almost-clones) can provide hooks to make that behave.
704          *
705          * Note that ACPI doesn't preclude putting these registers into
706          * "extended" areas of the chip, including some that we won't yet
707          * expect CMOS_READ and friends to handle.
708          */
709         if (info) {
710                 if (info->flags)
711                         flags = info->flags;
712                 if (info->address_space)
713                         address_space = info->address_space;
714 
715                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
716                         cmos_rtc.day_alrm = info->rtc_day_alarm;
717                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
718                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
719                 if (info->rtc_century && info->rtc_century < 128)
720                         cmos_rtc.century = info->rtc_century;
721 
722                 if (info->wake_on && info->wake_off) {
723                         cmos_rtc.wake_on = info->wake_on;
724                         cmos_rtc.wake_off = info->wake_off;
725                 }
726         }
727 
728         cmos_rtc.dev = dev;
729         dev_set_drvdata(dev, &cmos_rtc);
730 
731         cmos_rtc.rtc = rtc_device_register(driver_name, dev,
732                                 &cmos_rtc_ops, THIS_MODULE);
733         if (IS_ERR(cmos_rtc.rtc)) {
734                 retval = PTR_ERR(cmos_rtc.rtc);
735                 goto cleanup0;
736         }
737 
738         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
739 
740         spin_lock_irq(&rtc_lock);
741 
742         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
743                 /* force periodic irq to CMOS reset default of 1024Hz;
744                  *
745                  * REVISIT it's been reported that at least one x86_64 ALI
746                  * mobo doesn't use 32KHz here ... for portability we might
747                  * need to do something about other clock frequencies.
748                  */
749                 cmos_rtc.rtc->irq_freq = 1024;
750                 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
751                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
752         }
753 
754         /* disable irqs */
755         if (is_valid_irq(rtc_irq))
756                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
757 
758         rtc_control = CMOS_READ(RTC_CONTROL);
759 
760         spin_unlock_irq(&rtc_lock);
761 
762         /* FIXME:
763          * <asm-generic/rtc.h> doesn't know 12-hour mode either.
764          */
765         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
766                 dev_warn(dev, "only 24-hr supported\n");
767                 retval = -ENXIO;
768                 goto cleanup1;
769         }
770 
771         if (is_valid_irq(rtc_irq)) {
772                 irq_handler_t rtc_cmos_int_handler;
773 
774                 if (is_hpet_enabled()) {
775                         rtc_cmos_int_handler = hpet_rtc_interrupt;
776                         retval = hpet_register_irq_handler(cmos_interrupt);
777                         if (retval) {
778                                 dev_warn(dev, "hpet_register_irq_handler "
779                                                 " failed in rtc_init().");
780                                 goto cleanup1;
781                         }
782                 } else
783                         rtc_cmos_int_handler = cmos_interrupt;
784 
785                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
786                                 0, dev_name(&cmos_rtc.rtc->dev),
787                                 cmos_rtc.rtc);
788                 if (retval < 0) {
789                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
790                         goto cleanup1;
791                 }
792         }
793         hpet_rtc_timer_init();
794 
795         /* export at least the first block of NVRAM */
796         nvram.size = address_space - NVRAM_OFFSET;
797         retval = sysfs_create_bin_file(&dev->kobj, &nvram);
798         if (retval < 0) {
799                 dev_dbg(dev, "can't create nvram file? %d\n", retval);
800                 goto cleanup2;
801         }
802 
803         dev_info(dev, "%s%s, %zd bytes nvram%s\n",
804                 !is_valid_irq(rtc_irq) ? "no alarms" :
805                         cmos_rtc.mon_alrm ? "alarms up to one year" :
806                         cmos_rtc.day_alrm ? "alarms up to one month" :
807                         "alarms up to one day",
808                 cmos_rtc.century ? ", y3k" : "",
809                 nvram.size,
810                 is_hpet_enabled() ? ", hpet irqs" : "");
811 
812         return 0;
813 
814 cleanup2:
815         if (is_valid_irq(rtc_irq))
816                 free_irq(rtc_irq, cmos_rtc.rtc);
817 cleanup1:
818         cmos_rtc.dev = NULL;
819         rtc_device_unregister(cmos_rtc.rtc);
820 cleanup0:
821         if (RTC_IOMAPPED)
822                 release_region(ports->start, resource_size(ports));
823         else
824                 release_mem_region(ports->start, resource_size(ports));
825         return retval;
826 }
827 
828 static void cmos_do_shutdown(int rtc_irq)
829 {
830         spin_lock_irq(&rtc_lock);
831         if (is_valid_irq(rtc_irq))
832                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
833         spin_unlock_irq(&rtc_lock);
834 }
835 
836 static void __exit cmos_do_remove(struct device *dev)
837 {
838         struct cmos_rtc *cmos = dev_get_drvdata(dev);
839         struct resource *ports;
840 
841         cmos_do_shutdown(cmos->irq);
842 
843         sysfs_remove_bin_file(&dev->kobj, &nvram);
844 
845         if (is_valid_irq(cmos->irq)) {
846                 free_irq(cmos->irq, cmos->rtc);
847                 hpet_unregister_irq_handler(cmos_interrupt);
848         }
849 
850         rtc_device_unregister(cmos->rtc);
851         cmos->rtc = NULL;
852 
853         ports = cmos->iomem;
854         if (RTC_IOMAPPED)
855                 release_region(ports->start, resource_size(ports));
856         else
857                 release_mem_region(ports->start, resource_size(ports));
858         cmos->iomem = NULL;
859 
860         cmos->dev = NULL;
861 }
862 
863 #ifdef CONFIG_PM
864 
865 static int cmos_suspend(struct device *dev)
866 {
867         struct cmos_rtc *cmos = dev_get_drvdata(dev);
868         unsigned char   tmp;
869 
870         /* only the alarm might be a wakeup event source */
871         spin_lock_irq(&rtc_lock);
872         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
873         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
874                 unsigned char   mask;
875 
876                 if (device_may_wakeup(dev))
877                         mask = RTC_IRQMASK & ~RTC_AIE;
878                 else
879                         mask = RTC_IRQMASK;
880                 tmp &= ~mask;
881                 CMOS_WRITE(tmp, RTC_CONTROL);
882                 hpet_mask_rtc_irq_bit(mask);
883 
884                 cmos_checkintr(cmos, tmp);
885         }
886         spin_unlock_irq(&rtc_lock);
887 
888         if (tmp & RTC_AIE) {
889                 cmos->enabled_wake = 1;
890                 if (cmos->wake_on)
891                         cmos->wake_on(dev);
892                 else
893                         enable_irq_wake(cmos->irq);
894         }
895 
896         dev_dbg(dev, "suspend%s, ctrl %02x\n",
897                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
898                         tmp);
899 
900         return 0;
901 }
902 
903 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
904  * after a detour through G3 "mechanical off", although the ACPI spec
905  * says wakeup should only work from G1/S4 "hibernate".  To most users,
906  * distinctions between S4 and S5 are pointless.  So when the hardware
907  * allows, don't draw that distinction.
908  */
909 static inline int cmos_poweroff(struct device *dev)
910 {
911         return cmos_suspend(dev);
912 }
913 
914 #ifdef  CONFIG_PM_SLEEP
915 
916 static int cmos_resume(struct device *dev)
917 {
918         struct cmos_rtc *cmos = dev_get_drvdata(dev);
919         unsigned char tmp;
920 
921         if (cmos->enabled_wake) {
922                 if (cmos->wake_off)
923                         cmos->wake_off(dev);
924                 else
925                         disable_irq_wake(cmos->irq);
926                 cmos->enabled_wake = 0;
927         }
928 
929         spin_lock_irq(&rtc_lock);
930         tmp = cmos->suspend_ctrl;
931         cmos->suspend_ctrl = 0;
932         /* re-enable any irqs previously active */
933         if (tmp & RTC_IRQMASK) {
934                 unsigned char   mask;
935 
936                 if (device_may_wakeup(dev))
937                         hpet_rtc_timer_init();
938 
939                 do {
940                         CMOS_WRITE(tmp, RTC_CONTROL);
941                         hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
942 
943                         mask = CMOS_READ(RTC_INTR_FLAGS);
944                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
945                         if (!is_hpet_enabled() || !is_intr(mask))
946                                 break;
947 
948                         /* force one-shot behavior if HPET blocked
949                          * the wake alarm's irq
950                          */
951                         rtc_update_irq(cmos->rtc, 1, mask);
952                         tmp &= ~RTC_AIE;
953                         hpet_mask_rtc_irq_bit(RTC_AIE);
954                 } while (mask & RTC_AIE);
955         }
956         spin_unlock_irq(&rtc_lock);
957 
958         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
959 
960         return 0;
961 }
962 
963 #endif
964 #else
965 
966 static inline int cmos_poweroff(struct device *dev)
967 {
968         return -ENOSYS;
969 }
970 
971 #endif
972 
973 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
974 
975 /*----------------------------------------------------------------*/
976 
977 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
978  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
979  * probably list them in similar PNPBIOS tables; so PNP is more common.
980  *
981  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
982  * predate even PNPBIOS should set up platform_bus devices.
983  */
984 
985 #ifdef  CONFIG_ACPI
986 
987 #include <linux/acpi.h>
988 
989 static u32 rtc_handler(void *context)
990 {
991         struct device *dev = context;
992 
993         pm_wakeup_event(dev, 0);
994         acpi_clear_event(ACPI_EVENT_RTC);
995         acpi_disable_event(ACPI_EVENT_RTC, 0);
996         return ACPI_INTERRUPT_HANDLED;
997 }
998 
999 static inline void rtc_wake_setup(struct device *dev)
1000 {
1001         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1002         /*
1003          * After the RTC handler is installed, the Fixed_RTC event should
1004          * be disabled. Only when the RTC alarm is set will it be enabled.
1005          */
1006         acpi_clear_event(ACPI_EVENT_RTC);
1007         acpi_disable_event(ACPI_EVENT_RTC, 0);
1008 }
1009 
1010 static void rtc_wake_on(struct device *dev)
1011 {
1012         acpi_clear_event(ACPI_EVENT_RTC);
1013         acpi_enable_event(ACPI_EVENT_RTC, 0);
1014 }
1015 
1016 static void rtc_wake_off(struct device *dev)
1017 {
1018         acpi_disable_event(ACPI_EVENT_RTC, 0);
1019 }
1020 
1021 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1022  * its device node and pass extra config data.  This helps its driver use
1023  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1024  * that this board's RTC is wakeup-capable (per ACPI spec).
1025  */
1026 static struct cmos_rtc_board_info acpi_rtc_info;
1027 
1028 static void cmos_wake_setup(struct device *dev)
1029 {
1030         if (acpi_disabled)
1031                 return;
1032 
1033         rtc_wake_setup(dev);
1034         acpi_rtc_info.wake_on = rtc_wake_on;
1035         acpi_rtc_info.wake_off = rtc_wake_off;
1036 
1037         /* workaround bug in some ACPI tables */
1038         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1039                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1040                         acpi_gbl_FADT.month_alarm);
1041                 acpi_gbl_FADT.month_alarm = 0;
1042         }
1043 
1044         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1045         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1046         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1047 
1048         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1049         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1050                 dev_info(dev, "RTC can wake from S4\n");
1051 
1052         dev->platform_data = &acpi_rtc_info;
1053 
1054         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1055         device_init_wakeup(dev, 1);
1056 }
1057 
1058 #else
1059 
1060 static void cmos_wake_setup(struct device *dev)
1061 {
1062 }
1063 
1064 #endif
1065 
1066 #ifdef  CONFIG_PNP
1067 
1068 #include <linux/pnp.h>
1069 
1070 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1071 {
1072         cmos_wake_setup(&pnp->dev);
1073 
1074         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1075                 /* Some machines contain a PNP entry for the RTC, but
1076                  * don't define the IRQ. It should always be safe to
1077                  * hardcode it in these cases
1078                  */
1079                 return cmos_do_probe(&pnp->dev,
1080                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1081         else
1082                 return cmos_do_probe(&pnp->dev,
1083                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1084                                 pnp_irq(pnp, 0));
1085 }
1086 
1087 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1088 {
1089         cmos_do_remove(&pnp->dev);
1090 }
1091 
1092 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1093 {
1094         struct device *dev = &pnp->dev;
1095         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1096 
1097         if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(dev))
1098                 return;
1099 
1100         cmos_do_shutdown(cmos->irq);
1101 }
1102 
1103 static const struct pnp_device_id rtc_ids[] = {
1104         { .id = "PNP0b00", },
1105         { .id = "PNP0b01", },
1106         { .id = "PNP0b02", },
1107         { },
1108 };
1109 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1110 
1111 static struct pnp_driver cmos_pnp_driver = {
1112         .name           = (char *) driver_name,
1113         .id_table       = rtc_ids,
1114         .probe          = cmos_pnp_probe,
1115         .remove         = __exit_p(cmos_pnp_remove),
1116         .shutdown       = cmos_pnp_shutdown,
1117 
1118         /* flag ensures resume() gets called, and stops syslog spam */
1119         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1120         .driver         = {
1121                         .pm = &cmos_pm_ops,
1122         },
1123 };
1124 
1125 #endif  /* CONFIG_PNP */
1126 
1127 #ifdef CONFIG_OF
1128 static const struct of_device_id of_cmos_match[] = {
1129         {
1130                 .compatible = "motorola,mc146818",
1131         },
1132         { },
1133 };
1134 MODULE_DEVICE_TABLE(of, of_cmos_match);
1135 
1136 static __init void cmos_of_init(struct platform_device *pdev)
1137 {
1138         struct device_node *node = pdev->dev.of_node;
1139         struct rtc_time time;
1140         int ret;
1141         const __be32 *val;
1142 
1143         if (!node)
1144                 return;
1145 
1146         val = of_get_property(node, "ctrl-reg", NULL);
1147         if (val)
1148                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1149 
1150         val = of_get_property(node, "freq-reg", NULL);
1151         if (val)
1152                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1153 
1154         get_rtc_time(&time);
1155         ret = rtc_valid_tm(&time);
1156         if (ret) {
1157                 struct rtc_time def_time = {
1158                         .tm_year = 1,
1159                         .tm_mday = 1,
1160                 };
1161                 set_rtc_time(&def_time);
1162         }
1163 }
1164 #else
1165 static inline void cmos_of_init(struct platform_device *pdev) {}
1166 #endif
1167 /*----------------------------------------------------------------*/
1168 
1169 /* Platform setup should have set up an RTC device, when PNP is
1170  * unavailable ... this could happen even on (older) PCs.
1171  */
1172 
1173 static int __init cmos_platform_probe(struct platform_device *pdev)
1174 {
1175         struct resource *resource;
1176         int irq;
1177 
1178         cmos_of_init(pdev);
1179         cmos_wake_setup(&pdev->dev);
1180 
1181         if (RTC_IOMAPPED)
1182                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1183         else
1184                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1185         irq = platform_get_irq(pdev, 0);
1186         if (irq < 0)
1187                 irq = -1;
1188 
1189         return cmos_do_probe(&pdev->dev, resource, irq);
1190 }
1191 
1192 static int __exit cmos_platform_remove(struct platform_device *pdev)
1193 {
1194         cmos_do_remove(&pdev->dev);
1195         return 0;
1196 }
1197 
1198 static void cmos_platform_shutdown(struct platform_device *pdev)
1199 {
1200         struct device *dev = &pdev->dev;
1201         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1202 
1203         if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(dev))
1204                 return;
1205 
1206         cmos_do_shutdown(cmos->irq);
1207 }
1208 
1209 /* work with hotplug and coldplug */
1210 MODULE_ALIAS("platform:rtc_cmos");
1211 
1212 static struct platform_driver cmos_platform_driver = {
1213         .remove         = __exit_p(cmos_platform_remove),
1214         .shutdown       = cmos_platform_shutdown,
1215         .driver = {
1216                 .name           = driver_name,
1217 #ifdef CONFIG_PM
1218                 .pm             = &cmos_pm_ops,
1219 #endif
1220                 .of_match_table = of_match_ptr(of_cmos_match),
1221         }
1222 };
1223 
1224 #ifdef CONFIG_PNP
1225 static bool pnp_driver_registered;
1226 #endif
1227 static bool platform_driver_registered;
1228 
1229 static int __init cmos_init(void)
1230 {
1231         int retval = 0;
1232 
1233 #ifdef  CONFIG_PNP
1234         retval = pnp_register_driver(&cmos_pnp_driver);
1235         if (retval == 0)
1236                 pnp_driver_registered = true;
1237 #endif
1238 
1239         if (!cmos_rtc.dev) {
1240                 retval = platform_driver_probe(&cmos_platform_driver,
1241                                                cmos_platform_probe);
1242                 if (retval == 0)
1243                         platform_driver_registered = true;
1244         }
1245 
1246         dmi_check_system(rtc_quirks);
1247 
1248         if (retval == 0)
1249                 return 0;
1250 
1251 #ifdef  CONFIG_PNP
1252         if (pnp_driver_registered)
1253                 pnp_unregister_driver(&cmos_pnp_driver);
1254 #endif
1255         return retval;
1256 }
1257 module_init(cmos_init);
1258 
1259 static void __exit cmos_exit(void)
1260 {
1261 #ifdef  CONFIG_PNP
1262         if (pnp_driver_registered)
1263                 pnp_unregister_driver(&cmos_pnp_driver);
1264 #endif
1265         if (platform_driver_registered)
1266                 platform_driver_unregister(&cmos_platform_driver);
1267 }
1268 module_exit(cmos_exit);
1269 
1270 
1271 MODULE_AUTHOR("David Brownell");
1272 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1273 MODULE_LICENSE("GPL");
1274 

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