// SPDX-License-Identifier: GPL-2.0-or-later /* * RTC class driver for "CMOS RTC": PCs, ACPI, etc * * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c) * Copyright (C) 2006 David Brownell (convert to new framework) */ /* * The original "cmos clock" chip was an MC146818 chip, now obsolete. * That defined the register interface now provided by all PCs, some * non-PC systems, and incorporated into ACPI. Modern PC chipsets * integrate an MC146818 clone in their southbridge, and boards use * that instead of discrete clones like the DS12887 or M48T86. There * are also clones that connect using the LPC bus. * * That register API is also used directly by various other drivers * (notably for integrated NVRAM), infrastructure (x86 has code to * bypass the RTC framework, directly reading the RTC during boot * and updating minutes/seconds for systems using NTP synch) and * utilities (like userspace 'hwclock', if no /dev node exists). * * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with * interrupts disabled, holding the global rtc_lock, to exclude those * other drivers and utilities on correctly configured systems. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_X86 #include #include #include #endif /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */ #include #ifdef CONFIG_ACPI /* * Use ACPI SCI to replace HPET interrupt for RTC Alarm event * * If cleared, ACPI SCI is only used to wake up the system from suspend * * If set, ACPI SCI is used to handle UIE/AIE and system wakeup */ static bool use_acpi_alarm; module_param(use_acpi_alarm, bool, 0444); static inline int cmos_use_acpi_alarm(void) { return use_acpi_alarm; } #else /* !CONFIG_ACPI */ static inline int cmos_use_acpi_alarm(void) { return 0; } #endif struct cmos_rtc { struct rtc_device *rtc; struct device *dev; int irq; struct resource *iomem; time64_t alarm_expires; void (*wake_on)(struct device *); void (*wake_off)(struct device *); u8 enabled_wake; u8 suspend_ctrl; /* newer hardware extends the original register set */ u8 day_alrm; u8 mon_alrm; u8 century; struct rtc_wkalrm saved_wkalrm; }; /* both platform and pnp busses use negative numbers for invalid irqs */ #define is_valid_irq(n) ((n) > 0) static const char driver_name[] = "rtc_cmos"; /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear; * always mask it against the irq enable bits in RTC_CONTROL. Bit values * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both. */ #define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF) static inline int is_intr(u8 rtc_intr) { if (!(rtc_intr & RTC_IRQF)) return 0; return rtc_intr & RTC_IRQMASK; } /*----------------------------------------------------------------*/ /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly * used in a broken "legacy replacement" mode. The breakage includes * HPET #1 hijacking the IRQ for this RTC, and being unavailable for * other (better) use. * * When that broken mode is in use, platform glue provides a partial * emulation of hardware RTC IRQ facilities using HPET #1. We don't * want to use HPET for anything except those IRQs though... */ #ifdef CONFIG_HPET_EMULATE_RTC #include #else static inline int is_hpet_enabled(void) { return 0; } static inline int hpet_mask_rtc_irq_bit(unsigned long mask) { return 0; } static inline int hpet_set_rtc_irq_bit(unsigned long mask) { return 0; } static inline int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec) { return 0; } static inline int hpet_set_periodic_freq(unsigned long freq) { return 0; } static inline int hpet_rtc_dropped_irq(void) { return 0; } static inline int hpet_rtc_timer_init(void) { return 0; } extern irq_handler_t hpet_rtc_interrupt; static inline int hpet_register_irq_handler(irq_handler_t handler) { return 0; } static inline int hpet_unregister_irq_handler(irq_handler_t handler) { return 0; } #endif /* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */ static inline int use_hpet_alarm(void) { return is_hpet_enabled() && !cmos_use_acpi_alarm(); } /*----------------------------------------------------------------*/ #ifdef RTC_PORT /* Most newer x86 systems have two register banks, the first used * for RTC and NVRAM and the second only for NVRAM. Caller must * own rtc_lock ... and we won't worry about access during NMI. */ #define can_bank2 true static inline unsigned char cmos_read_bank2(unsigned char addr) { outb(addr, RTC_PORT(2)); return inb(RTC_PORT(3)); } static inline void cmos_write_bank2(unsigned char val, unsigned char addr) { outb(addr, RTC_PORT(2)); outb(val, RTC_PORT(3)); } #else #define can_bank2 false static inline unsigned char cmos_read_bank2(unsigned char addr) { return 0; } static inline void cmos_write_bank2(unsigned char val, unsigned char addr) { } #endif /*----------------------------------------------------------------*/ static int cmos_read_time(struct device *dev, struct rtc_time *t) { int ret; /* * If pm_trace abused the RTC for storage, set the timespec to 0, * which tells the caller that this RTC value is unusable. */ if (!pm_trace_rtc_valid()) return -EIO; ret = mc146818_get_time(t); if (ret < 0) { dev_err_ratelimited(dev, "unable to read current time\n"); return ret; } return 0; } static int cmos_set_time(struct device *dev, struct rtc_time *t) { /* NOTE: this ignores the issue whereby updating the seconds * takes effect exactly 500ms after we write the register. * (Also queueing and other delays before we get this far.) */ return mc146818_set_time(t); } struct cmos_read_alarm_callback_param { struct cmos_rtc *cmos; struct rtc_time *time; unsigned char rtc_control; }; static void cmos_read_alarm_callback(unsigned char __always_unused seconds, void *param_in) { struct cmos_read_alarm_callback_param *p = (struct cmos_read_alarm_callback_param *)param_in; struct rtc_time *time = p->time; time->tm_sec = CMOS_READ(RTC_SECONDS_ALARM); time->tm_min = CMOS_READ(RTC_MINUTES_ALARM); time->tm_hour = CMOS_READ(RTC_HOURS_ALARM); if (p->cmos->day_alrm) { /* ignore upper bits on readback per ACPI spec */ time->tm_mday = CMOS_READ(p->cmos->day_alrm) & 0x3f; if (!time->tm_mday) time->tm_mday = -1; if (p->cmos->mon_alrm) { time->tm_mon = CMOS_READ(p->cmos->mon_alrm); if (!time->tm_mon) time->tm_mon = -1; } } p->rtc_control = CMOS_READ(RTC_CONTROL); } static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t) { struct cmos_rtc *cmos = dev_get_drvdata(dev); struct cmos_read_alarm_callback_param p = { .cmos = cmos, .time = &t->time, }; /* This not only a rtc_op, but also called directly */ if (!is_valid_irq(cmos->irq)) return -ETIMEDOUT; /* Basic alarms only support hour, minute, and seconds fields. * Some also support day and month, for alarms up to a year in * the future. */ /* Some Intel chipsets disconnect the alarm registers when the clock * update is in progress - during this time reads return bogus values * and writes may fail silently. See for example "7th Generation Intel® * Processor Family I/O for U/Y Platforms [...] Datasheet", section * 27.7.1 * * Use the mc146818_avoid_UIP() function to avoid this. */ if (!mc146818_avoid_UIP(cmos_read_alarm_callback, &p)) return -EIO; if (!(p.rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { if (((unsigned)t->time.tm_sec) < 0x60) t->time.tm_sec = bcd2bin(t->time.tm_sec); else t->time.tm_sec = -1; if (((unsigned)t->time.tm_min) < 0x60) t->time.tm_min = bcd2bin(t->time.tm_min); else t->time.tm_min = -1; if (((unsigned)t->time.tm_hour) < 0x24) t->time.tm_hour = bcd2bin(t->time.tm_hour); else t->time.tm_hour = -1; if (cmos->day_alrm) { if (((unsigned)t->time.tm_mday) <= 0x31) t->time.tm_mday = bcd2bin(t->time.tm_mday); else t->time.tm_mday = -1; if (cmos->mon_alrm) { if (((unsigned)t->time.tm_mon) <= 0x12) t->time.tm_mon = bcd2bin(t->time.tm_mon)-1; else t->time.tm_mon = -1; } } } t->enabled = !!(p.rtc_control & RTC_AIE); t->pending = 0; return 0; } static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control) { unsigned char rtc_intr; /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS; * allegedly some older rtcs need that to handle irqs properly */ rtc_intr = CMOS_READ(RTC_INTR_FLAGS); if (use_hpet_alarm()) return; rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF; if (is_intr(rtc_intr)) rtc_update_irq(cmos->rtc, 1, rtc_intr); } static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask) { unsigned char rtc_control; /* flush any pending IRQ status, notably for update irqs, * before we enable new IRQs */ rtc_control = CMOS_READ(RTC_CONTROL); cmos_checkintr(cmos, rtc_control); rtc_control |= mask; CMOS_WRITE(rtc_control, RTC_CONTROL); if (use_hpet_alarm()) hpet_set_rtc_irq_bit(mask); if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) { if (cmos->wake_on) cmos->wake_on(cmos->dev); } cmos_checkintr(cmos, rtc_control); } static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask) { unsigned char rtc_control; rtc_control = CMOS_READ(RTC_CONTROL); rtc_control &= ~mask; CMOS_WRITE(rtc_control, RTC_CONTROL); if (use_hpet_alarm()) hpet_mask_rtc_irq_bit(mask); if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) { if (cmos->wake_off) cmos->wake_off(cmos->dev); } cmos_checkintr(cmos, rtc_control); } static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t) { struct cmos_rtc *cmos = dev_get_drvdata(dev); struct rtc_time now; cmos_read_time(dev, &now); if (!cmos->day_alrm) { time64_t t_max_date; time64_t t_alrm; t_max_date = rtc_tm_to_time64(&now); t_max_date += 24 * 60 * 60 - 1; t_alrm = rtc_tm_to_time64(&t->time); if (t_alrm > t_max_date) { dev_err(dev, "Alarms can be up to one day in the future\n"); return -EINVAL; } } else if (!cmos->mon_alrm) { struct rtc_time max_date = now; time64_t t_max_date; time64_t t_alrm; int max_mday; if (max_date.tm_mon == 11) { max_date.tm_mon = 0; max_date.tm_year += 1; } else { max_date.tm_mon += 1; } max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year); if (max_date.tm_mday > max_mday) max_date.tm_mday = max_mday; t_max_date = rtc_tm_to_time64(&max_date); t_max_date -= 1; t_alrm = rtc_tm_to_time64(&t->time); if (t_alrm > t_max_date) { dev_err(dev, "Alarms can be up to one month in the future\n"); return -EINVAL; } } else { struct rtc_time max_date = now; time64_t t_max_date; time64_t t_alrm; int max_mday; max_date.tm_year += 1; max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year); if (max_date.tm_mday > max_mday) max_date.tm_mday = max_mday; t_max_date = rtc_tm_to_time64(&max_date); t_max_date -= 1; t_alrm = rtc_tm_to_time64(&t->time); if (t_alrm > t_max_date) { dev_err(dev, "Alarms can be up to one year in the future\n"); return -EINVAL; } } return 0; } struct cmos_set_alarm_callback_param { struct cmos_rtc *cmos; unsigned char mon, mday, hrs, min, sec; struct rtc_wkalrm *t; }; /* Note: this function may be executed by mc146818_avoid_UIP() more then * once */ static void cmos_set_alarm_callback(unsigned char __always_unused seconds, void *param_in) { struct cmos_set_alarm_callback_param *p = (struct cmos_set_alarm_callback_param *)param_in; /* next rtc irq must not be from previous alarm setting */ cmos_irq_disable(p->cmos, RTC_AIE); /* update alarm */ CMOS_WRITE(p->hrs, RTC_HOURS_ALARM); CMOS_WRITE(p->min, RTC_MINUTES_ALARM); CMOS_WRITE(p->sec, RTC_SECONDS_ALARM); /* the system may support an "enhanced" alarm */ if (p->cmos->day_alrm) { CMOS_WRITE(p->mday, p->cmos->day_alrm); if (p->cmos->mon_alrm) CMOS_WRITE(p->mon, p->cmos->mon_alrm); } if (use_hpet_alarm()) { /* * FIXME the HPET alarm glue currently ignores day_alrm * and mon_alrm ... */ hpet_set_alarm_time(p->t->time.tm_hour, p->t->time.tm_min, p->t->time.tm_sec); } if (p->t->enabled) cmos_irq_enable(p->cmos, RTC_AIE); } static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) { struct cmos_rtc *cmos = dev_get_drvdata(dev); struct cmos_set_alarm_callback_param p = { .cmos = cmos, .t = t }; unsigned char rtc_control; int ret; /* This not only a rtc_op, but also called directly */ if (!is_valid_irq(cmos->irq)) return -EIO; ret = cmos_validate_alarm(dev, t); if (ret < 0) return ret; p.mon = t->time.tm_mon + 1; p.mday = t->time.tm_mday; p.hrs = t->time.tm_hour; p.min = t->time.tm_min; p.sec = t->time.tm_sec; spin_lock_irq(&rtc_lock); rtc_control = CMOS_READ(RTC_CONTROL); spin_unlock_irq(&rtc_lock); if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { /* Writing 0xff means "don't care" or "match all". */ p.mon = (p.mon <= 12) ? bin2bcd(p.mon) : 0xff; p.mday = (p.mday >= 1 && p.mday <= 31) ? bin2bcd(p.mday) : 0xff; p.hrs = (p.hrs < 24) ? bin2bcd(p.hrs) : 0xff; p.min = (p.min < 60) ? bin2bcd(p.min) : 0xff; p.sec = (p.sec < 60) ? bin2bcd(p.sec) : 0xff; } /* * Some Intel chipsets disconnect the alarm registers when the clock * update is in progress - during this time writes fail silently. * * Use mc146818_avoid_UIP() to avoid this. */ if (!mc146818_avoid_UIP(cmos_set_alarm_callback, &p)) return -ETIMEDOUT; cmos->alarm_expires = rtc_tm_to_time64(&t->time); return 0; } static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct cmos_rtc *cmos = dev_get_drvdata(dev); unsigned long flags; spin_lock_irqsave(&rtc_lock, flags); if (enabled) cmos_irq_enable(cmos, RTC_AIE); else cmos_irq_disable(cmos, RTC_AIE); spin_unlock_irqrestore(&rtc_lock, flags); return 0; } #if IS_ENABLED(CONFIG_RTC_INTF_PROC) static int cmos_procfs(struct device *dev, struct seq_file *seq) { struct cmos_rtc *cmos = dev_get_drvdata(dev); unsigned char rtc_control, valid; spin_lock_irq(&rtc_lock); rtc_control = CMOS_READ(RTC_CONTROL); valid = CMOS_READ(RTC_VALID); spin_unlock_irq(&rtc_lock); /* NOTE: at least ICH6 reports battery status using a different * (non-RTC) bit; and SQWE is ignored on many current systems. */ seq_printf(seq, "periodic_IRQ\t: %s\n" "update_IRQ\t: %s\n" "HPET_emulated\t: %s\n" // "square_wave\t: %s\n" "BCD\t\t: %s\n" "DST_enable\t: %s\n" "periodic_freq\t: %d\n" "batt_status\t: %s\n", (rtc_control & RTC_PIE) ? "yes" : "no", (rtc_control & RTC_UIE) ? "yes" : "no", use_hpet_alarm() ? "yes" : "no", // (rtc_control & RTC_SQWE) ? "yes" : "no", (rtc_control & RTC_DM_BINARY) ? "no" : "yes", (rtc_control & RTC_DST_EN) ? "yes" : "no", cmos->rtc->irq_freq, (valid & RTC_VRT) ? "okay" : "dead"); return 0; } #else #define cmos_procfs NULL #endif static const struct rtc_class_ops cmos_rtc_ops = { .read_time = cmos_read_time, .set_time = cmos_set_time, .read_alarm = cmos_read_alarm, .set_alarm = cmos_set_alarm, .proc = cmos_procfs, .alarm_irq_enable = cmos_alarm_irq_enable, }; static const struct rtc_class_ops cmos_rtc_ops_no_alarm = { .read_time = cmos_read_time, .set_time = cmos_set_time, .proc = cmos_procfs, }; /*----------------------------------------------------------------*/ /* * All these chips have at least 64 bytes of address space, shared by * RTC registers and NVRAM. Most of those bytes of NVRAM are used * by boot firmware. Modern chips have 128 or 256 bytes. */ #define NVRAM_OFFSET (RTC_REG_D + 1) static int cmos_nvram_read(void *priv, unsigned int off, void *val, size_t count) { unsigned char *buf = val; int retval; off += NVRAM_OFFSET; spin_lock_irq(&rtc_lock); for (retval = 0; count; count--, off++, retval++) { if (off < 128) *buf++ = CMOS_READ(off); else if (can_bank2) *buf++ = cmos_read_bank2(off); else break; } spin_unlock_irq(&rtc_lock); return retval; } static int cmos_nvram_write(void *priv, unsigned int off, void *val, size_t count) { struct cmos_rtc *cmos = priv; unsigned char *buf = val; int retval; /* NOTE: on at least PCs and Ataris, the boot firmware uses a * checksum on part of the NVRAM data. That's currently ignored * here. If userspace is smart enough to know what fields of * NVRAM to update, updating checksums is also part of its job. */ off += NVRAM_OFFSET; spin_lock_irq(&rtc_lock); for (retval = 0; count; count--, off++, retval++) { /* don't trash RTC registers */ if (off == cmos->day_alrm || off == cmos->mon_alrm || off == cmos->century) buf++; else if (off < 128) CMOS_WRITE(*buf++, off); else if (can_bank2) cmos_write_bank2(*buf++, off); else break; } spin_unlock_irq(&rtc_lock); return retval; } /*----------------------------------------------------------------*/ static struct cmos_rtc cmos_rtc; static irqreturn_t cmos_interrupt(int irq, void *p) { u8 irqstat; u8 rtc_control; spin_lock(&rtc_lock); /* When the HPET interrupt handler calls us, the interrupt * status is passed as arg1 instead of the irq number. But * always clear irq status, even when HPET is in the way. * * Note that HPET and RTC are almost certainly out of phase, * giving different IRQ status ... */ irqstat = CMOS_READ(RTC_INTR_FLAGS); rtc_control = CMOS_READ(RTC_CONTROL); if (use_hpet_alarm()) irqstat = (unsigned long)irq & 0xF0; /* If we were suspended, RTC_CONTROL may not be accurate since the * bios may have cleared it. */ if (!cmos_rtc.suspend_ctrl) irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF; else irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF; /* All Linux RTC alarms should be treated as if they were oneshot. * Similar code may be needed in system wakeup paths, in case the * alarm woke the system. */ if (irqstat & RTC_AIE) { cmos_rtc.suspend_ctrl &= ~RTC_AIE; rtc_control &= ~RTC_AIE; CMOS_WRITE(rtc_control, RTC_CONTROL); if (use_hpet_alarm()) hpet_mask_rtc_irq_bit(RTC_AIE); CMOS_READ(RTC_INTR_FLAGS); } spin_unlock(&rtc_lock); if (is_intr(irqstat)) { rtc_update_irq(p, 1, irqstat); return IRQ_HANDLED; } else return IRQ_NONE; } #ifdef CONFIG_ACPI #include static u32 rtc_handler(void *context) { struct device *dev = context; struct cmos_rtc *cmos = dev_get_drvdata(dev); unsigned char rtc_control = 0; unsigned char rtc_intr; unsigned long flags; /* * Always update rtc irq when ACPI is used as RTC Alarm. * Or else, ACPI SCI is enabled during suspend/resume only, * update rtc irq in that case. */ if (cmos_use_acpi_alarm()) cmos_interrupt(0, (void *)cmos->rtc); else { /* Fix me: can we use cmos_interrupt() here as well? */ spin_lock_irqsave(&rtc_lock, flags); if (cmos_rtc.suspend_ctrl) rtc_control = CMOS_READ(RTC_CONTROL); if (rtc_control & RTC_AIE) { cmos_rtc.suspend_ctrl &= ~RTC_AIE; CMOS_WRITE(rtc_control, RTC_CONTROL); rtc_intr = CMOS_READ(RTC_INTR_FLAGS); rtc_update_irq(cmos->rtc, 1, rtc_intr); } spin_unlock_irqrestore(&rtc_lock, flags); } pm_wakeup_hard_event(dev); acpi_clear_event(ACPI_EVENT_RTC); acpi_disable_event(ACPI_EVENT_RTC, 0); return ACPI_INTERRUPT_HANDLED; } static void acpi_rtc_event_setup(struct device *dev) { if (acpi_disabled) return; acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev); /* * After the RTC handler is installed, the Fixed_RTC event should * be disabled. Only when the RTC alarm is set will it be enabled. */ acpi_clear_event(ACPI_EVENT_RTC); acpi_disable_event(ACPI_EVENT_RTC, 0); } static void acpi_rtc_event_cleanup(void) { if (acpi_disabled) return; acpi_remove_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler); } static void rtc_wake_on(struct device *dev) { acpi_clear_event(ACPI_EVENT_RTC); acpi_enable_event(ACPI_EVENT_RTC, 0); } static void rtc_wake_off(struct device *dev) { acpi_disable_event(ACPI_EVENT_RTC, 0); } #ifdef CONFIG_X86 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */ static void use_acpi_alarm_quirks(void) { if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) return; if (!is_hpet_enabled()) return; if (dmi_get_bios_year() < 2015) return; use_acpi_alarm = true; } #else static inline void use_acpi_alarm_quirks(void) { } #endif static void acpi_cmos_wake_setup(struct device *dev) { if (acpi_disabled) return; use_acpi_alarm_quirks(); cmos_rtc.wake_on = rtc_wake_on; cmos_rtc.wake_off = rtc_wake_off; /* ACPI tables bug workaround. */ if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) { dev_dbg(dev, "bogus FADT month_alarm (%d)\n", acpi_gbl_FADT.month_alarm); acpi_gbl_FADT.month_alarm = 0; } cmos_rtc.day_alrm = acpi_gbl_FADT.day_alarm; cmos_rtc.mon_alrm = acpi_gbl_FADT.month_alarm; cmos_rtc.century = acpi_gbl_FADT.century; if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE) dev_info(dev, "RTC can wake from S4\n"); /* RTC always wakes from S1/S2/S3, and often S4/STD */ device_init_wakeup(dev, 1); } static void cmos_check_acpi_rtc_status(struct device *dev, unsigned char *rtc_control) { struct cmos_rtc *cmos = dev_get_drvdata(dev); acpi_event_status rtc_status; acpi_status status; if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC) return; status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status); if (ACPI_FAILURE(status)) { dev_err(dev, "Could not get RTC status\n"); } else if (rtc_status & ACPI_EVENT_FLAG_SET) { unsigned char mask; *rtc_control &= ~RTC_AIE; CMOS_WRITE(*rtc_control, RTC_CONTROL); mask = CMOS_READ(RTC_INTR_FLAGS); rtc_update_irq(cmos->rtc, 1, mask); } } #else /* !CONFIG_ACPI */ static inline void acpi_rtc_event_setup(struct device *dev) { } static inline void acpi_rtc_event_cleanup(void) { } static inline void acpi_cmos_wake_setup(struct device *dev) { } static inline void cmos_check_acpi_rtc_status(struct device *dev, unsigned char *rtc_control) { } #endif /* CONFIG_ACPI */ #ifdef CONFIG_PNP #define INITSECTION #else #define INITSECTION __init #endif static int INITSECTION cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq) { struct cmos_rtc_board_info *info = dev_get_platdata(dev); int retval = 0; unsigned char rtc_control; unsigned address_space; u32 flags = 0; struct nvmem_config nvmem_cfg = { .name = "cmos_nvram", .word_size = 1, .stride = 1, .reg_read = cmos_nvram_read, .reg_write = cmos_nvram_write, .priv = &cmos_rtc, }; /* there can be only one ... */ if (cmos_rtc.dev) return -EBUSY; if (!ports) return -ENODEV; /* Claim I/O ports ASAP, minimizing conflict with legacy driver. * * REVISIT non-x86 systems may instead use memory space resources * (needing ioremap etc), not i/o space resources like this ... */ if (RTC_IOMAPPED) ports = request_region(ports->start, resource_size(ports), driver_name); else ports = request_mem_region(ports->start, resource_size(ports), driver_name); if (!ports) { dev_dbg(dev, "i/o registers already in use\n"); return -EBUSY; } cmos_rtc.irq = rtc_irq; cmos_rtc.iomem = ports; /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM * driver did, but don't reject unknown configs. Old hardware * won't address 128 bytes. Newer chips have multiple banks, * though they may not be listed in one I/O resource. */ #if defined(CONFIG_ATARI) address_space = 64; #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \ || defined(__sparc__) || defined(__mips__) \ || defined(__powerpc__) address_space = 128; #else #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes. address_space = 128; #endif if (can_bank2 && ports->end > (ports->start + 1)) address_space = 256; /* For ACPI systems extension info comes from the FADT. On others, * board specific setup provides it as appropriate. Systems where * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and * some almost-clones) can provide hooks to make that behave. * * Note that ACPI doesn't preclude putting these registers into * "extended" areas of the chip, including some that we won't yet * expect CMOS_READ and friends to handle. */ if (info) { if (info->flags) flags = info->flags; if (info->address_space) address_space = info->address_space; cmos_rtc.day_alrm = info->rtc_day_alarm; cmos_rtc.mon_alrm = info->rtc_mon_alarm; cmos_rtc.century = info->rtc_century; if (info->wake_on && info->wake_off) { cmos_rtc.wake_on = info->wake_on; cmos_rtc.wake_off = info->wake_off; } } else { acpi_cmos_wake_setup(dev); } if (cmos_rtc.day_alrm >= 128) cmos_rtc.day_alrm = 0; if (cmos_rtc.mon_alrm >= 128) cmos_rtc.mon_alrm = 0; if (cmos_rtc.century >= 128) cmos_rtc.century = 0; cmos_rtc.dev = dev; dev_set_drvdata(dev, &cmos_rtc); cmos_rtc.rtc = devm_rtc_allocate_device(dev); if (IS_ERR(cmos_rtc.rtc)) { retval = PTR_ERR(cmos_rtc.rtc); goto cleanup0; } rename_region(ports, dev_name(&cmos_rtc.rtc->dev)); if (!mc146818_does_rtc_work()) { dev_warn(dev, "broken or not accessible\n"); retval = -ENXIO; goto cleanup1; } spin_lock_irq(&rtc_lock); if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) { /* force periodic irq to CMOS reset default of 1024Hz; * * REVISIT it's been reported that at least one x86_64 ALI * mobo doesn't use 32KHz here ... for portability we might * need to do something about other clock frequencies. */ cmos_rtc.rtc->irq_freq = 1024; if (use_hpet_alarm()) hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq); CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT); } /* disable irqs */ if (is_valid_irq(rtc_irq)) cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE); rtc_control = CMOS_READ(RTC_CONTROL); spin_unlock_irq(&rtc_lock); if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) { dev_warn(dev, "only 24-hr supported\n"); retval = -ENXIO; goto cleanup1; } if (use_hpet_alarm()) hpet_rtc_timer_init(); if (is_valid_irq(rtc_irq)) { irq_handler_t rtc_cmos_int_handler; if (use_hpet_alarm()) { rtc_cmos_int_handler = hpet_rtc_interrupt; retval = hpet_register_irq_handler(cmos_interrupt); if (retval) { hpet_mask_rtc_irq_bit(RTC_IRQMASK); dev_warn(dev, "hpet_register_irq_handler " " failed in rtc_init()."); goto cleanup1; } } else rtc_cmos_int_handler = cmos_interrupt; retval = request_irq(rtc_irq, rtc_cmos_int_handler, 0, dev_name(&cmos_rtc.rtc->dev), cmos_rtc.rtc); if (retval < 0) { dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq); goto cleanup1; } cmos_rtc.rtc->ops = &cmos_rtc_ops; } else { cmos_rtc.rtc->ops = &cmos_rtc_ops_no_alarm; } cmos_rtc.rtc->nvram_old_abi = true; retval = rtc_register_device(cmos_rtc.rtc); if (retval) goto cleanup2; /* export at least the first block of NVRAM */ nvmem_cfg.size = address_space - NVRAM_OFFSET; if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg)) dev_err(dev, "nvmem registration failed\n"); /* * Everything has gone well so far, so by default register a handler for * the ACPI RTC fixed event. */ if (!info) acpi_rtc_event_setup(dev); dev_info(dev, "%s%s, %d bytes nvram%s\n", !is_valid_irq(rtc_irq) ? "no alarms" : cmos_rtc.mon_alrm ? "alarms up to one year" : cmos_rtc.day_alrm ? "alarms up to one month" : "alarms up to one day", cmos_rtc.century ? ", y3k" : "", nvmem_cfg.size, use_hpet_alarm() ? ", hpet irqs" : ""); return 0; cleanup2: if (is_valid_irq(rtc_irq)) free_irq(rtc_irq, cmos_rtc.rtc); cleanup1: cmos_rtc.dev = NULL; cleanup0: if (RTC_IOMAPPED) release_region(ports->start, resource_size(ports)); else release_mem_region(ports->start, resource_size(ports)); return retval; } static void cmos_do_shutdown(int rtc_irq) { spin_lock_irq(&rtc_lock); if (is_valid_irq(rtc_irq)) cmos_irq_disable(&cmos_rtc, RTC_IRQMASK); spin_unlock_irq(&rtc_lock); } static void cmos_do_remove(struct device *dev) { struct cmos_rtc *cmos = dev_get_drvdata(dev); struct resource *ports; cmos_do_shutdown(cmos->irq); if (is_valid_irq(cmos->irq)) { free_irq(cmos->irq, cmos->rtc); if (use_hpet_alarm()) hpet_unregister_irq_handler(cmos_interrupt); } if (!dev_get_platdata(dev)) acpi_rtc_event_cleanup(); cmos->rtc = NULL; ports = cmos->iomem; if (RTC_IOMAPPED) release_region(ports->start, resource_size(ports)); else release_mem_region(ports->start, resource_size(ports)); cmos->iomem = NULL; cmos->dev = NULL; } static int cmos_aie_poweroff(struct device *dev) { struct cmos_rtc *cmos = dev_get_drvdata(dev); struct rtc_time now; time64_t t_now; int retval = 0; unsigned char rtc_control; if (!cmos->alarm_expires) return -EINVAL; spin_lock_irq(&rtc_lock); rtc_control = CMOS_READ(RTC_CONTROL); spin_unlock_irq(&rtc_lock); /* We only care about the situation where AIE is disabled. */ if (rtc_control & RTC_AIE) return -EBUSY; cmos_read_time(dev, &now); t_now = rtc_tm_to_time64(&now); /* * When enabling "RTC wake-up" in BIOS setup, the machine reboots * automatically right after shutdown on some buggy boxes. * This automatic rebooting issue won't happen when the alarm * time is larger than now+1 seconds. * * If the alarm time is equal to now+1 seconds, the issue can be * prevented by cancelling the alarm. */ if (cmos->alarm_expires == t_now + 1) { struct rtc_wkalrm alarm; /* Cancel the AIE timer by configuring the past time. */ rtc_time64_to_tm(t_now - 1, &alarm.time); alarm.enabled = 0; retval = cmos_set_alarm(dev, &alarm); } else if (cmos->alarm_expires > t_now + 1) { retval = -EBUSY; } return retval; } static int cmos_suspend(struct device *dev) { struct cmos_rtc *cmos = dev_get_drvdata(dev); unsigned char tmp; /* only the alarm might be a wakeup event source */ spin_lock_irq(&rtc_lock); cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL); if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) { unsigned char mask; if (device_may_wakeup(dev)) mask = RTC_IRQMASK & ~RTC_AIE; else mask = RTC_IRQMASK; tmp &= ~mask; CMOS_WRITE(tmp, RTC_CONTROL); if (use_hpet_alarm()) hpet_mask_rtc_irq_bit(mask); cmos_checkintr(cmos, tmp); } spin_unlock_irq(&rtc_lock); if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) { cmos->enabled_wake = 1; if (cmos->wake_on) cmos->wake_on(dev); else enable_irq_wake(cmos->irq); } memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm)); cmos_read_alarm(dev, &cmos->saved_wkalrm); dev_dbg(dev, "suspend%s, ctrl %02x\n", (tmp & RTC_AIE) ? ", alarm may wake" : "", tmp); return 0; } /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even * after a detour through G3 "mechanical off", although the ACPI spec * says wakeup should only work from G1/S4 "hibernate". To most users, * distinctions between S4 and S5 are pointless. So when the hardware * allows, don't draw that distinction. */ static inline int cmos_poweroff(struct device *dev) { if (!IS_ENABLED(CONFIG_PM)) return -ENOSYS; return cmos_suspend(dev); } static void cmos_check_wkalrm(struct device *dev) { struct cmos_rtc *cmos = dev_get_drvdata(dev); struct rtc_wkalrm current_alarm; time64_t t_now; time64_t t_current_expires; time64_t t_saved_expires; struct rtc_time now; /* Check if we have RTC Alarm armed */ if (!(cmos->suspend_ctrl & RTC_AIE)) return; cmos_read_time(dev, &now); t_now = rtc_tm_to_time64(&now); /* * ACPI RTC wake event is cleared after resume from STR, * ACK the rtc irq here */ if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) { local_irq_disable(); cmos_interrupt(0, (void *)cmos->rtc); local_irq_enable(); return; } memset(¤t_alarm, 0, sizeof(struct rtc_wkalrm)); cmos_read_alarm(dev, ¤t_alarm); t_current_expires = rtc_tm_to_time64(¤t_alarm.time); t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time); if (t_current_expires != t_saved_expires || cmos->saved_wkalrm.enabled != current_alarm.enabled) { cmos_set_alarm(dev, &cmos->saved_wkalrm); } } static int __maybe_unused cmos_resume(struct device *dev) { struct cmos_rtc *cmos = dev_get_drvdata(dev); unsigned char tmp; if (cmos->enabled_wake && !cmos_use_acpi_alarm()) { if (cmos->wake_off) cmos->wake_off(dev); else disable_irq_wake(cmos->irq); cmos->enabled_wake = 0; } /* The BIOS might have changed the alarm, restore it */ cmos_check_wkalrm(dev); spin_lock_irq(&rtc_lock); tmp = cmos->suspend_ctrl; cmos->suspend_ctrl = 0; /* re-enable any irqs previously active */ if (tmp & RTC_IRQMASK) { unsigned char mask; if (device_may_wakeup(dev) && use_hpet_alarm()) hpet_rtc_timer_init(); do { CMOS_WRITE(tmp, RTC_CONTROL); if (use_hpet_alarm()) hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK); mask = CMOS_READ(RTC_INTR_FLAGS); mask &= (tmp & RTC_IRQMASK) | RTC_IRQF; if (!use_hpet_alarm() || !is_intr(mask)) break; /* force one-shot behavior if HPET blocked * the wake alarm's irq */ rtc_update_irq(cmos->rtc, 1, mask); tmp &= ~RTC_AIE; hpet_mask_rtc_irq_bit(RTC_AIE); } while (mask & RTC_AIE); if (tmp & RTC_AIE) cmos_check_acpi_rtc_status(dev, &tmp); } spin_unlock_irq(&rtc_lock); dev_dbg(dev, "resume, ctrl %02x\n", tmp); return 0; } static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume); /*----------------------------------------------------------------*/ /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus. * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs * probably list them in similar PNPBIOS tables; so PNP is more common. * * We don't use legacy "poke at the hardware" probing. Ancient PCs that * predate even PNPBIOS should set up platform_bus devices. */ #ifdef CONFIG_PNP #include static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) { int irq; if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) { irq = 0; #ifdef CONFIG_X86 /* Some machines contain a PNP entry for the RTC, but * don't define the IRQ. It should always be safe to * hardcode it on systems with a legacy PIC. */ if (nr_legacy_irqs()) irq = RTC_IRQ; #endif } else { irq = pnp_irq(pnp, 0); } return cmos_do_probe(&pnp->dev, pnp_get_resource(pnp, IORESOURCE_IO, 0), irq); } static void cmos_pnp_remove(struct pnp_dev *pnp) { cmos_do_remove(&pnp->dev); } static void cmos_pnp_shutdown(struct pnp_dev *pnp) { struct device *dev = &pnp->dev; struct cmos_rtc *cmos = dev_get_drvdata(dev); if (system_state == SYSTEM_POWER_OFF) { int retval = cmos_poweroff(dev); if (cmos_aie_poweroff(dev) < 0 && !retval) return; } cmos_do_shutdown(cmos->irq); } static const struct pnp_device_id rtc_ids[] = { { .id = "PNP0b00", }, { .id = "PNP0b01", }, { .id = "PNP0b02", }, { }, }; MODULE_DEVICE_TABLE(pnp, rtc_ids); static struct pnp_driver cmos_pnp_driver = { .name = driver_name, .id_table = rtc_ids, .probe = cmos_pnp_probe, .remove = cmos_pnp_remove, .shutdown = cmos_pnp_shutdown, /* flag ensures resume() gets called, and stops syslog spam */ .flags = PNP_DRIVER_RES_DO_NOT_CHANGE, .driver = { .pm = &cmos_pm_ops, }, }; #endif /* CONFIG_PNP */ #ifdef CONFIG_OF static const struct of_device_id of_cmos_match[] = { { .compatible = "motorola,mc146818", }, { }, }; MODULE_DEVICE_TABLE(of, of_cmos_match); static __init void cmos_of_init(struct platform_device *pdev) { struct device_node *node = pdev->dev.of_node; const __be32 *val; if (!node) return; val = of_get_property(node, "ctrl-reg", NULL); if (val) CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL); val = of_get_property(node, "freq-reg", NULL); if (val) CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT); } #else static inline void cmos_of_init(struct platform_device *pdev) {} #endif /*----------------------------------------------------------------*/ /* Platform setup should have set up an RTC device, when PNP is * unavailable ... this could happen even on (older) PCs. */ static int __init cmos_platform_probe(struct platform_device *pdev) { struct resource *resource; int irq; cmos_of_init(pdev); if (RTC_IOMAPPED) resource = platform_get_resource(pdev, IORESOURCE_IO, 0); else resource = platform_get_resource(pdev, IORESOURCE_MEM, 0); irq = platform_get_irq(pdev, 0); if (irq < 0) irq = -1; return cmos_do_probe(&pdev->dev, resource, irq); } static int cmos_platform_remove(struct platform_device *pdev) { cmos_do_remove(&pdev->dev); return 0; } static void cmos_platform_shutdown(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct cmos_rtc *cmos = dev_get_drvdata(dev); if (system_state == SYSTEM_POWER_OFF) { int retval = cmos_poweroff(dev); if (cmos_aie_poweroff(dev) < 0 && !retval) return; } cmos_do_shutdown(cmos->irq); } /* work with hotplug and coldplug */ MODULE_ALIAS("platform:rtc_cmos"); static struct platform_driver cmos_platform_driver = { .remove = cmos_platform_remove, .shutdown = cmos_platform_shutdown, .driver = { .name = driver_name, .pm = &cmos_pm_ops, .of_match_table = of_match_ptr(of_cmos_match), } }; #ifdef CONFIG_PNP static bool pnp_driver_registered; #endif static bool platform_driver_registered; static int __init cmos_init(void) { int retval = 0; #ifdef CONFIG_PNP retval = pnp_register_driver(&cmos_pnp_driver); if (retval == 0) pnp_driver_registered = true; #endif if (!cmos_rtc.dev) { retval = platform_driver_probe(&cmos_platform_driver, cmos_platform_probe); if (retval == 0) platform_driver_registered = true; } if (retval == 0) return 0; #ifdef CONFIG_PNP if (pnp_driver_registered) pnp_unregister_driver(&cmos_pnp_driver); #endif return retval; } module_init(cmos_init); static void __exit cmos_exit(void) { #ifdef CONFIG_PNP if (pnp_driver_registered) pnp_unregister_driver(&cmos_pnp_driver); #endif if (platform_driver_registered) platform_driver_unregister(&cmos_platform_driver); } module_exit(cmos_exit); MODULE_AUTHOR("David Brownell"); MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs"); MODULE_LICENSE("GPL");