diff options
Diffstat (limited to 'drivers/rtc/rtc-cmos.c')
| -rw-r--r-- | drivers/rtc/rtc-cmos.c | 1579 |
1 files changed, 1579 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c new file mode 100644 index 000000000..e0a798923 --- /dev/null +++ b/drivers/rtc/rtc-cmos.c @@ -0,0 +1,1579 @@ +// 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 <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/spinlock.h> +#include <linux/platform_device.h> +#include <linux/log2.h> +#include <linux/pm.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#ifdef CONFIG_X86 +#include <asm/i8259.h> +#include <asm/processor.h> +#include <linux/dmi.h> +#endif + +/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */ +#include <linux/mc146818rtc.h> + +#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 <asm/hpet.h> +#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, 1000); + 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, 10, &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, 10, &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, +}; + +/*----------------------------------------------------------------*/ + +/* + * 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 <linux/acpi.h> + +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 +static void use_acpi_alarm_quirks(void) +{ + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_INTEL: + if (dmi_get_bios_year() < 2015) + return; + break; + case X86_VENDOR_AMD: + case X86_VENDOR_HYGON: + if (dmi_get_bios_year() < 2021) + return; + break; + default: + return; + } + if (!is_hpet_enabled()) + 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; + } + } else { + clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features); + } + + cmos_rtc.rtc->ops = &cmos_rtc_ops; + + retval = devm_rtc_register_device(cmos_rtc.rtc); + if (retval) + goto cleanup2; + + /* Set the sync offset for the periodic 11min update correct */ + cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2; + + /* export at least the first block of NVRAM */ + nvmem_cfg.size = address_space - NVRAM_OFFSET; + devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg); + + /* + * 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 <linux/pnp.h> + +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"); |