diff options
Diffstat (limited to 'drivers/rtc/rtc-cmos.c')
| -rw-r--r-- | drivers/rtc/rtc-cmos.c | 725 |
1 files changed, 725 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c new file mode 100644 index 000000000000..85bf795abdcc --- /dev/null +++ b/drivers/rtc/rtc-cmos.c @@ -0,0 +1,725 @@ +/* + * 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) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +/* + * 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. + */ +#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/mod_devicetable.h> + +/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */ +#include <asm-generic/rtc.h> + + +struct cmos_rtc { + struct rtc_device *rtc; + struct device *dev; + int irq; + struct resource *iomem; + + u8 suspend_ctrl; + + /* newer hardware extends the original register set */ + u8 day_alrm; + u8 mon_alrm; + u8 century; +}; + +/* 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"; + +/*----------------------------------------------------------------*/ + +static int cmos_read_time(struct device *dev, struct rtc_time *t) +{ + /* REVISIT: if the clock has a "century" register, use + * that instead of the heuristic in get_rtc_time(). + * That'll make Y3K compatility (year > 2070) easy! + */ + get_rtc_time(t); + return 0; +} + +static int cmos_set_time(struct device *dev, struct rtc_time *t) +{ + /* REVISIT: set the "century" register if available + * + * 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 set_rtc_time(t); +} + +static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t) +{ + struct cmos_rtc *cmos = dev_get_drvdata(dev); + unsigned char rtc_control; + + if (!is_valid_irq(cmos->irq)) + return -EIO; + + /* Basic alarms only support hour, minute, and seconds fields. + * Some also support day and month, for alarms up to a year in + * the future. + */ + t->time.tm_mday = -1; + t->time.tm_mon = -1; + + spin_lock_irq(&rtc_lock); + t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM); + t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM); + t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM); + + if (cmos->day_alrm) { + t->time.tm_mday = CMOS_READ(cmos->day_alrm); + if (!t->time.tm_mday) + t->time.tm_mday = -1; + + if (cmos->mon_alrm) { + t->time.tm_mon = CMOS_READ(cmos->mon_alrm); + if (!t->time.tm_mon) + t->time.tm_mon = -1; + } + } + + rtc_control = CMOS_READ(RTC_CONTROL); + spin_unlock_irq(&rtc_lock); + + /* REVISIT this assumes PC style usage: 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->time.tm_year = -1; + + t->enabled = !!(rtc_control & RTC_AIE); + t->pending = 0; + + return 0; +} + +static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) +{ + struct cmos_rtc *cmos = dev_get_drvdata(dev); + unsigned char mon, mday, hrs, min, sec; + unsigned char rtc_control, rtc_intr; + + if (!is_valid_irq(cmos->irq)) + return -EIO; + + /* REVISIT this assumes PC style usage: always BCD */ + + /* Writing 0xff means "don't care" or "match all". */ + + mon = t->time.tm_mon; + mon = (mon < 12) ? BIN2BCD(mon) : 0xff; + mon++; + + mday = t->time.tm_mday; + mday = (mday >= 1 && mday <= 31) ? BIN2BCD(mday) : 0xff; + + hrs = t->time.tm_hour; + hrs = (hrs < 24) ? BIN2BCD(hrs) : 0xff; + + min = t->time.tm_min; + min = (min < 60) ? BIN2BCD(min) : 0xff; + + sec = t->time.tm_sec; + sec = (sec < 60) ? BIN2BCD(sec) : 0xff; + + spin_lock_irq(&rtc_lock); + + /* next rtc irq must not be from previous alarm setting */ + rtc_control = CMOS_READ(RTC_CONTROL); + rtc_control &= ~RTC_AIE; + CMOS_WRITE(rtc_control, RTC_CONTROL); + rtc_intr = CMOS_READ(RTC_INTR_FLAGS); + if (rtc_intr) + rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr); + + /* update alarm */ + CMOS_WRITE(hrs, RTC_HOURS_ALARM); + CMOS_WRITE(min, RTC_MINUTES_ALARM); + CMOS_WRITE(sec, RTC_SECONDS_ALARM); + + /* the system may support an "enhanced" alarm */ + if (cmos->day_alrm) { + CMOS_WRITE(mday, cmos->day_alrm); + if (cmos->mon_alrm) + CMOS_WRITE(mon, cmos->mon_alrm); + } + + if (t->enabled) { + rtc_control |= RTC_AIE; + CMOS_WRITE(rtc_control, RTC_CONTROL); + rtc_intr = CMOS_READ(RTC_INTR_FLAGS); + if (rtc_intr) + rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr); + } + + spin_unlock_irq(&rtc_lock); + + return 0; +} + +static int cmos_set_freq(struct device *dev, int freq) +{ + struct cmos_rtc *cmos = dev_get_drvdata(dev); + int f; + unsigned long flags; + + if (!is_valid_irq(cmos->irq)) + return -ENXIO; + + /* 0 = no irqs; 1 = 2^15 Hz ... 15 = 2^0 Hz */ + f = ffs(freq); + if (f != 0) { + if (f-- > 16 || freq != (1 << f)) + return -EINVAL; + f = 16 - f; + } + + spin_lock_irqsave(&rtc_lock, flags); + CMOS_WRITE(RTC_REF_CLCK_32KHZ | f, RTC_FREQ_SELECT); + spin_unlock_irqrestore(&rtc_lock, flags); + + return 0; +} + +#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE) + +static int +cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) +{ + struct cmos_rtc *cmos = dev_get_drvdata(dev); + unsigned char rtc_control, rtc_intr; + unsigned long flags; + + switch (cmd) { + case RTC_AIE_OFF: + case RTC_AIE_ON: + case RTC_UIE_OFF: + case RTC_UIE_ON: + case RTC_PIE_OFF: + case RTC_PIE_ON: + if (!is_valid_irq(cmos->irq)) + return -EINVAL; + break; + default: + return -ENOIOCTLCMD; + } + + spin_lock_irqsave(&rtc_lock, flags); + rtc_control = CMOS_READ(RTC_CONTROL); + switch (cmd) { + case RTC_AIE_OFF: /* alarm off */ + rtc_control &= ~RTC_AIE; + break; + case RTC_AIE_ON: /* alarm on */ + rtc_control |= RTC_AIE; + break; + case RTC_UIE_OFF: /* update off */ + rtc_control &= ~RTC_UIE; + break; + case RTC_UIE_ON: /* update on */ + rtc_control |= RTC_UIE; + break; + case RTC_PIE_OFF: /* periodic off */ + rtc_control &= ~RTC_PIE; + break; + case RTC_PIE_ON: /* periodic on */ + rtc_control |= RTC_PIE; + break; + } + CMOS_WRITE(rtc_control, RTC_CONTROL); + rtc_intr = CMOS_READ(RTC_INTR_FLAGS); + if (rtc_intr) + rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr); + spin_unlock_irqrestore(&rtc_lock, flags); + return 0; +} + +#else +#define cmos_rtc_ioctl NULL +#endif + +#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE) + +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. + */ + return seq_printf(seq, + "periodic_IRQ\t: %s\n" + "update_IRQ\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", + // (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"); +} + +#else +#define cmos_procfs NULL +#endif + +static const struct rtc_class_ops cmos_rtc_ops = { + .ioctl = cmos_rtc_ioctl, + .read_time = cmos_read_time, + .set_time = cmos_set_time, + .read_alarm = cmos_read_alarm, + .set_alarm = cmos_set_alarm, + .proc = cmos_procfs, + .irq_set_freq = cmos_set_freq, +}; + +/*----------------------------------------------------------------*/ + +static struct cmos_rtc cmos_rtc; + +static irqreturn_t cmos_interrupt(int irq, void *p) +{ + u8 irqstat; + + spin_lock(&rtc_lock); + irqstat = CMOS_READ(RTC_INTR_FLAGS); + spin_unlock(&rtc_lock); + + if (irqstat) { + /* NOTE: irqstat may have e.g. RTC_PF set + * even when RTC_PIE is clear... + */ + rtc_update_irq(p, 1, irqstat); + return IRQ_HANDLED; + } else + return IRQ_NONE; +} + +#ifdef CONFIG_PNPACPI +#define is_pnpacpi() 1 +#define INITSECTION + +#else +#define is_pnpacpi() 0 +#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->platform_data; + int retval = 0; + unsigned char rtc_control; + + /* there can be only one ... */ + if (cmos_rtc.dev) + return -EBUSY; + + if (!ports) + return -ENODEV; + + cmos_rtc.irq = rtc_irq; + cmos_rtc.iomem = ports; + + /* For ACPI systems the info comes from the FADT. On others, + * board specific setup provides it as appropriate. + */ + if (info) { + cmos_rtc.day_alrm = info->rtc_day_alarm; + cmos_rtc.mon_alrm = info->rtc_mon_alarm; + cmos_rtc.century = info->rtc_century; + } + + cmos_rtc.rtc = rtc_device_register(driver_name, dev, + &cmos_rtc_ops, THIS_MODULE); + if (IS_ERR(cmos_rtc.rtc)) + return PTR_ERR(cmos_rtc.rtc); + + cmos_rtc.dev = dev; + dev_set_drvdata(dev, &cmos_rtc); + + /* platform and pnp busses handle resources incompatibly. + * + * REVISIT for non-x86 systems we may need to handle io memory + * resources: ioremap them, and request_mem_region(). + */ + if (is_pnpacpi()) { + retval = request_resource(&ioport_resource, ports); + if (retval < 0) { + dev_dbg(dev, "i/o registers already in use\n"); + goto cleanup0; + } + } + rename_region(ports, cmos_rtc.rtc->class_dev.class_id); + + spin_lock_irq(&rtc_lock); + + /* 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_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT); + cmos_rtc.rtc->irq_freq = 1024; + + /* disable irqs. + * + * NOTE after changing RTC_xIE bits we always read INTR_FLAGS; + * allegedly some older rtcs need that to handle irqs properly + */ + rtc_control = CMOS_READ(RTC_CONTROL); + rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE); + CMOS_WRITE(rtc_control, RTC_CONTROL); + CMOS_READ(RTC_INTR_FLAGS); + + spin_unlock_irq(&rtc_lock); + + /* FIXME teach the alarm code how to handle binary mode; + * <asm-generic/rtc.h> doesn't know 12-hour mode either. + */ + if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY))) { + dev_dbg(dev, "only 24-hr BCD mode supported\n"); + retval = -ENXIO; + goto cleanup1; + } + + if (is_valid_irq(rtc_irq)) + retval = request_irq(rtc_irq, cmos_interrupt, IRQF_DISABLED, + cmos_rtc.rtc->class_dev.class_id, + &cmos_rtc.rtc->class_dev); + if (retval < 0) { + dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq); + goto cleanup1; + } + + /* REVISIT optionally make 50 or 114 bytes NVRAM available, + * like rtc-ds1553, rtc-ds1742 ... this will often include + * registers for century, and day/month alarm. + */ + + pr_info("%s: alarms up to one %s%s\n", + cmos_rtc.rtc->class_dev.class_id, + is_valid_irq(rtc_irq) + ? (cmos_rtc.mon_alrm + ? "year" + : (cmos_rtc.day_alrm + ? "month" : "day")) + : "no", + cmos_rtc.century ? ", y3k" : "" + ); + + return 0; + +cleanup1: + rename_region(ports, NULL); +cleanup0: + rtc_device_unregister(cmos_rtc.rtc); + return retval; +} + +static void cmos_do_shutdown(void) +{ + unsigned char rtc_control; + + spin_lock_irq(&rtc_lock); + rtc_control = CMOS_READ(RTC_CONTROL); + rtc_control &= ~(RTC_PIE|RTC_AIE|RTC_UIE); + CMOS_WRITE(rtc_control, RTC_CONTROL); + CMOS_READ(RTC_INTR_FLAGS); + spin_unlock_irq(&rtc_lock); +} + +static void __exit cmos_do_remove(struct device *dev) +{ + struct cmos_rtc *cmos = dev_get_drvdata(dev); + + cmos_do_shutdown(); + + if (is_pnpacpi()) + release_resource(cmos->iomem); + rename_region(cmos->iomem, NULL); + + if (is_valid_irq(cmos->irq)) + free_irq(cmos->irq, &cmos_rtc.rtc->class_dev); + + rtc_device_unregister(cmos_rtc.rtc); + + cmos_rtc.dev = NULL; + dev_set_drvdata(dev, NULL); +} + +#ifdef CONFIG_PM + +static int cmos_suspend(struct device *dev, pm_message_t mesg) +{ + struct cmos_rtc *cmos = dev_get_drvdata(dev); + int do_wake = device_may_wakeup(dev); + unsigned char tmp, irqstat; + + /* 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)) { + if (do_wake) + tmp &= ~(RTC_PIE|RTC_UIE); + else + tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE); + CMOS_WRITE(tmp, RTC_CONTROL); + irqstat = CMOS_READ(RTC_INTR_FLAGS); + } else + irqstat = 0; + spin_unlock_irq(&rtc_lock); + + if (irqstat) + rtc_update_irq(&cmos->rtc->class_dev, 1, irqstat); + + /* ACPI HOOK: enable ACPI_EVENT_RTC when (tmp & RTC_AIE) + * ... it'd be best if we could do that under rtc_lock. + */ + + pr_debug("%s: suspend%s, ctrl %02x\n", + cmos_rtc.rtc->class_dev.class_id, + (tmp & RTC_AIE) ? ", alarm may wake" : "", + tmp); + + return 0; +} + +static int cmos_resume(struct device *dev) +{ + struct cmos_rtc *cmos = dev_get_drvdata(dev); + unsigned char tmp = cmos->suspend_ctrl; + + /* REVISIT: a mechanism to resync the system clock (jiffies) + * on resume should be portable between platforms ... + */ + + /* re-enable any irqs previously active */ + if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) { + + /* ACPI HOOK: disable ACPI_EVENT_RTC when (tmp & RTC_AIE) */ + + spin_lock_irq(&rtc_lock); + CMOS_WRITE(tmp, RTC_CONTROL); + tmp = CMOS_READ(RTC_INTR_FLAGS); + spin_unlock_irq(&rtc_lock); + if (tmp) + rtc_update_irq(&cmos->rtc->class_dev, 1, tmp); + } + + pr_debug("%s: resume, ctrl %02x\n", + cmos_rtc.rtc->class_dev.class_id, + cmos->suspend_ctrl); + + + return 0; +} + +#else +#define cmos_suspend NULL +#define cmos_resume NULL +#endif + +/*----------------------------------------------------------------*/ + +/* The "CMOS" RTC normally lives on the platform_bus. On ACPI systems, + * the device node may alternatively be created as a PNP device. + */ + +#ifdef CONFIG_PNPACPI + +#include <linux/pnp.h> + +static int __devinit +cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) +{ + /* REVISIT paranoia argues for a shutdown notifier, since PNP + * drivers can't provide shutdown() methods to disable IRQs. + * Or better yet, fix PNP to allow those methods... + */ + return cmos_do_probe(&pnp->dev, + &pnp->res.port_resource[0], + pnp->res.irq_resource[0].start); +} + +static void __exit cmos_pnp_remove(struct pnp_dev *pnp) +{ + cmos_do_remove(&pnp->dev); +} + +#ifdef CONFIG_PM + +static int cmos_pnp_suspend(struct pnp_dev *pnp, pm_message_t mesg) +{ + return cmos_suspend(&pnp->dev, mesg); +} + +static int cmos_pnp_resume(struct pnp_dev *pnp) +{ + return cmos_resume(&pnp->dev); +} + +#else +#define cmos_pnp_suspend NULL +#define cmos_pnp_resume NULL +#endif + + +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 = (char *) driver_name, + .id_table = rtc_ids, + .probe = cmos_pnp_probe, + .remove = __exit_p(cmos_pnp_remove), + + /* flag ensures resume() gets called, and stops syslog spam */ + .flags = PNP_DRIVER_RES_DO_NOT_CHANGE, + .suspend = cmos_pnp_suspend, + .resume = cmos_pnp_resume, +}; + +static int __init cmos_init(void) +{ + return pnp_register_driver(&cmos_pnp_driver); +} +module_init(cmos_init); + +static void __exit cmos_exit(void) +{ + pnp_unregister_driver(&cmos_pnp_driver); +} +module_exit(cmos_exit); + +#else /* no PNPACPI */ + +/*----------------------------------------------------------------*/ + +/* Platform setup should have set up an RTC device, when PNPACPI is + * unavailable ... this is the normal case, common even on PCs. + */ + +static int __init cmos_platform_probe(struct platform_device *pdev) +{ + return cmos_do_probe(&pdev->dev, + platform_get_resource(pdev, IORESOURCE_IO, 0), + platform_get_irq(pdev, 0)); +} + +static int __exit cmos_platform_remove(struct platform_device *pdev) +{ + cmos_do_remove(&pdev->dev); + return 0; +} + +static void cmos_platform_shutdown(struct platform_device *pdev) +{ + cmos_do_shutdown(); +} + +static struct platform_driver cmos_platform_driver = { + .remove = __exit_p(cmos_platform_remove), + .shutdown = cmos_platform_shutdown, + .driver = { + .name = (char *) driver_name, + .suspend = cmos_suspend, + .resume = cmos_resume, + } +}; + +static int __init cmos_init(void) +{ + return platform_driver_probe(&cmos_platform_driver, + cmos_platform_probe); +} +module_init(cmos_init); + +static void __exit cmos_exit(void) +{ + platform_driver_unregister(&cmos_platform_driver); +} +module_exit(cmos_exit); + + +#endif /* !PNPACPI */ + +MODULE_AUTHOR("David Brownell"); +MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs"); +MODULE_LICENSE("GPL"); |