diff options
Diffstat (limited to 'drivers/char/rtc.c')
| -rw-r--r-- | drivers/char/rtc.c | 1316 |
1 files changed, 1316 insertions, 0 deletions
diff --git a/drivers/char/rtc.c b/drivers/char/rtc.c new file mode 100644 index 000000000..4948c8bda --- /dev/null +++ b/drivers/char/rtc.c @@ -0,0 +1,1316 @@ +/* + * Real Time Clock interface for Linux + * + * Copyright (C) 1996 Paul Gortmaker + * + * This driver allows use of the real time clock (built into + * nearly all computers) from user space. It exports the /dev/rtc + * interface supporting various ioctl() and also the + * /proc/driver/rtc pseudo-file for status information. + * + * The ioctls can be used to set the interrupt behaviour and + * generation rate from the RTC via IRQ 8. Then the /dev/rtc + * interface can be used to make use of these timer interrupts, + * be they interval or alarm based. + * + * The /dev/rtc interface will block on reads until an interrupt + * has been received. If a RTC interrupt has already happened, + * it will output an unsigned long and then block. The output value + * contains the interrupt status in the low byte and the number of + * interrupts since the last read in the remaining high bytes. The + * /dev/rtc interface can also be used with the select(2) call. + * + * 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. + * + * Based on other minimal char device drivers, like Alan's + * watchdog, Ted's random, etc. etc. + * + * 1.07 Paul Gortmaker. + * 1.08 Miquel van Smoorenburg: disallow certain things on the + * DEC Alpha as the CMOS clock is also used for other things. + * 1.09 Nikita Schmidt: epoch support and some Alpha cleanup. + * 1.09a Pete Zaitcev: Sun SPARC + * 1.09b Jeff Garzik: Modularize, init cleanup + * 1.09c Jeff Garzik: SMP cleanup + * 1.10 Paul Barton-Davis: add support for async I/O + * 1.10a Andrea Arcangeli: Alpha updates + * 1.10b Andrew Morton: SMP lock fix + * 1.10c Cesar Barros: SMP locking fixes and cleanup + * 1.10d Paul Gortmaker: delete paranoia check in rtc_exit + * 1.10e Maciej W. Rozycki: Handle DECstation's year weirdness. + * 1.11 Takashi Iwai: Kernel access functions + * rtc_register/rtc_unregister/rtc_control + * 1.11a Daniele Bellucci: Audit create_proc_read_entry in rtc_init + * 1.12 Venkatesh Pallipadi: Hooks for emulating rtc on HPET base-timer + * CONFIG_HPET_EMULATE_RTC + * 1.12a Maciej W. Rozycki: Handle memory-mapped chips properly. + * 1.12ac Alan Cox: Allow read access to the day of week register + * 1.12b David John: Remove calls to the BKL. + */ + +#define RTC_VERSION "1.12b" + +/* + * Note that *all* calls to CMOS_READ and CMOS_WRITE are done with + * interrupts disabled. Due to the index-port/data-port (0x70/0x71) + * design of the RTC, we don't want two different things trying to + * get to it at once. (e.g. the periodic 11 min sync from + * kernel/time/ntp.c vs. this driver.) + */ + +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/miscdevice.h> +#include <linux/ioport.h> +#include <linux/fcntl.h> +#include <linux/mc146818rtc.h> +#include <linux/init.h> +#include <linux/poll.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/spinlock.h> +#include <linux/sched/signal.h> +#include <linux/sysctl.h> +#include <linux/wait.h> +#include <linux/bcd.h> +#include <linux/delay.h> +#include <linux/uaccess.h> +#include <linux/ratelimit.h> + +#include <asm/current.h> + +#ifdef CONFIG_X86 +#include <asm/hpet.h> +#endif + +#ifdef CONFIG_SPARC32 +#include <linux/of.h> +#include <linux/of_device.h> +#include <asm/io.h> + +static unsigned long rtc_port; +static int rtc_irq; +#endif + +#ifdef CONFIG_HPET_EMULATE_RTC +#undef RTC_IRQ +#endif + +#ifdef RTC_IRQ +static int rtc_has_irq = 1; +#endif + +#ifndef CONFIG_HPET_EMULATE_RTC +#define is_hpet_enabled() 0 +#define hpet_set_alarm_time(hrs, min, sec) 0 +#define hpet_set_periodic_freq(arg) 0 +#define hpet_mask_rtc_irq_bit(arg) 0 +#define hpet_set_rtc_irq_bit(arg) 0 +#define hpet_rtc_timer_init() do { } while (0) +#define hpet_rtc_dropped_irq() 0 +#define hpet_register_irq_handler(h) ({ 0; }) +#define hpet_unregister_irq_handler(h) ({ 0; }) +#ifdef RTC_IRQ +static irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id) +{ + return 0; +} +#endif +#endif + +/* + * We sponge a minor off of the misc major. No need slurping + * up another valuable major dev number for this. If you add + * an ioctl, make sure you don't conflict with SPARC's RTC + * ioctls. + */ + +static struct fasync_struct *rtc_async_queue; + +static DECLARE_WAIT_QUEUE_HEAD(rtc_wait); + +#ifdef RTC_IRQ +static void rtc_dropped_irq(struct timer_list *unused); + +static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq); +#endif + +static ssize_t rtc_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos); + +static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg); +static void rtc_get_rtc_time(struct rtc_time *rtc_tm); + +#ifdef RTC_IRQ +static __poll_t rtc_poll(struct file *file, poll_table *wait); +#endif + +static void get_rtc_alm_time(struct rtc_time *alm_tm); +#ifdef RTC_IRQ +static void set_rtc_irq_bit_locked(unsigned char bit); +static void mask_rtc_irq_bit_locked(unsigned char bit); + +static inline void set_rtc_irq_bit(unsigned char bit) +{ + spin_lock_irq(&rtc_lock); + set_rtc_irq_bit_locked(bit); + spin_unlock_irq(&rtc_lock); +} + +static void mask_rtc_irq_bit(unsigned char bit) +{ + spin_lock_irq(&rtc_lock); + mask_rtc_irq_bit_locked(bit); + spin_unlock_irq(&rtc_lock); +} +#endif + +#ifdef CONFIG_PROC_FS +static int rtc_proc_show(struct seq_file *seq, void *v); +#endif + +/* + * Bits in rtc_status. (6 bits of room for future expansion) + */ + +#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ +#define RTC_TIMER_ON 0x02 /* missed irq timer active */ + +/* + * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is + * protected by the spin lock rtc_lock. However, ioctl can still disable the + * timer in rtc_status and then with del_timer after the interrupt has read + * rtc_status but before mod_timer is called, which would then reenable the + * timer (but you would need to have an awful timing before you'd trip on it) + */ +static unsigned long rtc_status; /* bitmapped status byte. */ +static unsigned long rtc_freq; /* Current periodic IRQ rate */ +static unsigned long rtc_irq_data; /* our output to the world */ +static unsigned long rtc_max_user_freq = 64; /* > this, need CAP_SYS_RESOURCE */ + +/* + * If this driver ever becomes modularised, it will be really nice + * to make the epoch retain its value across module reload... + */ + +static unsigned long epoch = 1900; /* year corresponding to 0x00 */ + +static const unsigned char days_in_mo[] = +{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; + +/* + * Returns true if a clock update is in progress + */ +static inline unsigned char rtc_is_updating(void) +{ + unsigned long flags; + unsigned char uip; + + spin_lock_irqsave(&rtc_lock, flags); + uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP); + spin_unlock_irqrestore(&rtc_lock, flags); + return uip; +} + +#ifdef RTC_IRQ +/* + * A very tiny interrupt handler. It runs with interrupts disabled, + * but there is possibility of conflicting with the set_rtc_mmss() + * call (the rtc irq and the timer irq can easily run at the same + * time in two different CPUs). So we need to serialize + * accesses to the chip with the rtc_lock spinlock that each + * architecture should implement in the timer code. + * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.) + */ + +static irqreturn_t rtc_interrupt(int irq, void *dev_id) +{ + /* + * Can be an alarm interrupt, update complete interrupt, + * or a periodic interrupt. We store the status in the + * low byte and the number of interrupts received since + * the last read in the remainder of rtc_irq_data. + */ + + spin_lock(&rtc_lock); + rtc_irq_data += 0x100; + rtc_irq_data &= ~0xff; + if (is_hpet_enabled()) { + /* + * In this case it is HPET RTC interrupt handler + * calling us, with the interrupt information + * passed as arg1, instead of irq. + */ + rtc_irq_data |= (unsigned long)irq & 0xF0; + } else { + rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); + } + + if (rtc_status & RTC_TIMER_ON) + mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100); + + spin_unlock(&rtc_lock); + + wake_up_interruptible(&rtc_wait); + + kill_fasync(&rtc_async_queue, SIGIO, POLL_IN); + + return IRQ_HANDLED; +} +#endif + +/* + * sysctl-tuning infrastructure. + */ +static struct ctl_table rtc_table[] = { + { + .procname = "max-user-freq", + .data = &rtc_max_user_freq, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { } +}; + +static struct ctl_table rtc_root[] = { + { + .procname = "rtc", + .mode = 0555, + .child = rtc_table, + }, + { } +}; + +static struct ctl_table dev_root[] = { + { + .procname = "dev", + .mode = 0555, + .child = rtc_root, + }, + { } +}; + +static struct ctl_table_header *sysctl_header; + +static int __init init_sysctl(void) +{ + sysctl_header = register_sysctl_table(dev_root); + return 0; +} + +static void __exit cleanup_sysctl(void) +{ + unregister_sysctl_table(sysctl_header); +} + +/* + * Now all the various file operations that we export. + */ + +static ssize_t rtc_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ +#ifndef RTC_IRQ + return -EIO; +#else + DECLARE_WAITQUEUE(wait, current); + unsigned long data; + ssize_t retval; + + if (rtc_has_irq == 0) + return -EIO; + + /* + * Historically this function used to assume that sizeof(unsigned long) + * is the same in userspace and kernelspace. This lead to problems + * for configurations with multiple ABIs such a the MIPS o32 and 64 + * ABIs supported on the same kernel. So now we support read of both + * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the + * userspace ABI. + */ + if (count != sizeof(unsigned int) && count != sizeof(unsigned long)) + return -EINVAL; + + add_wait_queue(&rtc_wait, &wait); + + do { + /* First make it right. Then make it fast. Putting this whole + * block within the parentheses of a while would be too + * confusing. And no, xchg() is not the answer. */ + + __set_current_state(TASK_INTERRUPTIBLE); + + spin_lock_irq(&rtc_lock); + data = rtc_irq_data; + rtc_irq_data = 0; + spin_unlock_irq(&rtc_lock); + + if (data != 0) + break; + + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + goto out; + } + if (signal_pending(current)) { + retval = -ERESTARTSYS; + goto out; + } + schedule(); + } while (1); + + if (count == sizeof(unsigned int)) { + retval = put_user(data, + (unsigned int __user *)buf) ?: sizeof(int); + } else { + retval = put_user(data, + (unsigned long __user *)buf) ?: sizeof(long); + } + if (!retval) + retval = count; + out: + __set_current_state(TASK_RUNNING); + remove_wait_queue(&rtc_wait, &wait); + + return retval; +#endif +} + +static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel) +{ + struct rtc_time wtime; + +#ifdef RTC_IRQ + if (rtc_has_irq == 0) { + switch (cmd) { + case RTC_AIE_OFF: + case RTC_AIE_ON: + case RTC_PIE_OFF: + case RTC_PIE_ON: + case RTC_UIE_OFF: + case RTC_UIE_ON: + case RTC_IRQP_READ: + case RTC_IRQP_SET: + return -EINVAL; + } + } +#endif + + switch (cmd) { +#ifdef RTC_IRQ + case RTC_AIE_OFF: /* Mask alarm int. enab. bit */ + { + mask_rtc_irq_bit(RTC_AIE); + return 0; + } + case RTC_AIE_ON: /* Allow alarm interrupts. */ + { + set_rtc_irq_bit(RTC_AIE); + return 0; + } + case RTC_PIE_OFF: /* Mask periodic int. enab. bit */ + { + /* can be called from isr via rtc_control() */ + unsigned long flags; + + spin_lock_irqsave(&rtc_lock, flags); + mask_rtc_irq_bit_locked(RTC_PIE); + if (rtc_status & RTC_TIMER_ON) { + rtc_status &= ~RTC_TIMER_ON; + del_timer(&rtc_irq_timer); + } + spin_unlock_irqrestore(&rtc_lock, flags); + + return 0; + } + case RTC_PIE_ON: /* Allow periodic ints */ + { + /* can be called from isr via rtc_control() */ + unsigned long flags; + + /* + * We don't really want Joe User enabling more + * than 64Hz of interrupts on a multi-user machine. + */ + if (!kernel && (rtc_freq > rtc_max_user_freq) && + (!capable(CAP_SYS_RESOURCE))) + return -EACCES; + + spin_lock_irqsave(&rtc_lock, flags); + if (!(rtc_status & RTC_TIMER_ON)) { + mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + + 2*HZ/100); + rtc_status |= RTC_TIMER_ON; + } + set_rtc_irq_bit_locked(RTC_PIE); + spin_unlock_irqrestore(&rtc_lock, flags); + + return 0; + } + case RTC_UIE_OFF: /* Mask ints from RTC updates. */ + { + mask_rtc_irq_bit(RTC_UIE); + return 0; + } + case RTC_UIE_ON: /* Allow ints for RTC updates. */ + { + set_rtc_irq_bit(RTC_UIE); + return 0; + } +#endif + case RTC_ALM_READ: /* Read the present alarm time */ + { + /* + * This returns a struct rtc_time. Reading >= 0xc0 + * means "don't care" or "match all". Only the tm_hour, + * tm_min, and tm_sec values are filled in. + */ + memset(&wtime, 0, sizeof(struct rtc_time)); + get_rtc_alm_time(&wtime); + break; + } + case RTC_ALM_SET: /* Store a time into the alarm */ + { + /* + * This expects a struct rtc_time. Writing 0xff means + * "don't care" or "match all". Only the tm_hour, + * tm_min and tm_sec are used. + */ + unsigned char hrs, min, sec; + struct rtc_time alm_tm; + + if (copy_from_user(&alm_tm, (struct rtc_time __user *)arg, + sizeof(struct rtc_time))) + return -EFAULT; + + hrs = alm_tm.tm_hour; + min = alm_tm.tm_min; + sec = alm_tm.tm_sec; + + spin_lock_irq(&rtc_lock); + if (hpet_set_alarm_time(hrs, min, sec)) { + /* + * Fallthru and set alarm time in CMOS too, + * so that we will get proper value in RTC_ALM_READ + */ + } + if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || + RTC_ALWAYS_BCD) { + if (sec < 60) + sec = bin2bcd(sec); + else + sec = 0xff; + + if (min < 60) + min = bin2bcd(min); + else + min = 0xff; + + if (hrs < 24) + hrs = bin2bcd(hrs); + else + hrs = 0xff; + } + CMOS_WRITE(hrs, RTC_HOURS_ALARM); + CMOS_WRITE(min, RTC_MINUTES_ALARM); + CMOS_WRITE(sec, RTC_SECONDS_ALARM); + spin_unlock_irq(&rtc_lock); + + return 0; + } + case RTC_RD_TIME: /* Read the time/date from RTC */ + { + memset(&wtime, 0, sizeof(struct rtc_time)); + rtc_get_rtc_time(&wtime); + break; + } + case RTC_SET_TIME: /* Set the RTC */ + { + struct rtc_time rtc_tm; + unsigned char mon, day, hrs, min, sec, leap_yr; + unsigned char save_control, save_freq_select; + unsigned int yrs; +#ifdef CONFIG_MACH_DECSTATION + unsigned int real_yrs; +#endif + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg, + sizeof(struct rtc_time))) + return -EFAULT; + + yrs = rtc_tm.tm_year + 1900; + mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */ + day = rtc_tm.tm_mday; + hrs = rtc_tm.tm_hour; + min = rtc_tm.tm_min; + sec = rtc_tm.tm_sec; + + if (yrs < 1970) + return -EINVAL; + + leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); + + if ((mon > 12) || (day == 0)) + return -EINVAL; + + if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) + return -EINVAL; + + if ((hrs >= 24) || (min >= 60) || (sec >= 60)) + return -EINVAL; + + yrs -= epoch; + if (yrs > 255) /* They are unsigned */ + return -EINVAL; + + spin_lock_irq(&rtc_lock); +#ifdef CONFIG_MACH_DECSTATION + real_yrs = yrs; + yrs = 72; + + /* + * We want to keep the year set to 73 until March + * for non-leap years, so that Feb, 29th is handled + * correctly. + */ + if (!leap_yr && mon < 3) { + real_yrs--; + yrs = 73; + } +#endif + /* These limits and adjustments are independent of + * whether the chip is in binary mode or not. + */ + if (yrs > 169) { + spin_unlock_irq(&rtc_lock); + return -EINVAL; + } + if (yrs >= 100) + yrs -= 100; + + if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) + || RTC_ALWAYS_BCD) { + sec = bin2bcd(sec); + min = bin2bcd(min); + hrs = bin2bcd(hrs); + day = bin2bcd(day); + mon = bin2bcd(mon); + yrs = bin2bcd(yrs); + } + + save_control = CMOS_READ(RTC_CONTROL); + CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); + save_freq_select = CMOS_READ(RTC_FREQ_SELECT); + CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); + +#ifdef CONFIG_MACH_DECSTATION + CMOS_WRITE(real_yrs, RTC_DEC_YEAR); +#endif + CMOS_WRITE(yrs, RTC_YEAR); + CMOS_WRITE(mon, RTC_MONTH); + CMOS_WRITE(day, RTC_DAY_OF_MONTH); + CMOS_WRITE(hrs, RTC_HOURS); + CMOS_WRITE(min, RTC_MINUTES); + CMOS_WRITE(sec, RTC_SECONDS); + + CMOS_WRITE(save_control, RTC_CONTROL); + CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); + + spin_unlock_irq(&rtc_lock); + return 0; + } +#ifdef RTC_IRQ + case RTC_IRQP_READ: /* Read the periodic IRQ rate. */ + { + return put_user(rtc_freq, (unsigned long __user *)arg); + } + case RTC_IRQP_SET: /* Set periodic IRQ rate. */ + { + int tmp = 0; + unsigned char val; + /* can be called from isr via rtc_control() */ + unsigned long flags; + + /* + * The max we can do is 8192Hz. + */ + if ((arg < 2) || (arg > 8192)) + return -EINVAL; + /* + * We don't really want Joe User generating more + * than 64Hz of interrupts on a multi-user machine. + */ + if (!kernel && (arg > rtc_max_user_freq) && + !capable(CAP_SYS_RESOURCE)) + return -EACCES; + + while (arg > (1<<tmp)) + tmp++; + + /* + * Check that the input was really a power of 2. + */ + if (arg != (1<<tmp)) + return -EINVAL; + + rtc_freq = arg; + + spin_lock_irqsave(&rtc_lock, flags); + if (hpet_set_periodic_freq(arg)) { + spin_unlock_irqrestore(&rtc_lock, flags); + return 0; + } + + val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0; + val |= (16 - tmp); + CMOS_WRITE(val, RTC_FREQ_SELECT); + spin_unlock_irqrestore(&rtc_lock, flags); + return 0; + } +#endif + case RTC_EPOCH_READ: /* Read the epoch. */ + { + return put_user(epoch, (unsigned long __user *)arg); + } + case RTC_EPOCH_SET: /* Set the epoch. */ + { + /* + * There were no RTC clocks before 1900. + */ + if (arg < 1900) + return -EINVAL; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + epoch = arg; + return 0; + } + default: + return -ENOTTY; + } + return copy_to_user((void __user *)arg, + &wtime, sizeof wtime) ? -EFAULT : 0; +} + +static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + long ret; + ret = rtc_do_ioctl(cmd, arg, 0); + return ret; +} + +/* + * We enforce only one user at a time here with the open/close. + * Also clear the previous interrupt data on an open, and clean + * up things on a close. + */ +static int rtc_open(struct inode *inode, struct file *file) +{ + spin_lock_irq(&rtc_lock); + + if (rtc_status & RTC_IS_OPEN) + goto out_busy; + + rtc_status |= RTC_IS_OPEN; + + rtc_irq_data = 0; + spin_unlock_irq(&rtc_lock); + return 0; + +out_busy: + spin_unlock_irq(&rtc_lock); + return -EBUSY; +} + +static int rtc_fasync(int fd, struct file *filp, int on) +{ + return fasync_helper(fd, filp, on, &rtc_async_queue); +} + +static int rtc_release(struct inode *inode, struct file *file) +{ +#ifdef RTC_IRQ + unsigned char tmp; + + if (rtc_has_irq == 0) + goto no_irq; + + /* + * Turn off all interrupts once the device is no longer + * in use, and clear the data. + */ + + spin_lock_irq(&rtc_lock); + if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) { + tmp = CMOS_READ(RTC_CONTROL); + tmp &= ~RTC_PIE; + tmp &= ~RTC_AIE; + tmp &= ~RTC_UIE; + CMOS_WRITE(tmp, RTC_CONTROL); + CMOS_READ(RTC_INTR_FLAGS); + } + if (rtc_status & RTC_TIMER_ON) { + rtc_status &= ~RTC_TIMER_ON; + del_timer(&rtc_irq_timer); + } + spin_unlock_irq(&rtc_lock); + +no_irq: +#endif + + spin_lock_irq(&rtc_lock); + rtc_irq_data = 0; + rtc_status &= ~RTC_IS_OPEN; + spin_unlock_irq(&rtc_lock); + + return 0; +} + +#ifdef RTC_IRQ +static __poll_t rtc_poll(struct file *file, poll_table *wait) +{ + unsigned long l; + + if (rtc_has_irq == 0) + return 0; + + poll_wait(file, &rtc_wait, wait); + + spin_lock_irq(&rtc_lock); + l = rtc_irq_data; + spin_unlock_irq(&rtc_lock); + + if (l != 0) + return EPOLLIN | EPOLLRDNORM; + return 0; +} +#endif + +/* + * The various file operations we support. + */ + +static const struct file_operations rtc_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .read = rtc_read, +#ifdef RTC_IRQ + .poll = rtc_poll, +#endif + .unlocked_ioctl = rtc_ioctl, + .open = rtc_open, + .release = rtc_release, + .fasync = rtc_fasync, +}; + +static struct miscdevice rtc_dev = { + .minor = RTC_MINOR, + .name = "rtc", + .fops = &rtc_fops, +}; + +static resource_size_t rtc_size; + +static struct resource * __init rtc_request_region(resource_size_t size) +{ + struct resource *r; + + if (RTC_IOMAPPED) + r = request_region(RTC_PORT(0), size, "rtc"); + else + r = request_mem_region(RTC_PORT(0), size, "rtc"); + + if (r) + rtc_size = size; + + return r; +} + +static void rtc_release_region(void) +{ + if (RTC_IOMAPPED) + release_region(RTC_PORT(0), rtc_size); + else + release_mem_region(RTC_PORT(0), rtc_size); +} + +static int __init rtc_init(void) +{ +#ifdef CONFIG_PROC_FS + struct proc_dir_entry *ent; +#endif +#if defined(__alpha__) || defined(__mips__) + unsigned int year, ctrl; + char *guess = NULL; +#endif +#ifdef CONFIG_SPARC32 + struct device_node *ebus_dp; + struct platform_device *op; +#else + void *r; +#ifdef RTC_IRQ + irq_handler_t rtc_int_handler_ptr; +#endif +#endif + +#ifdef CONFIG_SPARC32 + for_each_node_by_name(ebus_dp, "ebus") { + struct device_node *dp; + for (dp = ebus_dp; dp; dp = dp->sibling) { + if (!strcmp(dp->name, "rtc")) { + op = of_find_device_by_node(dp); + if (op) { + rtc_port = op->resource[0].start; + rtc_irq = op->irqs[0]; + goto found; + } + } + } + } + rtc_has_irq = 0; + printk(KERN_ERR "rtc_init: no PC rtc found\n"); + return -EIO; + +found: + if (!rtc_irq) { + rtc_has_irq = 0; + goto no_irq; + } + + /* + * XXX Interrupt pin #7 in Espresso is shared between RTC and + * PCI Slot 2 INTA# (and some INTx# in Slot 1). + */ + if (request_irq(rtc_irq, rtc_interrupt, IRQF_SHARED, "rtc", + (void *)&rtc_port)) { + rtc_has_irq = 0; + printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq); + return -EIO; + } +no_irq: +#else + r = rtc_request_region(RTC_IO_EXTENT); + + /* + * If we've already requested a smaller range (for example, because + * PNPBIOS or ACPI told us how the device is configured), the request + * above might fail because it's too big. + * + * If so, request just the range we actually use. + */ + if (!r) + r = rtc_request_region(RTC_IO_EXTENT_USED); + if (!r) { +#ifdef RTC_IRQ + rtc_has_irq = 0; +#endif + printk(KERN_ERR "rtc: I/O resource %lx is not free.\n", + (long)(RTC_PORT(0))); + return -EIO; + } + +#ifdef RTC_IRQ + if (is_hpet_enabled()) { + int err; + + rtc_int_handler_ptr = hpet_rtc_interrupt; + err = hpet_register_irq_handler(rtc_interrupt); + if (err != 0) { + printk(KERN_WARNING "hpet_register_irq_handler failed " + "in rtc_init()."); + return err; + } + } else { + rtc_int_handler_ptr = rtc_interrupt; + } + + if (request_irq(RTC_IRQ, rtc_int_handler_ptr, 0, "rtc", NULL)) { + /* Yeah right, seeing as irq 8 doesn't even hit the bus. */ + rtc_has_irq = 0; + printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ); + rtc_release_region(); + + return -EIO; + } + hpet_rtc_timer_init(); + +#endif + +#endif /* CONFIG_SPARC32 vs. others */ + + if (misc_register(&rtc_dev)) { +#ifdef RTC_IRQ + free_irq(RTC_IRQ, NULL); + hpet_unregister_irq_handler(rtc_interrupt); + rtc_has_irq = 0; +#endif + rtc_release_region(); + return -ENODEV; + } + +#ifdef CONFIG_PROC_FS + ent = proc_create_single("driver/rtc", 0, NULL, rtc_proc_show); + if (!ent) + printk(KERN_WARNING "rtc: Failed to register with procfs.\n"); +#endif + +#if defined(__alpha__) || defined(__mips__) + rtc_freq = HZ; + + /* Each operating system on an Alpha uses its own epoch. + Let's try to guess which one we are using now. */ + + if (rtc_is_updating() != 0) + msleep(20); + + spin_lock_irq(&rtc_lock); + year = CMOS_READ(RTC_YEAR); + ctrl = CMOS_READ(RTC_CONTROL); + spin_unlock_irq(&rtc_lock); + + if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) + year = bcd2bin(year); /* This should never happen... */ + + if (year < 20) { + epoch = 2000; + guess = "SRM (post-2000)"; + } else if (year >= 20 && year < 48) { + epoch = 1980; + guess = "ARC console"; + } else if (year >= 48 && year < 72) { + epoch = 1952; + guess = "Digital UNIX"; +#if defined(__mips__) + } else if (year >= 72 && year < 74) { + epoch = 2000; + guess = "Digital DECstation"; +#else + } else if (year >= 70) { + epoch = 1900; + guess = "Standard PC (1900)"; +#endif + } + if (guess) + printk(KERN_INFO "rtc: %s epoch (%lu) detected\n", + guess, epoch); +#endif +#ifdef RTC_IRQ + if (rtc_has_irq == 0) + goto no_irq2; + + spin_lock_irq(&rtc_lock); + rtc_freq = 1024; + if (!hpet_set_periodic_freq(rtc_freq)) { + /* + * Initialize periodic frequency to CMOS reset default, + * which is 1024Hz + */ + CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06), + RTC_FREQ_SELECT); + } + spin_unlock_irq(&rtc_lock); +no_irq2: +#endif + + (void) init_sysctl(); + + printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n"); + + return 0; +} + +static void __exit rtc_exit(void) +{ + cleanup_sysctl(); + remove_proc_entry("driver/rtc", NULL); + misc_deregister(&rtc_dev); + +#ifdef CONFIG_SPARC32 + if (rtc_has_irq) + free_irq(rtc_irq, &rtc_port); +#else + rtc_release_region(); +#ifdef RTC_IRQ + if (rtc_has_irq) { + free_irq(RTC_IRQ, NULL); + hpet_unregister_irq_handler(hpet_rtc_interrupt); + } +#endif +#endif /* CONFIG_SPARC32 */ +} + +module_init(rtc_init); +module_exit(rtc_exit); + +#ifdef RTC_IRQ +/* + * At IRQ rates >= 4096Hz, an interrupt may get lost altogether. + * (usually during an IDE disk interrupt, with IRQ unmasking off) + * Since the interrupt handler doesn't get called, the IRQ status + * byte doesn't get read, and the RTC stops generating interrupts. + * A timer is set, and will call this function if/when that happens. + * To get it out of this stalled state, we just read the status. + * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost. + * (You *really* shouldn't be trying to use a non-realtime system + * for something that requires a steady > 1KHz signal anyways.) + */ + +static void rtc_dropped_irq(struct timer_list *unused) +{ + unsigned long freq; + + spin_lock_irq(&rtc_lock); + + if (hpet_rtc_dropped_irq()) { + spin_unlock_irq(&rtc_lock); + return; + } + + /* Just in case someone disabled the timer from behind our back... */ + if (rtc_status & RTC_TIMER_ON) + mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100); + + rtc_irq_data += ((rtc_freq/HZ)<<8); + rtc_irq_data &= ~0xff; + rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); /* restart */ + + freq = rtc_freq; + + spin_unlock_irq(&rtc_lock); + + printk_ratelimited(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", + freq); + + /* Now we have new data */ + wake_up_interruptible(&rtc_wait); + + kill_fasync(&rtc_async_queue, SIGIO, POLL_IN); +} +#endif + +#ifdef CONFIG_PROC_FS +/* + * Info exported via "/proc/driver/rtc". + */ + +static int rtc_proc_show(struct seq_file *seq, void *v) +{ +#define YN(bit) ((ctrl & bit) ? "yes" : "no") +#define NY(bit) ((ctrl & bit) ? "no" : "yes") + struct rtc_time tm; + unsigned char batt, ctrl; + unsigned long freq; + + spin_lock_irq(&rtc_lock); + batt = CMOS_READ(RTC_VALID) & RTC_VRT; + ctrl = CMOS_READ(RTC_CONTROL); + freq = rtc_freq; + spin_unlock_irq(&rtc_lock); + + + rtc_get_rtc_time(&tm); + + /* + * There is no way to tell if the luser has the RTC set for local + * time or for Universal Standard Time (GMT). Probably local though. + */ + seq_printf(seq, + "rtc_time\t: %02d:%02d:%02d\n" + "rtc_date\t: %04d-%02d-%02d\n" + "rtc_epoch\t: %04lu\n", + tm.tm_hour, tm.tm_min, tm.tm_sec, + tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch); + + get_rtc_alm_time(&tm); + + /* + * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will + * match any value for that particular field. Values that are + * greater than a valid time, but less than 0xc0 shouldn't appear. + */ + seq_puts(seq, "alarm\t\t: "); + if (tm.tm_hour <= 24) + seq_printf(seq, "%02d:", tm.tm_hour); + else + seq_puts(seq, "**:"); + + if (tm.tm_min <= 59) + seq_printf(seq, "%02d:", tm.tm_min); + else + seq_puts(seq, "**:"); + + if (tm.tm_sec <= 59) + seq_printf(seq, "%02d\n", tm.tm_sec); + else + seq_puts(seq, "**\n"); + + seq_printf(seq, + "DST_enable\t: %s\n" + "BCD\t\t: %s\n" + "24hr\t\t: %s\n" + "square_wave\t: %s\n" + "alarm_IRQ\t: %s\n" + "update_IRQ\t: %s\n" + "periodic_IRQ\t: %s\n" + "periodic_freq\t: %ld\n" + "batt_status\t: %s\n", + YN(RTC_DST_EN), + NY(RTC_DM_BINARY), + YN(RTC_24H), + YN(RTC_SQWE), + YN(RTC_AIE), + YN(RTC_UIE), + YN(RTC_PIE), + freq, + batt ? "okay" : "dead"); + + return 0; +#undef YN +#undef NY +} +#endif + +static void rtc_get_rtc_time(struct rtc_time *rtc_tm) +{ + unsigned long uip_watchdog = jiffies, flags; + unsigned char ctrl; +#ifdef CONFIG_MACH_DECSTATION + unsigned int real_year; +#endif + + /* + * read RTC once any update in progress is done. The update + * can take just over 2ms. We wait 20ms. There is no need to + * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP. + * If you need to know *exactly* when a second has started, enable + * periodic update complete interrupts, (via ioctl) and then + * immediately read /dev/rtc which will block until you get the IRQ. + * Once the read clears, read the RTC time (again via ioctl). Easy. + */ + + while (rtc_is_updating() != 0 && + time_before(jiffies, uip_watchdog + 2*HZ/100)) + cpu_relax(); + + /* + * Only the values that we read from the RTC are set. We leave + * tm_wday, tm_yday and tm_isdst untouched. Note that while the + * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is + * only updated by the RTC when initially set to a non-zero value. + */ + spin_lock_irqsave(&rtc_lock, flags); + rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS); + rtc_tm->tm_min = CMOS_READ(RTC_MINUTES); + rtc_tm->tm_hour = CMOS_READ(RTC_HOURS); + rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH); + rtc_tm->tm_mon = CMOS_READ(RTC_MONTH); + rtc_tm->tm_year = CMOS_READ(RTC_YEAR); + /* Only set from 2.6.16 onwards */ + rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK); + +#ifdef CONFIG_MACH_DECSTATION + real_year = CMOS_READ(RTC_DEC_YEAR); +#endif + ctrl = CMOS_READ(RTC_CONTROL); + spin_unlock_irqrestore(&rtc_lock, flags); + + if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { + rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec); + rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min); + rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour); + rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday); + rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon); + rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year); + rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday); + } + +#ifdef CONFIG_MACH_DECSTATION + rtc_tm->tm_year += real_year - 72; +#endif + + /* + * Account for differences between how the RTC uses the values + * and how they are defined in a struct rtc_time; + */ + rtc_tm->tm_year += epoch - 1900; + if (rtc_tm->tm_year <= 69) + rtc_tm->tm_year += 100; + + rtc_tm->tm_mon--; +} + +static void get_rtc_alm_time(struct rtc_time *alm_tm) +{ + unsigned char ctrl; + + /* + * Only the values that we read from the RTC are set. That + * means only tm_hour, tm_min, and tm_sec. + */ + spin_lock_irq(&rtc_lock); + alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM); + alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM); + alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM); + ctrl = CMOS_READ(RTC_CONTROL); + spin_unlock_irq(&rtc_lock); + + if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { + alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec); + alm_tm->tm_min = bcd2bin(alm_tm->tm_min); + alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour); + } +} + +#ifdef RTC_IRQ +/* + * Used to disable/enable interrupts for any one of UIE, AIE, PIE. + * Rumour has it that if you frob the interrupt enable/disable + * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to + * ensure you actually start getting interrupts. Probably for + * compatibility with older/broken chipset RTC implementations. + * We also clear out any old irq data after an ioctl() that + * meddles with the interrupt enable/disable bits. + */ + +static void mask_rtc_irq_bit_locked(unsigned char bit) +{ + unsigned char val; + + if (hpet_mask_rtc_irq_bit(bit)) + return; + val = CMOS_READ(RTC_CONTROL); + val &= ~bit; + CMOS_WRITE(val, RTC_CONTROL); + CMOS_READ(RTC_INTR_FLAGS); + + rtc_irq_data = 0; +} + +static void set_rtc_irq_bit_locked(unsigned char bit) +{ + unsigned char val; + + if (hpet_set_rtc_irq_bit(bit)) + return; + val = CMOS_READ(RTC_CONTROL); + val |= bit; + CMOS_WRITE(val, RTC_CONTROL); + CMOS_READ(RTC_INTR_FLAGS); + + rtc_irq_data = 0; +} +#endif + +MODULE_AUTHOR("Paul Gortmaker"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(RTC_MINOR); |