/* * 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 */ #define RTC_VERSION "1.12ac" /* * 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 time.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/smp_lock.h> #include <linux/sysctl.h> #include <linux/wait.h> #include <linux/bcd.h> #include <linux/delay.h> #include <linux/uaccess.h> #include <asm/current.h> #include <asm/system.h> #ifdef CONFIG_X86 #include <asm/hpet.h> #endif #ifdef CONFIG_SPARC32 #include <linux/pci.h> #include <linux/jiffies.h> #include <asm/ebus.h> static unsigned long rtc_port; static int rtc_irq = PCI_IRQ_NONE; #endif #ifdef CONFIG_HPET_RTC_IRQ #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(unsigned long data); static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq, 0, 0); #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 unsigned int 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_open(struct inode *inode, struct file *file); #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 big kernel 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 */ #ifdef RTC_IRQ /* * rtc_task_lock nests inside rtc_lock. */ static DEFINE_SPINLOCK(rtc_task_lock); static rtc_task_t *rtc_callback; #endif /* * 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 IRQF_DISABLED set, * 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); /* Now do the rest of the actions */ spin_lock(&rtc_task_lock); if (rtc_callback) rtc_callback->func(rtc_callback->private_data); spin_unlock(&rtc_task_lock); wake_up_interruptible(&rtc_wait); kill_fasync(&rtc_async_queue, SIGIO, POLL_IN); return IRQ_HANDLED; } #endif /* * sysctl-tuning infrastructure. */ static ctl_table rtc_table[] = { { .ctl_name = CTL_UNNUMBERED, .procname = "max-user-freq", .data = &rtc_max_user_freq, .maxlen = sizeof(int), .mode = 0644, .proc_handler = &proc_dointvec, }, { .ctl_name = 0 } }; static ctl_table rtc_root[] = { { .ctl_name = CTL_UNNUMBERED, .procname = "rtc", .mode = 0555, .child = rtc_table, }, { .ctl_name = 0 } }; static ctl_table dev_root[] = { { .ctl_name = CTL_DEV, .procname = "dev", .mode = 0555, .child = rtc_root, }, { .ctl_name = 0 } }; 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) BIN_TO_BCD(sec); else sec = 0xff; if (min < 60) BIN_TO_BCD(min); else min = 0xff; if (hrs < 24) BIN_TO_BCD(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) { BIN_TO_BCD(sec); BIN_TO_BCD(min); BIN_TO_BCD(hrs); BIN_TO_BCD(day); BIN_TO_BCD(mon); BIN_TO_BCD(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; lock_kernel(); ret = rtc_do_ioctl(cmd, arg, 0); unlock_kernel(); 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. */ /* We use rtc_lock to protect against concurrent opens. So the BKL is not * needed here. Or anywhere else in this driver. */ static int rtc_open(struct inode *inode, struct file *file) { lock_kernel(); 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); unlock_kernel(); return 0; out_busy: spin_unlock_irq(&rtc_lock); unlock_kernel(); 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); if (file->f_flags & FASYNC) rtc_fasync(-1, file, 0); 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 /* Called without the kernel lock - fine */ static unsigned int 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 POLLIN | POLLRDNORM; return 0; } #endif int rtc_register(rtc_task_t *task) { #ifndef RTC_IRQ return -EIO; #else if (task == NULL || task->func == NULL) return -EINVAL; spin_lock_irq(&rtc_lock); if (rtc_status & RTC_IS_OPEN) { spin_unlock_irq(&rtc_lock); return -EBUSY; } spin_lock(&rtc_task_lock); if (rtc_callback) { spin_unlock(&rtc_task_lock); spin_unlock_irq(&rtc_lock); return -EBUSY; } rtc_status |= RTC_IS_OPEN; rtc_callback = task; spin_unlock(&rtc_task_lock); spin_unlock_irq(&rtc_lock); return 0; #endif } EXPORT_SYMBOL(rtc_register); int rtc_unregister(rtc_task_t *task) { #ifndef RTC_IRQ return -EIO; #else unsigned char tmp; spin_lock_irq(&rtc_lock); spin_lock(&rtc_task_lock); if (rtc_callback != task) { spin_unlock(&rtc_task_lock); spin_unlock_irq(&rtc_lock); return -ENXIO; } rtc_callback = NULL; /* disable controls */ 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); } rtc_status &= ~RTC_IS_OPEN; spin_unlock(&rtc_task_lock); spin_unlock_irq(&rtc_lock); return 0; #endif } EXPORT_SYMBOL(rtc_unregister); int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg) { #ifndef RTC_IRQ return -EIO; #else unsigned long flags; if (cmd != RTC_PIE_ON && cmd != RTC_PIE_OFF && cmd != RTC_IRQP_SET) return -EINVAL; spin_lock_irqsave(&rtc_task_lock, flags); if (rtc_callback != task) { spin_unlock_irqrestore(&rtc_task_lock, flags); return -ENXIO; } spin_unlock_irqrestore(&rtc_task_lock, flags); return rtc_do_ioctl(cmd, arg, 1); #endif } EXPORT_SYMBOL(rtc_control); /* * 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, }; #ifdef CONFIG_PROC_FS static const struct file_operations rtc_proc_fops = { .owner = THIS_MODULE, .open = rtc_proc_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; #endif 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 linux_ebus *ebus; struct linux_ebus_device *edev; #else void *r; #ifdef RTC_IRQ irq_handler_t rtc_int_handler_ptr; #endif #endif #ifdef CONFIG_SPARC32 for_each_ebus(ebus) { for_each_ebusdev(edev, ebus) { if (strcmp(edev->prom_node->name, "rtc") == 0) { rtc_port = edev->resource[0].start; rtc_irq = edev->irqs[0]; goto found; } } } rtc_has_irq = 0; printk(KERN_ERR "rtc_init: no PC rtc found\n"); return -EIO; found: if (rtc_irq == PCI_IRQ_NONE) { 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, IRQF_DISABLED, "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("driver/rtc", 0, NULL, &rtc_proc_fops); 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) BCD_TO_BIN(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(unsigned long data) { 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); if (printk_ratelimit()) { printk(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 } static int rtc_proc_open(struct inode *inode, struct file *file) { return single_open(file, rtc_proc_show, NULL); } #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) { BCD_TO_BIN(rtc_tm->tm_sec); BCD_TO_BIN(rtc_tm->tm_min); BCD_TO_BIN(rtc_tm->tm_hour); BCD_TO_BIN(rtc_tm->tm_mday); BCD_TO_BIN(rtc_tm->tm_mon); BCD_TO_BIN(rtc_tm->tm_year); BCD_TO_BIN(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) { BCD_TO_BIN(alm_tm->tm_sec); BCD_TO_BIN(alm_tm->tm_min); BCD_TO_BIN(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);