/* * Real Time Clock interface for * - q40 and other m68k machines, * - HP PARISC machines * - PowerPC machines * emulate some RTC irq capabilities in software * * Copyright (C) 1999 Richard Zidlicky * * based on Paul Gortmaker's rtc.c device and * Sam Creasey Generic rtc driver * * 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 where * supported. * * 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. * * 1.01 fix for 2.3.X rz@linux-m68k.org * 1.02 merged with code from genrtc.c rz@linux-m68k.org * 1.03 make it more portable zippel@linux-m68k.org * 1.04 removed useless timer code rz@linux-m68k.org * 1.05 portable RTC_UIE emulation rz@linux-m68k.org * 1.06 set_rtc_time can return an error trini@kernel.crashing.org * 1.07 ported to HP PARISC (hppa) Helge Deller <deller@gmx.de> */ #define RTC_VERSION "1.07" #include <linux/module.h> #include <linux/sched.h> #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/fcntl.h> #include <linux/rtc.h> #include <linux/init.h> #include <linux/poll.h> #include <linux/proc_fs.h> #include <linux/mutex.h> #include <linux/workqueue.h> #include <asm/uaccess.h> #include <asm/rtc.h> /* * 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 DEFINE_MUTEX(gen_rtc_mutex); static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait); /* * Bits in gen_rtc_status. */ #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ static unsigned char gen_rtc_status; /* bitmapped status byte. */ static unsigned long gen_rtc_irq_data; /* our output to the world */ /* months start at 0 now */ static unsigned char days_in_mo[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; static int irq_active; #ifdef CONFIG_GEN_RTC_X static struct work_struct genrtc_task; static struct timer_list timer_task; static unsigned int oldsecs; static int lostint; static unsigned long tt_exp; static void gen_rtc_timer(unsigned long data); static volatile int stask_active; /* schedule_work */ static volatile int ttask_active; /* timer_task */ static int stop_rtc_timers; /* don't requeue tasks */ static DEFINE_SPINLOCK(gen_rtc_lock); static void gen_rtc_interrupt(unsigned long arg); /* * Routine to poll RTC seconds field for change as often as possible, * after first RTC_UIE use timer to reduce polling */ static void genrtc_troutine(struct work_struct *work) { unsigned int tmp = get_rtc_ss(); if (stop_rtc_timers) { stask_active = 0; return; } if (oldsecs != tmp){ oldsecs = tmp; timer_task.function = gen_rtc_timer; timer_task.expires = jiffies + HZ - (HZ/10); tt_exp=timer_task.expires; ttask_active=1; stask_active=0; add_timer(&timer_task); gen_rtc_interrupt(0); } else if (schedule_work(&genrtc_task) == 0) stask_active = 0; } static void gen_rtc_timer(unsigned long data) { lostint = get_rtc_ss() - oldsecs ; if (lostint<0) lostint = 60 - lostint; if (time_after(jiffies, tt_exp)) printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n", jiffies-tt_exp); ttask_active=0; stask_active=1; if ((schedule_work(&genrtc_task) == 0)) stask_active = 0; } /* * call gen_rtc_interrupt function to signal an RTC_UIE, * arg is unused. * Could be invoked either from a real interrupt handler or * from some routine that periodically (eg 100HZ) monitors * whether RTC_SECS changed */ static void gen_rtc_interrupt(unsigned long arg) { /* 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. */ gen_rtc_irq_data += 0x100; gen_rtc_irq_data &= ~0xff; gen_rtc_irq_data |= RTC_UIE; if (lostint){ printk("genrtc: system delaying clock ticks?\n"); /* increment count so that userspace knows something is wrong */ gen_rtc_irq_data += ((lostint-1)<<8); lostint = 0; } wake_up_interruptible(&gen_rtc_wait); } /* * Now all the various file operations that we export. */ static ssize_t gen_rtc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { unsigned long data; ssize_t retval; if (count != sizeof (unsigned int) && count != sizeof (unsigned long)) return -EINVAL; if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data) return -EAGAIN; retval = wait_event_interruptible(gen_rtc_wait, (data = xchg(&gen_rtc_irq_data, 0))); if (retval) goto out; /* first test allows optimizer to nuke this case for 32-bit machines */ if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) { unsigned int uidata = data; retval = put_user(uidata, (unsigned int __user *)buf) ?: sizeof(unsigned int); } else { retval = put_user(data, (unsigned long __user *)buf) ?: sizeof(unsigned long); } out: return retval; } static unsigned int gen_rtc_poll(struct file *file, struct poll_table_struct *wait) { poll_wait(file, &gen_rtc_wait, wait); if (gen_rtc_irq_data != 0) return POLLIN | POLLRDNORM; return 0; } #endif /* * Used to disable/enable interrupts, only RTC_UIE supported * We also clear out any old irq data after an ioctl() that * meddles with the interrupt enable/disable bits. */ static inline void gen_clear_rtc_irq_bit(unsigned char bit) { #ifdef CONFIG_GEN_RTC_X stop_rtc_timers = 1; if (ttask_active){ del_timer_sync(&timer_task); ttask_active = 0; } while (stask_active) schedule(); spin_lock(&gen_rtc_lock); irq_active = 0; spin_unlock(&gen_rtc_lock); #endif } static inline int gen_set_rtc_irq_bit(unsigned char bit) { #ifdef CONFIG_GEN_RTC_X spin_lock(&gen_rtc_lock); if ( !irq_active ) { irq_active = 1; stop_rtc_timers = 0; lostint = 0; INIT_WORK(&genrtc_task, genrtc_troutine); oldsecs = get_rtc_ss(); init_timer(&timer_task); stask_active = 1; if (schedule_work(&genrtc_task) == 0){ stask_active = 0; } } spin_unlock(&gen_rtc_lock); gen_rtc_irq_data = 0; return 0; #else return -EINVAL; #endif } static int gen_rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct rtc_time wtime; struct rtc_pll_info pll; void __user *argp = (void __user *)arg; switch (cmd) { case RTC_PLL_GET: if (get_rtc_pll(&pll)) return -EINVAL; else return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0; case RTC_PLL_SET: if (!capable(CAP_SYS_TIME)) return -EACCES; if (copy_from_user(&pll, argp, sizeof(pll))) return -EFAULT; return set_rtc_pll(&pll); case RTC_UIE_OFF: /* disable ints from RTC updates. */ gen_clear_rtc_irq_bit(RTC_UIE); return 0; case RTC_UIE_ON: /* enable ints for RTC updates. */ return gen_set_rtc_irq_bit(RTC_UIE); case RTC_RD_TIME: /* Read the time/date from RTC */ /* this doesn't get week-day, who cares */ memset(&wtime, 0, sizeof(wtime)); get_rtc_time(&wtime); return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0; case RTC_SET_TIME: /* Set the RTC */ { int year; unsigned char leap_yr; if (!capable(CAP_SYS_TIME)) return -EACCES; if (copy_from_user(&wtime, argp, sizeof(wtime))) return -EFAULT; year = wtime.tm_year + 1900; leap_yr = ((!(year % 4) && (year % 100)) || !(year % 400)); if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1)) return -EINVAL; if (wtime.tm_mday < 0 || wtime.tm_mday > (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr))) return -EINVAL; if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 || wtime.tm_min < 0 || wtime.tm_min >= 60 || wtime.tm_sec < 0 || wtime.tm_sec >= 60) return -EINVAL; return set_rtc_time(&wtime); } } return -EINVAL; } static long gen_rtc_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int ret; mutex_lock(&gen_rtc_mutex); ret = gen_rtc_ioctl(file, cmd, arg); mutex_unlock(&gen_rtc_mutex); 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 gen_rtc_open(struct inode *inode, struct file *file) { mutex_lock(&gen_rtc_mutex); if (gen_rtc_status & RTC_IS_OPEN) { mutex_unlock(&gen_rtc_mutex); return -EBUSY; } gen_rtc_status |= RTC_IS_OPEN; gen_rtc_irq_data = 0; irq_active = 0; mutex_unlock(&gen_rtc_mutex); return 0; } static int gen_rtc_release(struct inode *inode, struct file *file) { /* * Turn off all interrupts once the device is no longer * in use and clear the data. */ gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE); gen_rtc_status &= ~RTC_IS_OPEN; return 0; } #ifdef CONFIG_PROC_FS /* * Info exported via "/proc/driver/rtc". */ static int gen_rtc_proc_output(char *buf) { char *p; struct rtc_time tm; unsigned int flags; struct rtc_pll_info pll; p = buf; flags = get_rtc_time(&tm); p += sprintf(p, "rtc_time\t: %02d:%02d:%02d\n" "rtc_date\t: %04d-%02d-%02d\n" "rtc_epoch\t: %04u\n", tm.tm_hour, tm.tm_min, tm.tm_sec, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900); tm.tm_hour = tm.tm_min = tm.tm_sec = 0; p += sprintf(p, "alarm\t\t: "); if (tm.tm_hour <= 24) p += sprintf(p, "%02d:", tm.tm_hour); else p += sprintf(p, "**:"); if (tm.tm_min <= 59) p += sprintf(p, "%02d:", tm.tm_min); else p += sprintf(p, "**:"); if (tm.tm_sec <= 59) p += sprintf(p, "%02d\n", tm.tm_sec); else p += sprintf(p, "**\n"); p += sprintf(p, "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", (flags & RTC_DST_EN) ? "yes" : "no", (flags & RTC_DM_BINARY) ? "no" : "yes", (flags & RTC_24H) ? "yes" : "no", (flags & RTC_SQWE) ? "yes" : "no", (flags & RTC_AIE) ? "yes" : "no", irq_active ? "yes" : "no", (flags & RTC_PIE) ? "yes" : "no", 0L /* freq */, (flags & RTC_BATT_BAD) ? "bad" : "okay"); if (!get_rtc_pll(&pll)) p += sprintf(p, "PLL adjustment\t: %d\n" "PLL max +ve adjustment\t: %d\n" "PLL max -ve adjustment\t: %d\n" "PLL +ve adjustment factor\t: %d\n" "PLL -ve adjustment factor\t: %d\n" "PLL frequency\t: %ld\n", pll.pll_value, pll.pll_max, pll.pll_min, pll.pll_posmult, pll.pll_negmult, pll.pll_clock); return p - buf; } static int gen_rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data) { int len = gen_rtc_proc_output (page); if (len <= off+count) *eof = 1; *start = page + off; len -= off; if (len>count) len = count; if (len<0) len = 0; return len; } static int __init gen_rtc_proc_init(void) { struct proc_dir_entry *r; r = create_proc_read_entry("driver/rtc", 0, NULL, gen_rtc_read_proc, NULL); if (!r) return -ENOMEM; return 0; } #else static inline int gen_rtc_proc_init(void) { return 0; } #endif /* CONFIG_PROC_FS */ /* * The various file operations we support. */ static const struct file_operations gen_rtc_fops = { .owner = THIS_MODULE, #ifdef CONFIG_GEN_RTC_X .read = gen_rtc_read, .poll = gen_rtc_poll, #endif .unlocked_ioctl = gen_rtc_unlocked_ioctl, .open = gen_rtc_open, .release = gen_rtc_release, .llseek = noop_llseek, }; static struct miscdevice rtc_gen_dev = { .minor = RTC_MINOR, .name = "rtc", .fops = &gen_rtc_fops, }; static int __init rtc_generic_init(void) { int retval; printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION); retval = misc_register(&rtc_gen_dev); if (retval < 0) return retval; retval = gen_rtc_proc_init(); if (retval) { misc_deregister(&rtc_gen_dev); return retval; } return 0; } static void __exit rtc_generic_exit(void) { remove_proc_entry ("driver/rtc", NULL); misc_deregister(&rtc_gen_dev); } module_init(rtc_generic_init); module_exit(rtc_generic_exit); MODULE_AUTHOR("Richard Zidlicky"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(RTC_MINOR);