/* * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip * * Real Time Clock interface for Linux * * TODO: Implement periodic interrupts. * * Copyright (C) 2000 Silicon Graphics, Inc. * Written by Ulf Carlsson (ulfc@engr.sgi.com) * * Based on code written by 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/rtc * pseudo-file for status information. * * 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. * */ #define RTC_VERSION "1.09b" #include <linux/bcd.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/rtc.h> #include <linux/init.h> #include <linux/poll.h> #include <linux/proc_fs.h> #include <asm/m48t35.h> #include <asm/sn/ioc3.h> #include <asm/io.h> #include <asm/uaccess.h> #include <asm/system.h> #include <asm/sn/klconfig.h> #include <asm/sn/sn0/ip27.h> #include <asm/sn/sn0/hub.h> #include <asm/sn/sn_private.h> static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg); static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data); static void get_rtc_time(struct rtc_time *rtc_tm); /* * 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 */ static unsigned char rtc_status; /* bitmapped status byte. */ static unsigned long rtc_freq; /* Current periodic IRQ rate */ static struct m48t35_rtc *rtc; /* * 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 = 1970; /* year corresponding to 0x00 */ static const unsigned char days_in_mo[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { struct rtc_time wtime; switch (cmd) { case RTC_RD_TIME: /* Read the time/date from 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 int yrs; if (!capable(CAP_SYS_TIME)) return -EACCES; if (copy_from_user(&rtc_tm, (struct rtc_time*)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; if ((yrs -= epoch) > 255) /* They are unsigned */ return -EINVAL; if (yrs > 169) return -EINVAL; if (yrs >= 100) yrs -= 100; sec = BIN2BCD(sec); min = BIN2BCD(min); hrs = BIN2BCD(hrs); day = BIN2BCD(day); mon = BIN2BCD(mon); yrs = BIN2BCD(yrs); spin_lock_irq(&rtc_lock); rtc->control |= M48T35_RTC_SET; rtc->year = yrs; rtc->month = mon; rtc->date = day; rtc->hour = hrs; rtc->min = min; rtc->sec = sec; rtc->control &= ~M48T35_RTC_SET; spin_unlock_irq(&rtc_lock); return 0; } default: return -EINVAL; } return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0; } /* * 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) { spin_unlock_irq(&rtc_lock); return -EBUSY; } rtc_status |= RTC_IS_OPEN; spin_unlock_irq(&rtc_lock); return 0; } static int rtc_release(struct inode *inode, struct file *file) { /* * Turn off all interrupts once the device is no longer * in use, and clear the data. */ spin_lock_irq(&rtc_lock); rtc_status &= ~RTC_IS_OPEN; spin_unlock_irq(&rtc_lock); return 0; } /* * The various file operations we support. */ static const struct file_operations rtc_fops = { .owner = THIS_MODULE, .ioctl = rtc_ioctl, .open = rtc_open, .release = rtc_release, }; static struct miscdevice rtc_dev= { RTC_MINOR, "rtc", &rtc_fops }; static int __init rtc_init(void) { rtc = (struct m48t35_rtc *) (KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base + IOC3_BYTEBUS_DEV0); printk(KERN_INFO "Real Time Clock Driver v%s\n", RTC_VERSION); if (misc_register(&rtc_dev)) { printk(KERN_ERR "rtc: cannot register misc device.\n"); return -ENODEV; } if (!create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)) { printk(KERN_ERR "rtc: cannot create /proc/rtc.\n"); misc_deregister(&rtc_dev); return -ENOENT; } rtc_freq = 1024; return 0; } static void __exit rtc_exit (void) { /* interrupts and timer disabled at this point by rtc_release */ remove_proc_entry ("rtc", NULL); misc_deregister(&rtc_dev); } module_init(rtc_init); module_exit(rtc_exit); /* * Info exported via "/proc/rtc". */ static int rtc_get_status(char *buf) { char *p; struct rtc_time tm; /* * Just emulate the standard /proc/rtc */ p = buf; 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. */ p += sprintf(p, "rtc_time\t: %02d:%02d:%02d\n" "rtc_date\t: %04d-%02d-%02d\n" "rtc_epoch\t: %04lu\n" "24hr\t\t: yes\n", tm.tm_hour, tm.tm_min, tm.tm_sec, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch); return p - buf; } static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data) { int len = rtc_get_status(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 void get_rtc_time(struct rtc_time *rtc_tm) { /* * Do we need to wait for the last update to finish? */ /* * Only the values that we read from the RTC are set. We leave * tm_wday, tm_yday and tm_isdst untouched. Even though the * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated * by the RTC when initially set to a non-zero value. */ spin_lock_irq(&rtc_lock); rtc->control |= M48T35_RTC_READ; rtc_tm->tm_sec = rtc->sec; rtc_tm->tm_min = rtc->min; rtc_tm->tm_hour = rtc->hour; rtc_tm->tm_mday = rtc->date; rtc_tm->tm_mon = rtc->month; rtc_tm->tm_year = rtc->year; rtc->control &= ~M48T35_RTC_READ; spin_unlock_irq(&rtc_lock); 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); /* * Account for differences between how the RTC uses the values * and how they are defined in a struct rtc_time; */ if ((rtc_tm->tm_year += (epoch - 1900)) <= 69) rtc_tm->tm_year += 100; rtc_tm->tm_mon--; }