diff options
Diffstat (limited to 'drivers/char/ip27-rtc.c')
| -rw-r--r-- | drivers/char/ip27-rtc.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/drivers/char/ip27-rtc.c b/drivers/char/ip27-rtc.c new file mode 100644 index 00000000000..3acdac3c967 --- /dev/null +++ b/drivers/char/ip27-rtc.c @@ -0,0 +1,327 @@ +/* + * 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 <linux/smp_lock.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 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--; +} |