LXR linux/arch/m68k/mvme16x/rtc.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *      Real Time Clock interface for Linux on the MVME16x
   4 *
   5 * Based on the PC driver by Paul Gortmaker.
   6 */
   7
   8#define RTC_VERSION             "1.00"
   9
  10#include <linux/types.h>
  11#include <linux/errno.h>
  12#include <linux/miscdevice.h>
  13#include <linux/ioport.h>
  14#include <linux/capability.h>
  15#include <linux/fcntl.h>
  16#include <linux/init.h>
  17#include <linux/poll.h>
  18#include <linux/rtc.h>  /* For struct rtc_time and ioctls, etc */
  19#include <linux/bcd.h>
  20#include <asm/mvme16xhw.h>
  21
  22#include <asm/io.h>
  23#include <linux/uaccess.h>
  24#include <asm/setup.h>
  25
  26/*
  27 *      We sponge a minor off of the misc major. No need slurping
  28 *      up another valuable major dev number for this. If you add
  29 *      an ioctl, make sure you don't conflict with SPARC's RTC
  30 *      ioctls.
  31 */
  32
  33static const unsigned char days_in_mo[] =
  34{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  35
  36static atomic_t rtc_ready = ATOMIC_INIT(1);
  37
  38static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  39{
  40        volatile MK48T08ptr_t rtc = (MK48T08ptr_t)MVME_RTC_BASE;
  41        unsigned long flags;
  42        struct rtc_time wtime;
  43        void __user *argp = (void __user *)arg;
  44
  45        switch (cmd) {
  46        case RTC_RD_TIME:       /* Read the time/date from RTC  */
  47        {
  48                local_irq_save(flags);
  49                /* Ensure clock and real-time-mode-register are accessible */
  50                rtc->ctrl = RTC_READ;
  51                memset(&wtime, 0, sizeof(struct rtc_time));
  52                wtime.tm_sec =  bcd2bin(rtc->bcd_sec);
  53                wtime.tm_min =  bcd2bin(rtc->bcd_min);
  54                wtime.tm_hour = bcd2bin(rtc->bcd_hr);
  55                wtime.tm_mday =  bcd2bin(rtc->bcd_dom);
  56                wtime.tm_mon =  bcd2bin(rtc->bcd_mth)-1;
  57                wtime.tm_year = bcd2bin(rtc->bcd_year);
  58                if (wtime.tm_year < 70)
  59                        wtime.tm_year += 100;
  60                wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;
  61                rtc->ctrl = 0;
  62                local_irq_restore(flags);
  63                return copy_to_user(argp, &wtime, sizeof wtime) ?
  64                                                                -EFAULT : 0;
  65        }
  66        case RTC_SET_TIME:      /* Set the RTC */
  67        {
  68                struct rtc_time rtc_tm;
  69                unsigned char mon, day, hrs, min, sec, leap_yr;
  70                unsigned int yrs;
  71
  72                if (!capable(CAP_SYS_ADMIN))
  73                        return -EACCES;
  74
  75                if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
  76                        return -EFAULT;
  77
  78                yrs = rtc_tm.tm_year;
  79                if (yrs < 1900)
  80                        yrs += 1900;
  81                mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
  82                day = rtc_tm.tm_mday;
  83                hrs = rtc_tm.tm_hour;
  84                min = rtc_tm.tm_min;
  85                sec = rtc_tm.tm_sec;
  86
  87                leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
  88
  89                if ((mon > 12) || (day == 0))
  90                        return -EINVAL;
  91
  92                if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
  93                        return -EINVAL;
  94
  95                if ((hrs >= 24) || (min >= 60) || (sec >= 60))
  96                        return -EINVAL;
  97
  98                if (yrs >= 2070)
  99                        return -EINVAL;
 100
 101                local_irq_save(flags);
 102                rtc->ctrl     = RTC_WRITE;
 103
 104                rtc->bcd_sec  = bin2bcd(sec);
 105                rtc->bcd_min  = bin2bcd(min);
 106                rtc->bcd_hr   = bin2bcd(hrs);
 107                rtc->bcd_dom  = bin2bcd(day);
 108                rtc->bcd_mth  = bin2bcd(mon);
 109                rtc->bcd_year = bin2bcd(yrs%100);
 110
 111                rtc->ctrl     = 0;
 112                local_irq_restore(flags);
 113                return 0;
 114        }
 115        default:
 116                return -EINVAL;
 117        }
 118}
 119
 120/*
 121 * We enforce only one user at a time here with the open/close.
 122 */
 123static int rtc_open(struct inode *inode, struct file *file)
 124{
 125        if( !atomic_dec_and_test(&rtc_ready) )
 126        {
 127                atomic_inc( &rtc_ready );
 128                return -EBUSY;
 129        }
 130        return 0;
 131}
 132
 133static int rtc_release(struct inode *inode, struct file *file)
 134{
 135        atomic_inc( &rtc_ready );
 136        return 0;
 137}
 138
 139/*
 140 *      The various file operations we support.
 141 */
 142
 143static const struct file_operations rtc_fops = {
 144        .unlocked_ioctl = rtc_ioctl,
 145        .open           = rtc_open,
 146        .release        = rtc_release,
 147        .llseek         = noop_llseek,
 148};
 149
 150static struct miscdevice rtc_dev=
 151{
 152        .minor =        RTC_MINOR,
 153        .name =         "rtc",
 154        .fops =         &rtc_fops
 155};
 156
 157static int __init rtc_MK48T08_init(void)
 158{
 159        if (!MACH_IS_MVME16x)
 160                return -ENODEV;
 161
 162        pr_info("MK48T08 Real Time Clock Driver v%s\n", RTC_VERSION);
 163        return misc_register(&rtc_dev);
 164}
 165device_initcall(rtc_MK48T08_init);
 166