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
  33 static const unsigned char days_in_mo[] =
  34 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  35
  36 static atomic_t rtc_ready = ATOMIC_INIT(1);
  37
  38 static 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  */
 123 static 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
 133 static 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
 143 static 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
 150 static struct miscdevice rtc_dev=
 151 {
 152         .minor =        RTC_MINOR,
 153         .name =         "rtc",
 154         .fops =         &rtc_fops
 155 };
 156
 157 static 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 }
 165 device_initcall(rtc_MK48T08_init);