arch/m68k/bvme6000/rtc.c

   1 /*
   2  *      Real Time Clock interface for Linux on the BVME6000
   3  *
   4  * Based on the PC driver by Paul Gortmaker.
   5  */
   6
   7 #define RTC_VERSION             "1.00"
   8
   9 #include <linux/types.h>
  10 #include <linux/errno.h>
  11 #include <linux/miscdevice.h>
  12 #include <linux/ioport.h>
  13 #include <linux/capability.h>
  14 #include <linux/fcntl.h>
  15 #include <linux/init.h>
  16 #include <linux/poll.h>
  17 #include <linux/module.h>
  18 #include <linux/rtc.h>  /* For struct rtc_time and ioctls, etc */
  19 #include <linux/bcd.h>
  20 #include <asm/bvme6000hw.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 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_status = ATOMIC_INIT(1);
  37
  38 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  39 {
  40         volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
  41         unsigned char msr;
  42         unsigned long flags;
  43         struct rtc_time wtime;
  44         void __user *argp = (void __user *)arg;
  45
  46         switch (cmd) {
  47         case RTC_RD_TIME:       /* Read the time/date from RTC  */
  48         {
  49                 local_irq_save(flags);
  50                 /* Ensure clock and real-time-mode-register are accessible */
  51                 msr = rtc->msr & 0xc0;
  52                 rtc->msr = 0x40;
  53                 memset(&wtime, 0, sizeof(struct rtc_time));
  54                 do {
  55                         wtime.tm_sec =  bcd2bin(rtc->bcd_sec);
  56                         wtime.tm_min =  bcd2bin(rtc->bcd_min);
  57                         wtime.tm_hour = bcd2bin(rtc->bcd_hr);
  58                         wtime.tm_mday =  bcd2bin(rtc->bcd_dom);
  59                         wtime.tm_mon =  bcd2bin(rtc->bcd_mth)-1;
  60                         wtime.tm_year = bcd2bin(rtc->bcd_year);
  61                         if (wtime.tm_year < 70)
  62                                 wtime.tm_year += 100;
  63                         wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;
  64                 } while (wtime.tm_sec != bcd2bin(rtc->bcd_sec));
  65                 rtc->msr = msr;
  66                 local_irq_restore(flags);
  67                 return copy_to_user(argp, &wtime, sizeof wtime) ?
  68                                                                 -EFAULT : 0;
  69         }
  70         case RTC_SET_TIME:      /* Set the RTC */
  71         {
  72                 struct rtc_time rtc_tm;
  73                 unsigned char mon, day, hrs, min, sec, leap_yr;
  74                 unsigned int yrs;
  75
  76                 if (!capable(CAP_SYS_ADMIN))
  77                         return -EACCES;
  78
  79                 if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
  80                         return -EFAULT;
  81
  82                 yrs = rtc_tm.tm_year;
  83                 if (yrs < 1900)
  84                         yrs += 1900;
  85                 mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
  86                 day = rtc_tm.tm_mday;
  87                 hrs = rtc_tm.tm_hour;
  88                 min = rtc_tm.tm_min;
  89                 sec = rtc_tm.tm_sec;
  90
  91                 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
  92
  93                 if ((mon > 12) || (mon < 1) || (day == 0))
  94                         return -EINVAL;
  95
  96                 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
  97                         return -EINVAL;
  98
  99                 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 100                         return -EINVAL;
 101
 102                 if (yrs >= 2070)
 103                         return -EINVAL;
 104
 105                 local_irq_save(flags);
 106                 /* Ensure clock and real-time-mode-register are accessible */
 107                 msr = rtc->msr & 0xc0;
 108                 rtc->msr = 0x40;
 109
 110                 rtc->t0cr_rtmr = yrs%4;
 111                 rtc->bcd_tenms = 0;
 112                 rtc->bcd_sec   = bin2bcd(sec);
 113                 rtc->bcd_min   = bin2bcd(min);
 114                 rtc->bcd_hr    = bin2bcd(hrs);
 115                 rtc->bcd_dom   = bin2bcd(day);
 116                 rtc->bcd_mth   = bin2bcd(mon);
 117                 rtc->bcd_year  = bin2bcd(yrs%100);
 118                 if (rtc_tm.tm_wday >= 0)
 119                         rtc->bcd_dow = bin2bcd(rtc_tm.tm_wday+1);
 120                 rtc->t0cr_rtmr = yrs%4 | 0x08;
 121
 122                 rtc->msr = msr;
 123                 local_irq_restore(flags);
 124                 return 0;
 125         }
 126         default:
 127                 return -EINVAL;
 128         }
 129 }
 130
 131 /*
 132  * We enforce only one user at a time here with the open/close.
 133  */
 134 static int rtc_open(struct inode *inode, struct file *file)
 135 {
 136         if (!atomic_dec_and_test(&rtc_status)) {
 137                 atomic_inc(&rtc_status);
 138                 return -EBUSY;
 139         }
 140         return 0;
 141 }
 142
 143 static int rtc_release(struct inode *inode, struct file *file)
 144 {
 145         atomic_inc(&rtc_status);
 146         return 0;
 147 }
 148
 149 /*
 150  *      The various file operations we support.
 151  */
 152
 153 static const struct file_operations rtc_fops = {
 154         .unlocked_ioctl = rtc_ioctl,
 155         .open           = rtc_open,
 156         .release        = rtc_release,
 157         .llseek         = noop_llseek,
 158 };
 159
 160 static struct miscdevice rtc_dev = {
 161         .minor =        RTC_MINOR,
 162         .name =         "rtc",
 163         .fops =         &rtc_fops
 164 };
 165
 166 static int __init rtc_DP8570A_init(void)
 167 {
 168         if (!MACH_IS_BVME6000)
 169                 return -ENODEV;
 170
 171         pr_info("DP8570A Real Time Clock Driver v%s\n", RTC_VERSION);
 172         return misc_register(&rtc_dev);
 173 }
 174 module_init(rtc_DP8570A_init);