arch/m68k/bvme6000/rtc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *      Real Time Clock interface for Linux on the BVME6000
   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/module.h>
  19 #include <linux/rtc.h>  /* For struct rtc_time and ioctls, etc */
  20 #include <linux/bcd.h>
  21 #include <asm/bvme6000hw.h>
  22
  23 #include <asm/io.h>
  24 #include <linux/uaccess.h>
  25 #include <asm/setup.h>
  26
  27 /*
  28  *      We sponge a minor off of the misc major. No need slurping
  29  *      up another valuable major dev number for this. If you add
  30  *      an ioctl, make sure you don't conflict with SPARC's RTC
  31  *      ioctls.
  32  */
  33
  34 static unsigned char days_in_mo[] =
  35 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  36
  37 static atomic_t rtc_status = ATOMIC_INIT(1);
  38
  39 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  40 {
  41         volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
  42         unsigned char msr;
  43         unsigned long flags;
  44         struct rtc_time wtime;
  45         void __user *argp = (void __user *)arg;
  46
  47         switch (cmd) {
  48         case RTC_RD_TIME:       /* Read the time/date from RTC  */
  49         {
  50                 local_irq_save(flags);
  51                 /* Ensure clock and real-time-mode-register are accessible */
  52                 msr = rtc->msr & 0xc0;
  53                 rtc->msr = 0x40;
  54                 memset(&wtime, 0, sizeof(struct rtc_time));
  55                 do {
  56                         wtime.tm_sec =  bcd2bin(rtc->bcd_sec);
  57                         wtime.tm_min =  bcd2bin(rtc->bcd_min);
  58                         wtime.tm_hour = bcd2bin(rtc->bcd_hr);
  59                         wtime.tm_mday =  bcd2bin(rtc->bcd_dom);
  60                         wtime.tm_mon =  bcd2bin(rtc->bcd_mth)-1;
  61                         wtime.tm_year = bcd2bin(rtc->bcd_year);
  62                         if (wtime.tm_year < 70)
  63                                 wtime.tm_year += 100;
  64                         wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;
  65                 } while (wtime.tm_sec != bcd2bin(rtc->bcd_sec));
  66                 rtc->msr = msr;
  67                 local_irq_restore(flags);
  68                 return copy_to_user(argp, &wtime, sizeof wtime) ?
  69                                                                 -EFAULT : 0;
  70         }
  71         case RTC_SET_TIME:      /* Set the RTC */
  72         {
  73                 struct rtc_time rtc_tm;
  74                 unsigned char mon, day, hrs, min, sec, leap_yr;
  75                 unsigned int yrs;
  76
  77                 if (!capable(CAP_SYS_ADMIN))
  78                         return -EACCES;
  79
  80                 if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
  81                         return -EFAULT;
  82
  83                 yrs = rtc_tm.tm_year;
  84                 if (yrs < 1900)
  85                         yrs += 1900;
  86                 mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
  87                 day = rtc_tm.tm_mday;
  88                 hrs = rtc_tm.tm_hour;
  89                 min = rtc_tm.tm_min;
  90                 sec = rtc_tm.tm_sec;
  91
  92                 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
  93
  94                 if ((mon > 12) || (mon < 1) || (day == 0))
  95                         return -EINVAL;
  96
  97                 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
  98                         return -EINVAL;
  99
 100                 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 101                         return -EINVAL;
 102
 103                 if (yrs >= 2070)
 104                         return -EINVAL;
 105
 106                 local_irq_save(flags);
 107                 /* Ensure clock and real-time-mode-register are accessible */
 108                 msr = rtc->msr & 0xc0;
 109                 rtc->msr = 0x40;
 110
 111                 rtc->t0cr_rtmr = yrs%4;
 112                 rtc->bcd_tenms = 0;
 113                 rtc->bcd_sec   = bin2bcd(sec);
 114                 rtc->bcd_min   = bin2bcd(min);
 115                 rtc->bcd_hr    = bin2bcd(hrs);
 116                 rtc->bcd_dom   = bin2bcd(day);
 117                 rtc->bcd_mth   = bin2bcd(mon);
 118                 rtc->bcd_year  = bin2bcd(yrs%100);
 119                 if (rtc_tm.tm_wday >= 0)
 120                         rtc->bcd_dow = bin2bcd(rtc_tm.tm_wday+1);
 121                 rtc->t0cr_rtmr = yrs%4 | 0x08;
 122
 123                 rtc->msr = msr;
 124                 local_irq_restore(flags);
 125                 return 0;
 126         }
 127         default:
 128                 return -EINVAL;
 129         }
 130 }
 131
 132 /*
 133  * We enforce only one user at a time here with the open/close.
 134  */
 135 static int rtc_open(struct inode *inode, struct file *file)
 136 {
 137         if (!atomic_dec_and_test(&rtc_status)) {
 138                 atomic_inc(&rtc_status);
 139                 return -EBUSY;
 140         }
 141         return 0;
 142 }
 143
 144 static int rtc_release(struct inode *inode, struct file *file)
 145 {
 146         atomic_inc(&rtc_status);
 147         return 0;
 148 }
 149
 150 /*
 151  *      The various file operations we support.
 152  */
 153
 154 static const struct file_operations rtc_fops = {
 155         .unlocked_ioctl = rtc_ioctl,
 156         .open           = rtc_open,
 157         .release        = rtc_release,
 158         .llseek         = noop_llseek,
 159 };
 160
 161 static struct miscdevice rtc_dev = {
 162         .minor =        RTC_MINOR,
 163         .name =         "rtc",
 164         .fops =         &rtc_fops
 165 };
 166
 167 static int __init rtc_DP8570A_init(void)
 168 {
 169         if (!MACH_IS_BVME6000)
 170                 return -ENODEV;
 171
 172         pr_info("DP8570A Real Time Clock Driver v%s\n", RTC_VERSION);
 173         return misc_register(&rtc_dev);
 174 }
 175 module_init(rtc_DP8570A_init);