linux/arch/m68k/bvme6000/rtc.c
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   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
  34static unsigned char days_in_mo[] =
  35{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  36
  37static atomic_t rtc_status = ATOMIC_INIT(1);
  38
  39static 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 */
 135static 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
 144static 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
 154static 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
 161static struct miscdevice rtc_dev = {
 162        .minor =        RTC_MINOR,
 163        .name =         "rtc",
 164        .fops =         &rtc_fops
 165};
 166
 167static 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}
 175module_init(rtc_DP8570A_init);
 176