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); 166