Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip |
| 3 | * |
| 4 | * Real Time Clock interface for Linux |
| 5 | * |
| 6 | * TODO: Implement periodic interrupts. |
| 7 | * |
| 8 | * Copyright (C) 2000 Silicon Graphics, Inc. |
| 9 | * Written by Ulf Carlsson (ulfc@engr.sgi.com) |
| 10 | * |
| 11 | * Based on code written by Paul Gortmaker. |
| 12 | * |
| 13 | * This driver allows use of the real time clock (built into |
| 14 | * nearly all computers) from user space. It exports the /dev/rtc |
| 15 | * interface supporting various ioctl() and also the /proc/rtc |
| 16 | * pseudo-file for status information. |
| 17 | * |
| 18 | * This program is free software; you can redistribute it and/or |
| 19 | * modify it under the terms of the GNU General Public License |
| 20 | * as published by the Free Software Foundation; either version |
| 21 | * 2 of the License, or (at your option) any later version. |
| 22 | * |
| 23 | */ |
| 24 | |
| 25 | #define RTC_VERSION "1.09b" |
| 26 | |
| 27 | #include <linux/bcd.h> |
| 28 | #include <linux/module.h> |
| 29 | #include <linux/kernel.h> |
Arnd Bergmann | b0e54f7c | 2008-05-20 19:16:03 +0200 | [diff] [blame] | 30 | #include <linux/smp_lock.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/types.h> |
| 32 | #include <linux/miscdevice.h> |
| 33 | #include <linux/ioport.h> |
| 34 | #include <linux/fcntl.h> |
| 35 | #include <linux/rtc.h> |
| 36 | #include <linux/init.h> |
| 37 | #include <linux/poll.h> |
| 38 | #include <linux/proc_fs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | |
| 40 | #include <asm/m48t35.h> |
| 41 | #include <asm/sn/ioc3.h> |
| 42 | #include <asm/io.h> |
| 43 | #include <asm/uaccess.h> |
| 44 | #include <asm/system.h> |
| 45 | #include <asm/sn/klconfig.h> |
| 46 | #include <asm/sn/sn0/ip27.h> |
| 47 | #include <asm/sn/sn0/hub.h> |
| 48 | #include <asm/sn/sn_private.h> |
| 49 | |
Cyrill Gorcunov | 102f4a0 | 2008-02-06 01:38:53 -0800 | [diff] [blame] | 50 | static long rtc_ioctl(struct file *filp, unsigned int cmd, |
| 51 | unsigned long arg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | |
| 53 | static int rtc_read_proc(char *page, char **start, off_t off, |
| 54 | int count, int *eof, void *data); |
| 55 | |
| 56 | static void get_rtc_time(struct rtc_time *rtc_tm); |
| 57 | |
| 58 | /* |
| 59 | * Bits in rtc_status. (6 bits of room for future expansion) |
| 60 | */ |
| 61 | |
| 62 | #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ |
| 63 | #define RTC_TIMER_ON 0x02 /* missed irq timer active */ |
| 64 | |
| 65 | static unsigned char rtc_status; /* bitmapped status byte. */ |
| 66 | static unsigned long rtc_freq; /* Current periodic IRQ rate */ |
| 67 | static struct m48t35_rtc *rtc; |
| 68 | |
| 69 | /* |
| 70 | * If this driver ever becomes modularised, it will be really nice |
| 71 | * to make the epoch retain its value across module reload... |
| 72 | */ |
| 73 | |
| 74 | static unsigned long epoch = 1970; /* year corresponding to 0x00 */ |
| 75 | |
| 76 | static const unsigned char days_in_mo[] = |
| 77 | {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; |
| 78 | |
Cyrill Gorcunov | 102f4a0 | 2008-02-06 01:38:53 -0800 | [diff] [blame] | 79 | static long rtc_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | { |
| 81 | |
| 82 | struct rtc_time wtime; |
| 83 | |
| 84 | switch (cmd) { |
| 85 | case RTC_RD_TIME: /* Read the time/date from RTC */ |
| 86 | { |
| 87 | get_rtc_time(&wtime); |
| 88 | break; |
| 89 | } |
| 90 | case RTC_SET_TIME: /* Set the RTC */ |
| 91 | { |
| 92 | struct rtc_time rtc_tm; |
| 93 | unsigned char mon, day, hrs, min, sec, leap_yr; |
| 94 | unsigned int yrs; |
| 95 | |
| 96 | if (!capable(CAP_SYS_TIME)) |
| 97 | return -EACCES; |
| 98 | |
| 99 | if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, |
| 100 | sizeof(struct rtc_time))) |
| 101 | return -EFAULT; |
| 102 | |
| 103 | yrs = rtc_tm.tm_year + 1900; |
| 104 | mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */ |
| 105 | day = rtc_tm.tm_mday; |
| 106 | hrs = rtc_tm.tm_hour; |
| 107 | min = rtc_tm.tm_min; |
| 108 | sec = rtc_tm.tm_sec; |
| 109 | |
| 110 | if (yrs < 1970) |
| 111 | return -EINVAL; |
| 112 | |
| 113 | leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); |
| 114 | |
| 115 | if ((mon > 12) || (day == 0)) |
| 116 | return -EINVAL; |
| 117 | |
| 118 | if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) |
| 119 | return -EINVAL; |
| 120 | |
| 121 | if ((hrs >= 24) || (min >= 60) || (sec >= 60)) |
| 122 | return -EINVAL; |
| 123 | |
| 124 | if ((yrs -= epoch) > 255) /* They are unsigned */ |
| 125 | return -EINVAL; |
| 126 | |
| 127 | if (yrs > 169) |
| 128 | return -EINVAL; |
| 129 | |
| 130 | if (yrs >= 100) |
| 131 | yrs -= 100; |
| 132 | |
| 133 | sec = BIN2BCD(sec); |
| 134 | min = BIN2BCD(min); |
| 135 | hrs = BIN2BCD(hrs); |
| 136 | day = BIN2BCD(day); |
| 137 | mon = BIN2BCD(mon); |
| 138 | yrs = BIN2BCD(yrs); |
| 139 | |
| 140 | spin_lock_irq(&rtc_lock); |
| 141 | rtc->control |= M48T35_RTC_SET; |
| 142 | rtc->year = yrs; |
| 143 | rtc->month = mon; |
| 144 | rtc->date = day; |
| 145 | rtc->hour = hrs; |
| 146 | rtc->min = min; |
| 147 | rtc->sec = sec; |
| 148 | rtc->control &= ~M48T35_RTC_SET; |
| 149 | spin_unlock_irq(&rtc_lock); |
| 150 | |
| 151 | return 0; |
| 152 | } |
| 153 | default: |
| 154 | return -EINVAL; |
| 155 | } |
| 156 | return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0; |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * We enforce only one user at a time here with the open/close. |
| 161 | * Also clear the previous interrupt data on an open, and clean |
| 162 | * up things on a close. |
| 163 | */ |
| 164 | |
| 165 | static int rtc_open(struct inode *inode, struct file *file) |
| 166 | { |
Arnd Bergmann | b0e54f7c | 2008-05-20 19:16:03 +0200 | [diff] [blame] | 167 | lock_kernel(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 168 | spin_lock_irq(&rtc_lock); |
| 169 | |
| 170 | if (rtc_status & RTC_IS_OPEN) { |
| 171 | spin_unlock_irq(&rtc_lock); |
Arnd Bergmann | b0e54f7c | 2008-05-20 19:16:03 +0200 | [diff] [blame] | 172 | unlock_kernel(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | return -EBUSY; |
| 174 | } |
| 175 | |
| 176 | rtc_status |= RTC_IS_OPEN; |
| 177 | spin_unlock_irq(&rtc_lock); |
Arnd Bergmann | b0e54f7c | 2008-05-20 19:16:03 +0200 | [diff] [blame] | 178 | unlock_kernel(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | |
| 180 | return 0; |
| 181 | } |
| 182 | |
| 183 | static int rtc_release(struct inode *inode, struct file *file) |
| 184 | { |
| 185 | /* |
| 186 | * Turn off all interrupts once the device is no longer |
| 187 | * in use, and clear the data. |
| 188 | */ |
| 189 | |
| 190 | spin_lock_irq(&rtc_lock); |
| 191 | rtc_status &= ~RTC_IS_OPEN; |
| 192 | spin_unlock_irq(&rtc_lock); |
| 193 | |
| 194 | return 0; |
| 195 | } |
| 196 | |
| 197 | /* |
| 198 | * The various file operations we support. |
| 199 | */ |
| 200 | |
Arjan van de Ven | 62322d2 | 2006-07-03 00:24:21 -0700 | [diff] [blame] | 201 | static const struct file_operations rtc_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | .owner = THIS_MODULE, |
Cyrill Gorcunov | 102f4a0 | 2008-02-06 01:38:53 -0800 | [diff] [blame] | 203 | .unlocked_ioctl = rtc_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | .open = rtc_open, |
| 205 | .release = rtc_release, |
| 206 | }; |
| 207 | |
| 208 | static struct miscdevice rtc_dev= |
| 209 | { |
| 210 | RTC_MINOR, |
| 211 | "rtc", |
| 212 | &rtc_fops |
| 213 | }; |
| 214 | |
| 215 | static int __init rtc_init(void) |
| 216 | { |
| 217 | rtc = (struct m48t35_rtc *) |
| 218 | (KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base + IOC3_BYTEBUS_DEV0); |
| 219 | |
| 220 | printk(KERN_INFO "Real Time Clock Driver v%s\n", RTC_VERSION); |
| 221 | if (misc_register(&rtc_dev)) { |
| 222 | printk(KERN_ERR "rtc: cannot register misc device.\n"); |
| 223 | return -ENODEV; |
| 224 | } |
| 225 | if (!create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)) { |
| 226 | printk(KERN_ERR "rtc: cannot create /proc/rtc.\n"); |
| 227 | misc_deregister(&rtc_dev); |
| 228 | return -ENOENT; |
| 229 | } |
| 230 | |
| 231 | rtc_freq = 1024; |
| 232 | |
| 233 | return 0; |
| 234 | } |
| 235 | |
| 236 | static void __exit rtc_exit (void) |
| 237 | { |
| 238 | /* interrupts and timer disabled at this point by rtc_release */ |
| 239 | |
| 240 | remove_proc_entry ("rtc", NULL); |
| 241 | misc_deregister(&rtc_dev); |
| 242 | } |
| 243 | |
| 244 | module_init(rtc_init); |
| 245 | module_exit(rtc_exit); |
| 246 | |
| 247 | /* |
| 248 | * Info exported via "/proc/rtc". |
| 249 | */ |
| 250 | |
| 251 | static int rtc_get_status(char *buf) |
| 252 | { |
| 253 | char *p; |
| 254 | struct rtc_time tm; |
| 255 | |
| 256 | /* |
| 257 | * Just emulate the standard /proc/rtc |
| 258 | */ |
| 259 | |
| 260 | p = buf; |
| 261 | |
| 262 | get_rtc_time(&tm); |
| 263 | |
| 264 | /* |
| 265 | * There is no way to tell if the luser has the RTC set for local |
| 266 | * time or for Universal Standard Time (GMT). Probably local though. |
| 267 | */ |
| 268 | p += sprintf(p, |
| 269 | "rtc_time\t: %02d:%02d:%02d\n" |
| 270 | "rtc_date\t: %04d-%02d-%02d\n" |
| 271 | "rtc_epoch\t: %04lu\n" |
| 272 | "24hr\t\t: yes\n", |
| 273 | tm.tm_hour, tm.tm_min, tm.tm_sec, |
| 274 | tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch); |
| 275 | |
| 276 | return p - buf; |
| 277 | } |
| 278 | |
| 279 | static int rtc_read_proc(char *page, char **start, off_t off, |
| 280 | int count, int *eof, void *data) |
| 281 | { |
| 282 | int len = rtc_get_status(page); |
| 283 | if (len <= off+count) *eof = 1; |
| 284 | *start = page + off; |
| 285 | len -= off; |
| 286 | if (len>count) len = count; |
| 287 | if (len<0) len = 0; |
| 288 | return len; |
| 289 | } |
| 290 | |
| 291 | static void get_rtc_time(struct rtc_time *rtc_tm) |
| 292 | { |
| 293 | /* |
| 294 | * Do we need to wait for the last update to finish? |
| 295 | */ |
| 296 | |
| 297 | /* |
| 298 | * Only the values that we read from the RTC are set. We leave |
| 299 | * tm_wday, tm_yday and tm_isdst untouched. Even though the |
| 300 | * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated |
| 301 | * by the RTC when initially set to a non-zero value. |
| 302 | */ |
| 303 | spin_lock_irq(&rtc_lock); |
| 304 | rtc->control |= M48T35_RTC_READ; |
| 305 | rtc_tm->tm_sec = rtc->sec; |
| 306 | rtc_tm->tm_min = rtc->min; |
| 307 | rtc_tm->tm_hour = rtc->hour; |
| 308 | rtc_tm->tm_mday = rtc->date; |
| 309 | rtc_tm->tm_mon = rtc->month; |
| 310 | rtc_tm->tm_year = rtc->year; |
| 311 | rtc->control &= ~M48T35_RTC_READ; |
| 312 | spin_unlock_irq(&rtc_lock); |
| 313 | |
| 314 | rtc_tm->tm_sec = BCD2BIN(rtc_tm->tm_sec); |
| 315 | rtc_tm->tm_min = BCD2BIN(rtc_tm->tm_min); |
| 316 | rtc_tm->tm_hour = BCD2BIN(rtc_tm->tm_hour); |
| 317 | rtc_tm->tm_mday = BCD2BIN(rtc_tm->tm_mday); |
| 318 | rtc_tm->tm_mon = BCD2BIN(rtc_tm->tm_mon); |
| 319 | rtc_tm->tm_year = BCD2BIN(rtc_tm->tm_year); |
| 320 | |
| 321 | /* |
| 322 | * Account for differences between how the RTC uses the values |
| 323 | * and how they are defined in a struct rtc_time; |
| 324 | */ |
| 325 | if ((rtc_tm->tm_year += (epoch - 1900)) <= 69) |
| 326 | rtc_tm->tm_year += 100; |
| 327 | |
| 328 | rtc_tm->tm_mon--; |
| 329 | } |