arch/ppc64/kernel/rtc.c

   1 /*
   2  *      Real Time Clock interface for PPC64.
   3  *
   4  *      Based on rtc.c by Paul Gortmaker
   5  *
   6  *      This driver allows use of the real time clock
   7  *      from user space. It exports the /dev/rtc
   8  *      interface supporting various ioctl() and also the
   9  *      /proc/driver/rtc pseudo-file for status information.
  10  *
  11  *      Interface does not support RTC interrupts nor an alarm.
  12  *
  13  *      This program is free software; you can redistribute it and/or
  14  *      modify it under the terms of the GNU General Public License
  15  *      as published by the Free Software Foundation; either version
  16  *      2 of the License, or (at your option) any later version.
  17  *
  18  *      1.0     Mike Corrigan:    IBM iSeries rtc support
  19  *      1.1     Dave Engebretsen: IBM pSeries rtc support
  20  */
  21
  22 #define RTC_VERSION             "1.1"
  23
  24 #include <linux/config.h>
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/types.h>
  28 #include <linux/miscdevice.h>
  29 #include <linux/ioport.h>
  30 #include <linux/fcntl.h>
  31 #include <linux/mc146818rtc.h>
  32 #include <linux/init.h>
  33 #include <linux/poll.h>
  34 #include <linux/proc_fs.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/bcd.h>
  37 #include <linux/interrupt.h>
  38
  39 #include <asm/io.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/system.h>
  42 #include <asm/time.h>
  43 #include <asm/rtas.h>
  44
  45 #include <asm/iSeries/LparData.h>
  46 #include <asm/iSeries/mf.h>
  47 #include <asm/machdep.h>
  48 #include <asm/iSeries/ItSpCommArea.h>
  49
  50 extern int piranha_simulator;
  51
  52 /*
  53  *      We sponge a minor off of the misc major. No need slurping
  54  *      up another valuable major dev number for this. If you add
  55  *      an ioctl, make sure you don't conflict with SPARC's RTC
  56  *      ioctls.
  57  */
  58
  59 static ssize_t rtc_read(struct file *file, char __user *buf,
  60                         size_t count, loff_t *ppos);
  61
  62 static int rtc_ioctl(struct inode *inode, struct file *file,
  63                      unsigned int cmd, unsigned long arg);
  64
  65 static int rtc_read_proc(char *page, char **start, off_t off,
  66                          int count, int *eof, void *data);
  67
  68 /*
  69  *      If this driver ever becomes modularised, it will be really nice
  70  *      to make the epoch retain its value across module reload...
  71  */
  72
  73 static unsigned long epoch = 1900;      /* year corresponding to 0x00   */
  74
  75 static const unsigned char days_in_mo[] =
  76 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  77
  78 /*
  79  *      Now all the various file operations that we export.
  80  */
  81
  82 static ssize_t rtc_read(struct file *file, char __user *buf,
  83                         size_t count, loff_t *ppos)
  84 {
  85         return -EIO;
  86 }
  87
  88 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  89                      unsigned long arg)
  90 {
  91         struct rtc_time wtime;
  92
  93         switch (cmd) {
  94         case RTC_RD_TIME:       /* Read the time/date from RTC  */
  95         {
  96                 memset(&wtime, 0, sizeof(struct rtc_time));
  97                 ppc_md.get_rtc_time(&wtime);
  98                 break;
  99         }
 100         case RTC_SET_TIME:      /* Set the RTC */
 101         {
 102                 struct rtc_time rtc_tm;
 103                 unsigned char mon, day, hrs, min, sec, leap_yr;
 104                 unsigned int yrs;
 105
 106                 if (!capable(CAP_SYS_TIME))
 107                         return -EACCES;
 108
 109                 if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
 110                                    sizeof(struct rtc_time)))
 111                         return -EFAULT;
 112
 113                 yrs = rtc_tm.tm_year;
 114                 mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
 115                 day = rtc_tm.tm_mday;
 116                 hrs = rtc_tm.tm_hour;
 117                 min = rtc_tm.tm_min;
 118                 sec = rtc_tm.tm_sec;
 119
 120                 if (yrs < 70)
 121                         return -EINVAL;
 122
 123                 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
 124
 125                 if ((mon > 12) || (day == 0))
 126                         return -EINVAL;
 127
 128                 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
 129                         return -EINVAL;
 130
 131                 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 132                         return -EINVAL;
 133
 134                 if ( yrs > 169 )
 135                         return -EINVAL;
 136
 137                 ppc_md.set_rtc_time(&rtc_tm);
 138
 139                 return 0;
 140         }
 141         case RTC_EPOCH_READ:    /* Read the epoch.      */
 142         {
 143                 return put_user (epoch, (unsigned long __user *)arg);
 144         }
 145         case RTC_EPOCH_SET:     /* Set the epoch.       */
 146         {
 147                 /*
 148                  * There were no RTC clocks before 1900.
 149                  */
 150                 if (arg < 1900)
 151                         return -EINVAL;
 152
 153                 if (!capable(CAP_SYS_TIME))
 154                         return -EACCES;
 155
 156                 epoch = arg;
 157                 return 0;
 158         }
 159         default:
 160                 return -EINVAL;
 161         }
 162         return copy_to_user((void __user *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
 163 }
 164
 165 static int rtc_open(struct inode *inode, struct file *file)
 166 {
 167         nonseekable_open(inode, file);
 168         return 0;
 169 }
 170
 171 static int rtc_release(struct inode *inode, struct file *file)
 172 {
 173         return 0;
 174 }
 175
 176 /*
 177  *      The various file operations we support.
 178  */
 179 static struct file_operations rtc_fops = {
 180         .owner =        THIS_MODULE,
 181         .llseek =       no_llseek,
 182         .read =         rtc_read,
 183         .ioctl =        rtc_ioctl,
 184         .open =         rtc_open,
 185         .release =      rtc_release,
 186 };
 187
 188 static struct miscdevice rtc_dev = {
 189         .minor =        RTC_MINOR,
 190         .name =         "rtc",
 191         .fops =         &rtc_fops
 192 };
 193
 194 static int __init rtc_init(void)
 195 {
 196         int retval;
 197
 198         retval = misc_register(&rtc_dev);
 199         if(retval < 0)
 200                 return retval;
 201
 202 #ifdef CONFIG_PROC_FS
 203         if (create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)
 204                         == NULL) {
 205                 misc_deregister(&rtc_dev);
 206                 return -ENOMEM;
 207         }
 208 #endif
 209
 210         printk(KERN_INFO "i/pSeries Real Time Clock Driver v" RTC_VERSION "\n");
 211
 212         return 0;
 213 }
 214
 215 static void __exit rtc_exit (void)
 216 {
 217         remove_proc_entry ("driver/rtc", NULL);
 218         misc_deregister(&rtc_dev);
 219 }
 220
 221 module_init(rtc_init);
 222 module_exit(rtc_exit);
 223
 224 /*
 225  *      Info exported via "/proc/driver/rtc".
 226  */
 227
 228 static int rtc_proc_output (char *buf)
 229 {
 230
 231         char *p;
 232         struct rtc_time tm;
 233
 234         p = buf;
 235
 236         ppc_md.get_rtc_time(&tm);
 237
 238         /*
 239          * There is no way to tell if the luser has the RTC set for local
 240          * time or for Universal Standard Time (GMT). Probably local though.
 241          */
 242         p += sprintf(p,
 243                      "rtc_time\t: %02d:%02d:%02d\n"
 244                      "rtc_date\t: %04d-%02d-%02d\n"
 245                      "rtc_epoch\t: %04lu\n",
 246                      tm.tm_hour, tm.tm_min, tm.tm_sec,
 247                      tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
 248
 249         p += sprintf(p,
 250                      "DST_enable\t: no\n"
 251                      "BCD\t\t: yes\n"
 252                      "24hr\t\t: yes\n" );
 253
 254         return  p - buf;
 255 }
 256
 257 static int rtc_read_proc(char *page, char **start, off_t off,
 258                          int count, int *eof, void *data)
 259 {
 260         int len = rtc_proc_output (page);
 261         if (len <= off+count) *eof = 1;
 262         *start = page + off;
 263         len -= off;
 264         if (len>count) len = count;
 265         if (len<0) len = 0;
 266         return len;
 267 }
 268
 269 #ifdef CONFIG_PPC_ISERIES
 270 /*
 271  * Get the RTC from the virtual service processor
 272  * This requires flowing LpEvents to the primary partition
 273  */
 274 void iSeries_get_rtc_time(struct rtc_time *rtc_tm)
 275 {
 276         if (piranha_simulator)
 277                 return;
 278
 279         mf_get_rtc(rtc_tm);
 280         rtc_tm->tm_mon--;
 281 }
 282
 283 /*
 284  * Set the RTC in the virtual service processor
 285  * This requires flowing LpEvents to the primary partition
 286  */
 287 int iSeries_set_rtc_time(struct rtc_time *tm)
 288 {
 289         mf_set_rtc(tm);
 290         return 0;
 291 }
 292
 293 void iSeries_get_boot_time(struct rtc_time *tm)
 294 {
 295         unsigned long time;
 296         static unsigned long lastsec = 1;
 297
 298         u32 dataWord1 = *((u32 *)(&xSpCommArea.xBcdTimeAtIplStart));
 299         u32 dataWord2 = *(((u32 *)&(xSpCommArea.xBcdTimeAtIplStart)) + 1);
 300         int year = 1970;
 301         int year1 = ( dataWord1 >> 24 ) & 0x000000FF;
 302         int year2 = ( dataWord1 >> 16 ) & 0x000000FF;
 303         int sec = ( dataWord1 >> 8 ) & 0x000000FF;
 304         int min = dataWord1 & 0x000000FF;
 305         int hour = ( dataWord2 >> 24 ) & 0x000000FF;
 306         int day = ( dataWord2 >> 8 ) & 0x000000FF;
 307         int mon = dataWord2 & 0x000000FF;
 308
 309         if ( piranha_simulator )
 310                 return;
 311
 312         BCD_TO_BIN(sec);
 313         BCD_TO_BIN(min);
 314         BCD_TO_BIN(hour);
 315         BCD_TO_BIN(day);
 316         BCD_TO_BIN(mon);
 317         BCD_TO_BIN(year1);
 318         BCD_TO_BIN(year2);
 319         year = year1 * 100 + year2;
 320
 321         time = mktime(year, mon, day, hour, min, sec);
 322         time += ( jiffies / HZ );
 323
 324         /* Now THIS is a nasty hack!
 325         * It ensures that the first two calls get different answers.
 326         * That way the loop in init_time (time.c) will not think
 327         * the clock is stuck.
 328         */
 329         if ( lastsec ) {
 330                 time -= lastsec;
 331                 --lastsec;
 332         }
 333
 334         to_tm(time, tm);
 335         tm->tm_year -= 1900;
 336         tm->tm_mon  -= 1;
 337 }
 338 #endif
 339
 340 #ifdef CONFIG_PPC_RTAS
 341 #define MAX_RTC_WAIT 5000       /* 5 sec */
 342 #define RTAS_CLOCK_BUSY (-2)
 343 void pSeries_get_boot_time(struct rtc_time *rtc_tm)
 344 {
 345         int ret[8];
 346         int error, wait_time;
 347         unsigned long max_wait_tb;
 348
 349         max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
 350         do {
 351                 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
 352                 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
 353                         wait_time = rtas_extended_busy_delay_time(error);
 354                         /* This is boot time so we spin. */
 355                         udelay(wait_time*1000);
 356                         error = RTAS_CLOCK_BUSY;
 357                 }
 358         } while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
 359
 360         if (error != 0 && printk_ratelimit()) {
 361                 printk(KERN_WARNING "error: reading the clock failed (%d)\n",
 362                         error);
 363                 return;
 364         }
 365
 366         rtc_tm->tm_sec = ret[5];
 367         rtc_tm->tm_min = ret[4];
 368         rtc_tm->tm_hour = ret[3];
 369         rtc_tm->tm_mday = ret[2];
 370         rtc_tm->tm_mon = ret[1] - 1;
 371         rtc_tm->tm_year = ret[0] - 1900;
 372 }
 373
 374 /* NOTE: get_rtc_time will get an error if executed in interrupt context
 375  * and if a delay is needed to read the clock.  In this case we just
 376  * silently return without updating rtc_tm.
 377  */
 378 void pSeries_get_rtc_time(struct rtc_time *rtc_tm)
 379 {
 380         int ret[8];
 381         int error, wait_time;
 382         unsigned long max_wait_tb;
 383
 384         max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
 385         do {
 386                 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
 387                 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
 388                         if (in_interrupt() && printk_ratelimit()) {
 389                                 printk(KERN_WARNING "error: reading clock would delay interrupt\n");
 390                                 return; /* delay not allowed */
 391                         }
 392                         wait_time = rtas_extended_busy_delay_time(error);
 393                         set_current_state(TASK_INTERRUPTIBLE);
 394                         schedule_timeout(wait_time);
 395                         error = RTAS_CLOCK_BUSY;
 396                 }
 397         } while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
 398
 399         if (error != 0 && printk_ratelimit()) {
 400                 printk(KERN_WARNING "error: reading the clock failed (%d)\n",
 401                        error);
 402                 return;
 403         }
 404
 405         rtc_tm->tm_sec = ret[5];
 406         rtc_tm->tm_min = ret[4];
 407         rtc_tm->tm_hour = ret[3];
 408         rtc_tm->tm_mday = ret[2];
 409         rtc_tm->tm_mon = ret[1] - 1;
 410         rtc_tm->tm_year = ret[0] - 1900;
 411 }
 412
 413 int pSeries_set_rtc_time(struct rtc_time *tm)
 414 {
 415         int error, wait_time;
 416         unsigned long max_wait_tb;
 417
 418         max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
 419         do {
 420                 error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
 421                                   tm->tm_year + 1900, tm->tm_mon + 1,
 422                                   tm->tm_mday, tm->tm_hour, tm->tm_min,
 423                                   tm->tm_sec, 0);
 424                 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
 425                         if (in_interrupt())
 426                                 return 1;       /* probably decrementer */
 427                         wait_time = rtas_extended_busy_delay_time(error);
 428                         set_current_state(TASK_INTERRUPTIBLE);
 429                         schedule_timeout(wait_time);
 430                         error = RTAS_CLOCK_BUSY;
 431                 }
 432         } while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
 433
 434         if (error != 0 && printk_ratelimit())
 435                 printk(KERN_WARNING "error: setting the clock failed (%d)\n",
 436                        error);
 437
 438         return 0;
 439 }
 440 #endif