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 #include <linux/delay.h>
  39
  40 #include <asm/io.h>
  41 #include <asm/uaccess.h>
  42 #include <asm/system.h>
  43 #include <asm/time.h>
  44 #include <asm/rtas.h>
  45
  46 #include <asm/iSeries/mf.h>
  47 #include <asm/machdep.h>
  48
  49 extern int piranha_simulator;
  50
  51 /*
  52  *      We sponge a minor off of the misc major. No need slurping
  53  *      up another valuable major dev number for this. If you add
  54  *      an ioctl, make sure you don't conflict with SPARC's RTC
  55  *      ioctls.
  56  */
  57
  58 static ssize_t rtc_read(struct file *file, char __user *buf,
  59                         size_t count, loff_t *ppos);
  60
  61 static int rtc_ioctl(struct inode *inode, struct file *file,
  62                      unsigned int cmd, unsigned long arg);
  63
  64 static int rtc_read_proc(char *page, char **start, off_t off,
  65                          int count, int *eof, void *data);
  66
  67 /*
  68  *      If this driver ever becomes modularised, it will be really nice
  69  *      to make the epoch retain its value across module reload...
  70  */
  71
  72 static unsigned long epoch = 1900;      /* year corresponding to 0x00   */
  73
  74 static const unsigned char days_in_mo[] =
  75 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  76
  77 /*
  78  *      Now all the various file operations that we export.
  79  */
  80
  81 static ssize_t rtc_read(struct file *file, char __user *buf,
  82                         size_t count, loff_t *ppos)
  83 {
  84         return -EIO;
  85 }
  86
  87 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  88                      unsigned long arg)
  89 {
  90         struct rtc_time wtime;
  91
  92         switch (cmd) {
  93         case RTC_RD_TIME:       /* Read the time/date from RTC  */
  94         {
  95                 memset(&wtime, 0, sizeof(struct rtc_time));
  96                 ppc_md.get_rtc_time(&wtime);
  97                 break;
  98         }
  99         case RTC_SET_TIME:      /* Set the RTC */
 100         {
 101                 struct rtc_time rtc_tm;
 102                 unsigned char mon, day, hrs, min, sec, leap_yr;
 103                 unsigned int yrs;
 104
 105                 if (!capable(CAP_SYS_TIME))
 106                         return -EACCES;
 107
 108                 if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
 109                                    sizeof(struct rtc_time)))
 110                         return -EFAULT;
 111
 112                 yrs = rtc_tm.tm_year;
 113                 mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
 114                 day = rtc_tm.tm_mday;
 115                 hrs = rtc_tm.tm_hour;
 116                 min = rtc_tm.tm_min;
 117                 sec = rtc_tm.tm_sec;
 118
 119                 if (yrs < 70)
 120                         return -EINVAL;
 121
 122                 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
 123
 124                 if ((mon > 12) || (day == 0))
 125                         return -EINVAL;
 126
 127                 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
 128                         return -EINVAL;
 129
 130                 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 131                         return -EINVAL;
 132
 133                 if ( yrs > 169 )
 134                         return -EINVAL;
 135
 136                 ppc_md.set_rtc_time(&rtc_tm);
 137
 138                 return 0;
 139         }
 140         case RTC_EPOCH_READ:    /* Read the epoch.      */
 141         {
 142                 return put_user (epoch, (unsigned long __user *)arg);
 143         }
 144         case RTC_EPOCH_SET:     /* Set the epoch.       */
 145         {
 146                 /*
 147                  * There were no RTC clocks before 1900.
 148                  */
 149                 if (arg < 1900)
 150                         return -EINVAL;
 151
 152                 if (!capable(CAP_SYS_TIME))
 153                         return -EACCES;
 154
 155                 epoch = arg;
 156                 return 0;
 157         }
 158         default:
 159                 return -EINVAL;
 160         }
 161         return copy_to_user((void __user *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
 162 }
 163
 164 static int rtc_open(struct inode *inode, struct file *file)
 165 {
 166         nonseekable_open(inode, file);
 167         return 0;
 168 }
 169
 170 static int rtc_release(struct inode *inode, struct file *file)
 171 {
 172         return 0;
 173 }
 174
 175 /*
 176  *      The various file operations we support.
 177  */
 178 static struct file_operations rtc_fops = {
 179         .owner =        THIS_MODULE,
 180         .llseek =       no_llseek,
 181         .read =         rtc_read,
 182         .ioctl =        rtc_ioctl,
 183         .open =         rtc_open,
 184         .release =      rtc_release,
 185 };
 186
 187 static struct miscdevice rtc_dev = {
 188         .minor =        RTC_MINOR,
 189         .name =         "rtc",
 190         .fops =         &rtc_fops
 191 };
 192
 193 static int __init rtc_init(void)
 194 {
 195         int retval;
 196
 197         retval = misc_register(&rtc_dev);
 198         if(retval < 0)
 199                 return retval;
 200
 201 #ifdef CONFIG_PROC_FS
 202         if (create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)
 203                         == NULL) {
 204                 misc_deregister(&rtc_dev);
 205                 return -ENOMEM;
 206         }
 207 #endif
 208
 209         printk(KERN_INFO "i/pSeries Real Time Clock Driver v" RTC_VERSION "\n");
 210
 211         return 0;
 212 }
 213
 214 static void __exit rtc_exit (void)
 215 {
 216         remove_proc_entry ("driver/rtc", NULL);
 217         misc_deregister(&rtc_dev);
 218 }
 219
 220 module_init(rtc_init);
 221 module_exit(rtc_exit);
 222
 223 /*
 224  *      Info exported via "/proc/driver/rtc".
 225  */
 226
 227 static int rtc_proc_output (char *buf)
 228 {
 229
 230         char *p;
 231         struct rtc_time tm;
 232
 233         p = buf;
 234
 235         ppc_md.get_rtc_time(&tm);
 236
 237         /*
 238          * There is no way to tell if the luser has the RTC set for local
 239          * time or for Universal Standard Time (GMT). Probably local though.
 240          */
 241         p += sprintf(p,
 242                      "rtc_time\t: %02d:%02d:%02d\n"
 243                      "rtc_date\t: %04d-%02d-%02d\n"
 244                      "rtc_epoch\t: %04lu\n",
 245                      tm.tm_hour, tm.tm_min, tm.tm_sec,
 246                      tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
 247
 248         p += sprintf(p,
 249                      "DST_enable\t: no\n"
 250                      "BCD\t\t: yes\n"
 251                      "24hr\t\t: yes\n" );
 252
 253         return  p - buf;
 254 }
 255
 256 static int rtc_read_proc(char *page, char **start, off_t off,
 257                          int count, int *eof, void *data)
 258 {
 259         int len = rtc_proc_output (page);
 260         if (len <= off+count) *eof = 1;
 261         *start = page + off;
 262         len -= off;
 263         if (len>count) len = count;
 264         if (len<0) len = 0;
 265         return len;
 266 }
 267
 268 #ifdef CONFIG_PPC_ISERIES
 269 /*
 270  * Get the RTC from the virtual service processor
 271  * This requires flowing LpEvents to the primary partition
 272  */
 273 void iSeries_get_rtc_time(struct rtc_time *rtc_tm)
 274 {
 275         if (piranha_simulator)
 276                 return;
 277
 278         mf_get_rtc(rtc_tm);
 279         rtc_tm->tm_mon--;
 280 }
 281
 282 /*
 283  * Set the RTC in the virtual service processor
 284  * This requires flowing LpEvents to the primary partition
 285  */
 286 int iSeries_set_rtc_time(struct rtc_time *tm)
 287 {
 288         mf_set_rtc(tm);
 289         return 0;
 290 }
 291
 292 void iSeries_get_boot_time(struct rtc_time *tm)
 293 {
 294         if ( piranha_simulator )
 295                 return;
 296
 297         mf_get_boot_rtc(tm);
 298         tm->tm_mon  -= 1;
 299 }
 300 #endif
 301
 302 #ifdef CONFIG_PPC_RTAS
 303 #define MAX_RTC_WAIT 5000       /* 5 sec */
 304 #define RTAS_CLOCK_BUSY (-2)
 305 void rtas_get_boot_time(struct rtc_time *rtc_tm)
 306 {
 307         int ret[8];
 308         int error, wait_time;
 309         unsigned long max_wait_tb;
 310
 311         max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
 312         do {
 313                 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
 314                 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
 315                         wait_time = rtas_extended_busy_delay_time(error);
 316                         /* This is boot time so we spin. */
 317                         udelay(wait_time*1000);
 318                         error = RTAS_CLOCK_BUSY;
 319                 }
 320         } while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
 321
 322         if (error != 0 && printk_ratelimit()) {
 323                 printk(KERN_WARNING "error: reading the clock failed (%d)\n",
 324                         error);
 325                 return;
 326         }
 327
 328         rtc_tm->tm_sec = ret[5];
 329         rtc_tm->tm_min = ret[4];
 330         rtc_tm->tm_hour = ret[3];
 331         rtc_tm->tm_mday = ret[2];
 332         rtc_tm->tm_mon = ret[1] - 1;
 333         rtc_tm->tm_year = ret[0] - 1900;
 334 }
 335
 336 /* NOTE: get_rtc_time will get an error if executed in interrupt context
 337  * and if a delay is needed to read the clock.  In this case we just
 338  * silently return without updating rtc_tm.
 339  */
 340 void rtas_get_rtc_time(struct rtc_time *rtc_tm)
 341 {
 342         int ret[8];
 343         int error, wait_time;
 344         unsigned long max_wait_tb;
 345
 346         max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
 347         do {
 348                 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
 349                 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
 350                         if (in_interrupt() && printk_ratelimit()) {
 351                                 printk(KERN_WARNING "error: reading clock would delay interrupt\n");
 352                                 return; /* delay not allowed */
 353                         }
 354                         wait_time = rtas_extended_busy_delay_time(error);
 355                         msleep_interruptible(wait_time);
 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 int rtas_set_rtc_time(struct rtc_time *tm)
 375 {
 376         int error, wait_time;
 377         unsigned long max_wait_tb;
 378
 379         max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
 380         do {
 381                 error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
 382                                   tm->tm_year + 1900, tm->tm_mon + 1,
 383                                   tm->tm_mday, tm->tm_hour, tm->tm_min,
 384                                   tm->tm_sec, 0);
 385                 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
 386                         if (in_interrupt())
 387                                 return 1;       /* probably decrementer */
 388                         wait_time = rtas_extended_busy_delay_time(error);
 389                         msleep_interruptible(wait_time);
 390                         error = RTAS_CLOCK_BUSY;
 391                 }
 392         } while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
 393
 394         if (error != 0 && printk_ratelimit())
 395                 printk(KERN_WARNING "error: setting the clock failed (%d)\n",
 396                        error);
 397
 398         return 0;
 399 }
 400 #endif