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