Logo Search packages:      
Sourcecode: linux version File versions  Download package

genrtc.c

/*
 *    Real Time Clock interface for
 *          - q40 and other m68k machines,
 *          - HP PARISC machines
 *          - PowerPC machines
 *      emulate some RTC irq capabilities in software
 *
 *      Copyright (C) 1999 Richard Zidlicky
 *
 *    based on Paul Gortmaker's rtc.c device and
 *           Sam Creasey Generic rtc driver
 *
 *    This driver allows use of the real time clock (built into
 *    nearly all computers) from user space. It exports the /dev/rtc
 *    interface supporting various ioctl() and also the /proc/driver/rtc
 *    pseudo-file for status information.
 *
 *    The ioctls can be used to set the interrupt behaviour where
 *    supported.
 *
 *    The /dev/rtc interface will block on reads until an interrupt
 *    has been received. If a RTC interrupt has already happened,
 *    it will output an unsigned long and then block. The output value
 *    contains the interrupt status in the low byte and the number of
 *    interrupts since the last read in the remaining high bytes. The
 *    /dev/rtc interface can also be used with the select(2) call.
 *
 *    This program is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU General Public License
 *    as published by the Free Software Foundation; either version
 *    2 of the License, or (at your option) any later version.
 *

 *      1.01 fix for 2.3.X                    rz@linux-m68k.org
 *      1.02 merged with code from genrtc.c   rz@linux-m68k.org
 *      1.03 make it more portable            zippel@linux-m68k.org
 *      1.04 removed useless timer code       rz@linux-m68k.org
 *      1.05 portable RTC_UIE emulation       rz@linux-m68k.org
 *      1.06 set_rtc_time can return an error trini@kernel.crashing.org
 *      1.07 ported to HP PARISC (hppa)         Helge Deller <deller@gmx.de>
 */

#define RTC_VERSION     "1.07"

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/fcntl.h>

#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/workqueue.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/rtc.h>

/*
 *    We sponge a minor off of the misc major. No need slurping
 *    up another valuable major dev number for this. If you add
 *    an ioctl, make sure you don't conflict with SPARC's RTC
 *    ioctls.
 */

static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait);

/*
 *    Bits in gen_rtc_status.
 */

#define RTC_IS_OPEN           0x01  /* means /dev/rtc is in use   */

static unsigned char gen_rtc_status;      /* bitmapped status byte.     */
static unsigned long gen_rtc_irq_data;    /* our output to the world    */

/* months start at 0 now */
static unsigned char days_in_mo[] =
{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

static int irq_active;

#ifdef CONFIG_GEN_RTC_X
static struct work_struct genrtc_task;
static struct timer_list timer_task;

static unsigned int oldsecs;
static int lostint;
static unsigned long tt_exp;

static void gen_rtc_timer(unsigned long data);

static volatile int stask_active;              /* schedule_work */
static volatile int ttask_active;              /* timer_task */
static int stop_rtc_timers;                    /* don't requeue tasks */
static DEFINE_SPINLOCK(gen_rtc_lock);

static void gen_rtc_interrupt(unsigned long arg);

/*
 * Routine to poll RTC seconds field for change as often as possible,
 * after first RTC_UIE use timer to reduce polling
 */
static void genrtc_troutine(struct work_struct *work)
{
      unsigned int tmp = get_rtc_ss();
      
      if (stop_rtc_timers) {
            stask_active = 0;
            return;
      }

      if (oldsecs != tmp){
            oldsecs = tmp;

            timer_task.function = gen_rtc_timer;
            timer_task.expires = jiffies + HZ - (HZ/10);
            tt_exp=timer_task.expires;
            ttask_active=1;
            stask_active=0;
            add_timer(&timer_task);

            gen_rtc_interrupt(0);
      } else if (schedule_work(&genrtc_task) == 0)
            stask_active = 0;
}

static void gen_rtc_timer(unsigned long data)
{
      lostint = get_rtc_ss() - oldsecs ;
      if (lostint<0) 
            lostint = 60 - lostint;
      if (time_after(jiffies, tt_exp))
            printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n",
                   jiffies-tt_exp);
      ttask_active=0;
      stask_active=1;
      if ((schedule_work(&genrtc_task) == 0))
            stask_active = 0;
}

/* 
 * call gen_rtc_interrupt function to signal an RTC_UIE,
 * arg is unused.
 * Could be invoked either from a real interrupt handler or
 * from some routine that periodically (eg 100HZ) monitors
 * whether RTC_SECS changed
 */
static void gen_rtc_interrupt(unsigned long arg)
{
      /*  We store the status in the low byte and the number of
       *    interrupts received since the last read in the remainder
       *    of rtc_irq_data.  */

      gen_rtc_irq_data += 0x100;
      gen_rtc_irq_data &= ~0xff;
      gen_rtc_irq_data |= RTC_UIE;

      if (lostint){
            printk("genrtc: system delaying clock ticks?\n");
            /* increment count so that userspace knows something is wrong */
            gen_rtc_irq_data += ((lostint-1)<<8);
            lostint = 0;
      }

      wake_up_interruptible(&gen_rtc_wait);
}

/*
 *    Now all the various file operations that we export.
 */
static ssize_t gen_rtc_read(struct file *file, char __user *buf,
                  size_t count, loff_t *ppos)
{
      unsigned long data;
      ssize_t retval;

      if (count != sizeof (unsigned int) && count != sizeof (unsigned long))
            return -EINVAL;

      if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data)
            return -EAGAIN;

      retval = wait_event_interruptible(gen_rtc_wait,
                  (data = xchg(&gen_rtc_irq_data, 0)));
      if (retval)
            goto out;

      /* first test allows optimizer to nuke this case for 32-bit machines */
      if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) {
            unsigned int uidata = data;
            retval = put_user(uidata, (unsigned int __user *)buf) ?:
                  sizeof(unsigned int);
      }
      else {
            retval = put_user(data, (unsigned long __user *)buf) ?:
                  sizeof(unsigned long);
      }
out:
      return retval;
}

static unsigned int gen_rtc_poll(struct file *file,
                         struct poll_table_struct *wait)
{
      poll_wait(file, &gen_rtc_wait, wait);
      if (gen_rtc_irq_data != 0)
            return POLLIN | POLLRDNORM;
      return 0;
}

#endif

/*
 * Used to disable/enable interrupts, only RTC_UIE supported
 * We also clear out any old irq data after an ioctl() that
 * meddles with the interrupt enable/disable bits.
 */

static inline void gen_clear_rtc_irq_bit(unsigned char bit)
{
#ifdef CONFIG_GEN_RTC_X
      stop_rtc_timers = 1;
      if (ttask_active){
            del_timer_sync(&timer_task);
            ttask_active = 0;
      }
      while (stask_active)
            schedule();

      spin_lock(&gen_rtc_lock);
      irq_active = 0;
      spin_unlock(&gen_rtc_lock);
#endif
}

static inline int gen_set_rtc_irq_bit(unsigned char bit)
{
#ifdef CONFIG_GEN_RTC_X
      spin_lock(&gen_rtc_lock);
      if ( !irq_active ) {
            irq_active = 1;
            stop_rtc_timers = 0;
            lostint = 0;
            INIT_WORK(&genrtc_task, genrtc_troutine);
            oldsecs = get_rtc_ss();
            init_timer(&timer_task);

            stask_active = 1;
            if (schedule_work(&genrtc_task) == 0){
                  stask_active = 0;
            }
      }
      spin_unlock(&gen_rtc_lock);
      gen_rtc_irq_data = 0;
      return 0;
#else
      return -EINVAL;
#endif
}

static int gen_rtc_ioctl(struct inode *inode, struct file *file,
                   unsigned int cmd, unsigned long arg)
{
      struct rtc_time wtime;
      struct rtc_pll_info pll;
      void __user *argp = (void __user *)arg;

      switch (cmd) {

      case RTC_PLL_GET:
          if (get_rtc_pll(&pll))
                return -EINVAL;
          else
                return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;

      case RTC_PLL_SET:
            if (!capable(CAP_SYS_TIME))
                  return -EACCES;
            if (copy_from_user(&pll, argp, sizeof(pll)))
                  return -EFAULT;
          return set_rtc_pll(&pll);

      case RTC_UIE_OFF: /* disable ints from RTC updates.   */
            gen_clear_rtc_irq_bit(RTC_UIE);
            return 0;

      case RTC_UIE_ON:  /* enable ints for RTC updates.     */
              return gen_set_rtc_irq_bit(RTC_UIE);

      case RTC_RD_TIME: /* Read the time/date from RTC      */
            /* this doesn't get week-day, who cares */
            memset(&wtime, 0, sizeof(wtime));
            get_rtc_time(&wtime);

            return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0;

      case RTC_SET_TIME:      /* Set the RTC */
          {
            int year;
            unsigned char leap_yr;

            if (!capable(CAP_SYS_TIME))
                  return -EACCES;

            if (copy_from_user(&wtime, argp, sizeof(wtime)))
                  return -EFAULT;

            year = wtime.tm_year + 1900;
            leap_yr = ((!(year % 4) && (year % 100)) ||
                     !(year % 400));

            if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1))
                  return -EINVAL;

            if (wtime.tm_mday < 0 || wtime.tm_mday >
                (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr)))
                  return -EINVAL;

            if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 ||
                wtime.tm_min < 0 || wtime.tm_min >= 60 ||
                wtime.tm_sec < 0 || wtime.tm_sec >= 60)
                  return -EINVAL;

            return set_rtc_time(&wtime);
          }
      }

      return -EINVAL;
}

/*
 *    We enforce only one user at a time here with the open/close.
 *    Also clear the previous interrupt data on an open, and clean
 *    up things on a close.
 */

static int gen_rtc_open(struct inode *inode, struct file *file)
{
      if (gen_rtc_status & RTC_IS_OPEN)
            return -EBUSY;

      gen_rtc_status |= RTC_IS_OPEN;
      gen_rtc_irq_data = 0;
      irq_active = 0;

      return 0;
}

static int gen_rtc_release(struct inode *inode, struct file *file)
{
      /*
       * Turn off all interrupts once the device is no longer
       * in use and clear the data.
       */

      gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);

      gen_rtc_status &= ~RTC_IS_OPEN;
      return 0;
}


#ifdef CONFIG_PROC_FS

/*
 *    Info exported via "/proc/driver/rtc".
 */

static int gen_rtc_proc_output(char *buf)
{
      char *p;
      struct rtc_time tm;
      unsigned int flags;
      struct rtc_pll_info pll;

      p = buf;

      flags = get_rtc_time(&tm);

      p += sprintf(p,
                 "rtc_time\t: %02d:%02d:%02d\n"
                 "rtc_date\t: %04d-%02d-%02d\n"
                 "rtc_epoch\t: %04u\n",
                 tm.tm_hour, tm.tm_min, tm.tm_sec,
                 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900);

      tm.tm_hour = tm.tm_min = tm.tm_sec = 0;

      p += sprintf(p, "alarm\t\t: ");
      if (tm.tm_hour <= 24)
            p += sprintf(p, "%02d:", tm.tm_hour);
      else
            p += sprintf(p, "**:");

      if (tm.tm_min <= 59)
            p += sprintf(p, "%02d:", tm.tm_min);
      else
            p += sprintf(p, "**:");

      if (tm.tm_sec <= 59)
            p += sprintf(p, "%02d\n", tm.tm_sec);
      else
            p += sprintf(p, "**\n");

      p += sprintf(p,
                 "DST_enable\t: %s\n"
                 "BCD\t\t: %s\n"
                 "24hr\t\t: %s\n"
                 "square_wave\t: %s\n"
                 "alarm_IRQ\t: %s\n"
                 "update_IRQ\t: %s\n"
                 "periodic_IRQ\t: %s\n"
                 "periodic_freq\t: %ld\n"
                 "batt_status\t: %s\n",
                 (flags & RTC_DST_EN) ? "yes" : "no",
                 (flags & RTC_DM_BINARY) ? "no" : "yes",
                 (flags & RTC_24H) ? "yes" : "no",
                 (flags & RTC_SQWE) ? "yes" : "no",
                 (flags & RTC_AIE) ? "yes" : "no",
                 irq_active ? "yes" : "no",
                 (flags & RTC_PIE) ? "yes" : "no",
                 0L /* freq */,
                 (flags & RTC_BATT_BAD) ? "bad" : "okay");
      if (!get_rtc_pll(&pll))
          p += sprintf(p,
                   "PLL adjustment\t: %d\n"
                   "PLL max +ve adjustment\t: %d\n"
                   "PLL max -ve adjustment\t: %d\n"
                   "PLL +ve adjustment factor\t: %d\n"
                   "PLL -ve adjustment factor\t: %d\n"
                   "PLL frequency\t: %ld\n",
                   pll.pll_value,
                   pll.pll_max,
                   pll.pll_min,
                   pll.pll_posmult,
                   pll.pll_negmult,
                   pll.pll_clock);
      return p - buf;
}

static int gen_rtc_read_proc(char *page, char **start, off_t off,
                       int count, int *eof, void *data)
{
      int len = gen_rtc_proc_output (page);
        if (len <= off+count) *eof = 1;
      *start = page + off;
      len -= off;
        if (len>count) len = count;
        if (len<0) len = 0;
      return len;
}

static int __init gen_rtc_proc_init(void)
{
      struct proc_dir_entry *r;

      r = create_proc_read_entry("driver/rtc", 0, NULL, gen_rtc_read_proc, NULL);
      if (!r)
            return -ENOMEM;
      return 0;
}
#else
static inline int gen_rtc_proc_init(void) { return 0; }
#endif /* CONFIG_PROC_FS */


/*
 *    The various file operations we support.
 */

static const struct file_operations gen_rtc_fops = {
      .owner            = THIS_MODULE,
#ifdef CONFIG_GEN_RTC_X
      .read       = gen_rtc_read,
      .poll       = gen_rtc_poll,
#endif
      .ioctl            = gen_rtc_ioctl,
      .open       = gen_rtc_open,
      .release    = gen_rtc_release,
};

static struct miscdevice rtc_gen_dev =
{
      .minor            = RTC_MINOR,
      .name       = "rtc",
      .fops       = &gen_rtc_fops,
};

static int __init rtc_generic_init(void)
{
      int retval;

      printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION);

      retval = misc_register(&rtc_gen_dev);
      if (retval < 0)
            return retval;

      retval = gen_rtc_proc_init();
      if (retval) {
            misc_deregister(&rtc_gen_dev);
            return retval;
      }

      return 0;
}

static void __exit rtc_generic_exit(void)
{
      remove_proc_entry ("driver/rtc", NULL);
      misc_deregister(&rtc_gen_dev);
}


module_init(rtc_generic_init);
module_exit(rtc_generic_exit);

MODULE_AUTHOR("Richard Zidlicky");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(RTC_MINOR);

Generated by  Doxygen 1.6.0   Back to index