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rtctime.c

/*
 *  linux/arch/arm/common/rtctime.c
 *
 *  Copyright (C) 2003 Deep Blue Solutions Ltd.
 *  Based on sa1100-rtc.c, Nils Faerber, CIH, Nicolas Pitre.
 *  Based on rtc.c by Paul Gortmaker
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/miscdevice.h>
#include <linux/spinlock.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/mutex.h>

#include <asm/rtc.h>

static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
static struct fasync_struct *rtc_async_queue;

/*
 * rtc_lock protects rtc_irq_data
 */
static DEFINE_SPINLOCK(rtc_lock);
static unsigned long rtc_irq_data;

/*
 * rtc_sem protects rtc_inuse and rtc_ops
 */
static DEFINE_MUTEX(rtc_mutex);
static unsigned long rtc_inuse;
static struct rtc_ops *rtc_ops;

#define rtc_epoch 1900UL

/*
 * Calculate the next alarm time given the requested alarm time mask
 * and the current time.
 */
void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, struct rtc_time *alrm)
{
      unsigned long next_time;
      unsigned long now_time;

      next->tm_year = now->tm_year;
      next->tm_mon = now->tm_mon;
      next->tm_mday = now->tm_mday;
      next->tm_hour = alrm->tm_hour;
      next->tm_min = alrm->tm_min;
      next->tm_sec = alrm->tm_sec;

      rtc_tm_to_time(now, &now_time);
      rtc_tm_to_time(next, &next_time);

      if (next_time < now_time) {
            /* Advance one day */
            next_time += 60 * 60 * 24;
            rtc_time_to_tm(next_time, next);
      }
}
EXPORT_SYMBOL(rtc_next_alarm_time);

static inline int rtc_arm_read_time(struct rtc_ops *ops, struct rtc_time *tm)
{
      memset(tm, 0, sizeof(struct rtc_time));
      return ops->read_time(tm);
}

static inline int rtc_arm_set_time(struct rtc_ops *ops, struct rtc_time *tm)
{
      int ret;

      ret = rtc_valid_tm(tm);
      if (ret == 0)
            ret = ops->set_time(tm);

      return ret;
}

static inline int rtc_arm_read_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
{
      int ret = -EINVAL;
      if (ops->read_alarm) {
            memset(alrm, 0, sizeof(struct rtc_wkalrm));
            ret = ops->read_alarm(alrm);
      }
      return ret;
}

static inline int rtc_arm_set_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
{
      int ret = -EINVAL;
      if (ops->set_alarm)
            ret = ops->set_alarm(alrm);
      return ret;
}

void rtc_update(unsigned long num, unsigned long events)
{
      spin_lock(&rtc_lock);
      rtc_irq_data = (rtc_irq_data + (num << 8)) | events;
      spin_unlock(&rtc_lock);

      wake_up_interruptible(&rtc_wait);
      kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
}
EXPORT_SYMBOL(rtc_update);


static ssize_t
rtc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
      DECLARE_WAITQUEUE(wait, current);
      unsigned long data;
      ssize_t ret;

      if (count < sizeof(unsigned long))
            return -EINVAL;

      add_wait_queue(&rtc_wait, &wait);
      do {
            __set_current_state(TASK_INTERRUPTIBLE);

            spin_lock_irq(&rtc_lock);
            data = rtc_irq_data;
            rtc_irq_data = 0;
            spin_unlock_irq(&rtc_lock);

            if (data != 0) {
                  ret = 0;
                  break;
            }
            if (file->f_flags & O_NONBLOCK) {
                  ret = -EAGAIN;
                  break;
            }
            if (signal_pending(current)) {
                  ret = -ERESTARTSYS;
                  break;
            }
            schedule();
      } while (1);
      set_current_state(TASK_RUNNING);
      remove_wait_queue(&rtc_wait, &wait);

      if (ret == 0) {
            ret = put_user(data, (unsigned long __user *)buf);
            if (ret == 0)
                  ret = sizeof(unsigned long);
      }
      return ret;
}

static unsigned int rtc_poll(struct file *file, poll_table *wait)
{
      unsigned long data;

      poll_wait(file, &rtc_wait, wait);

      spin_lock_irq(&rtc_lock);
      data = rtc_irq_data;
      spin_unlock_irq(&rtc_lock);

      return data != 0 ? POLLIN | POLLRDNORM : 0;
}

static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
                 unsigned long arg)
{
      struct rtc_ops *ops = file->private_data;
      struct rtc_time tm;
      struct rtc_wkalrm alrm;
      void __user *uarg = (void __user *)arg;
      int ret = -EINVAL;

      switch (cmd) {
      case RTC_ALM_READ:
            ret = rtc_arm_read_alarm(ops, &alrm);
            if (ret)
                  break;
            ret = copy_to_user(uarg, &alrm.time, sizeof(tm));
            if (ret)
                  ret = -EFAULT;
            break;

      case RTC_ALM_SET:
            ret = copy_from_user(&alrm.time, uarg, sizeof(tm));
            if (ret) {
                  ret = -EFAULT;
                  break;
            }
            alrm.enabled = 0;
            alrm.pending = 0;
            alrm.time.tm_mday = -1;
            alrm.time.tm_mon = -1;
            alrm.time.tm_year = -1;
            alrm.time.tm_wday = -1;
            alrm.time.tm_yday = -1;
            alrm.time.tm_isdst = -1;
            ret = rtc_arm_set_alarm(ops, &alrm);
            break;

      case RTC_RD_TIME:
            ret = rtc_arm_read_time(ops, &tm);
            if (ret)
                  break;
            ret = copy_to_user(uarg, &tm, sizeof(tm));
            if (ret)
                  ret = -EFAULT;
            break;

      case RTC_SET_TIME:
            if (!capable(CAP_SYS_TIME)) {
                  ret = -EACCES;
                  break;
            }
            ret = copy_from_user(&tm, uarg, sizeof(tm));
            if (ret) {
                  ret = -EFAULT;
                  break;
            }
            ret = rtc_arm_set_time(ops, &tm);
            break;

      case RTC_EPOCH_SET:
#ifndef rtc_epoch
            /*
             * There were no RTC clocks before 1900.
             */
            if (arg < 1900) {
                  ret = -EINVAL;
                  break;
            }
            if (!capable(CAP_SYS_TIME)) {
                  ret = -EACCES;
                  break;
            }
            rtc_epoch = arg;
            ret = 0;
#endif
            break;

      case RTC_EPOCH_READ:
            ret = put_user(rtc_epoch, (unsigned long __user *)uarg);
            break;

      case RTC_WKALM_SET:
            ret = copy_from_user(&alrm, uarg, sizeof(alrm));
            if (ret) {
                  ret = -EFAULT;
                  break;
            }
            ret = rtc_arm_set_alarm(ops, &alrm);
            break;

      case RTC_WKALM_RD:
            ret = rtc_arm_read_alarm(ops, &alrm);
            if (ret)
                  break;
            ret = copy_to_user(uarg, &alrm, sizeof(alrm));
            if (ret)
                  ret = -EFAULT;
            break;

      default:
            if (ops->ioctl)
                  ret = ops->ioctl(cmd, arg);
            break;
      }
      return ret;
}

static int rtc_open(struct inode *inode, struct file *file)
{
      int ret;

      mutex_lock(&rtc_mutex);

      if (rtc_inuse) {
            ret = -EBUSY;
      } else if (!rtc_ops || !try_module_get(rtc_ops->owner)) {
            ret = -ENODEV;
      } else {
            file->private_data = rtc_ops;

            ret = rtc_ops->open ? rtc_ops->open() : 0;
            if (ret == 0) {
                  spin_lock_irq(&rtc_lock);
                  rtc_irq_data = 0;
                  spin_unlock_irq(&rtc_lock);

                  rtc_inuse = 1;
            }
      }
      mutex_unlock(&rtc_mutex);

      return ret;
}

static int rtc_release(struct inode *inode, struct file *file)
{
      struct rtc_ops *ops = file->private_data;

      if (ops->release)
            ops->release();

      spin_lock_irq(&rtc_lock);
      rtc_irq_data = 0;
      spin_unlock_irq(&rtc_lock);

      module_put(rtc_ops->owner);
      rtc_inuse = 0;

      return 0;
}

static int rtc_fasync(int fd, struct file *file, int on)
{
      return fasync_helper(fd, file, on, &rtc_async_queue);
}

static const struct file_operations rtc_fops = {
      .owner            = THIS_MODULE,
      .llseek           = no_llseek,
      .read       = rtc_read,
      .poll       = rtc_poll,
      .ioctl            = rtc_ioctl,
      .open       = rtc_open,
      .release    = rtc_release,
      .fasync           = rtc_fasync,
};

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


static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data)
{
      struct rtc_ops *ops = data;
      struct rtc_wkalrm alrm;
      struct rtc_time tm;
      char *p = page;

      if (rtc_arm_read_time(ops, &tm) == 0) {
            p += sprintf(p,
                  "rtc_time\t: %02d:%02d:%02d\n"
                  "rtc_date\t: %04d-%02d-%02d\n"
                  "rtc_epoch\t: %04lu\n",
                  tm.tm_hour, tm.tm_min, tm.tm_sec,
                  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
                  rtc_epoch);
      }

      if (rtc_arm_read_alarm(ops, &alrm) == 0) {
            p += sprintf(p, "alrm_time\t: ");
            if ((unsigned int)alrm.time.tm_hour <= 24)
                  p += sprintf(p, "%02d:", alrm.time.tm_hour);
            else
                  p += sprintf(p, "**:");
            if ((unsigned int)alrm.time.tm_min <= 59)
                  p += sprintf(p, "%02d:", alrm.time.tm_min);
            else
                  p += sprintf(p, "**:");
            if ((unsigned int)alrm.time.tm_sec <= 59)
                  p += sprintf(p, "%02d\n", alrm.time.tm_sec);
            else
                  p += sprintf(p, "**\n");

            p += sprintf(p, "alrm_date\t: ");
            if ((unsigned int)alrm.time.tm_year <= 200)
                  p += sprintf(p, "%04d-", alrm.time.tm_year + 1900);
            else
                  p += sprintf(p, "****-");
            if ((unsigned int)alrm.time.tm_mon <= 11)
                  p += sprintf(p, "%02d-", alrm.time.tm_mon + 1);
            else
                  p += sprintf(p, "**-");
            if ((unsigned int)alrm.time.tm_mday <= 31)
                  p += sprintf(p, "%02d\n", alrm.time.tm_mday);
            else
                  p += sprintf(p, "**\n");
            p += sprintf(p, "alrm_wakeup\t: %s\n",
                       alrm.enabled ? "yes" : "no");
            p += sprintf(p, "alrm_pending\t: %s\n",
                       alrm.pending ? "yes" : "no");
      }

      if (ops->proc)
            p += ops->proc(p);

      return p - page;
}

int register_rtc(struct rtc_ops *ops)
{
      int ret = -EBUSY;

      mutex_lock(&rtc_mutex);
      if (rtc_ops == NULL) {
            rtc_ops = ops;

            ret = misc_register(&rtc_miscdev);
            if (ret == 0)
                  create_proc_read_entry("driver/rtc", 0, NULL,
                                     rtc_read_proc, ops);
      }
      mutex_unlock(&rtc_mutex);

      return ret;
}
EXPORT_SYMBOL(register_rtc);

void unregister_rtc(struct rtc_ops *rtc)
{
      mutex_lock(&rtc_mutex);
      if (rtc == rtc_ops) {
            remove_proc_entry("driver/rtc", NULL);
            misc_deregister(&rtc_miscdev);
            rtc_ops = NULL;
      }
      mutex_unlock(&rtc_mutex);
}
EXPORT_SYMBOL(unregister_rtc);

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