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/*

 * RTC subsystem, dev interface

 *

 * Copyright (C) 2005 Tower Technologies

 * Author: Alessandro Zummo <a.zummo@towertech.it>

 *

 * based on arch/arm/common/rtctime.c

 *

 * 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/rtc.h>

#include "rtc-core.h"

static dev_t rtc_devt;

#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */

static int rtc_dev_open(struct inode *inode, struct file *file)

{

        int err;

        struct rtc_device *rtc = container_of(inode->i_cdev,

                                        struct rtc_device, char_dev);

        const struct rtc_class_ops *ops = rtc->ops;

        if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))

                return -EBUSY;

        file->private_data = rtc;

        err = ops->open ? ops->open(rtc->dev.parent) : 0;

        if (err == 0) {

                spin_lock_irq(&rtc->irq_lock);

                rtc->irq_data = 0;

                spin_unlock_irq(&rtc->irq_lock);

                return 0;

        }

        /* something has gone wrong */

        clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);

        return err;

}

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

/*

 * Routine to poll RTC seconds field for change as often as possible,

 * after first RTC_UIE use timer to reduce polling

 */

static void rtc_uie_task(struct work_struct *work)

{

        struct rtc_device *rtc =

                container_of(work, struct rtc_device, uie_task);

        struct rtc_time tm;

        int num = 0;

        int err;

        err = rtc_read_time(rtc, &tm);

        local_irq_disable();

        spin_lock(&rtc->irq_lock);

        if (rtc->stop_uie_polling || err) {

                rtc->uie_task_active = 0;

        } else if (rtc->oldsecs != tm.tm_sec) {

                num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;

                rtc->oldsecs = tm.tm_sec;

                rtc->uie_timer.expires = jiffies + HZ - (HZ/10);

                rtc->uie_timer_active = 1;

                rtc->uie_task_active = 0;

                add_timer(&rtc->uie_timer);

        } else if (schedule_work(&rtc->uie_task) == 0) {

                rtc->uie_task_active = 0;

        }

        spin_unlock(&rtc->irq_lock);

        if (num)

                rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF);

        local_irq_enable();

}

static void rtc_uie_timer(unsigned long data)

{

        struct rtc_device *rtc = (struct rtc_device *)data;

        unsigned long flags;

        spin_lock_irqsave(&rtc->irq_lock, flags);

        rtc->uie_timer_active = 0;

        rtc->uie_task_active = 1;

        if ((schedule_work(&rtc->uie_task) == 0))

                rtc->uie_task_active = 0;

        spin_unlock_irqrestore(&rtc->irq_lock, flags);

}

static void clear_uie(struct rtc_device *rtc)

{

        spin_lock_irq(&rtc->irq_lock);

        if (rtc->irq_active) {

                rtc->stop_uie_polling = 1;

                if (rtc->uie_timer_active) {

                        spin_unlock_irq(&rtc->irq_lock);

                        del_timer_sync(&rtc->uie_timer);

                        spin_lock_irq(&rtc->irq_lock);

                        rtc->uie_timer_active = 0;

                }

                if (rtc->uie_task_active) {

                        spin_unlock_irq(&rtc->irq_lock);

                        flush_scheduled_work();

                        spin_lock_irq(&rtc->irq_lock);

                }

                rtc->irq_active = 0;

        }

        spin_unlock_irq(&rtc->irq_lock);

}

static int set_uie(struct rtc_device *rtc)

{

        struct rtc_time tm;

        int err;

        err = rtc_read_time(rtc, &tm);

        if (err)

                return err;

        spin_lock_irq(&rtc->irq_lock);

        if (!rtc->irq_active) {

                rtc->irq_active = 1;

                rtc->stop_uie_polling = 0;

                rtc->oldsecs = tm.tm_sec;

                rtc->uie_task_active = 1;

                if (schedule_work(&rtc->uie_task) == 0)

                        rtc->uie_task_active = 0;

        }

        rtc->irq_data = 0;

        spin_unlock_irq(&rtc->irq_lock);

        return 0;

}

#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */

static ssize_t

rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)

{

        struct rtc_device *rtc = file->private_data;

        DECLARE_WAITQUEUE(wait, current);

        unsigned long data;

        ssize_t ret;

        if (count != sizeof(unsigned int) && count < sizeof(unsigned long))

                return -EINVAL;

        add_wait_queue(&rtc->irq_queue, &wait);

        do {

                __set_current_state(TASK_INTERRUPTIBLE);

                spin_lock_irq(&rtc->irq_lock);

                data = rtc->irq_data;

                rtc->irq_data = 0;

                spin_unlock_irq(&rtc->irq_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->irq_queue, &wait);

        if (ret == 0) {

                /* Check for any data updates */

                if (rtc->ops->read_callback)

                        data = rtc->ops->read_callback(rtc->dev.parent,

                                                       data);

                if (sizeof(int) != sizeof(long) &&

                    count == sizeof(unsigned int))

                        ret = put_user(data, (unsigned int __user *)buf) ?:

                                sizeof(unsigned int);

                else

                        ret = put_user(data, (unsigned long __user *)buf) ?:

                                sizeof(unsigned long);

        }

        return ret;

}

static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)

{

        struct rtc_device *rtc = file->private_data;

        unsigned long data;

        poll_wait(file, &rtc->irq_queue, wait);

        data = rtc->irq_data;

        return (data != 0) ? (POLLIN | POLLRDNORM) : 0;

}

static int rtc_dev_ioctl(struct inode *inode, struct file *file,

                unsigned int cmd, unsigned long arg)

{

        int err = 0;

        struct rtc_device *rtc = file->private_data;

        const struct rtc_class_ops *ops = rtc->ops;

        struct rtc_time tm;

        struct rtc_wkalrm alarm;

        void __user *uarg = (void __user *) arg;

        /* check that the calling task has appropriate permissions

         * for certain ioctls. doing this check here is useful

         * to avoid duplicate code in each driver.

         */

        switch (cmd) {

        case RTC_EPOCH_SET:

        case RTC_SET_TIME:

                if (!capable(CAP_SYS_TIME))

                        return -EACCES;

                break;

        case RTC_IRQP_SET:

                if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))

                        return -EACCES;

                break;

        case RTC_PIE_ON:

                if (rtc->irq_freq > rtc->max_user_freq &&

                                !capable(CAP_SYS_RESOURCE))

                        return -EACCES;

                break;

        }

        /* try the driver's ioctl interface */

        if (ops->ioctl) {

                err = ops->ioctl(rtc->dev.parent, cmd, arg);

                if (err != -ENOIOCTLCMD)

                        return err;

        }

        /* if the driver does not provide the ioctl interface

         * or if that particular ioctl was not implemented

         * (-ENOIOCTLCMD), we will try to emulate here.

         */

        switch (cmd) {

        case RTC_ALM_READ:

                err = rtc_read_alarm(rtc, &alarm);

                if (err < 0)

                        return err;

                if (copy_to_user(uarg, &alarm.time, sizeof(tm)))

                        return -EFAULT;

                break;

        case RTC_ALM_SET:

                if (copy_from_user(&alarm.time, uarg, sizeof(tm)))

                        return -EFAULT;

                alarm.enabled = 0;

                alarm.pending = 0;

                alarm.time.tm_wday = -1;

                alarm.time.tm_yday = -1;

                alarm.time.tm_isdst = -1;

                /* RTC_ALM_SET alarms may be up to 24 hours in the future.

                 * Rather than expecting every RTC to implement "don't care"

                 * for day/month/year fields, just force the alarm to have

                 * the right values for those fields.

                 *

                 * RTC_WKALM_SET should be used instead.  Not only does it

                 * eliminate the need for a separate RTC_AIE_ON call, it

                 * doesn't have the "alarm 23:59:59 in the future" race.

                 *

                 * NOTE:  some legacy code may have used invalid fields as

                 * wildcards, exposing hardware "periodic alarm" capabilities.

                 * Not supported here.

                 */

                {

                        unsigned long now, then;

                        err = rtc_read_time(rtc, &tm);

                        if (err < 0)

                                return err;

                        rtc_tm_to_time(&tm, &now);

                        alarm.time.tm_mday = tm.tm_mday;

                        alarm.time.tm_mon = tm.tm_mon;

                        alarm.time.tm_year = tm.tm_year;

                        err  = rtc_valid_tm(&alarm.time);

                        if (err < 0)

                                return err;

                        rtc_tm_to_time(&alarm.time, &then);

                        /* alarm may need to wrap into tomorrow */

                        if (then < now) {

                                rtc_time_to_tm(now + 24 * 60 * 60, &tm);

                                alarm.time.tm_mday = tm.tm_mday;

                                alarm.time.tm_mon = tm.tm_mon;

                                alarm.time.tm_year = tm.tm_year;

                        }

                }

                err = rtc_set_alarm(rtc, &alarm);

                break;

        case RTC_RD_TIME:

                err = rtc_read_time(rtc, &tm);

                if (err < 0)

                        return err;

                if (copy_to_user(uarg, &tm, sizeof(tm)))

                        return -EFAULT;

                break;

        case RTC_SET_TIME:

                if (copy_from_user(&tm, uarg, sizeof(tm)))

                        return -EFAULT;

                err = rtc_set_time(rtc, &tm);

                break;

        case RTC_PIE_ON:

                err = rtc_irq_set_state(rtc, NULL, 1);

                break;

        case RTC_PIE_OFF:

                err = rtc_irq_set_state(rtc, NULL, 0);

                break;

        case RTC_IRQP_SET:

                err = rtc_irq_set_freq(rtc, NULL, arg);

                break;

        case RTC_IRQP_READ:

                err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);

                break;

#if 0

        case RTC_EPOCH_SET:

#ifndef rtc_epoch

                /*

                 * There were no RTC clocks before 1900.

                 */

                if (arg < 1900) {

                        err = -EINVAL;

                        break;

                }

                rtc_epoch = arg;

                err = 0;

#endif

                break;

        case RTC_EPOCH_READ:

                err = put_user(rtc_epoch, (unsigned long __user *)uarg);

                break;

#endif

        case RTC_WKALM_SET:

                if (copy_from_user(&alarm, uarg, sizeof(alarm)))

                        return -EFAULT;

                err = rtc_set_alarm(rtc, &alarm);

                break;

        case RTC_WKALM_RD:

                err = rtc_read_alarm(rtc, &alarm);

                if (err < 0)

                        return err;

                if (copy_to_user(uarg, &alarm, sizeof(alarm)))

                        return -EFAULT;

                break;

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

        case RTC_UIE_OFF:

                clear_uie(rtc);

                return 0;

        case RTC_UIE_ON:

                return set_uie(rtc);

#endif

        default:

                err = -ENOTTY;

                break;

        }

        return err;

}

static int rtc_dev_release(struct inode *inode, struct file *file)

{

        struct rtc_device *rtc = file->private_data;

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

        clear_uie(rtc);

#endif

        if (rtc->ops->release)

                rtc->ops->release(rtc->dev.parent);

        clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);

        return 0;

}

static int rtc_dev_fasync(int fd, struct file *file, int on)

{

        struct rtc_device *rtc = file->private_data;

        return fasync_helper(fd, file, on, &rtc->async_queue);

}

static const struct file_operations rtc_dev_fops = {

        .owner          = THIS_MODULE,

        .llseek         = no_llseek,

        .read           = rtc_dev_read,

        .poll           = rtc_dev_poll,

        .ioctl          = rtc_dev_ioctl,

        .open           = rtc_dev_open,

        .release        = rtc_dev_release,

        .fasync         = rtc_dev_fasync,

};

/* insertion/removal hooks */

void rtc_dev_prepare(struct rtc_device *rtc)

{

        if (!rtc_devt)

                return;

        if (rtc->id >= RTC_DEV_MAX) {

                pr_debug("%s: too many RTC devices\n", rtc->name);

                return;

        }

        rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

        INIT_WORK(&rtc->uie_task, rtc_uie_task);

        setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);

#endif

        cdev_init(&rtc->char_dev, &rtc_dev_fops);

        rtc->char_dev.owner = rtc->owner;

}

void rtc_dev_add_device(struct rtc_device *rtc)

{

        if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))

                printk(KERN_WARNING "%s: failed to add char device %d:%d\n",

                        rtc->name, MAJOR(rtc_devt), rtc->id);

        else

                pr_debug("%s: dev (%d:%d)\n", rtc->name,

                        MAJOR(rtc_devt), rtc->id);

}

void rtc_dev_del_device(struct rtc_device *rtc)

{

        if (rtc->dev.devt)

                cdev_del(&rtc->char_dev);

}

void __init rtc_dev_init(void)

{

        int err;

        err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");

        if (err < 0)

                printk(KERN_ERR "%s: failed to allocate char dev region\n",

                        __FILE__);

}

void __exit rtc_dev_exit(void)

{

        if (rtc_devt)

                unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);

}