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/*

 *      Wdt977  0.04:   A Watchdog Device for Netwinder W83977AF chip

 *

 *      (c) Copyright 1998 Rebel.com (Woody Suwalski <woody@netwinder.org>)

 *

 *                      -----------------------

 *

 *      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.

 *

 *                      -----------------------

 *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>

 *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT

 *      19-Dec-2001 Woody Suwalski: Netwinder fixes, ioctl interface

 *      06-Jan-2002 Woody Suwalski: For compatibility, convert all timeouts

 *                                  from minutes to seconds.

 *      07-Jul-2003 Daniele Bellucci: Audit return code of misc_register in

 *                                    nwwatchdog_init.

 *      25-Oct-2005 Woody Suwalski: Convert addresses to #defs, add spinlocks

 *                                  remove limitiation to be used on Netwinders only

 */

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/miscdevice.h>

#include <linux/init.h>

#include <linux/ioport.h>

#include <linux/watchdog.h>

#include <linux/notifier.h>

#include <linux/reboot.h>

#include <asm/io.h>

#include <asm/system.h>

#include <asm/mach-types.h>

#include <asm/uaccess.h>

#define WATCHDOG_VERSION  "0.04"

#define WATCHDOG_NAME     "Wdt977"

#define PFX WATCHDOG_NAME ": "

#define DRIVER_VERSION    WATCHDOG_NAME " driver, v" WATCHDOG_VERSION "\n"

#define IO_INDEX_PORT   0x370           /* on some systems it can be 0x3F0 */

#define IO_DATA_PORT    (IO_INDEX_PORT+1)

#define UNLOCK_DATA     0x87

#define LOCK_DATA       0xAA

#define DEVICE_REGISTER 0x07

#define DEFAULT_TIMEOUT 60                      /* default timeout in seconds */

static  int timeout = DEFAULT_TIMEOUT;

static  int timeoutM;                           /* timeout in minutes */

static  unsigned long timer_alive;

static  int testmode;

static  char expect_close;

static  DEFINE_SPINLOCK(spinlock);

module_param(timeout, int, 0);

MODULE_PARM_DESC(timeout,"Watchdog timeout in seconds (60..15300), default=" __MODULE_STRING(DEFAULT_TIMEOUT) ")");

module_param(testmode, int, 0);

MODULE_PARM_DESC(testmode,"Watchdog testmode (1 = no reboot), default=0");

static int nowayout = WATCHDOG_NOWAYOUT;

module_param(nowayout, int, 0);

MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

/*

 * Start the watchdog

 */

static int wdt977_start(void)

{

        unsigned long flags;

        spin_lock_irqsave(&spinlock, flags);

        /* unlock the SuperIO chip */

        outb_p(UNLOCK_DATA, IO_INDEX_PORT);

        outb_p(UNLOCK_DATA, IO_INDEX_PORT);

        /* select device Aux2 (device=8) and set watchdog regs F2, F3 and F4

         * F2 has the timeout in minutes

         * F3 could be set to the POWER LED blink (with GP17 set to PowerLed)

         *   at timeout, and to reset timer on kbd/mouse activity (not impl.)

         * F4 is used to just clear the TIMEOUT'ed state (bit 0)

         */

        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);

        outb_p(0x08, IO_DATA_PORT);

        outb_p(0xF2, IO_INDEX_PORT);

        outb_p(timeoutM, IO_DATA_PORT);

        outb_p(0xF3, IO_INDEX_PORT);

        outb_p(0x00, IO_DATA_PORT);     /* another setting is 0E for kbd/mouse/LED */

        outb_p(0xF4, IO_INDEX_PORT);

        outb_p(0x00, IO_DATA_PORT);

        /* at last select device Aux1 (dev=7) and set GP16 as a watchdog output */

        /* in test mode watch the bit 1 on F4 to indicate "triggered" */

        if (!testmode)

        {

                outb_p(DEVICE_REGISTER, IO_INDEX_PORT);

                outb_p(0x07, IO_DATA_PORT);

                outb_p(0xE6, IO_INDEX_PORT);

                outb_p(0x08, IO_DATA_PORT);

        }

        /* lock the SuperIO chip */

        outb_p(LOCK_DATA, IO_INDEX_PORT);

        spin_unlock_irqrestore(&spinlock, flags);

        printk(KERN_INFO PFX "activated.\n");

        return 0;

}

/*

 * Stop the watchdog

 */

static int wdt977_stop(void)

{

        unsigned long flags;

        spin_lock_irqsave(&spinlock, flags);

        /* unlock the SuperIO chip */

        outb_p(UNLOCK_DATA, IO_INDEX_PORT);

        outb_p(UNLOCK_DATA, IO_INDEX_PORT);

        /* select device Aux2 (device=8) and set watchdog regs F2,F3 and F4

        * F3 is reset to its default state

        * F4 can clear the TIMEOUT'ed state (bit 0) - back to default

        * We can not use GP17 as a PowerLed, as we use its usage as a RedLed

        */

        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);

        outb_p(0x08, IO_DATA_PORT);

        outb_p(0xF2, IO_INDEX_PORT);

        outb_p(0xFF, IO_DATA_PORT);

        outb_p(0xF3, IO_INDEX_PORT);

        outb_p(0x00, IO_DATA_PORT);

        outb_p(0xF4, IO_INDEX_PORT);

        outb_p(0x00, IO_DATA_PORT);

        outb_p(0xF2, IO_INDEX_PORT);

        outb_p(0x00, IO_DATA_PORT);

        /* at last select device Aux1 (dev=7) and set GP16 as a watchdog output */

        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);

        outb_p(0x07, IO_DATA_PORT);

        outb_p(0xE6, IO_INDEX_PORT);

        outb_p(0x08, IO_DATA_PORT);

        /* lock the SuperIO chip */

        outb_p(LOCK_DATA, IO_INDEX_PORT);

        spin_unlock_irqrestore(&spinlock, flags);

        printk(KERN_INFO PFX "shutdown.\n");

        return 0;

}

/*

 * Send a keepalive ping to the watchdog

 * This is done by simply re-writing the timeout to reg. 0xF2

 */

static int wdt977_keepalive(void)

{

        unsigned long flags;

        spin_lock_irqsave(&spinlock, flags);

        /* unlock the SuperIO chip */

        outb_p(UNLOCK_DATA, IO_INDEX_PORT);

        outb_p(UNLOCK_DATA, IO_INDEX_PORT);

        /* select device Aux2 (device=8) and kicks watchdog reg F2 */

        /* F2 has the timeout in minutes */

        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);

        outb_p(0x08, IO_DATA_PORT);

        outb_p(0xF2, IO_INDEX_PORT);

        outb_p(timeoutM, IO_DATA_PORT);

        /* lock the SuperIO chip */

        outb_p(LOCK_DATA, IO_INDEX_PORT);

        spin_unlock_irqrestore(&spinlock, flags);

        return 0;

}

/*

 * Set the watchdog timeout value

 */

static int wdt977_set_timeout(int t)

{

        int tmrval;

        /* convert seconds to minutes, rounding up */

        tmrval = (t + 59) / 60;

        if (machine_is_netwinder()) {

                /* we have a hw bug somewhere, so each 977 minute is actually only 30sec

                 *  this limits the max timeout to half of device max of 255 minutes...

                 */

                tmrval += tmrval;

        }

        if ((tmrval < 1) || (tmrval > 255))

                return -EINVAL;

        /* timeout is the timeout in seconds, timeoutM is the timeout in minutes) */

        timeout = t;

        timeoutM = tmrval;

        return 0;

}

/*

 * Get the watchdog status

 */

static int wdt977_get_status(int *status)

{

        int new_status;

        unsigned long flags;

        spin_lock_irqsave(&spinlock, flags);

        /* unlock the SuperIO chip */

        outb_p(UNLOCK_DATA, IO_INDEX_PORT);

        outb_p(UNLOCK_DATA, IO_INDEX_PORT);

        /* select device Aux2 (device=8) and read watchdog reg F4 */

        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);

        outb_p(0x08, IO_DATA_PORT);

        outb_p(0xF4, IO_INDEX_PORT);

        new_status = inb_p(IO_DATA_PORT);

        /* lock the SuperIO chip */

        outb_p(LOCK_DATA, IO_INDEX_PORT);

        spin_unlock_irqrestore(&spinlock, flags);

        *status=0;

        if (new_status & 1)

                *status |= WDIOF_CARDRESET;

        return 0;

}

/*

 *      /dev/watchdog handling

 */

static int wdt977_open(struct inode *inode, struct file *file)

{

        /* If the watchdog is alive we don't need to start it again */

        if( test_and_set_bit(0,&timer_alive) )

                return -EBUSY;

        if (nowayout)

                __module_get(THIS_MODULE);

        wdt977_start();

        return nonseekable_open(inode, file);

}

static int wdt977_release(struct inode *inode, struct file *file)

{

        /*

         *      Shut off the timer.

         *      Lock it in if it's a module and we set nowayout

         */

        if (expect_close == 42)

        {

                wdt977_stop();

                clear_bit(0,&timer_alive);

        } else {

                wdt977_keepalive();

                printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");

        }

        expect_close = 0;

        return 0;

}

/*

 *      wdt977_write:

 *      @file: file handle to the watchdog

 *      @buf: buffer to write (unused as data does not matter here

 *      @count: count of bytes

 *      @ppos: pointer to the position to write. No seeks allowed

 *

 *      A write to a watchdog device is defined as a keepalive signal. Any

 *      write of data will do, as we we don't define content meaning.

 */

static ssize_t wdt977_write(struct file *file, const char __user *buf,

                            size_t count, loff_t *ppos)

{

        if (count)

        {

                if (!nowayout)

                {

                        size_t i;

                        /* In case it was set long ago */

                        expect_close = 0;

                        for (i = 0; i != count; i++)

                        {

                                char c;

                                if (get_user(c, buf + i))

                                        return -EFAULT;

                                if (c == 'V')

                                        expect_close = 42;

                        }

                }

                /* someone wrote to us, we should restart timer */

                wdt977_keepalive();

        }

        return count;

}

/*

 *      wdt977_ioctl:

 *      @inode: inode of the device

 *      @file: file handle to the device

 *      @cmd: watchdog command

 *      @arg: argument pointer

 *

 *      The watchdog API defines a common set of functions for all watchdogs

 *      according to their available features.

 */

static struct watchdog_info ident = {

        .options =              WDIOF_SETTIMEOUT |

                                WDIOF_MAGICCLOSE |

                                WDIOF_KEEPALIVEPING,

        .firmware_version =     1,

        .identity =             WATCHDOG_NAME,

};

static int wdt977_ioctl(struct inode *inode, struct file *file,

        unsigned int cmd, unsigned long arg)

{

        int status;

        int new_options, retval = -EINVAL;

        int new_timeout;

        union {

                struct watchdog_info __user *ident;

                int __user *i;

        } uarg;

        uarg.i = (int __user *)arg;

        switch(cmd)

        {

        default:

                return -ENOTTY;

        case WDIOC_GETSUPPORT:

                return copy_to_user(uarg.ident, &ident,

                        sizeof(ident)) ? -EFAULT : 0;

        case WDIOC_GETSTATUS:

                wdt977_get_status(&status);

                return put_user(status, uarg.i);

        case WDIOC_GETBOOTSTATUS:

                return put_user(0, uarg.i);

        case WDIOC_KEEPALIVE:

                wdt977_keepalive();

                return 0;

        case WDIOC_SETOPTIONS:

                if (get_user (new_options, uarg.i))

                        return -EFAULT;

                if (new_options & WDIOS_DISABLECARD) {

                        wdt977_stop();

                        retval = 0;

                }

                if (new_options & WDIOS_ENABLECARD) {

                        wdt977_start();

                        retval = 0;

                }

                return retval;

        case WDIOC_SETTIMEOUT:

                if (get_user(new_timeout, uarg.i))

                        return -EFAULT;

                if (wdt977_set_timeout(new_timeout))

                    return -EINVAL;

                wdt977_keepalive();

                /* Fall */

        case WDIOC_GETTIMEOUT:

                return put_user(timeout, uarg.i);

        }

}

static int wdt977_notify_sys(struct notifier_block *this, unsigned long code,

        void *unused)

{

        if(code==SYS_DOWN || code==SYS_HALT)

                wdt977_stop();

        return NOTIFY_DONE;

}

static const struct file_operations wdt977_fops=

{

        .owner          = THIS_MODULE,

        .llseek         = no_llseek,

        .write          = wdt977_write,

        .ioctl          = wdt977_ioctl,

        .open           = wdt977_open,

        .release        = wdt977_release,

};

static struct miscdevice wdt977_miscdev=

{

        .minor          = WATCHDOG_MINOR,

        .name           = "watchdog",

        .fops           = &wdt977_fops,

};

static struct notifier_block wdt977_notifier = {

        .notifier_call = wdt977_notify_sys,

};

static int __init wd977_init(void)

{

        int rc;

        //if (!machine_is_netwinder())

        //      return -ENODEV;

        printk(KERN_INFO PFX DRIVER_VERSION);

        /* Check that the timeout value is within it's range ; if not reset to the default */

        if (wdt977_set_timeout(timeout))

        {

                wdt977_set_timeout(DEFAULT_TIMEOUT);

                printk(KERN_INFO PFX "timeout value must be 60<timeout<15300, using %d\n",

                        DEFAULT_TIMEOUT);

        }

        /* on Netwinder the IOports are already reserved by

         * arch/arm/mach-footbridge/netwinder-hw.c

         */

        if (!machine_is_netwinder())

        {

                if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME))

                {

                        printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",

                                IO_INDEX_PORT);

                        rc = -EIO;

                        goto err_out;

                }

        }

        rc = misc_register(&wdt977_miscdev);

        if (rc)

        {

                printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",

                        wdt977_miscdev.minor, rc);

                goto err_out_region;

        }

        rc = register_reboot_notifier(&wdt977_notifier);

        if (rc)

        {

                printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",

                        rc);

                goto err_out_miscdev;

        }

        printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d, testmode=%i)\n",

                timeout, nowayout, testmode);

        return 0;

err_out_miscdev:

        misc_deregister(&wdt977_miscdev);

err_out_region:

        if (!machine_is_netwinder())

                release_region(IO_INDEX_PORT,2);

err_out:

        return rc;

}

static void __exit wd977_exit(void)

{

        wdt977_stop();

        misc_deregister(&wdt977_miscdev);

        unregister_reboot_notifier(&wdt977_notifier);

        release_region(IO_INDEX_PORT,2);

}

module_init(wd977_init);

module_exit(wd977_exit);

MODULE_AUTHOR("Woody Suwalski <woodys@xandros.com>");

MODULE_DESCRIPTION("W83977AF Watchdog driver");

MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);