/*
   *	Industrial Computer Source PCI-WDT500/501 driver
   *

   *	(c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,

   *						All Rights Reserved.

   *
   *	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.
   *
   *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
   *	warranty for any of this software. This material is provided
   *	"AS-IS" and at no charge.
   *
   *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
   *
   *	Release 0.10.
   *
   *	Fixes
   *		Dave Gregorich	:	Modularisation and minor bugs
   *		Alan Cox	:	Added the watchdog ioctl() stuff
   *		Alan Cox	:	Fixed the reboot problem (as noted by
   *					Matt Crocker).
   *		Alan Cox	:	Added wdt= boot option
   *		Alan Cox	:	Cleaned up copy/user stuff
   *		Tim Hockin	:	Added insmod parameters, comment cleanup
   *					Parameterized timeout
   *		JP Nollmann	:	Added support for PCI wdt501p
   *		Alan Cox	:	Split ISA and PCI cards into two drivers
   *		Jeff Garzik	:	PCI cleanups

   *		Tigran Aivazian	:	Restructured wdtpci_init_one() to handle
   *					failures

   *		Joel Becker	:	Added WDIOC_GET/SETTIMEOUT

   *		Zwane Mwaikambo	:	Magic char closing, locking changes,
   *					cleanups

   *		Matt Domsch	:	nowayout module option
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/types.h>
  #include <linux/miscdevice.h>
  #include <linux/watchdog.h>
  #include <linux/ioport.h>

  #include <linux/delay.h>

  #include <linux/notifier.h>
  #include <linux/reboot.h>

  #include <linux/fs.h>
  #include <linux/pci.h>

  #include <linux/io.h>
  #include <linux/uaccess.h>

  
  #define WDT_IS_PCI
  #include "wd501p.h"

  /* We can only use 1 card due to the /dev/watchdog restriction */
  static int dev_count;

  static unsigned long open_lock;

  static DEFINE_SPINLOCK(wdtpci_lock);

  static char expect_close;

  static resource_size_t io;

  static int irq;
  
  /* Default timeout */
  #define WD_TIMO 60			/* Default heartbeat = 60 seconds */
  
  static int heartbeat = WD_TIMO;
  static int wd_heartbeat;
  module_param(heartbeat, int, 0);

  MODULE_PARM_DESC(heartbeat,
  		"Watchdog heartbeat in seconds. (0<heartbeat<65536, default="
  				__MODULE_STRING(WD_TIMO) ")");

  static bool nowayout = WATCHDOG_NOWAYOUT;
  module_param(nowayout, bool, 0);

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

  /* Support for the Fan Tachometer on the PCI-WDT501 */
  static int tachometer;

  module_param(tachometer, int, 0);

  MODULE_PARM_DESC(tachometer,

  		"PCI-WDT501 Fan Tachometer support (0=disable, default=0)");
  
  static int type = 500;
  module_param(type, int, 0);
  MODULE_PARM_DESC(type,
  		"PCI-WDT501 Card type (500 or 501 , default=500)");

  
  /*
   *	Programming support
   */
  
  static void wdtpci_ctr_mode(int ctr, int mode)
  {

  	ctr <<= 6;
  	ctr |= 0x30;
  	ctr |= (mode << 1);
  	outb(ctr, WDT_CR);
  	udelay(8);

  }
  
  static void wdtpci_ctr_load(int ctr, int val)
  {

  	outb(val & 0xFF, WDT_COUNT0 + ctr);
  	udelay(8);
  	outb(val >> 8, WDT_COUNT0 + ctr);
  	udelay(8);

  }
  
  /**
   *	wdtpci_start:
   *
   *	Start the watchdog driver.
   */
  
  static int wdtpci_start(void)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&wdtpci_lock, flags);
  
  	/*
  	 * "pet" the watchdog, as Access says.
  	 * This resets the clock outputs.
  	 */

  	inb(WDT_DC);			/* Disable watchdog */
  	udelay(8);
  	wdtpci_ctr_mode(2, 0);		/* Program CTR2 for Mode 0:
  						Pulse on Terminal Count */
  	outb(0, WDT_DC);		/* Enable watchdog */
  	udelay(8);
  	inb(WDT_DC);			/* Disable watchdog */
  	udelay(8);
  	outb(0, WDT_CLOCK);		/* 2.0833MHz clock */
  	udelay(8);
  	inb(WDT_BUZZER);		/* disable */
  	udelay(8);
  	inb(WDT_OPTONOTRST);		/* disable */
  	udelay(8);
  	inb(WDT_OPTORST);		/* disable */
  	udelay(8);
  	inb(WDT_PROGOUT);		/* disable */
  	udelay(8);
  	wdtpci_ctr_mode(0, 3);		/* Program CTR0 for Mode 3:
  						Square Wave Generator */
  	wdtpci_ctr_mode(1, 2);		/* Program CTR1 for Mode 2:
  						Rate Generator */
  	wdtpci_ctr_mode(2, 1);		/* Program CTR2 for Mode 1:
  						Retriggerable One-Shot */
  	wdtpci_ctr_load(0, 20833);	/* count at 100Hz */
  	wdtpci_ctr_load(1, wd_heartbeat);/* Heartbeat */

  	/* DO NOT LOAD CTR2 on PCI card! -- JPN */

  	outb(0, WDT_DC);		/* Enable watchdog */
  	udelay(8);

  
  	spin_unlock_irqrestore(&wdtpci_lock, flags);
  	return 0;
  }
  
  /**
   *	wdtpci_stop:
   *
   *	Stop the watchdog driver.
   */

  static int wdtpci_stop(void)

  {
  	unsigned long flags;
  
  	/* Turn the card off */
  	spin_lock_irqsave(&wdtpci_lock, flags);

  	inb(WDT_DC);			/* Disable watchdog */
  	udelay(8);
  	wdtpci_ctr_load(2, 0);		/* 0 length reset pulses now */

  	spin_unlock_irqrestore(&wdtpci_lock, flags);
  	return 0;
  }
  
  /**
   *	wdtpci_ping:
   *

   *	Reload counter one with the watchdog heartbeat. We don't bother
   *	reloading the cascade counter.

   */
  
  static int wdtpci_ping(void)
  {
  	unsigned long flags;

  	spin_lock_irqsave(&wdtpci_lock, flags);

  	/* Write a watchdog value */
  	inb(WDT_DC);			/* Disable watchdog */
  	udelay(8);
  	wdtpci_ctr_mode(1, 2);		/* Re-Program CTR1 for Mode 2:
  							Rate Generator */
  	wdtpci_ctr_load(1, wd_heartbeat);/* Heartbeat */
  	outb(0, WDT_DC);		/* Enable watchdog */
  	udelay(8);

  	spin_unlock_irqrestore(&wdtpci_lock, flags);
  	return 0;
  }
  
  /**
   *	wdtpci_set_heartbeat:
   *	@t:		the new heartbeat value that needs to be set.
   *

   *	Set a new heartbeat value for the watchdog device. If the heartbeat
   *	value is incorrect we keep the old value and return -EINVAL.
   *	If successful we return 0.

   */
  static int wdtpci_set_heartbeat(int t)
  {
  	/* Arbitrary, can't find the card's limits */

  	if (t < 1 || t > 65535)

  		return -EINVAL;
  
  	heartbeat = t;
  	wd_heartbeat = t * 100;
  	return 0;
  }
  
  /**
   *	wdtpci_get_status:
   *	@status:		the new status.
   *
   *	Extract the status information from a WDT watchdog device. There are
   *	several board variants so we have to know which bits are valid. Some
   *	bits default to one and some to zero in order to be maximally painful.
   *
   *	we then map the bits onto the status ioctl flags.
   */
  
  static int wdtpci_get_status(int *status)
  {

  	unsigned char new_status;
  	unsigned long flags;
  
  	spin_lock_irqsave(&wdtpci_lock, flags);
  	new_status = inb(WDT_SR);
  	spin_unlock_irqrestore(&wdtpci_lock, flags);

  	*status = 0;

  	if (new_status & WDC_SR_ISOI0)
  		*status |= WDIOF_EXTERN1;
  	if (new_status & WDC_SR_ISII1)
  		*status |= WDIOF_EXTERN2;

  	if (type == 501) {
  		if (!(new_status & WDC_SR_TGOOD))
  			*status |= WDIOF_OVERHEAT;
  		if (!(new_status & WDC_SR_PSUOVER))
  			*status |= WDIOF_POWEROVER;
  		if (!(new_status & WDC_SR_PSUUNDR))
  			*status |= WDIOF_POWERUNDER;
  		if (tachometer) {
  			if (!(new_status & WDC_SR_FANGOOD))
  				*status |= WDIOF_FANFAULT;
  		}

  	}

  	return 0;
  }

  /**
   *	wdtpci_get_temperature:
   *
   *	Reports the temperature in degrees Fahrenheit. The API is in
   *	farenheit. It was designed by an imperial measurement luddite.
   */
  
  static int wdtpci_get_temperature(int *temperature)
  {

  	unsigned short c;
  	unsigned long flags;
  	spin_lock_irqsave(&wdtpci_lock, flags);
  	c = inb(WDT_RT);
  	udelay(8);
  	spin_unlock_irqrestore(&wdtpci_lock, flags);

  	*temperature = (c * 11 / 15) + 7;
  	return 0;
  }

  
  /**
   *	wdtpci_interrupt:
   *	@irq:		Interrupt number
   *	@dev_id:	Unused as we don't allow multiple devices.

   *
   *	Handle an interrupt from the board. These are raised when the status
   *	map changes in what the board considers an interesting way. That means
   *	a failure condition occurring.
   */

  static irqreturn_t wdtpci_interrupt(int irq, void *dev_id)

  {
  	/*
  	 *	Read the status register see what is up and
  	 *	then printk it.
  	 */

  	unsigned char status;
  
  	spin_lock(&wdtpci_lock);
  
  	status = inb(WDT_SR);
  	udelay(8);

  	pr_crit("status %d
  ", status);

  	if (type == 501) {
  		if (!(status & WDC_SR_TGOOD)) {

  			pr_crit("Overheat alarm (%d)
  ", inb(WDT_RT));

  			udelay(8);
  		}
  		if (!(status & WDC_SR_PSUOVER))

  			pr_crit("PSU over voltage
  ");

  		if (!(status & WDC_SR_PSUUNDR))

  			pr_crit("PSU under voltage
  ");

  		if (tachometer) {
  			if (!(status & WDC_SR_FANGOOD))

  				pr_crit("Possible fan fault
  ");

  		}

  	}

  	if (!(status & WDC_SR_WCCR)) {

  #ifdef SOFTWARE_REBOOT
  #ifdef ONLY_TESTING

  		pr_crit("Would Reboot
  ");

  #else

  		pr_crit("Initiating system reboot
  ");

  		emergency_restart();

  #endif
  #else

  		pr_crit("Reset in 5ms
  ");

  #endif

  	}

  	spin_unlock(&wdtpci_lock);

  	return IRQ_HANDLED;
  }
  
  
  /**
   *	wdtpci_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 wdtpci_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;
  			}
  		}
  		wdtpci_ping();
  	}

  	return count;
  }
  
  /**
   *	wdtpci_ioctl:

   *	@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. We only actually usefully support
   *	querying capabilities and current status.
   */

  static long wdtpci_ioctl(struct file *file, unsigned int cmd,
  							unsigned long arg)

  {

  	void __user *argp = (void __user *)arg;
  	int __user *p = argp;

  	int new_heartbeat;
  	int status;

  	struct watchdog_info ident = {

  		.options =		WDIOF_SETTIMEOUT|
  					WDIOF_MAGICCLOSE|
  					WDIOF_KEEPALIVEPING,
  		.firmware_version =	1,
  		.identity =		"PCI-WDT500/501",
  	};
  
  	/* Add options according to the card we have */
  	ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);

  	if (type == 501) {
  		ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
  							WDIOF_POWEROVER);
  		if (tachometer)
  			ident.options |= WDIOF_FANFAULT;
  	}

  	switch (cmd) {

  	case WDIOC_GETSUPPORT:
  		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
  	case WDIOC_GETSTATUS:
  		wdtpci_get_status(&status);
  		return put_user(status, p);
  	case WDIOC_GETBOOTSTATUS:
  		return put_user(0, p);
  	case WDIOC_KEEPALIVE:
  		wdtpci_ping();
  		return 0;
  	case WDIOC_SETTIMEOUT:
  		if (get_user(new_heartbeat, p))
  			return -EFAULT;
  		if (wdtpci_set_heartbeat(new_heartbeat))
  			return -EINVAL;
  		wdtpci_ping();
  		/* Fall */
  	case WDIOC_GETTIMEOUT:
  		return put_user(heartbeat, p);

  	default:
  		return -ENOTTY;
  	}

  }
  
  /**
   *	wdtpci_open:
   *	@inode: inode of device
   *	@file: file handle to device
   *
   *	The watchdog device has been opened. The watchdog device is single
   *	open and on opening we load the counters. Counter zero is a 100Hz
   *	cascade, into counter 1 which downcounts to reboot. When the counter
   *	triggers counter 2 downcounts the length of the reset pulse which
   *	set set to be as long as possible.
   */
  
  static int wdtpci_open(struct inode *inode, struct file *file)
  {

  	if (test_and_set_bit(0, &open_lock))

  		return -EBUSY;

  	if (nowayout)

  		__module_get(THIS_MODULE);

  	/*
  	 *	Activate
  	 */
  	wdtpci_start();
  	return nonseekable_open(inode, file);
  }
  
  /**
   *	wdtpci_release:
   *	@inode: inode to board
   *	@file: file handle to board
   *
   *	The watchdog has a configurable API. There is a religious dispute
   *	between people who want their watchdog to be able to shut down and
   *	those who want to be sure if the watchdog manager dies the machine
   *	reboots. In the former case we disable the counters, in the latter
   *	case you have to open it again very soon.
   */
  
  static int wdtpci_release(struct inode *inode, struct file *file)
  {
  	if (expect_close == 42) {
  		wdtpci_stop();
  	} else {

  		pr_crit("Unexpected close, not stopping timer!
  ");

  		wdtpci_ping();
  	}
  	expect_close = 0;

  	clear_bit(0, &open_lock);

  	return 0;
  }

  /**
   *	wdtpci_temp_read:
   *	@file: file handle to the watchdog board
   *	@buf: buffer to write 1 byte into
   *	@count: length of buffer
   *	@ptr: offset (no seek allowed)
   *
   *	Read reports the temperature in degrees Fahrenheit. The API is in
   *	fahrenheit. It was designed by an imperial measurement luddite.
   */

  static ssize_t wdtpci_temp_read(struct file *file, char __user *buf,
  						size_t count, loff_t *ptr)

  {
  	int temperature;
  
  	if (wdtpci_get_temperature(&temperature))
  		return -EFAULT;

  	if (copy_to_user(buf, &temperature, 1))

  		return -EFAULT;
  
  	return 1;
  }
  
  /**
   *	wdtpci_temp_open:
   *	@inode: inode of device
   *	@file: file handle to device
   *
   *	The temperature device has been opened.
   */
  
  static int wdtpci_temp_open(struct inode *inode, struct file *file)
  {
  	return nonseekable_open(inode, file);
  }
  
  /**
   *	wdtpci_temp_release:
   *	@inode: inode to board
   *	@file: file handle to board
   *
   *	The temperature device has been closed.
   */
  
  static int wdtpci_temp_release(struct inode *inode, struct file *file)
  {
  	return 0;
  }

  
  /**
   *	notify_sys:
   *	@this: our notifier block
   *	@code: the event being reported
   *	@unused: unused
   *
   *	Our notifier is called on system shutdowns. We want to turn the card
   *	off at reboot otherwise the machine will reboot again during memory
   *	test or worse yet during the following fsck. This would suck, in fact
   *	trust me - if it happens it does suck.
   */
  
  static int wdtpci_notify_sys(struct notifier_block *this, unsigned long code,

  							void *unused)

  {

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

  		wdtpci_stop();

  	return NOTIFY_DONE;
  }
  
  /*
   *	Kernel Interfaces
   */

  static const struct file_operations wdtpci_fops = {

  	.owner		= THIS_MODULE,
  	.llseek		= no_llseek,
  	.write		= wdtpci_write,

  	.unlocked_ioctl	= wdtpci_ioctl,

  	.open		= wdtpci_open,
  	.release	= wdtpci_release,
  };
  
  static struct miscdevice wdtpci_miscdev = {
  	.minor	= WATCHDOG_MINOR,
  	.name	= "watchdog",
  	.fops	= &wdtpci_fops,
  };

  static const struct file_operations wdtpci_temp_fops = {

  	.owner		= THIS_MODULE,
  	.llseek		= no_llseek,
  	.read		= wdtpci_temp_read,
  	.open		= wdtpci_temp_open,
  	.release	= wdtpci_temp_release,
  };
  
  static struct miscdevice temp_miscdev = {
  	.minor	= TEMP_MINOR,
  	.name	= "temperature",
  	.fops	= &wdtpci_temp_fops,
  };

  
  /*
   *	The WDT card needs to learn about soft shutdowns in order to
   *	turn the timebomb registers off.
   */
  
  static struct notifier_block wdtpci_notifier = {
  	.notifier_call = wdtpci_notify_sys,
  };

  static int wdtpci_init_one(struct pci_dev *dev,

  					const struct pci_device_id *ent)

  {
  	int ret = -EIO;
  
  	dev_count++;
  	if (dev_count > 1) {

  		pr_err("This driver only supports one device
  ");

  		return -ENODEV;
  	}

  	if (type != 500 && type != 501) {

  		pr_err("unknown card type '%d'
  ", type);

  		return -ENODEV;
  	}

  	if (pci_enable_device(dev)) {

  		pr_err("Not possible to enable PCI Device
  ");

  		return -ENODEV;
  	}

  	if (pci_resource_start(dev, 2) == 0x0000) {

  		pr_err("No I/O-Address for card detected
  ");

  		ret = -ENODEV;
  		goto out_pci;
  	}

  	if (pci_request_region(dev, 2, "wdt_pci")) {

  		pr_err("I/O address 0x%llx already in use
  ",
  		       (unsigned long long)pci_resource_start(dev, 2));

  		goto out_pci;
  	}

  	irq = dev->irq;
  	io = pci_resource_start(dev, 2);

  	if (request_irq(irq, wdtpci_interrupt, IRQF_SHARED,

  			 "wdt_pci", &wdtpci_miscdev)) {

  		pr_err("IRQ %d is not free
  ", irq);

  		goto out_reg;
  	}

  	pr_info("PCI-WDT500/501 (PCI-WDG-CSM) driver 0.10 at 0x%llx (Interrupt %d)
  ",
  		(unsigned long long)io, irq);

  	/* Check that the heartbeat value is within its range;
  	   if not reset to the default */

  	if (wdtpci_set_heartbeat(heartbeat)) {
  		wdtpci_set_heartbeat(WD_TIMO);

  		pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d
  ",
  			WD_TIMO);

  	}

  	ret = register_reboot_notifier(&wdtpci_notifier);

  	if (ret) {

  		pr_err("cannot register reboot notifier (err=%d)
  ", ret);

  		goto out_irq;
  	}

  	if (type == 501) {
  		ret = misc_register(&temp_miscdev);
  		if (ret) {

  			pr_err("cannot register miscdev on minor=%d (err=%d)
  ",
  			       TEMP_MINOR, ret);

  			goto out_rbt;
  		}

  	}

  	ret = misc_register(&wdtpci_miscdev);

  	if (ret) {

  		pr_err("cannot register miscdev on minor=%d (err=%d)
  ",
  		       WATCHDOG_MINOR, ret);

  		goto out_misc;
  	}

  	pr_info("initialized. heartbeat=%d sec (nowayout=%d)
  ",

  		heartbeat, nowayout);

  	if (type == 501)

  		pr_info("Fan Tachometer is %s
  ",
  			tachometer ? "Enabled" : "Disabled");

  
  	ret = 0;
  out:
  	return ret;
  
  out_misc:

  	if (type == 501)
  		misc_deregister(&temp_miscdev);

  out_rbt:

  	unregister_reboot_notifier(&wdtpci_notifier);
  out_irq:
  	free_irq(irq, &wdtpci_miscdev);
  out_reg:

  	pci_release_region(dev, 2);

  out_pci:
  	pci_disable_device(dev);
  	goto out;
  }

  static void wdtpci_remove_one(struct pci_dev *pdev)

  {
  	/* here we assume only one device will ever have
  	 * been picked up and registered by probe function */
  	misc_deregister(&wdtpci_miscdev);

  	if (type == 501)
  		misc_deregister(&temp_miscdev);

  	unregister_reboot_notifier(&wdtpci_notifier);
  	free_irq(irq, &wdtpci_miscdev);

  	pci_release_region(pdev, 2);

  	pci_disable_device(pdev);
  	dev_count--;
  }

  static const struct pci_device_id wdtpci_pci_tbl[] = {

  	{
  		.vendor	   = PCI_VENDOR_ID_ACCESSIO,

  		.device	   = PCI_DEVICE_ID_ACCESSIO_WDG_CSM,

  		.subvendor = PCI_ANY_ID,
  		.subdevice = PCI_ANY_ID,
  	},
  	{ 0, }, /* terminate list */
  };
  MODULE_DEVICE_TABLE(pci, wdtpci_pci_tbl);
  
  
  static struct pci_driver wdtpci_driver = {
  	.name		= "wdt_pci",
  	.id_table	= wdtpci_pci_tbl,
  	.probe		= wdtpci_init_one,

  	.remove		= wdtpci_remove_one,

  };

  module_pci_driver(wdtpci_driver);

  
  MODULE_AUTHOR("JP Nollmann, Alan Cox");
  MODULE_DESCRIPTION("Driver for the ICS PCI-WDT500/501 watchdog cards");
  MODULE_LICENSE("GPL");