/*
   * RDC321x watchdog driver
   *

   * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>

   *
   * This driver is highly inspired from the cpu5_wdt driver
   *
   * 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.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   *
   */
  
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/types.h>
  #include <linux/errno.h>
  #include <linux/miscdevice.h>
  #include <linux/fs.h>
  #include <linux/init.h>
  #include <linux/ioport.h>
  #include <linux/timer.h>
  #include <linux/completion.h>
  #include <linux/jiffies.h>
  #include <linux/platform_device.h>
  #include <linux/watchdog.h>
  #include <linux/io.h>
  #include <linux/uaccess.h>

  #include <linux/mfd/rdc321x.h>

  
  #define RDC_WDT_MASK	0x80000000 /* Mask */
  #define RDC_WDT_EN	0x00800000 /* Enable bit */
  #define RDC_WDT_WTI	0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
  #define RDC_WDT_RST	0x00100000 /* Reset bit */
  #define RDC_WDT_WIF	0x00040000 /* WDT IRQ Flag */
  #define RDC_WDT_IRT	0x00000100 /* IRQ Routing table */
  #define RDC_WDT_CNT	0x00000001 /* WDT count */
  
  #define RDC_CLS_TMR	0x80003844 /* Clear timer */
  
  #define RDC_WDT_INTERVAL	(HZ/10+1)
  
  static int ticks = 1000;
  
  /* some device data */
  
  static struct {
  	struct completion stop;
  	int running;
  	struct timer_list timer;
  	int queue;
  	int default_ticks;
  	unsigned long inuse;
  	spinlock_t lock;

  	struct pci_dev *sb_pdev;
  	int base_reg;

  } rdc321x_wdt_device;
  
  /* generic helper functions */
  
  static void rdc321x_wdt_trigger(unsigned long unused)
  {
  	unsigned long flags;

  	u32 val;

  
  	if (rdc321x_wdt_device.running)
  		ticks--;
  
  	/* keep watchdog alive */
  	spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);

  	pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
  					rdc321x_wdt_device.base_reg, &val);
  	val |= RDC_WDT_EN;
  	pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
  					rdc321x_wdt_device.base_reg, val);

  	spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
  
  	/* requeue?? */
  	if (rdc321x_wdt_device.queue && ticks)
  		mod_timer(&rdc321x_wdt_device.timer,
  				jiffies + RDC_WDT_INTERVAL);
  	else {
  		/* ticks doesn't matter anyway */
  		complete(&rdc321x_wdt_device.stop);
  	}
  
  }
  
  static void rdc321x_wdt_reset(void)
  {
  	ticks = rdc321x_wdt_device.default_ticks;
  }
  
  static void rdc321x_wdt_start(void)
  {
  	unsigned long flags;
  
  	if (!rdc321x_wdt_device.queue) {
  		rdc321x_wdt_device.queue = 1;
  
  		/* Clear the timer */
  		spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);

  		pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
  				rdc321x_wdt_device.base_reg, RDC_CLS_TMR);

  
  		/* Enable watchdog and set the timeout to 81.92 us */

  		pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
  					rdc321x_wdt_device.base_reg,
  					RDC_WDT_EN | RDC_WDT_CNT);

  		spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
  
  		mod_timer(&rdc321x_wdt_device.timer,
  				jiffies + RDC_WDT_INTERVAL);
  	}
  
  	/* if process dies, counter is not decremented */
  	rdc321x_wdt_device.running++;
  }
  
  static int rdc321x_wdt_stop(void)
  {
  	if (rdc321x_wdt_device.running)
  		rdc321x_wdt_device.running = 0;
  
  	ticks = rdc321x_wdt_device.default_ticks;
  
  	return -EIO;
  }
  
  /* filesystem operations */
  static int rdc321x_wdt_open(struct inode *inode, struct file *file)
  {
  	if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
  		return -EBUSY;
  
  	return nonseekable_open(inode, file);
  }
  
  static int rdc321x_wdt_release(struct inode *inode, struct file *file)
  {
  	clear_bit(0, &rdc321x_wdt_device.inuse);
  	return 0;
  }

  static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
  				unsigned long arg)

  {
  	void __user *argp = (void __user *)arg;

  	u32 value;

  	static const struct watchdog_info ident = {

  		.options = WDIOF_CARDRESET,
  		.identity = "RDC321x WDT",
  	};
  	unsigned long flags;
  
  	switch (cmd) {
  	case WDIOC_KEEPALIVE:
  		rdc321x_wdt_reset();
  		break;
  	case WDIOC_GETSTATUS:
  		/* Read the value from the DATA register */
  		spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);

  		pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
  					rdc321x_wdt_device.base_reg, &value);

  		spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);

  		if (copy_to_user(argp, &value, sizeof(u32)))

  			return -EFAULT;
  		break;
  	case WDIOC_GETSUPPORT:
  		if (copy_to_user(argp, &ident, sizeof(ident)))
  			return -EFAULT;
  		break;
  	case WDIOC_SETOPTIONS:
  		if (copy_from_user(&value, argp, sizeof(int)))
  			return -EFAULT;
  		switch (value) {
  		case WDIOS_ENABLECARD:
  			rdc321x_wdt_start();
  			break;
  		case WDIOS_DISABLECARD:
  			return rdc321x_wdt_stop();
  		default:
  			return -EINVAL;
  		}
  		break;
  	default:
  		return -ENOTTY;
  	}
  	return 0;
  }
  
  static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
  				size_t count, loff_t *ppos)
  {
  	if (!count)
  		return -EIO;
  
  	rdc321x_wdt_reset();
  
  	return count;
  }
  
  static const struct file_operations rdc321x_wdt_fops = {
  	.owner		= THIS_MODULE,
  	.llseek		= no_llseek,

  	.unlocked_ioctl	= rdc321x_wdt_ioctl,

  	.open		= rdc321x_wdt_open,
  	.write		= rdc321x_wdt_write,
  	.release	= rdc321x_wdt_release,
  };
  
  static struct miscdevice rdc321x_wdt_misc = {
  	.minor	= WATCHDOG_MINOR,
  	.name	= "watchdog",
  	.fops	= &rdc321x_wdt_fops,
  };
  
  static int __devinit rdc321x_wdt_probe(struct platform_device *pdev)
  {
  	int err;

  	struct resource *r;
  	struct rdc321x_wdt_pdata *pdata;

  	pdata = pdev->dev.platform_data;

  	if (!pdata) {
  		dev_err(&pdev->dev, "no platform data supplied
  ");
  		return -ENODEV;
  	}

  	r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");

  	if (!r) {
  		dev_err(&pdev->dev, "failed to get wdt-reg resource
  ");
  		return -ENODEV;
  	}
  
  	rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
  	rdc321x_wdt_device.base_reg = r->start;

  
  	err = misc_register(&rdc321x_wdt_misc);
  	if (err < 0) {

  		dev_err(&pdev->dev, "misc_register failed
  ");

  		return err;
  	}
  
  	spin_lock_init(&rdc321x_wdt_device.lock);
  
  	/* Reset the watchdog */

  	pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
  				rdc321x_wdt_device.base_reg, RDC_WDT_RST);

  
  	init_completion(&rdc321x_wdt_device.stop);
  	rdc321x_wdt_device.queue = 0;
  
  	clear_bit(0, &rdc321x_wdt_device.inuse);
  
  	setup_timer(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
  
  	rdc321x_wdt_device.default_ticks = ticks;

  	dev_info(&pdev->dev, "watchdog init success
  ");

  
  	return 0;
  }

  static int __devexit rdc321x_wdt_remove(struct platform_device *pdev)

  {
  	if (rdc321x_wdt_device.queue) {
  		rdc321x_wdt_device.queue = 0;
  		wait_for_completion(&rdc321x_wdt_device.stop);
  	}
  
  	misc_deregister(&rdc321x_wdt_misc);
  
  	return 0;
  }
  
  static struct platform_driver rdc321x_wdt_driver = {
  	.probe = rdc321x_wdt_probe,

  	.remove = __devexit_p(rdc321x_wdt_remove),

  	.driver = {
  		.owner = THIS_MODULE,
  		.name = "rdc321x-wdt",
  	},
  };

  module_platform_driver(rdc321x_wdt_driver);

  
  MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
  MODULE_DESCRIPTION("RDC321x watchdog driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);