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kernel/linux-imx6_3.14.28/drivers/watchdog/retu_wdt.c 4.5 KB
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  /*
   * Retu watchdog driver
   *
   * Copyright (C) 2004, 2005 Nokia Corporation
   *
   * Based on code written by Amit Kucheria and Michael Buesch.
   * Rewritten by Aaro Koskinen.
   *
   * This file is subject to the terms and conditions of the GNU General
   * Public License. See the file "COPYING" in the main directory of this
   * archive for more details.
   *
   * 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.
   */
  
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/errno.h>
  #include <linux/device.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/mfd/retu.h>
  #include <linux/watchdog.h>
  #include <linux/platform_device.h>
  
  /* Watchdog timer values in seconds */
  #define RETU_WDT_MAX_TIMER	63
  
  struct retu_wdt_dev {
  	struct retu_dev		*rdev;
  	struct device		*dev;
  	struct delayed_work	ping_work;
  };
  
  /*
   * Since Retu watchdog cannot be disabled in hardware, we must kick it
   * with a timer until userspace watchdog software takes over. If
   * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
   */
  static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
  {
  	retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
  	schedule_delayed_work(&wdev->ping_work,
  			round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
  }
  
  static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
  {
  	retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
  	cancel_delayed_work_sync(&wdev->ping_work);
  }
  
  static void retu_wdt_ping_work(struct work_struct *work)
  {
  	struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
  						struct retu_wdt_dev, ping_work);
  	retu_wdt_ping_enable(wdev);
  }
  
  static int retu_wdt_start(struct watchdog_device *wdog)
  {
  	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  
  	retu_wdt_ping_disable(wdev);
  
  	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  }
  
  static int retu_wdt_stop(struct watchdog_device *wdog)
  {
  	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  
  	retu_wdt_ping_enable(wdev);
  
  	return 0;
  }
  
  static int retu_wdt_ping(struct watchdog_device *wdog)
  {
  	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  
  	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  }
  
  static int retu_wdt_set_timeout(struct watchdog_device *wdog,
  				unsigned int timeout)
  {
  	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  
  	wdog->timeout = timeout;
  	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  }
  
  static const struct watchdog_info retu_wdt_info = {
  	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
  	.identity = "Retu watchdog",
  };
  
  static const struct watchdog_ops retu_wdt_ops = {
  	.owner		= THIS_MODULE,
  	.start		= retu_wdt_start,
  	.stop		= retu_wdt_stop,
  	.ping		= retu_wdt_ping,
  	.set_timeout	= retu_wdt_set_timeout,
  };
  
  static int retu_wdt_probe(struct platform_device *pdev)
  {
  	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
  	bool nowayout = WATCHDOG_NOWAYOUT;
  	struct watchdog_device *retu_wdt;
  	struct retu_wdt_dev *wdev;
  	int ret;
  
  	retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
  	if (!retu_wdt)
  		return -ENOMEM;
  
  	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
  	if (!wdev)
  		return -ENOMEM;
  
  	retu_wdt->info		= &retu_wdt_info;
  	retu_wdt->ops		= &retu_wdt_ops;
  	retu_wdt->timeout	= RETU_WDT_MAX_TIMER;
  	retu_wdt->min_timeout	= 0;
  	retu_wdt->max_timeout	= RETU_WDT_MAX_TIMER;
  
  	watchdog_set_drvdata(retu_wdt, wdev);
  	watchdog_set_nowayout(retu_wdt, nowayout);
  
  	wdev->rdev		= rdev;
  	wdev->dev		= &pdev->dev;
  
  	INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
  
  	ret = watchdog_register_device(retu_wdt);
  	if (ret < 0)
  		return ret;
  
  	if (nowayout)
  		retu_wdt_ping(retu_wdt);
  	else
  		retu_wdt_ping_enable(wdev);
  
  	platform_set_drvdata(pdev, retu_wdt);
  
  	return 0;
  }
  
  static int retu_wdt_remove(struct platform_device *pdev)
  {
  	struct watchdog_device *wdog = platform_get_drvdata(pdev);
  	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  
  	watchdog_unregister_device(wdog);
  	cancel_delayed_work_sync(&wdev->ping_work);
  
  	return 0;
  }
  
  static struct platform_driver retu_wdt_driver = {
  	.probe		= retu_wdt_probe,
  	.remove		= retu_wdt_remove,
  	.driver		= {
  		.name	= "retu-wdt",
  	},
  };
  module_platform_driver(retu_wdt_driver);
  
  MODULE_ALIAS("platform:retu-wdt");
  MODULE_DESCRIPTION("Retu watchdog");
  MODULE_AUTHOR("Amit Kucheria");
  MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
  MODULE_LICENSE("GPL");