drivers/watchdog/retu_wdt.c

   1 /*
   2  * Retu watchdog driver
   3  *
   4  * Copyright (C) 2004, 2005 Nokia Corporation
   5  *
   6  * Based on code written by Amit Kucheria and Michael Buesch.
   7  * Rewritten by Aaro Koskinen.
   8  *
   9  * This file is subject to the terms and conditions of the GNU General
  10  * Public License. See the file "COPYING" in the main directory of this
  11  * archive for more details.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/slab.h>
  20 #include <linux/errno.h>
  21 #include <linux/device.h>
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/mfd/retu.h>
  25 #include <linux/watchdog.h>
  26 #include <linux/platform_device.h>
  27
  28 /* Watchdog timer values in seconds */
  29 #define RETU_WDT_MAX_TIMER      63
  30
  31 struct retu_wdt_dev {
  32         struct retu_dev         *rdev;
  33         struct device           *dev;
  34         struct delayed_work     ping_work;
  35 };
  36
  37 /*
  38  * Since Retu watchdog cannot be disabled in hardware, we must kick it
  39  * with a timer until userspace watchdog software takes over. If
  40  * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
  41  */
  42 static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
  43 {
  44         retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
  45         schedule_delayed_work(&wdev->ping_work,
  46                         round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
  47 }
  48
  49 static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
  50 {
  51         retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
  52         cancel_delayed_work_sync(&wdev->ping_work);
  53 }
  54
  55 static void retu_wdt_ping_work(struct work_struct *work)
  56 {
  57         struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
  58                                                 struct retu_wdt_dev, ping_work);
  59         retu_wdt_ping_enable(wdev);
  60 }
  61
  62 static int retu_wdt_start(struct watchdog_device *wdog)
  63 {
  64         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  65
  66         retu_wdt_ping_disable(wdev);
  67
  68         return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  69 }
  70
  71 static int retu_wdt_stop(struct watchdog_device *wdog)
  72 {
  73         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  74
  75         retu_wdt_ping_enable(wdev);
  76
  77         return 0;
  78 }
  79
  80 static int retu_wdt_ping(struct watchdog_device *wdog)
  81 {
  82         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  83
  84         return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  85 }
  86
  87 static int retu_wdt_set_timeout(struct watchdog_device *wdog,
  88                                 unsigned int timeout)
  89 {
  90         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  91
  92         wdog->timeout = timeout;
  93         return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  94 }
  95
  96 static const struct watchdog_info retu_wdt_info = {
  97         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
  98         .identity = "Retu watchdog",
  99 };
 100
 101 static const struct watchdog_ops retu_wdt_ops = {
 102         .owner          = THIS_MODULE,
 103         .start          = retu_wdt_start,
 104         .stop           = retu_wdt_stop,
 105         .ping           = retu_wdt_ping,
 106         .set_timeout    = retu_wdt_set_timeout,
 107 };
 108
 109 static int retu_wdt_probe(struct platform_device *pdev)
 110 {
 111         struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
 112         bool nowayout = WATCHDOG_NOWAYOUT;
 113         struct watchdog_device *retu_wdt;
 114         struct retu_wdt_dev *wdev;
 115         int ret;
 116
 117         retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
 118         if (!retu_wdt)
 119                 return -ENOMEM;
 120
 121         wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
 122         if (!wdev)
 123                 return -ENOMEM;
 124
 125         retu_wdt->info          = &retu_wdt_info;
 126         retu_wdt->ops           = &retu_wdt_ops;
 127         retu_wdt->timeout       = RETU_WDT_MAX_TIMER;
 128         retu_wdt->min_timeout   = 0;
 129         retu_wdt->max_timeout   = RETU_WDT_MAX_TIMER;
 130         retu_wdt->parent        = &pdev->dev;
 131
 132         watchdog_set_drvdata(retu_wdt, wdev);
 133         watchdog_set_nowayout(retu_wdt, nowayout);
 134
 135         wdev->rdev              = rdev;
 136         wdev->dev               = &pdev->dev;
 137
 138         INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
 139
 140         ret = watchdog_register_device(retu_wdt);
 141         if (ret < 0)
 142                 return ret;
 143
 144         if (nowayout)
 145                 retu_wdt_ping(retu_wdt);
 146         else
 147                 retu_wdt_ping_enable(wdev);
 148
 149         platform_set_drvdata(pdev, retu_wdt);
 150
 151         return 0;
 152 }
 153
 154 static int retu_wdt_remove(struct platform_device *pdev)
 155 {
 156         struct watchdog_device *wdog = platform_get_drvdata(pdev);
 157         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 158
 159         watchdog_unregister_device(wdog);
 160         cancel_delayed_work_sync(&wdev->ping_work);
 161
 162         return 0;
 163 }
 164
 165 static struct platform_driver retu_wdt_driver = {
 166         .probe          = retu_wdt_probe,
 167         .remove         = retu_wdt_remove,
 168         .driver         = {
 169                 .name   = "retu-wdt",
 170         },
 171 };
 172 module_platform_driver(retu_wdt_driver);
 173
 174 MODULE_ALIAS("platform:retu-wdt");
 175 MODULE_DESCRIPTION("Retu watchdog");
 176 MODULE_AUTHOR("Amit Kucheria");
 177 MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
 178 MODULE_LICENSE("GPL");