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Linux/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/init.h>
 20 #include <linux/slab.h>
 21 #include <linux/errno.h>
 22 #include <linux/device.h>
 23 #include <linux/kernel.h>
 24 #include <linux/module.h>
 25 #include <linux/mfd/retu.h>
 26 #include <linux/watchdog.h>
 27 #include <linux/platform_device.h>
 28 
 29 /* Watchdog timer values in seconds */
 30 #define RETU_WDT_MAX_TIMER      63
 31 
 32 struct retu_wdt_dev {
 33         struct retu_dev         *rdev;
 34         struct device           *dev;
 35         struct delayed_work     ping_work;
 36 };
 37 
 38 /*
 39  * Since Retu watchdog cannot be disabled in hardware, we must kick it
 40  * with a timer until userspace watchdog software takes over. If
 41  * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
 42  */
 43 static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
 44 {
 45         retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
 46         schedule_delayed_work(&wdev->ping_work,
 47                         round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
 48 }
 49 
 50 static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
 51 {
 52         retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
 53         cancel_delayed_work_sync(&wdev->ping_work);
 54 }
 55 
 56 static void retu_wdt_ping_work(struct work_struct *work)
 57 {
 58         struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
 59                                                 struct retu_wdt_dev, ping_work);
 60         retu_wdt_ping_enable(wdev);
 61 }
 62 
 63 static int retu_wdt_start(struct watchdog_device *wdog)
 64 {
 65         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 66 
 67         retu_wdt_ping_disable(wdev);
 68 
 69         return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 70 }
 71 
 72 static int retu_wdt_stop(struct watchdog_device *wdog)
 73 {
 74         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 75 
 76         retu_wdt_ping_enable(wdev);
 77 
 78         return 0;
 79 }
 80 
 81 static int retu_wdt_ping(struct watchdog_device *wdog)
 82 {
 83         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 84 
 85         return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 86 }
 87 
 88 static int retu_wdt_set_timeout(struct watchdog_device *wdog,
 89                                 unsigned int timeout)
 90 {
 91         struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 92 
 93         wdog->timeout = timeout;
 94         return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 95 }
 96 
 97 static const struct watchdog_info retu_wdt_info = {
 98         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 99         .identity = "Retu watchdog",
100 };
101 
102 static const struct watchdog_ops retu_wdt_ops = {
103         .owner          = THIS_MODULE,
104         .start          = retu_wdt_start,
105         .stop           = retu_wdt_stop,
106         .ping           = retu_wdt_ping,
107         .set_timeout    = retu_wdt_set_timeout,
108 };
109 
110 static int retu_wdt_probe(struct platform_device *pdev)
111 {
112         struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
113         bool nowayout = WATCHDOG_NOWAYOUT;
114         struct watchdog_device *retu_wdt;
115         struct retu_wdt_dev *wdev;
116         int ret;
117 
118         retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
119         if (!retu_wdt)
120                 return -ENOMEM;
121 
122         wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
123         if (!wdev)
124                 return -ENOMEM;
125 
126         retu_wdt->info          = &retu_wdt_info;
127         retu_wdt->ops           = &retu_wdt_ops;
128         retu_wdt->timeout       = RETU_WDT_MAX_TIMER;
129         retu_wdt->min_timeout   = 0;
130         retu_wdt->max_timeout   = RETU_WDT_MAX_TIMER;
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");
179 

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