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