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"); 179