1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Retu watchdog driver 4 * 5 * Copyright (C) 2004, 2005 Nokia Corporation 6 * 7 * Based on code written by Amit Kucheria and Michael Buesch. 8 * Rewritten by Aaro Koskinen. 9 */ 10 11 #include <linux/slab.h> 12 #include <linux/errno.h> 13 #include <linux/device.h> 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/mfd/retu.h> 17 #include <linux/watchdog.h> 18 #include <linux/platform_device.h> 19 20 /* Watchdog timer values in seconds */ 21 #define RETU_WDT_MAX_TIMER 63 22 23 struct retu_wdt_dev { 24 struct retu_dev *rdev; 25 struct device *dev; 26 struct delayed_work ping_work; 27 }; 28 29 /* 30 * Since Retu watchdog cannot be disabled in hardware, we must kick it 31 * with a timer until userspace watchdog software takes over. If 32 * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding. 33 */ 34 static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev) 35 { 36 retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER); 37 schedule_delayed_work(&wdev->ping_work, 38 round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2)); 39 } 40 41 static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev) 42 { 43 retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER); 44 cancel_delayed_work_sync(&wdev->ping_work); 45 } 46 47 static void retu_wdt_ping_work(struct work_struct *work) 48 { 49 struct retu_wdt_dev *wdev = container_of(to_delayed_work(work), 50 struct retu_wdt_dev, ping_work); 51 retu_wdt_ping_enable(wdev); 52 } 53 54 static int retu_wdt_start(struct watchdog_device *wdog) 55 { 56 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); 57 58 retu_wdt_ping_disable(wdev); 59 60 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout); 61 } 62 63 static int retu_wdt_stop(struct watchdog_device *wdog) 64 { 65 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); 66 67 retu_wdt_ping_enable(wdev); 68 69 return 0; 70 } 71 72 static int retu_wdt_ping(struct watchdog_device *wdog) 73 { 74 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); 75 76 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout); 77 } 78 79 static int retu_wdt_set_timeout(struct watchdog_device *wdog, 80 unsigned int timeout) 81 { 82 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); 83 84 wdog->timeout = timeout; 85 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout); 86 } 87 88 static const struct watchdog_info retu_wdt_info = { 89 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 90 .identity = "Retu watchdog", 91 }; 92 93 static const struct watchdog_ops retu_wdt_ops = { 94 .owner = THIS_MODULE, 95 .start = retu_wdt_start, 96 .stop = retu_wdt_stop, 97 .ping = retu_wdt_ping, 98 .set_timeout = retu_wdt_set_timeout, 99 }; 100 101 static int retu_wdt_probe(struct platform_device *pdev) 102 { 103 struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent); 104 bool nowayout = WATCHDOG_NOWAYOUT; 105 struct watchdog_device *retu_wdt; 106 struct retu_wdt_dev *wdev; 107 int ret; 108 109 retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL); 110 if (!retu_wdt) 111 return -ENOMEM; 112 113 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); 114 if (!wdev) 115 return -ENOMEM; 116 117 retu_wdt->info = &retu_wdt_info; 118 retu_wdt->ops = &retu_wdt_ops; 119 retu_wdt->timeout = RETU_WDT_MAX_TIMER; 120 retu_wdt->min_timeout = 0; 121 retu_wdt->max_timeout = RETU_WDT_MAX_TIMER; 122 retu_wdt->parent = &pdev->dev; 123 124 watchdog_set_drvdata(retu_wdt, wdev); 125 watchdog_set_nowayout(retu_wdt, nowayout); 126 127 wdev->rdev = rdev; 128 wdev->dev = &pdev->dev; 129 130 INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work); 131 132 ret = watchdog_register_device(retu_wdt); 133 if (ret < 0) 134 return ret; 135 136 if (nowayout) 137 retu_wdt_ping(retu_wdt); 138 else 139 retu_wdt_ping_enable(wdev); 140 141 platform_set_drvdata(pdev, retu_wdt); 142 143 return 0; 144 } 145 146 static int retu_wdt_remove(struct platform_device *pdev) 147 { 148 struct watchdog_device *wdog = platform_get_drvdata(pdev); 149 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); 150 151 watchdog_unregister_device(wdog); 152 cancel_delayed_work_sync(&wdev->ping_work); 153 154 return 0; 155 } 156 157 static struct platform_driver retu_wdt_driver = { 158 .probe = retu_wdt_probe, 159 .remove = retu_wdt_remove, 160 .driver = { 161 .name = "retu-wdt", 162 }, 163 }; 164 module_platform_driver(retu_wdt_driver); 165 166 MODULE_ALIAS("platform:retu-wdt"); 167 MODULE_DESCRIPTION("Retu watchdog"); 168 MODULE_AUTHOR("Amit Kucheria"); 169 MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>"); 170 MODULE_LICENSE("GPL"); 171