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