1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28 4 * 5 * Author: Wolfram Sang <kernel@pengutronix.de> 6 * 7 * Copyright (C) 2011-12 Wolfram Sang, Pengutronix 8 */ 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/watchdog.h> 12 #include <linux/platform_device.h> 13 #include <linux/stmp3xxx_rtc_wdt.h> 14 #include <linux/notifier.h> 15 #include <linux/reboot.h> 16 17 #define WDOG_TICK_RATE 1000 /* 1 kHz clock */ 18 #define STMP3XXX_DEFAULT_TIMEOUT 19 19 #define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE) 20 21 static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT; 22 module_param(heartbeat, uint, 0); 23 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to " 24 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default " 25 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT)); 26 27 static int wdt_start(struct watchdog_device *wdd) 28 { 29 struct device *dev = watchdog_get_drvdata(wdd); 30 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev); 31 32 pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE); 33 return 0; 34 } 35 36 static int wdt_stop(struct watchdog_device *wdd) 37 { 38 struct device *dev = watchdog_get_drvdata(wdd); 39 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev); 40 41 pdata->wdt_set_timeout(dev->parent, 0); 42 return 0; 43 } 44 45 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout) 46 { 47 wdd->timeout = new_timeout; 48 return wdt_start(wdd); 49 } 50 51 static const struct watchdog_info stmp3xxx_wdt_ident = { 52 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 53 .identity = "STMP3XXX RTC Watchdog", 54 }; 55 56 static const struct watchdog_ops stmp3xxx_wdt_ops = { 57 .owner = THIS_MODULE, 58 .start = wdt_start, 59 .stop = wdt_stop, 60 .set_timeout = wdt_set_timeout, 61 }; 62 63 static struct watchdog_device stmp3xxx_wdd = { 64 .info = &stmp3xxx_wdt_ident, 65 .ops = &stmp3xxx_wdt_ops, 66 .min_timeout = 1, 67 .max_timeout = STMP3XXX_MAX_TIMEOUT, 68 .status = WATCHDOG_NOWAYOUT_INIT_STATUS, 69 }; 70 71 static int wdt_notify_sys(struct notifier_block *nb, unsigned long code, 72 void *unused) 73 { 74 switch (code) { 75 case SYS_DOWN: /* keep enabled, system might crash while going down */ 76 break; 77 case SYS_HALT: /* allow the system to actually halt */ 78 case SYS_POWER_OFF: 79 wdt_stop(&stmp3xxx_wdd); 80 break; 81 } 82 83 return NOTIFY_DONE; 84 } 85 86 static struct notifier_block wdt_notifier = { 87 .notifier_call = wdt_notify_sys, 88 }; 89 90 static int stmp3xxx_wdt_probe(struct platform_device *pdev) 91 { 92 struct device *dev = &pdev->dev; 93 int ret; 94 95 watchdog_set_drvdata(&stmp3xxx_wdd, dev); 96 97 stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT); 98 stmp3xxx_wdd.parent = dev; 99 100 ret = devm_watchdog_register_device(dev, &stmp3xxx_wdd); 101 if (ret < 0) 102 return ret; 103 104 if (register_reboot_notifier(&wdt_notifier)) 105 dev_warn(dev, "cannot register reboot notifier\n"); 106 107 dev_info(dev, "initialized watchdog with heartbeat %ds\n", 108 stmp3xxx_wdd.timeout); 109 return 0; 110 } 111 112 static void stmp3xxx_wdt_remove(struct platform_device *pdev) 113 { 114 unregister_reboot_notifier(&wdt_notifier); 115 } 116 117 static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev) 118 { 119 struct watchdog_device *wdd = &stmp3xxx_wdd; 120 121 if (watchdog_active(wdd)) 122 return wdt_stop(wdd); 123 124 return 0; 125 } 126 127 static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev) 128 { 129 struct watchdog_device *wdd = &stmp3xxx_wdd; 130 131 if (watchdog_active(wdd)) 132 return wdt_start(wdd); 133 134 return 0; 135 } 136 137 static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops, 138 stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume); 139 140 static struct platform_driver stmp3xxx_wdt_driver = { 141 .driver = { 142 .name = "stmp3xxx_rtc_wdt", 143 .pm = &stmp3xxx_wdt_pm_ops, 144 }, 145 .probe = stmp3xxx_wdt_probe, 146 .remove_new = stmp3xxx_wdt_remove, 147 }; 148 module_platform_driver(stmp3xxx_wdt_driver); 149 150 MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver"); 151 MODULE_LICENSE("GPL v2"); 152 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>"); 153