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
wdt_start(struct watchdog_device * wdd)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
wdt_stop(struct watchdog_device * wdd)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
wdt_set_timeout(struct watchdog_device * wdd,unsigned new_timeout)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
wdt_notify_sys(struct notifier_block * nb,unsigned long code,void * unused)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
stmp3xxx_wdt_probe(struct platform_device * pdev)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
stmp3xxx_wdt_remove(struct platform_device * pdev)112 static int stmp3xxx_wdt_remove(struct platform_device *pdev)
113 {
114 unregister_reboot_notifier(&wdt_notifier);
115 return 0;
116 }
117
stmp3xxx_wdt_suspend(struct device * dev)118 static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
119 {
120 struct watchdog_device *wdd = &stmp3xxx_wdd;
121
122 if (watchdog_active(wdd))
123 return wdt_stop(wdd);
124
125 return 0;
126 }
127
stmp3xxx_wdt_resume(struct device * dev)128 static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
129 {
130 struct watchdog_device *wdd = &stmp3xxx_wdd;
131
132 if (watchdog_active(wdd))
133 return wdt_start(wdd);
134
135 return 0;
136 }
137
138 static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
139 stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);
140
141 static struct platform_driver stmp3xxx_wdt_driver = {
142 .driver = {
143 .name = "stmp3xxx_rtc_wdt",
144 .pm = &stmp3xxx_wdt_pm_ops,
145 },
146 .probe = stmp3xxx_wdt_probe,
147 .remove = stmp3xxx_wdt_remove,
148 };
149 module_platform_driver(stmp3xxx_wdt_driver);
150
151 MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
152 MODULE_LICENSE("GPL v2");
153 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
154