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 */
retu_wdt_ping_enable(struct retu_wdt_dev * wdev)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
retu_wdt_ping_disable(struct retu_wdt_dev * wdev)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
retu_wdt_ping_work(struct work_struct * work)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
retu_wdt_start(struct watchdog_device * wdog)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
retu_wdt_stop(struct watchdog_device * wdog)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
retu_wdt_ping(struct watchdog_device * wdog)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
retu_wdt_set_timeout(struct watchdog_device * wdog,unsigned int timeout)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
retu_wdt_probe(struct platform_device * pdev)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
retu_wdt_remove(struct platform_device * pdev)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