1 /*
2 * Retu watchdog driver
3 *
4 * Copyright (C) 2004, 2005 Nokia Corporation
5 *
6 * Based on code written by Amit Kucheria and Michael Buesch.
7 * Rewritten by Aaro Koskinen.
8 *
9 * This file is subject to the terms and conditions of the GNU General
10 * Public License. See the file "COPYING" in the main directory of this
11 * archive for more details.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 */
18
19 #include <linux/slab.h>
20 #include <linux/errno.h>
21 #include <linux/device.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/mfd/retu.h>
25 #include <linux/watchdog.h>
26 #include <linux/platform_device.h>
27
28 /* Watchdog timer values in seconds */
29 #define RETU_WDT_MAX_TIMER 63
30
31 struct retu_wdt_dev {
32 struct retu_dev *rdev;
33 struct device *dev;
34 struct delayed_work ping_work;
35 };
36
37 /*
38 * Since Retu watchdog cannot be disabled in hardware, we must kick it
39 * with a timer until userspace watchdog software takes over. If
40 * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
41 */
retu_wdt_ping_enable(struct retu_wdt_dev * wdev)42 static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
43 {
44 retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
45 schedule_delayed_work(&wdev->ping_work,
46 round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
47 }
48
retu_wdt_ping_disable(struct retu_wdt_dev * wdev)49 static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
50 {
51 retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
52 cancel_delayed_work_sync(&wdev->ping_work);
53 }
54
retu_wdt_ping_work(struct work_struct * work)55 static void retu_wdt_ping_work(struct work_struct *work)
56 {
57 struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
58 struct retu_wdt_dev, ping_work);
59 retu_wdt_ping_enable(wdev);
60 }
61
retu_wdt_start(struct watchdog_device * wdog)62 static int retu_wdt_start(struct watchdog_device *wdog)
63 {
64 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
65
66 retu_wdt_ping_disable(wdev);
67
68 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
69 }
70
retu_wdt_stop(struct watchdog_device * wdog)71 static int retu_wdt_stop(struct watchdog_device *wdog)
72 {
73 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
74
75 retu_wdt_ping_enable(wdev);
76
77 return 0;
78 }
79
retu_wdt_ping(struct watchdog_device * wdog)80 static int retu_wdt_ping(struct watchdog_device *wdog)
81 {
82 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
83
84 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
85 }
86
retu_wdt_set_timeout(struct watchdog_device * wdog,unsigned int timeout)87 static int retu_wdt_set_timeout(struct watchdog_device *wdog,
88 unsigned int timeout)
89 {
90 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
91
92 wdog->timeout = timeout;
93 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
94 }
95
96 static const struct watchdog_info retu_wdt_info = {
97 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
98 .identity = "Retu watchdog",
99 };
100
101 static const struct watchdog_ops retu_wdt_ops = {
102 .owner = THIS_MODULE,
103 .start = retu_wdt_start,
104 .stop = retu_wdt_stop,
105 .ping = retu_wdt_ping,
106 .set_timeout = retu_wdt_set_timeout,
107 };
108
retu_wdt_probe(struct platform_device * pdev)109 static int retu_wdt_probe(struct platform_device *pdev)
110 {
111 struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
112 bool nowayout = WATCHDOG_NOWAYOUT;
113 struct watchdog_device *retu_wdt;
114 struct retu_wdt_dev *wdev;
115 int ret;
116
117 retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
118 if (!retu_wdt)
119 return -ENOMEM;
120
121 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
122 if (!wdev)
123 return -ENOMEM;
124
125 retu_wdt->info = &retu_wdt_info;
126 retu_wdt->ops = &retu_wdt_ops;
127 retu_wdt->timeout = RETU_WDT_MAX_TIMER;
128 retu_wdt->min_timeout = 0;
129 retu_wdt->max_timeout = RETU_WDT_MAX_TIMER;
130 retu_wdt->parent = &pdev->dev;
131
132 watchdog_set_drvdata(retu_wdt, wdev);
133 watchdog_set_nowayout(retu_wdt, nowayout);
134
135 wdev->rdev = rdev;
136 wdev->dev = &pdev->dev;
137
138 INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
139
140 ret = watchdog_register_device(retu_wdt);
141 if (ret < 0)
142 return ret;
143
144 if (nowayout)
145 retu_wdt_ping(retu_wdt);
146 else
147 retu_wdt_ping_enable(wdev);
148
149 platform_set_drvdata(pdev, retu_wdt);
150
151 return 0;
152 }
153
retu_wdt_remove(struct platform_device * pdev)154 static int retu_wdt_remove(struct platform_device *pdev)
155 {
156 struct watchdog_device *wdog = platform_get_drvdata(pdev);
157 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
158
159 watchdog_unregister_device(wdog);
160 cancel_delayed_work_sync(&wdev->ping_work);
161
162 return 0;
163 }
164
165 static struct platform_driver retu_wdt_driver = {
166 .probe = retu_wdt_probe,
167 .remove = retu_wdt_remove,
168 .driver = {
169 .name = "retu-wdt",
170 },
171 };
172 module_platform_driver(retu_wdt_driver);
173
174 MODULE_ALIAS("platform:retu-wdt");
175 MODULE_DESCRIPTION("Retu watchdog");
176 MODULE_AUTHOR("Amit Kucheria");
177 MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
178 MODULE_LICENSE("GPL");
179