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(dwork: &wdev->ping_work, |
39 | delay: 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(dwork: &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(wdd: 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(wdd: 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(wdd: 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(wdd: 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(dev: 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(dev: &pdev->dev, size: sizeof(*retu_wdt), GFP_KERNEL); |
111 | if (!retu_wdt) |
112 | return -ENOMEM; |
113 | |
114 | wdev = devm_kzalloc(dev: &pdev->dev, size: 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(wdd: retu_wdt, data: wdev); |
126 | watchdog_set_nowayout(wdd: retu_wdt, nowayout); |
127 | |
128 | wdev->rdev = rdev; |
129 | wdev->dev = &pdev->dev; |
130 | |
131 | ret = devm_delayed_work_autocancel(dev: &pdev->dev, w: &wdev->ping_work, |
132 | worker: retu_wdt_ping_work); |
133 | if (ret) |
134 | return ret; |
135 | |
136 | ret = devm_watchdog_register_device(dev: &pdev->dev, retu_wdt); |
137 | if (ret < 0) |
138 | return ret; |
139 | |
140 | if (nowayout) |
141 | retu_wdt_ping(wdog: 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 | |