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e14538e0 JJ |
1 | /* |
2 | * MOXA ART SoCs watchdog driver. | |
3 | * | |
4 | * Copyright (C) 2013 Jonas Jensen | |
5 | * | |
6 | * Jonas Jensen <jonas.jensen@gmail.com> | |
7 | * | |
8 | * This file is licensed under the terms of the GNU General Public | |
9 | * License version 2. This program is licensed "as is" without any | |
10 | * warranty of any kind, whether express or implied. | |
11 | */ | |
12 | ||
13 | #include <linux/clk.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/kernel.h> | |
ad0e0e68 | 18 | #include <linux/notifier.h> |
e14538e0 | 19 | #include <linux/platform_device.h> |
ad0e0e68 | 20 | #include <linux/reboot.h> |
e14538e0 JJ |
21 | #include <linux/watchdog.h> |
22 | #include <linux/moduleparam.h> | |
23 | ||
24 | #define REG_COUNT 0x4 | |
25 | #define REG_MODE 0x8 | |
26 | #define REG_ENABLE 0xC | |
27 | ||
28 | struct moxart_wdt_dev { | |
29 | struct watchdog_device dev; | |
30 | void __iomem *base; | |
31 | unsigned int clock_frequency; | |
ad0e0e68 | 32 | struct notifier_block restart_handler; |
e14538e0 JJ |
33 | }; |
34 | ||
35 | static int heartbeat; | |
36 | ||
ad0e0e68 GR |
37 | static int moxart_restart_handle(struct notifier_block *this, |
38 | unsigned long mode, void *cmd) | |
8773926d | 39 | { |
ad0e0e68 GR |
40 | struct moxart_wdt_dev *moxart_wdt = container_of(this, |
41 | struct moxart_wdt_dev, | |
42 | restart_handler); | |
43 | writel(1, moxart_wdt->base + REG_COUNT); | |
44 | writel(0x5ab9, moxart_wdt->base + REG_MODE); | |
45 | writel(0x03, moxart_wdt->base + REG_ENABLE); | |
46 | ||
47 | return NOTIFY_DONE; | |
8773926d JJ |
48 | } |
49 | ||
e14538e0 JJ |
50 | static int moxart_wdt_stop(struct watchdog_device *wdt_dev) |
51 | { | |
52 | struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); | |
53 | ||
54 | writel(0, moxart_wdt->base + REG_ENABLE); | |
55 | ||
56 | return 0; | |
57 | } | |
58 | ||
59 | static int moxart_wdt_start(struct watchdog_device *wdt_dev) | |
60 | { | |
61 | struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); | |
62 | ||
63 | writel(moxart_wdt->clock_frequency * wdt_dev->timeout, | |
64 | moxart_wdt->base + REG_COUNT); | |
65 | writel(0x5ab9, moxart_wdt->base + REG_MODE); | |
66 | writel(0x03, moxart_wdt->base + REG_ENABLE); | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
72 | unsigned int timeout) | |
73 | { | |
74 | wdt_dev->timeout = timeout; | |
75 | ||
76 | return 0; | |
77 | } | |
78 | ||
79 | static const struct watchdog_info moxart_wdt_info = { | |
80 | .identity = "moxart-wdt", | |
81 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
82 | WDIOF_MAGICCLOSE, | |
83 | }; | |
84 | ||
85 | static const struct watchdog_ops moxart_wdt_ops = { | |
86 | .owner = THIS_MODULE, | |
87 | .start = moxart_wdt_start, | |
88 | .stop = moxart_wdt_stop, | |
89 | .set_timeout = moxart_wdt_set_timeout, | |
90 | }; | |
91 | ||
92 | static int moxart_wdt_probe(struct platform_device *pdev) | |
93 | { | |
94 | struct moxart_wdt_dev *moxart_wdt; | |
95 | struct device *dev = &pdev->dev; | |
96 | struct device_node *node = dev->of_node; | |
97 | struct resource *res; | |
98 | struct clk *clk; | |
99 | int err; | |
100 | unsigned int max_timeout; | |
101 | bool nowayout = WATCHDOG_NOWAYOUT; | |
102 | ||
103 | moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); | |
104 | if (!moxart_wdt) | |
105 | return -ENOMEM; | |
106 | ||
107 | platform_set_drvdata(pdev, moxart_wdt); | |
108 | ||
109 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
110 | moxart_wdt->base = devm_ioremap_resource(dev, res); | |
111 | if (IS_ERR(moxart_wdt->base)) | |
112 | return PTR_ERR(moxart_wdt->base); | |
113 | ||
114 | clk = of_clk_get(node, 0); | |
115 | if (IS_ERR(clk)) { | |
116 | pr_err("%s: of_clk_get failed\n", __func__); | |
117 | return PTR_ERR(clk); | |
118 | } | |
119 | ||
120 | moxart_wdt->clock_frequency = clk_get_rate(clk); | |
121 | if (moxart_wdt->clock_frequency == 0) { | |
122 | pr_err("%s: incorrect clock frequency\n", __func__); | |
123 | return -EINVAL; | |
124 | } | |
125 | ||
126 | max_timeout = UINT_MAX / moxart_wdt->clock_frequency; | |
127 | ||
128 | moxart_wdt->dev.info = &moxart_wdt_info; | |
129 | moxart_wdt->dev.ops = &moxart_wdt_ops; | |
130 | moxart_wdt->dev.timeout = max_timeout; | |
131 | moxart_wdt->dev.min_timeout = 1; | |
132 | moxart_wdt->dev.max_timeout = max_timeout; | |
133 | moxart_wdt->dev.parent = dev; | |
134 | ||
135 | watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); | |
136 | watchdog_set_nowayout(&moxart_wdt->dev, nowayout); | |
137 | ||
138 | watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); | |
139 | ||
140 | err = watchdog_register_device(&moxart_wdt->dev); | |
141 | if (err) | |
142 | return err; | |
143 | ||
ad0e0e68 GR |
144 | moxart_wdt->restart_handler.notifier_call = moxart_restart_handle; |
145 | moxart_wdt->restart_handler.priority = 128; | |
146 | err = register_restart_handler(&moxart_wdt->restart_handler); | |
147 | if (err) | |
148 | dev_err(dev, "cannot register restart notifier (err=%d)\n", | |
149 | err); | |
8773926d | 150 | |
e14538e0 JJ |
151 | dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", |
152 | moxart_wdt->dev.timeout, nowayout); | |
153 | ||
154 | return 0; | |
155 | } | |
156 | ||
157 | static int moxart_wdt_remove(struct platform_device *pdev) | |
158 | { | |
159 | struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); | |
160 | ||
ad0e0e68 | 161 | unregister_restart_handler(&moxart_wdt->restart_handler); |
e14538e0 | 162 | moxart_wdt_stop(&moxart_wdt->dev); |
e14538e0 JJ |
163 | |
164 | return 0; | |
165 | } | |
166 | ||
167 | static const struct of_device_id moxart_watchdog_match[] = { | |
168 | { .compatible = "moxa,moxart-watchdog" }, | |
169 | { }, | |
170 | }; | |
c73318f4 | 171 | MODULE_DEVICE_TABLE(of, moxart_watchdog_match); |
e14538e0 JJ |
172 | |
173 | static struct platform_driver moxart_wdt_driver = { | |
174 | .probe = moxart_wdt_probe, | |
175 | .remove = moxart_wdt_remove, | |
176 | .driver = { | |
177 | .name = "moxart-watchdog", | |
e14538e0 JJ |
178 | .of_match_table = moxart_watchdog_match, |
179 | }, | |
180 | }; | |
181 | module_platform_driver(moxart_wdt_driver); | |
182 | ||
183 | module_param(heartbeat, int, 0); | |
184 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); | |
185 | ||
186 | MODULE_DESCRIPTION("MOXART watchdog driver"); | |
187 | MODULE_LICENSE("GPL"); | |
188 | MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); |