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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> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/watchdog.h> | |
20 | #include <linux/moduleparam.h> | |
21 | ||
8773926d JJ |
22 | #include <asm/system_misc.h> |
23 | ||
e14538e0 JJ |
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; | |
32 | }; | |
33 | ||
8773926d JJ |
34 | static struct moxart_wdt_dev *moxart_restart_ctx; |
35 | ||
e14538e0 JJ |
36 | static int heartbeat; |
37 | ||
8773926d JJ |
38 | static void moxart_wdt_restart(enum reboot_mode reboot_mode, const char *cmd) |
39 | { | |
40 | writel(1, moxart_restart_ctx->base + REG_COUNT); | |
41 | writel(0x5ab9, moxart_restart_ctx->base + REG_MODE); | |
42 | writel(0x03, moxart_restart_ctx->base + REG_ENABLE); | |
43 | } | |
44 | ||
e14538e0 JJ |
45 | static int moxart_wdt_stop(struct watchdog_device *wdt_dev) |
46 | { | |
47 | struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); | |
48 | ||
49 | writel(0, moxart_wdt->base + REG_ENABLE); | |
50 | ||
51 | return 0; | |
52 | } | |
53 | ||
54 | static int moxart_wdt_start(struct watchdog_device *wdt_dev) | |
55 | { | |
56 | struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); | |
57 | ||
58 | writel(moxart_wdt->clock_frequency * wdt_dev->timeout, | |
59 | moxart_wdt->base + REG_COUNT); | |
60 | writel(0x5ab9, moxart_wdt->base + REG_MODE); | |
61 | writel(0x03, moxart_wdt->base + REG_ENABLE); | |
62 | ||
63 | return 0; | |
64 | } | |
65 | ||
66 | static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
67 | unsigned int timeout) | |
68 | { | |
69 | wdt_dev->timeout = timeout; | |
70 | ||
71 | return 0; | |
72 | } | |
73 | ||
74 | static const struct watchdog_info moxart_wdt_info = { | |
75 | .identity = "moxart-wdt", | |
76 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
77 | WDIOF_MAGICCLOSE, | |
78 | }; | |
79 | ||
80 | static const struct watchdog_ops moxart_wdt_ops = { | |
81 | .owner = THIS_MODULE, | |
82 | .start = moxart_wdt_start, | |
83 | .stop = moxart_wdt_stop, | |
84 | .set_timeout = moxart_wdt_set_timeout, | |
85 | }; | |
86 | ||
87 | static int moxart_wdt_probe(struct platform_device *pdev) | |
88 | { | |
89 | struct moxart_wdt_dev *moxart_wdt; | |
90 | struct device *dev = &pdev->dev; | |
91 | struct device_node *node = dev->of_node; | |
92 | struct resource *res; | |
93 | struct clk *clk; | |
94 | int err; | |
95 | unsigned int max_timeout; | |
96 | bool nowayout = WATCHDOG_NOWAYOUT; | |
97 | ||
98 | moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); | |
99 | if (!moxart_wdt) | |
100 | return -ENOMEM; | |
101 | ||
102 | platform_set_drvdata(pdev, moxart_wdt); | |
103 | ||
104 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
105 | moxart_wdt->base = devm_ioremap_resource(dev, res); | |
106 | if (IS_ERR(moxart_wdt->base)) | |
107 | return PTR_ERR(moxart_wdt->base); | |
108 | ||
109 | clk = of_clk_get(node, 0); | |
110 | if (IS_ERR(clk)) { | |
111 | pr_err("%s: of_clk_get failed\n", __func__); | |
112 | return PTR_ERR(clk); | |
113 | } | |
114 | ||
115 | moxart_wdt->clock_frequency = clk_get_rate(clk); | |
116 | if (moxart_wdt->clock_frequency == 0) { | |
117 | pr_err("%s: incorrect clock frequency\n", __func__); | |
118 | return -EINVAL; | |
119 | } | |
120 | ||
121 | max_timeout = UINT_MAX / moxart_wdt->clock_frequency; | |
122 | ||
123 | moxart_wdt->dev.info = &moxart_wdt_info; | |
124 | moxart_wdt->dev.ops = &moxart_wdt_ops; | |
125 | moxart_wdt->dev.timeout = max_timeout; | |
126 | moxart_wdt->dev.min_timeout = 1; | |
127 | moxart_wdt->dev.max_timeout = max_timeout; | |
128 | moxart_wdt->dev.parent = dev; | |
129 | ||
130 | watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); | |
131 | watchdog_set_nowayout(&moxart_wdt->dev, nowayout); | |
132 | ||
133 | watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); | |
134 | ||
135 | err = watchdog_register_device(&moxart_wdt->dev); | |
136 | if (err) | |
137 | return err; | |
138 | ||
8773926d JJ |
139 | moxart_restart_ctx = moxart_wdt; |
140 | arm_pm_restart = moxart_wdt_restart; | |
141 | ||
e14538e0 JJ |
142 | dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", |
143 | moxart_wdt->dev.timeout, nowayout); | |
144 | ||
145 | return 0; | |
146 | } | |
147 | ||
148 | static int moxart_wdt_remove(struct platform_device *pdev) | |
149 | { | |
150 | struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); | |
151 | ||
8773926d | 152 | arm_pm_restart = NULL; |
e14538e0 JJ |
153 | moxart_wdt_stop(&moxart_wdt->dev); |
154 | watchdog_unregister_device(&moxart_wdt->dev); | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
159 | static const struct of_device_id moxart_watchdog_match[] = { | |
160 | { .compatible = "moxa,moxart-watchdog" }, | |
161 | { }, | |
162 | }; | |
163 | ||
164 | static struct platform_driver moxart_wdt_driver = { | |
165 | .probe = moxart_wdt_probe, | |
166 | .remove = moxart_wdt_remove, | |
167 | .driver = { | |
168 | .name = "moxart-watchdog", | |
169 | .owner = THIS_MODULE, | |
170 | .of_match_table = moxart_watchdog_match, | |
171 | }, | |
172 | }; | |
173 | module_platform_driver(moxart_wdt_driver); | |
174 | ||
175 | module_param(heartbeat, int, 0); | |
176 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); | |
177 | ||
178 | MODULE_DESCRIPTION("MOXART watchdog driver"); | |
179 | MODULE_LICENSE("GPL"); | |
180 | MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); |