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1 | /* |
2 | * Meson Watchdog Driver | |
3 | * | |
4 | * Copyright (c) 2014 Carlo Caione | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/clk.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/io.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/moduleparam.h> | |
20 | #include <linux/notifier.h> | |
21 | #include <linux/of.h> | |
22 | #include <linux/platform_device.h> | |
23 | #include <linux/reboot.h> | |
24 | #include <linux/types.h> | |
25 | #include <linux/watchdog.h> | |
26 | ||
27 | #define DRV_NAME "meson_wdt" | |
28 | ||
29 | #define MESON_WDT_TC 0x00 | |
30 | #define MESON_WDT_TC_EN BIT(22) | |
31 | #define MESON_WDT_TC_TM_MASK 0x3fffff | |
32 | #define MESON_WDT_DC_RESET (3 << 24) | |
33 | ||
34 | #define MESON_WDT_RESET 0x04 | |
35 | ||
36 | #define MESON_WDT_TIMEOUT 30 | |
37 | #define MESON_WDT_MIN_TIMEOUT 1 | |
38 | #define MESON_WDT_MAX_TIMEOUT (MESON_WDT_TC_TM_MASK / 100000) | |
39 | ||
40 | #define MESON_SEC_TO_TC(s) ((s) * 100000) | |
41 | ||
42 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
43 | static unsigned int timeout = MESON_WDT_TIMEOUT; | |
44 | ||
45 | struct meson_wdt_dev { | |
46 | struct watchdog_device wdt_dev; | |
47 | void __iomem *wdt_base; | |
48 | struct notifier_block restart_handler; | |
49 | }; | |
50 | ||
51 | static int meson_restart_handle(struct notifier_block *this, unsigned long mode, | |
52 | void *cmd) | |
53 | { | |
06980b24 | 54 | u32 tc_reboot = MESON_WDT_DC_RESET | MESON_WDT_TC_EN; |
22e1b8f6 CC |
55 | struct meson_wdt_dev *meson_wdt = container_of(this, |
56 | struct meson_wdt_dev, | |
57 | restart_handler); | |
58 | ||
59 | while (1) { | |
60 | writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC); | |
61 | mdelay(5); | |
62 | } | |
63 | ||
64 | return NOTIFY_DONE; | |
65 | } | |
66 | ||
67 | static int meson_wdt_ping(struct watchdog_device *wdt_dev) | |
68 | { | |
69 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
70 | ||
71 | writel(0, meson_wdt->wdt_base + MESON_WDT_RESET); | |
72 | ||
73 | return 0; | |
74 | } | |
75 | ||
76 | static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev, | |
77 | unsigned int timeout) | |
78 | { | |
79 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
80 | u32 reg; | |
81 | ||
82 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
83 | reg &= ~MESON_WDT_TC_TM_MASK; | |
84 | reg |= MESON_SEC_TO_TC(timeout); | |
85 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); | |
86 | } | |
87 | ||
88 | static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
89 | unsigned int timeout) | |
90 | { | |
91 | wdt_dev->timeout = timeout; | |
92 | ||
93 | meson_wdt_change_timeout(wdt_dev, timeout); | |
94 | meson_wdt_ping(wdt_dev); | |
95 | ||
96 | return 0; | |
97 | } | |
98 | ||
99 | static int meson_wdt_stop(struct watchdog_device *wdt_dev) | |
100 | { | |
101 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
102 | u32 reg; | |
103 | ||
104 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
105 | reg &= ~MESON_WDT_TC_EN; | |
106 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); | |
107 | ||
108 | return 0; | |
109 | } | |
110 | ||
111 | static int meson_wdt_start(struct watchdog_device *wdt_dev) | |
112 | { | |
113 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
114 | u32 reg; | |
115 | ||
116 | meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout); | |
117 | meson_wdt_ping(wdt_dev); | |
118 | ||
119 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
120 | reg |= MESON_WDT_TC_EN; | |
121 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); | |
122 | ||
123 | return 0; | |
124 | } | |
125 | ||
126 | static const struct watchdog_info meson_wdt_info = { | |
127 | .identity = DRV_NAME, | |
128 | .options = WDIOF_SETTIMEOUT | | |
129 | WDIOF_KEEPALIVEPING | | |
130 | WDIOF_MAGICCLOSE, | |
131 | }; | |
132 | ||
133 | static const struct watchdog_ops meson_wdt_ops = { | |
134 | .owner = THIS_MODULE, | |
135 | .start = meson_wdt_start, | |
136 | .stop = meson_wdt_stop, | |
137 | .ping = meson_wdt_ping, | |
138 | .set_timeout = meson_wdt_set_timeout, | |
139 | }; | |
140 | ||
141 | static int meson_wdt_probe(struct platform_device *pdev) | |
142 | { | |
143 | struct resource *res; | |
144 | struct meson_wdt_dev *meson_wdt; | |
145 | int err; | |
146 | ||
147 | meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL); | |
148 | if (!meson_wdt) | |
149 | return -ENOMEM; | |
150 | ||
151 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
152 | meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); | |
153 | if (IS_ERR(meson_wdt->wdt_base)) | |
154 | return PTR_ERR(meson_wdt->wdt_base); | |
155 | ||
156 | meson_wdt->wdt_dev.parent = &pdev->dev; | |
157 | meson_wdt->wdt_dev.info = &meson_wdt_info; | |
158 | meson_wdt->wdt_dev.ops = &meson_wdt_ops; | |
159 | meson_wdt->wdt_dev.timeout = MESON_WDT_TIMEOUT; | |
160 | meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT; | |
161 | meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT; | |
162 | ||
163 | watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt); | |
164 | ||
165 | watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev); | |
166 | watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout); | |
167 | ||
168 | meson_wdt_stop(&meson_wdt->wdt_dev); | |
169 | ||
170 | err = watchdog_register_device(&meson_wdt->wdt_dev); | |
171 | if (err) | |
172 | return err; | |
173 | ||
174 | platform_set_drvdata(pdev, meson_wdt); | |
175 | ||
176 | meson_wdt->restart_handler.notifier_call = meson_restart_handle; | |
177 | meson_wdt->restart_handler.priority = 128; | |
178 | err = register_restart_handler(&meson_wdt->restart_handler); | |
179 | if (err) | |
180 | dev_err(&pdev->dev, | |
181 | "cannot register restart handler (err=%d)\n", err); | |
182 | ||
183 | dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", | |
184 | meson_wdt->wdt_dev.timeout, nowayout); | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
189 | static int meson_wdt_remove(struct platform_device *pdev) | |
190 | { | |
191 | struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); | |
192 | ||
193 | unregister_restart_handler(&meson_wdt->restart_handler); | |
194 | ||
195 | watchdog_unregister_device(&meson_wdt->wdt_dev); | |
196 | ||
197 | return 0; | |
198 | } | |
199 | ||
200 | static void meson_wdt_shutdown(struct platform_device *pdev) | |
201 | { | |
202 | struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); | |
203 | ||
204 | meson_wdt_stop(&meson_wdt->wdt_dev); | |
205 | } | |
206 | ||
207 | static const struct of_device_id meson_wdt_dt_ids[] = { | |
208 | { .compatible = "amlogic,meson6-wdt" }, | |
209 | { /* sentinel */ } | |
210 | }; | |
211 | MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids); | |
212 | ||
213 | static struct platform_driver meson_wdt_driver = { | |
214 | .probe = meson_wdt_probe, | |
215 | .remove = meson_wdt_remove, | |
216 | .shutdown = meson_wdt_shutdown, | |
217 | .driver = { | |
218 | .owner = THIS_MODULE, | |
219 | .name = DRV_NAME, | |
220 | .of_match_table = meson_wdt_dt_ids, | |
221 | }, | |
222 | }; | |
223 | ||
224 | module_platform_driver(meson_wdt_driver); | |
225 | ||
226 | module_param(timeout, uint, 0); | |
227 | MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); | |
228 | ||
229 | module_param(nowayout, bool, 0); | |
230 | MODULE_PARM_DESC(nowayout, | |
231 | "Watchdog cannot be stopped once started (default=" | |
232 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
233 | ||
234 | MODULE_LICENSE("GPL"); | |
235 | MODULE_AUTHOR("Carlo Caione <carlo@caione.org>"); | |
236 | MODULE_DESCRIPTION("Meson Watchdog Timer Driver"); |