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f8394f61 GJ |
1 | /* |
2 | * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer. | |
3 | * | |
4 | * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org> | |
5 | * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org> | |
6 | * | |
7 | * This driver was based on: drivers/watchdog/ixp4xx_wdt.c | |
8 | * Author: Deepak Saxena <dsaxena@plexity.net> | |
9 | * Copyright 2004 (c) MontaVista, Software, Inc. | |
10 | * | |
11 | * which again was based on sa1100 driver, | |
12 | * Copyright (C) 2000 Oleg Drokin <green@crimea.edu> | |
13 | * | |
14 | * This program is free software; you can redistribute it and/or modify it | |
15 | * under the terms of the GNU General Public License version 2 as published | |
16 | * by the Free Software Foundation. | |
17 | * | |
18 | */ | |
19 | ||
20 | #include <linux/bitops.h> | |
21 | #include <linux/errno.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/miscdevice.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/moduleparam.h> | |
28 | #include <linux/platform_device.h> | |
29 | #include <linux/types.h> | |
30 | #include <linux/watchdog.h> | |
31 | #include <linux/clk.h> | |
32 | #include <linux/err.h> | |
33 | ||
34 | #include <asm/mach-ath79/ath79.h> | |
35 | #include <asm/mach-ath79/ar71xx_regs.h> | |
36 | ||
37 | #define DRIVER_NAME "ath79-wdt" | |
38 | ||
39 | #define WDT_TIMEOUT 15 /* seconds */ | |
40 | ||
41 | #define WDOG_CTRL_LAST_RESET BIT(31) | |
42 | #define WDOG_CTRL_ACTION_MASK 3 | |
43 | #define WDOG_CTRL_ACTION_NONE 0 /* no action */ | |
44 | #define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */ | |
45 | #define WDOG_CTRL_ACTION_NMI 2 /* NMI */ | |
46 | #define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */ | |
47 | ||
48 | static int nowayout = WATCHDOG_NOWAYOUT; | |
49 | module_param(nowayout, int, 0); | |
50 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " | |
51 | "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
52 | ||
53 | static int timeout = WDT_TIMEOUT; | |
54 | module_param(timeout, int, 0); | |
55 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds " | |
56 | "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)"); | |
57 | ||
58 | static unsigned long wdt_flags; | |
59 | ||
60 | #define WDT_FLAGS_BUSY 0 | |
61 | #define WDT_FLAGS_EXPECT_CLOSE 1 | |
62 | ||
63 | static struct clk *wdt_clk; | |
64 | static unsigned long wdt_freq; | |
65 | static int boot_status; | |
66 | static int max_timeout; | |
67 | ||
68 | static inline void ath79_wdt_keepalive(void) | |
69 | { | |
70 | ath79_reset_wr(AR71XX_RESET_REG_WDOG, wdt_freq * timeout); | |
71 | } | |
72 | ||
73 | static inline void ath79_wdt_enable(void) | |
74 | { | |
75 | ath79_wdt_keepalive(); | |
76 | ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR); | |
77 | } | |
78 | ||
79 | static inline void ath79_wdt_disable(void) | |
80 | { | |
81 | ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE); | |
82 | } | |
83 | ||
84 | static int ath79_wdt_set_timeout(int val) | |
85 | { | |
86 | if (val < 1 || val > max_timeout) | |
87 | return -EINVAL; | |
88 | ||
89 | timeout = val; | |
90 | ath79_wdt_keepalive(); | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | static int ath79_wdt_open(struct inode *inode, struct file *file) | |
96 | { | |
97 | if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags)) | |
98 | return -EBUSY; | |
99 | ||
100 | clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); | |
101 | ath79_wdt_enable(); | |
102 | ||
103 | return nonseekable_open(inode, file); | |
104 | } | |
105 | ||
106 | static int ath79_wdt_release(struct inode *inode, struct file *file) | |
107 | { | |
108 | if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags)) | |
109 | ath79_wdt_disable(); | |
110 | else { | |
111 | pr_crit(DRIVER_NAME ": device closed unexpectedly, " | |
112 | "watchdog timer will not stop!\n"); | |
113 | ath79_wdt_keepalive(); | |
114 | } | |
115 | ||
116 | clear_bit(WDT_FLAGS_BUSY, &wdt_flags); | |
117 | clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); | |
118 | ||
119 | return 0; | |
120 | } | |
121 | ||
122 | static ssize_t ath79_wdt_write(struct file *file, const char *data, | |
123 | size_t len, loff_t *ppos) | |
124 | { | |
125 | if (len) { | |
126 | if (!nowayout) { | |
127 | size_t i; | |
128 | ||
129 | clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); | |
130 | ||
131 | for (i = 0; i != len; i++) { | |
132 | char c; | |
133 | ||
134 | if (get_user(c, data + i)) | |
135 | return -EFAULT; | |
136 | ||
137 | if (c == 'V') | |
138 | set_bit(WDT_FLAGS_EXPECT_CLOSE, | |
139 | &wdt_flags); | |
140 | } | |
141 | } | |
142 | ||
143 | ath79_wdt_keepalive(); | |
144 | } | |
145 | ||
146 | return len; | |
147 | } | |
148 | ||
149 | static const struct watchdog_info ath79_wdt_info = { | |
150 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
151 | WDIOF_MAGICCLOSE | WDIOF_CARDRESET, | |
152 | .firmware_version = 0, | |
153 | .identity = "ATH79 watchdog", | |
154 | }; | |
155 | ||
156 | static long ath79_wdt_ioctl(struct file *file, unsigned int cmd, | |
157 | unsigned long arg) | |
158 | { | |
159 | void __user *argp = (void __user *)arg; | |
160 | int __user *p = argp; | |
161 | int err; | |
162 | int t; | |
163 | ||
164 | switch (cmd) { | |
165 | case WDIOC_GETSUPPORT: | |
166 | err = copy_to_user(argp, &ath79_wdt_info, | |
167 | sizeof(ath79_wdt_info)) ? -EFAULT : 0; | |
168 | break; | |
169 | ||
170 | case WDIOC_GETSTATUS: | |
171 | err = put_user(0, p); | |
172 | break; | |
173 | ||
174 | case WDIOC_GETBOOTSTATUS: | |
175 | err = put_user(boot_status, p); | |
176 | break; | |
177 | ||
178 | case WDIOC_KEEPALIVE: | |
179 | ath79_wdt_keepalive(); | |
180 | err = 0; | |
181 | break; | |
182 | ||
183 | case WDIOC_SETTIMEOUT: | |
184 | err = get_user(t, p); | |
185 | if (err) | |
186 | break; | |
187 | ||
188 | err = ath79_wdt_set_timeout(t); | |
189 | if (err) | |
190 | break; | |
191 | ||
192 | /* fallthrough */ | |
193 | case WDIOC_GETTIMEOUT: | |
194 | err = put_user(timeout, p); | |
195 | break; | |
196 | ||
197 | default: | |
198 | err = -ENOTTY; | |
199 | break; | |
200 | } | |
201 | ||
202 | return err; | |
203 | } | |
204 | ||
205 | static const struct file_operations ath79_wdt_fops = { | |
206 | .owner = THIS_MODULE, | |
207 | .llseek = no_llseek, | |
208 | .write = ath79_wdt_write, | |
209 | .unlocked_ioctl = ath79_wdt_ioctl, | |
210 | .open = ath79_wdt_open, | |
211 | .release = ath79_wdt_release, | |
212 | }; | |
213 | ||
214 | static struct miscdevice ath79_wdt_miscdev = { | |
215 | .minor = WATCHDOG_MINOR, | |
216 | .name = "watchdog", | |
217 | .fops = &ath79_wdt_fops, | |
218 | }; | |
219 | ||
220 | static int __devinit ath79_wdt_probe(struct platform_device *pdev) | |
221 | { | |
222 | u32 ctrl; | |
223 | int err; | |
224 | ||
225 | wdt_clk = clk_get(&pdev->dev, "wdt"); | |
226 | if (IS_ERR(wdt_clk)) | |
227 | return PTR_ERR(wdt_clk); | |
228 | ||
229 | err = clk_enable(wdt_clk); | |
230 | if (err) | |
231 | goto err_clk_put; | |
232 | ||
233 | wdt_freq = clk_get_rate(wdt_clk); | |
234 | if (!wdt_freq) { | |
235 | err = -EINVAL; | |
236 | goto err_clk_disable; | |
237 | } | |
238 | ||
239 | max_timeout = (0xfffffffful / wdt_freq); | |
240 | if (timeout < 1 || timeout > max_timeout) { | |
241 | timeout = max_timeout; | |
242 | dev_info(&pdev->dev, | |
243 | "timeout value must be 0 < timeout < %d, using %d\n", | |
244 | max_timeout, timeout); | |
245 | } | |
246 | ||
247 | ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL); | |
248 | boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0; | |
249 | ||
250 | err = misc_register(&ath79_wdt_miscdev); | |
251 | if (err) { | |
252 | dev_err(&pdev->dev, | |
253 | "unable to register misc device, err=%d\n", err); | |
254 | goto err_clk_disable; | |
255 | } | |
256 | ||
257 | return 0; | |
258 | ||
259 | err_clk_disable: | |
260 | clk_disable(wdt_clk); | |
261 | err_clk_put: | |
262 | clk_put(wdt_clk); | |
263 | return err; | |
264 | } | |
265 | ||
266 | static int __devexit ath79_wdt_remove(struct platform_device *pdev) | |
267 | { | |
268 | misc_deregister(&ath79_wdt_miscdev); | |
269 | clk_disable(wdt_clk); | |
270 | clk_put(wdt_clk); | |
271 | return 0; | |
272 | } | |
273 | ||
274 | static void ath97_wdt_shutdown(struct platform_device *pdev) | |
275 | { | |
276 | ath79_wdt_disable(); | |
277 | } | |
278 | ||
279 | static struct platform_driver ath79_wdt_driver = { | |
280 | .remove = __devexit_p(ath79_wdt_remove), | |
281 | .shutdown = ath97_wdt_shutdown, | |
282 | .driver = { | |
283 | .name = DRIVER_NAME, | |
284 | .owner = THIS_MODULE, | |
285 | }, | |
286 | }; | |
287 | ||
288 | static int __init ath79_wdt_init(void) | |
289 | { | |
290 | return platform_driver_probe(&ath79_wdt_driver, ath79_wdt_probe); | |
291 | } | |
292 | module_init(ath79_wdt_init); | |
293 | ||
294 | static void __exit ath79_wdt_exit(void) | |
295 | { | |
296 | platform_driver_unregister(&ath79_wdt_driver); | |
297 | } | |
298 | module_exit(ath79_wdt_exit); | |
299 | ||
300 | MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver"); | |
301 | MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org"); | |
302 | MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org"); | |
303 | MODULE_LICENSE("GPL v2"); | |
304 | MODULE_ALIAS("platform:" DRIVER_NAME); | |
305 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |