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853807fb AV |
1 | /* |
2 | * Watchdog driver for Atmel AT91RM9200 (Thunder) | |
3 | * | |
4 | * Copyright (C) 2003 SAN People (Pty) Ltd | |
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 | ||
1977f032 | 12 | #include <linux/bitops.h> |
853807fb AV |
13 | #include <linux/errno.h> |
14 | #include <linux/fs.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/miscdevice.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/moduleparam.h> | |
dfc7bd9c | 20 | #include <linux/platform_device.h> |
853807fb AV |
21 | #include <linux/types.h> |
22 | #include <linux/watchdog.h> | |
2760600d | 23 | #include <linux/uaccess.h> |
55d8baee | 24 | #include <asm/arch/at91_st.h> |
853807fb AV |
25 | |
26 | ||
dfc7bd9c AV |
27 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
28 | #define WDT_MAX_TIME 256 /* seconds */ | |
853807fb AV |
29 | |
30 | static int wdt_time = WDT_DEFAULT_TIME; | |
31 | static int nowayout = WATCHDOG_NOWAYOUT; | |
32 | ||
33 | module_param(wdt_time, int, 0); | |
2760600d AC |
34 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
35 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
853807fb | 36 | |
dfc7bd9c | 37 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
853807fb | 38 | module_param(nowayout, int, 0); |
2760600d AC |
39 | MODULE_PARM_DESC(nowayout, |
40 | "Watchdog cannot be stopped once started (default=" | |
41 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
dfc7bd9c | 42 | #endif |
853807fb AV |
43 | |
44 | ||
45 | static unsigned long at91wdt_busy; | |
46 | ||
47 | /* ......................................................................... */ | |
48 | ||
49 | /* | |
50 | * Disable the watchdog. | |
51 | */ | |
2760600d | 52 | static inline void at91_wdt_stop(void) |
853807fb AV |
53 | { |
54 | at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN); | |
55 | } | |
56 | ||
57 | /* | |
58 | * Enable and reset the watchdog. | |
59 | */ | |
2760600d | 60 | static inline void at91_wdt_start(void) |
853807fb | 61 | { |
2760600d AC |
62 | at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | |
63 | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); | |
853807fb AV |
64 | at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); |
65 | } | |
66 | ||
67 | /* | |
68 | * Reload the watchdog timer. (ie, pat the watchdog) | |
69 | */ | |
2760600d | 70 | static inline void at91_wdt_reload(void) |
853807fb AV |
71 | { |
72 | at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); | |
73 | } | |
74 | ||
75 | /* ......................................................................... */ | |
76 | ||
77 | /* | |
78 | * Watchdog device is opened, and watchdog starts running. | |
79 | */ | |
80 | static int at91_wdt_open(struct inode *inode, struct file *file) | |
81 | { | |
82 | if (test_and_set_bit(0, &at91wdt_busy)) | |
83 | return -EBUSY; | |
84 | ||
85 | at91_wdt_start(); | |
86 | return nonseekable_open(inode, file); | |
87 | } | |
88 | ||
89 | /* | |
90 | * Close the watchdog device. | |
91 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also | |
92 | * disabled. | |
93 | */ | |
94 | static int at91_wdt_close(struct inode *inode, struct file *file) | |
95 | { | |
2760600d | 96 | /* Disable the watchdog when file is closed */ |
853807fb | 97 | if (!nowayout) |
2760600d | 98 | at91_wdt_stop(); |
853807fb AV |
99 | |
100 | clear_bit(0, &at91wdt_busy); | |
101 | return 0; | |
102 | } | |
103 | ||
104 | /* | |
105 | * Change the watchdog time interval. | |
106 | */ | |
107 | static int at91_wdt_settimeout(int new_time) | |
108 | { | |
109 | /* | |
110 | * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz | |
111 | * | |
112 | * Since WDV is a 16-bit counter, the maximum period is | |
113 | * 65536 / 0.256 = 256 seconds. | |
114 | */ | |
115 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | |
116 | return -EINVAL; | |
117 | ||
2760600d AC |
118 | /* Set new watchdog time. It will be used when |
119 | at91_wdt_start() is called. */ | |
853807fb AV |
120 | wdt_time = new_time; |
121 | return 0; | |
122 | } | |
123 | ||
124 | static struct watchdog_info at91_wdt_info = { | |
125 | .identity = "at91 watchdog", | |
126 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
127 | }; | |
128 | ||
129 | /* | |
130 | * Handle commands from user-space. | |
131 | */ | |
2760600d AC |
132 | static long at91_wdt_ioct(struct file *file, |
133 | unsigned int cmd, unsigned long arg) | |
853807fb AV |
134 | { |
135 | void __user *argp = (void __user *)arg; | |
136 | int __user *p = argp; | |
137 | int new_value; | |
138 | ||
2760600d AC |
139 | switch (cmd) { |
140 | case WDIOC_KEEPALIVE: | |
141 | at91_wdt_reload(); /* pat the watchdog */ | |
142 | return 0; | |
143 | case WDIOC_GETSUPPORT: | |
144 | return copy_to_user(argp, &at91_wdt_info, | |
145 | sizeof(at91_wdt_info)) ? -EFAULT : 0; | |
146 | case WDIOC_SETTIMEOUT: | |
147 | if (get_user(new_value, p)) | |
148 | return -EFAULT; | |
149 | if (at91_wdt_settimeout(new_value)) | |
150 | return -EINVAL; | |
151 | /* Enable new time value */ | |
152 | at91_wdt_start(); | |
153 | /* Return current value */ | |
154 | return put_user(wdt_time, p); | |
155 | case WDIOC_GETTIMEOUT: | |
156 | return put_user(wdt_time, p); | |
157 | case WDIOC_GETSTATUS: | |
158 | case WDIOC_GETBOOTSTATUS: | |
159 | return put_user(0, p); | |
160 | case WDIOC_SETOPTIONS: | |
161 | if (get_user(new_value, p)) | |
162 | return -EFAULT; | |
163 | if (new_value & WDIOS_DISABLECARD) | |
164 | at91_wdt_stop(); | |
165 | if (new_value & WDIOS_ENABLECARD) | |
853807fb | 166 | at91_wdt_start(); |
2760600d AC |
167 | return 0; |
168 | default: | |
169 | return -ENOTTY; | |
853807fb AV |
170 | } |
171 | } | |
172 | ||
173 | /* | |
174 | * Pat the watchdog whenever device is written to. | |
175 | */ | |
2760600d AC |
176 | static ssize_t at91_wdt_write(struct file *file, const char *data, |
177 | size_t len, loff_t *ppos) | |
853807fb AV |
178 | { |
179 | at91_wdt_reload(); /* pat the watchdog */ | |
180 | return len; | |
181 | } | |
182 | ||
183 | /* ......................................................................... */ | |
184 | ||
62322d25 | 185 | static const struct file_operations at91wdt_fops = { |
853807fb AV |
186 | .owner = THIS_MODULE, |
187 | .llseek = no_llseek, | |
2760600d | 188 | .unlocked_ioctl = at91_wdt_ioctl, |
853807fb AV |
189 | .open = at91_wdt_open, |
190 | .release = at91_wdt_close, | |
191 | .write = at91_wdt_write, | |
192 | }; | |
193 | ||
194 | static struct miscdevice at91wdt_miscdev = { | |
195 | .minor = WATCHDOG_MINOR, | |
196 | .name = "watchdog", | |
197 | .fops = &at91wdt_fops, | |
198 | }; | |
199 | ||
dfc7bd9c | 200 | static int __init at91wdt_probe(struct platform_device *pdev) |
853807fb AV |
201 | { |
202 | int res; | |
203 | ||
e0b79e0b | 204 | if (at91wdt_miscdev.parent) |
dfc7bd9c | 205 | return -EBUSY; |
e0b79e0b | 206 | at91wdt_miscdev.parent = &pdev->dev; |
853807fb AV |
207 | |
208 | res = misc_register(&at91wdt_miscdev); | |
209 | if (res) | |
210 | return res; | |
211 | ||
2760600d AC |
212 | printk(KERN_INFO "AT91 Watchdog Timer enabled (%d seconds%s)\n", |
213 | wdt_time, nowayout ? ", nowayout" : ""); | |
853807fb AV |
214 | return 0; |
215 | } | |
216 | ||
dfc7bd9c AV |
217 | static int __exit at91wdt_remove(struct platform_device *pdev) |
218 | { | |
219 | int res; | |
220 | ||
221 | res = misc_deregister(&at91wdt_miscdev); | |
222 | if (!res) | |
e0b79e0b | 223 | at91wdt_miscdev.parent = NULL; |
dfc7bd9c AV |
224 | |
225 | return res; | |
226 | } | |
227 | ||
228 | static void at91wdt_shutdown(struct platform_device *pdev) | |
229 | { | |
230 | at91_wdt_stop(); | |
231 | } | |
232 | ||
233 | #ifdef CONFIG_PM | |
234 | ||
235 | static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
236 | { | |
237 | at91_wdt_stop(); | |
238 | return 0; | |
239 | } | |
240 | ||
241 | static int at91wdt_resume(struct platform_device *pdev) | |
242 | { | |
243 | if (at91wdt_busy) | |
244 | at91_wdt_start(); | |
245 | return 0; | |
246 | } | |
247 | ||
248 | #else | |
249 | #define at91wdt_suspend NULL | |
250 | #define at91wdt_resume NULL | |
251 | #endif | |
252 | ||
253 | static struct platform_driver at91wdt_driver = { | |
254 | .probe = at91wdt_probe, | |
255 | .remove = __exit_p(at91wdt_remove), | |
256 | .shutdown = at91wdt_shutdown, | |
257 | .suspend = at91wdt_suspend, | |
258 | .resume = at91wdt_resume, | |
259 | .driver = { | |
260 | .name = "at91_wdt", | |
261 | .owner = THIS_MODULE, | |
262 | }, | |
263 | }; | |
264 | ||
265 | static int __init at91_wdt_init(void) | |
266 | { | |
2760600d AC |
267 | /* Check that the heartbeat value is within range; |
268 | if not reset to the default */ | |
dfc7bd9c AV |
269 | if (at91_wdt_settimeout(wdt_time)) { |
270 | at91_wdt_settimeout(WDT_DEFAULT_TIME); | |
271 | pr_info("at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time); | |
272 | } | |
273 | ||
274 | return platform_driver_register(&at91wdt_driver); | |
275 | } | |
276 | ||
853807fb AV |
277 | static void __exit at91_wdt_exit(void) |
278 | { | |
dfc7bd9c | 279 | platform_driver_unregister(&at91wdt_driver); |
853807fb AV |
280 | } |
281 | ||
282 | module_init(at91_wdt_init); | |
283 | module_exit(at91_wdt_exit); | |
284 | ||
285 | MODULE_AUTHOR("Andrew Victor"); | |
286 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200"); | |
287 | MODULE_LICENSE("GPL"); | |
288 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
f37d193c | 289 | MODULE_ALIAS("platform:at91_wdt"); |