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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 | ||
853807fb AV |
12 | #include <linux/errno.h> |
13 | #include <linux/fs.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/miscdevice.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/moduleparam.h> | |
dfc7bd9c | 19 | #include <linux/platform_device.h> |
853807fb AV |
20 | #include <linux/types.h> |
21 | #include <linux/watchdog.h> | |
22 | #include <asm/bitops.h> | |
23 | #include <asm/uaccess.h> | |
24 | ||
25 | ||
dfc7bd9c AV |
26 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
27 | #define WDT_MAX_TIME 256 /* seconds */ | |
853807fb AV |
28 | |
29 | static int wdt_time = WDT_DEFAULT_TIME; | |
30 | static int nowayout = WATCHDOG_NOWAYOUT; | |
31 | ||
32 | module_param(wdt_time, int, 0); | |
33 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="__MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
34 | ||
dfc7bd9c | 35 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
853807fb AV |
36 | module_param(nowayout, int, 0); |
37 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
dfc7bd9c | 38 | #endif |
853807fb AV |
39 | |
40 | ||
41 | static unsigned long at91wdt_busy; | |
42 | ||
43 | /* ......................................................................... */ | |
44 | ||
45 | /* | |
46 | * Disable the watchdog. | |
47 | */ | |
48 | static void inline at91_wdt_stop(void) | |
49 | { | |
50 | at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN); | |
51 | } | |
52 | ||
53 | /* | |
54 | * Enable and reset the watchdog. | |
55 | */ | |
56 | static void inline at91_wdt_start(void) | |
57 | { | |
58 | at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); | |
59 | at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); | |
60 | } | |
61 | ||
62 | /* | |
63 | * Reload the watchdog timer. (ie, pat the watchdog) | |
64 | */ | |
65 | static void inline at91_wdt_reload(void) | |
66 | { | |
67 | at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); | |
68 | } | |
69 | ||
70 | /* ......................................................................... */ | |
71 | ||
72 | /* | |
73 | * Watchdog device is opened, and watchdog starts running. | |
74 | */ | |
75 | static int at91_wdt_open(struct inode *inode, struct file *file) | |
76 | { | |
77 | if (test_and_set_bit(0, &at91wdt_busy)) | |
78 | return -EBUSY; | |
79 | ||
80 | at91_wdt_start(); | |
81 | return nonseekable_open(inode, file); | |
82 | } | |
83 | ||
84 | /* | |
85 | * Close the watchdog device. | |
86 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also | |
87 | * disabled. | |
88 | */ | |
89 | static int at91_wdt_close(struct inode *inode, struct file *file) | |
90 | { | |
91 | if (!nowayout) | |
92 | at91_wdt_stop(); /* Disable the watchdog when file is closed */ | |
93 | ||
94 | clear_bit(0, &at91wdt_busy); | |
95 | return 0; | |
96 | } | |
97 | ||
98 | /* | |
99 | * Change the watchdog time interval. | |
100 | */ | |
101 | static int at91_wdt_settimeout(int new_time) | |
102 | { | |
103 | /* | |
104 | * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz | |
105 | * | |
106 | * Since WDV is a 16-bit counter, the maximum period is | |
107 | * 65536 / 0.256 = 256 seconds. | |
108 | */ | |
109 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | |
110 | return -EINVAL; | |
111 | ||
112 | /* Set new watchdog time. It will be used when at91_wdt_start() is called. */ | |
113 | wdt_time = new_time; | |
114 | return 0; | |
115 | } | |
116 | ||
117 | static struct watchdog_info at91_wdt_info = { | |
118 | .identity = "at91 watchdog", | |
119 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
120 | }; | |
121 | ||
122 | /* | |
123 | * Handle commands from user-space. | |
124 | */ | |
125 | static int at91_wdt_ioctl(struct inode *inode, struct file *file, | |
126 | unsigned int cmd, unsigned long arg) | |
127 | { | |
128 | void __user *argp = (void __user *)arg; | |
129 | int __user *p = argp; | |
130 | int new_value; | |
131 | ||
132 | switch(cmd) { | |
133 | case WDIOC_KEEPALIVE: | |
134 | at91_wdt_reload(); /* pat the watchdog */ | |
135 | return 0; | |
136 | ||
137 | case WDIOC_GETSUPPORT: | |
138 | return copy_to_user(argp, &at91_wdt_info, sizeof(at91_wdt_info)) ? -EFAULT : 0; | |
139 | ||
140 | case WDIOC_SETTIMEOUT: | |
141 | if (get_user(new_value, p)) | |
142 | return -EFAULT; | |
dfc7bd9c | 143 | |
853807fb AV |
144 | if (at91_wdt_settimeout(new_value)) |
145 | return -EINVAL; | |
146 | ||
147 | /* Enable new time value */ | |
148 | at91_wdt_start(); | |
149 | ||
150 | /* Return current value */ | |
151 | return put_user(wdt_time, p); | |
152 | ||
153 | case WDIOC_GETTIMEOUT: | |
154 | return put_user(wdt_time, p); | |
155 | ||
156 | case WDIOC_GETSTATUS: | |
157 | case WDIOC_GETBOOTSTATUS: | |
158 | return put_user(0, p); | |
159 | ||
160 | case WDIOC_SETOPTIONS: | |
161 | if (get_user(new_value, p)) | |
162 | return -EFAULT; | |
163 | ||
164 | if (new_value & WDIOS_DISABLECARD) | |
165 | at91_wdt_stop(); | |
166 | if (new_value & WDIOS_ENABLECARD) | |
167 | at91_wdt_start(); | |
168 | return 0; | |
169 | ||
170 | default: | |
795b89d2 | 171 | return -ENOTTY; |
853807fb AV |
172 | } |
173 | } | |
174 | ||
175 | /* | |
176 | * Pat the watchdog whenever device is written to. | |
177 | */ | |
178 | static ssize_t at91_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) | |
179 | { | |
180 | at91_wdt_reload(); /* pat the watchdog */ | |
181 | return len; | |
182 | } | |
183 | ||
184 | /* ......................................................................... */ | |
185 | ||
62322d25 | 186 | static const struct file_operations at91wdt_fops = { |
853807fb AV |
187 | .owner = THIS_MODULE, |
188 | .llseek = no_llseek, | |
189 | .ioctl = at91_wdt_ioctl, | |
190 | .open = at91_wdt_open, | |
191 | .release = at91_wdt_close, | |
192 | .write = at91_wdt_write, | |
193 | }; | |
194 | ||
195 | static struct miscdevice at91wdt_miscdev = { | |
196 | .minor = WATCHDOG_MINOR, | |
197 | .name = "watchdog", | |
198 | .fops = &at91wdt_fops, | |
199 | }; | |
200 | ||
dfc7bd9c | 201 | static int __init at91wdt_probe(struct platform_device *pdev) |
853807fb AV |
202 | { |
203 | int res; | |
204 | ||
dfc7bd9c AV |
205 | if (at91wdt_miscdev.dev) |
206 | return -EBUSY; | |
207 | at91wdt_miscdev.dev = &pdev->dev; | |
853807fb AV |
208 | |
209 | res = misc_register(&at91wdt_miscdev); | |
210 | if (res) | |
211 | return res; | |
212 | ||
dfc7bd9c | 213 | printk("AT91 Watchdog Timer enabled (%d seconds%s)\n", 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) | |
223 | at91wdt_miscdev.dev = NULL; | |
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 | { | |
267 | /* Check that the heartbeat value is within range; if not reset to the default */ | |
268 | if (at91_wdt_settimeout(wdt_time)) { | |
269 | at91_wdt_settimeout(WDT_DEFAULT_TIME); | |
270 | pr_info("at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time); | |
271 | } | |
272 | ||
273 | return platform_driver_register(&at91wdt_driver); | |
274 | } | |
275 | ||
853807fb AV |
276 | static void __exit at91_wdt_exit(void) |
277 | { | |
dfc7bd9c | 278 | platform_driver_unregister(&at91wdt_driver); |
853807fb AV |
279 | } |
280 | ||
281 | module_init(at91_wdt_init); | |
282 | module_exit(at91_wdt_exit); | |
283 | ||
284 | MODULE_AUTHOR("Andrew Victor"); | |
285 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200"); | |
286 | MODULE_LICENSE("GPL"); | |
287 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |