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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 | ||
27c766aa JP |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
1977f032 | 14 | #include <linux/bitops.h> |
853807fb AV |
15 | #include <linux/errno.h> |
16 | #include <linux/fs.h> | |
17 | #include <linux/init.h> | |
02e0746e | 18 | #include <linux/io.h> |
853807fb AV |
19 | #include <linux/kernel.h> |
20 | #include <linux/miscdevice.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/moduleparam.h> | |
dfc7bd9c | 23 | #include <linux/platform_device.h> |
853807fb AV |
24 | #include <linux/types.h> |
25 | #include <linux/watchdog.h> | |
2760600d | 26 | #include <linux/uaccess.h> |
a09e64fb | 27 | #include <mach/at91_st.h> |
853807fb | 28 | |
dfc7bd9c AV |
29 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
30 | #define WDT_MAX_TIME 256 /* seconds */ | |
853807fb AV |
31 | |
32 | static int wdt_time = WDT_DEFAULT_TIME; | |
86a1e189 | 33 | static bool nowayout = WATCHDOG_NOWAYOUT; |
853807fb AV |
34 | |
35 | module_param(wdt_time, int, 0); | |
2760600d AC |
36 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
37 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
853807fb | 38 | |
dfc7bd9c | 39 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
86a1e189 | 40 | module_param(nowayout, bool, 0); |
2760600d AC |
41 | MODULE_PARM_DESC(nowayout, |
42 | "Watchdog cannot be stopped once started (default=" | |
43 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
dfc7bd9c | 44 | #endif |
853807fb AV |
45 | |
46 | ||
47 | static unsigned long at91wdt_busy; | |
48 | ||
49 | /* ......................................................................... */ | |
50 | ||
51 | /* | |
52 | * Disable the watchdog. | |
53 | */ | |
2760600d | 54 | static inline void at91_wdt_stop(void) |
853807fb | 55 | { |
5e9cf5e1 | 56 | at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN); |
853807fb AV |
57 | } |
58 | ||
59 | /* | |
60 | * Enable and reset the watchdog. | |
61 | */ | |
2760600d | 62 | static inline void at91_wdt_start(void) |
853807fb | 63 | { |
5e9cf5e1 | 64 | at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | |
2760600d | 65 | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); |
5e9cf5e1 | 66 | at91_st_write(AT91_ST_CR, AT91_ST_WDRST); |
853807fb AV |
67 | } |
68 | ||
69 | /* | |
70 | * Reload the watchdog timer. (ie, pat the watchdog) | |
71 | */ | |
2760600d | 72 | static inline void at91_wdt_reload(void) |
853807fb | 73 | { |
5e9cf5e1 | 74 | at91_st_write(AT91_ST_CR, AT91_ST_WDRST); |
853807fb AV |
75 | } |
76 | ||
77 | /* ......................................................................... */ | |
78 | ||
79 | /* | |
80 | * Watchdog device is opened, and watchdog starts running. | |
81 | */ | |
82 | static int at91_wdt_open(struct inode *inode, struct file *file) | |
83 | { | |
84 | if (test_and_set_bit(0, &at91wdt_busy)) | |
85 | return -EBUSY; | |
86 | ||
87 | at91_wdt_start(); | |
88 | return nonseekable_open(inode, file); | |
89 | } | |
90 | ||
91 | /* | |
92 | * Close the watchdog device. | |
93 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also | |
94 | * disabled. | |
95 | */ | |
96 | static int at91_wdt_close(struct inode *inode, struct file *file) | |
97 | { | |
2760600d | 98 | /* Disable the watchdog when file is closed */ |
853807fb | 99 | if (!nowayout) |
2760600d | 100 | at91_wdt_stop(); |
853807fb AV |
101 | |
102 | clear_bit(0, &at91wdt_busy); | |
103 | return 0; | |
104 | } | |
105 | ||
106 | /* | |
107 | * Change the watchdog time interval. | |
108 | */ | |
109 | static int at91_wdt_settimeout(int new_time) | |
110 | { | |
111 | /* | |
2af29b78 | 112 | * All counting occurs at SLOW_CLOCK / 128 = 256 Hz |
853807fb AV |
113 | * |
114 | * Since WDV is a 16-bit counter, the maximum period is | |
2af29b78 | 115 | * 65536 / 256 = 256 seconds. |
853807fb AV |
116 | */ |
117 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | |
118 | return -EINVAL; | |
119 | ||
2760600d AC |
120 | /* Set new watchdog time. It will be used when |
121 | at91_wdt_start() is called. */ | |
853807fb AV |
122 | wdt_time = new_time; |
123 | return 0; | |
124 | } | |
125 | ||
42747d71 | 126 | static const struct watchdog_info at91_wdt_info = { |
853807fb AV |
127 | .identity = "at91 watchdog", |
128 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
129 | }; | |
130 | ||
131 | /* | |
132 | * Handle commands from user-space. | |
133 | */ | |
3c4fafd6 | 134 | static long at91_wdt_ioctl(struct file *file, |
2760600d | 135 | unsigned int cmd, unsigned long arg) |
853807fb AV |
136 | { |
137 | void __user *argp = (void __user *)arg; | |
138 | int __user *p = argp; | |
139 | int new_value; | |
140 | ||
2760600d | 141 | switch (cmd) { |
2760600d AC |
142 | case WDIOC_GETSUPPORT: |
143 | return copy_to_user(argp, &at91_wdt_info, | |
144 | sizeof(at91_wdt_info)) ? -EFAULT : 0; | |
2760600d AC |
145 | case WDIOC_GETSTATUS: |
146 | case WDIOC_GETBOOTSTATUS: | |
147 | return put_user(0, p); | |
148 | case WDIOC_SETOPTIONS: | |
149 | if (get_user(new_value, p)) | |
150 | return -EFAULT; | |
151 | if (new_value & WDIOS_DISABLECARD) | |
152 | at91_wdt_stop(); | |
153 | if (new_value & WDIOS_ENABLECARD) | |
853807fb | 154 | at91_wdt_start(); |
2760600d | 155 | return 0; |
0c06090c WVS |
156 | case WDIOC_KEEPALIVE: |
157 | at91_wdt_reload(); /* pat the watchdog */ | |
158 | return 0; | |
159 | case WDIOC_SETTIMEOUT: | |
160 | if (get_user(new_value, p)) | |
161 | return -EFAULT; | |
162 | if (at91_wdt_settimeout(new_value)) | |
163 | return -EINVAL; | |
164 | /* Enable new time value */ | |
165 | at91_wdt_start(); | |
166 | /* Return current value */ | |
167 | return put_user(wdt_time, p); | |
168 | case WDIOC_GETTIMEOUT: | |
169 | return put_user(wdt_time, p); | |
2760600d AC |
170 | default: |
171 | return -ENOTTY; | |
853807fb AV |
172 | } |
173 | } | |
174 | ||
175 | /* | |
176 | * Pat the watchdog whenever device is written to. | |
177 | */ | |
2760600d AC |
178 | static ssize_t at91_wdt_write(struct file *file, const char *data, |
179 | size_t len, loff_t *ppos) | |
853807fb AV |
180 | { |
181 | at91_wdt_reload(); /* pat the watchdog */ | |
182 | return len; | |
183 | } | |
184 | ||
185 | /* ......................................................................... */ | |
186 | ||
62322d25 | 187 | static const struct file_operations at91wdt_fops = { |
853807fb AV |
188 | .owner = THIS_MODULE, |
189 | .llseek = no_llseek, | |
2760600d | 190 | .unlocked_ioctl = at91_wdt_ioctl, |
853807fb AV |
191 | .open = at91_wdt_open, |
192 | .release = at91_wdt_close, | |
193 | .write = at91_wdt_write, | |
194 | }; | |
195 | ||
196 | static struct miscdevice at91wdt_miscdev = { | |
197 | .minor = WATCHDOG_MINOR, | |
198 | .name = "watchdog", | |
199 | .fops = &at91wdt_fops, | |
200 | }; | |
201 | ||
2d991a16 | 202 | static int at91wdt_probe(struct platform_device *pdev) |
853807fb AV |
203 | { |
204 | int res; | |
205 | ||
e0b79e0b | 206 | if (at91wdt_miscdev.parent) |
dfc7bd9c | 207 | return -EBUSY; |
e0b79e0b | 208 | at91wdt_miscdev.parent = &pdev->dev; |
853807fb AV |
209 | |
210 | res = misc_register(&at91wdt_miscdev); | |
211 | if (res) | |
212 | return res; | |
213 | ||
27c766aa JP |
214 | pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n", |
215 | wdt_time, nowayout ? ", nowayout" : ""); | |
853807fb AV |
216 | return 0; |
217 | } | |
218 | ||
4b12b896 | 219 | static int at91wdt_remove(struct platform_device *pdev) |
dfc7bd9c AV |
220 | { |
221 | int res; | |
222 | ||
223 | res = misc_deregister(&at91wdt_miscdev); | |
224 | if (!res) | |
e0b79e0b | 225 | at91wdt_miscdev.parent = NULL; |
dfc7bd9c AV |
226 | |
227 | return res; | |
228 | } | |
229 | ||
230 | static void at91wdt_shutdown(struct platform_device *pdev) | |
231 | { | |
232 | at91_wdt_stop(); | |
233 | } | |
234 | ||
235 | #ifdef CONFIG_PM | |
236 | ||
237 | static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
238 | { | |
239 | at91_wdt_stop(); | |
240 | return 0; | |
241 | } | |
242 | ||
243 | static int at91wdt_resume(struct platform_device *pdev) | |
244 | { | |
245 | if (at91wdt_busy) | |
246 | at91_wdt_start(); | |
95f62bdc | 247 | return 0; |
dfc7bd9c AV |
248 | } |
249 | ||
250 | #else | |
251 | #define at91wdt_suspend NULL | |
252 | #define at91wdt_resume NULL | |
253 | #endif | |
254 | ||
255 | static struct platform_driver at91wdt_driver = { | |
256 | .probe = at91wdt_probe, | |
82268714 | 257 | .remove = at91wdt_remove, |
dfc7bd9c AV |
258 | .shutdown = at91wdt_shutdown, |
259 | .suspend = at91wdt_suspend, | |
260 | .resume = at91wdt_resume, | |
261 | .driver = { | |
262 | .name = "at91_wdt", | |
263 | .owner = THIS_MODULE, | |
264 | }, | |
265 | }; | |
266 | ||
267 | static int __init at91_wdt_init(void) | |
268 | { | |
2760600d AC |
269 | /* Check that the heartbeat value is within range; |
270 | if not reset to the default */ | |
dfc7bd9c AV |
271 | if (at91_wdt_settimeout(wdt_time)) { |
272 | at91_wdt_settimeout(WDT_DEFAULT_TIME); | |
27c766aa JP |
273 | pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n", |
274 | wdt_time); | |
dfc7bd9c AV |
275 | } |
276 | ||
277 | return platform_driver_register(&at91wdt_driver); | |
278 | } | |
279 | ||
853807fb AV |
280 | static void __exit at91_wdt_exit(void) |
281 | { | |
dfc7bd9c | 282 | platform_driver_unregister(&at91wdt_driver); |
853807fb AV |
283 | } |
284 | ||
285 | module_init(at91_wdt_init); | |
286 | module_exit(at91_wdt_exit); | |
287 | ||
288 | MODULE_AUTHOR("Andrew Victor"); | |
289 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200"); | |
290 | MODULE_LICENSE("GPL"); | |
291 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
f37d193c | 292 | MODULE_ALIAS("platform:at91_wdt"); |