Commit | Line | Data |
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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> |
a6a1bcd3 JE |
27 | #include <linux/of.h> |
28 | #include <linux/of_device.h> | |
a09e64fb | 29 | #include <mach/at91_st.h> |
853807fb | 30 | |
dfc7bd9c AV |
31 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
32 | #define WDT_MAX_TIME 256 /* seconds */ | |
853807fb AV |
33 | |
34 | static int wdt_time = WDT_DEFAULT_TIME; | |
86a1e189 | 35 | static bool nowayout = WATCHDOG_NOWAYOUT; |
853807fb AV |
36 | |
37 | module_param(wdt_time, int, 0); | |
2760600d AC |
38 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
39 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
853807fb | 40 | |
dfc7bd9c | 41 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
86a1e189 | 42 | module_param(nowayout, bool, 0); |
2760600d AC |
43 | MODULE_PARM_DESC(nowayout, |
44 | "Watchdog cannot be stopped once started (default=" | |
45 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
dfc7bd9c | 46 | #endif |
853807fb AV |
47 | |
48 | ||
49 | static unsigned long at91wdt_busy; | |
50 | ||
51 | /* ......................................................................... */ | |
52 | ||
53 | /* | |
54 | * Disable the watchdog. | |
55 | */ | |
2760600d | 56 | static inline void at91_wdt_stop(void) |
853807fb | 57 | { |
5e9cf5e1 | 58 | at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN); |
853807fb AV |
59 | } |
60 | ||
61 | /* | |
62 | * Enable and reset the watchdog. | |
63 | */ | |
2760600d | 64 | static inline void at91_wdt_start(void) |
853807fb | 65 | { |
5e9cf5e1 | 66 | at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | |
2760600d | 67 | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); |
5e9cf5e1 | 68 | at91_st_write(AT91_ST_CR, AT91_ST_WDRST); |
853807fb AV |
69 | } |
70 | ||
71 | /* | |
72 | * Reload the watchdog timer. (ie, pat the watchdog) | |
73 | */ | |
2760600d | 74 | static inline void at91_wdt_reload(void) |
853807fb | 75 | { |
5e9cf5e1 | 76 | at91_st_write(AT91_ST_CR, AT91_ST_WDRST); |
853807fb AV |
77 | } |
78 | ||
79 | /* ......................................................................... */ | |
80 | ||
81 | /* | |
82 | * Watchdog device is opened, and watchdog starts running. | |
83 | */ | |
84 | static int at91_wdt_open(struct inode *inode, struct file *file) | |
85 | { | |
86 | if (test_and_set_bit(0, &at91wdt_busy)) | |
87 | return -EBUSY; | |
88 | ||
89 | at91_wdt_start(); | |
90 | return nonseekable_open(inode, file); | |
91 | } | |
92 | ||
93 | /* | |
94 | * Close the watchdog device. | |
95 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also | |
96 | * disabled. | |
97 | */ | |
98 | static int at91_wdt_close(struct inode *inode, struct file *file) | |
99 | { | |
2760600d | 100 | /* Disable the watchdog when file is closed */ |
853807fb | 101 | if (!nowayout) |
2760600d | 102 | at91_wdt_stop(); |
853807fb AV |
103 | |
104 | clear_bit(0, &at91wdt_busy); | |
105 | return 0; | |
106 | } | |
107 | ||
108 | /* | |
109 | * Change the watchdog time interval. | |
110 | */ | |
111 | static int at91_wdt_settimeout(int new_time) | |
112 | { | |
113 | /* | |
2af29b78 | 114 | * All counting occurs at SLOW_CLOCK / 128 = 256 Hz |
853807fb AV |
115 | * |
116 | * Since WDV is a 16-bit counter, the maximum period is | |
2af29b78 | 117 | * 65536 / 256 = 256 seconds. |
853807fb AV |
118 | */ |
119 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | |
120 | return -EINVAL; | |
121 | ||
2760600d AC |
122 | /* Set new watchdog time. It will be used when |
123 | at91_wdt_start() is called. */ | |
853807fb AV |
124 | wdt_time = new_time; |
125 | return 0; | |
126 | } | |
127 | ||
42747d71 | 128 | static const struct watchdog_info at91_wdt_info = { |
853807fb AV |
129 | .identity = "at91 watchdog", |
130 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
131 | }; | |
132 | ||
133 | /* | |
134 | * Handle commands from user-space. | |
135 | */ | |
3c4fafd6 | 136 | static long at91_wdt_ioctl(struct file *file, |
2760600d | 137 | unsigned int cmd, unsigned long arg) |
853807fb AV |
138 | { |
139 | void __user *argp = (void __user *)arg; | |
140 | int __user *p = argp; | |
141 | int new_value; | |
142 | ||
2760600d | 143 | switch (cmd) { |
2760600d AC |
144 | case WDIOC_GETSUPPORT: |
145 | return copy_to_user(argp, &at91_wdt_info, | |
146 | sizeof(at91_wdt_info)) ? -EFAULT : 0; | |
2760600d AC |
147 | case WDIOC_GETSTATUS: |
148 | case WDIOC_GETBOOTSTATUS: | |
149 | return put_user(0, p); | |
150 | case WDIOC_SETOPTIONS: | |
151 | if (get_user(new_value, p)) | |
152 | return -EFAULT; | |
153 | if (new_value & WDIOS_DISABLECARD) | |
154 | at91_wdt_stop(); | |
155 | if (new_value & WDIOS_ENABLECARD) | |
853807fb | 156 | at91_wdt_start(); |
2760600d | 157 | return 0; |
0c06090c WVS |
158 | case WDIOC_KEEPALIVE: |
159 | at91_wdt_reload(); /* pat the watchdog */ | |
160 | return 0; | |
161 | case WDIOC_SETTIMEOUT: | |
162 | if (get_user(new_value, p)) | |
163 | return -EFAULT; | |
164 | if (at91_wdt_settimeout(new_value)) | |
165 | return -EINVAL; | |
166 | /* Enable new time value */ | |
167 | at91_wdt_start(); | |
168 | /* Return current value */ | |
169 | return put_user(wdt_time, p); | |
170 | case WDIOC_GETTIMEOUT: | |
171 | return put_user(wdt_time, p); | |
2760600d AC |
172 | default: |
173 | return -ENOTTY; | |
853807fb AV |
174 | } |
175 | } | |
176 | ||
177 | /* | |
178 | * Pat the watchdog whenever device is written to. | |
179 | */ | |
2760600d AC |
180 | static ssize_t at91_wdt_write(struct file *file, const char *data, |
181 | size_t len, loff_t *ppos) | |
853807fb AV |
182 | { |
183 | at91_wdt_reload(); /* pat the watchdog */ | |
184 | return len; | |
185 | } | |
186 | ||
187 | /* ......................................................................... */ | |
188 | ||
62322d25 | 189 | static const struct file_operations at91wdt_fops = { |
853807fb AV |
190 | .owner = THIS_MODULE, |
191 | .llseek = no_llseek, | |
2760600d | 192 | .unlocked_ioctl = at91_wdt_ioctl, |
853807fb AV |
193 | .open = at91_wdt_open, |
194 | .release = at91_wdt_close, | |
195 | .write = at91_wdt_write, | |
196 | }; | |
197 | ||
198 | static struct miscdevice at91wdt_miscdev = { | |
199 | .minor = WATCHDOG_MINOR, | |
200 | .name = "watchdog", | |
201 | .fops = &at91wdt_fops, | |
202 | }; | |
203 | ||
2d991a16 | 204 | static int at91wdt_probe(struct platform_device *pdev) |
853807fb AV |
205 | { |
206 | int res; | |
207 | ||
e0b79e0b | 208 | if (at91wdt_miscdev.parent) |
dfc7bd9c | 209 | return -EBUSY; |
e0b79e0b | 210 | at91wdt_miscdev.parent = &pdev->dev; |
853807fb AV |
211 | |
212 | res = misc_register(&at91wdt_miscdev); | |
213 | if (res) | |
214 | return res; | |
215 | ||
27c766aa JP |
216 | pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n", |
217 | wdt_time, nowayout ? ", nowayout" : ""); | |
853807fb AV |
218 | return 0; |
219 | } | |
220 | ||
4b12b896 | 221 | static int at91wdt_remove(struct platform_device *pdev) |
dfc7bd9c AV |
222 | { |
223 | int res; | |
224 | ||
225 | res = misc_deregister(&at91wdt_miscdev); | |
226 | if (!res) | |
e0b79e0b | 227 | at91wdt_miscdev.parent = NULL; |
dfc7bd9c AV |
228 | |
229 | return res; | |
230 | } | |
231 | ||
232 | static void at91wdt_shutdown(struct platform_device *pdev) | |
233 | { | |
234 | at91_wdt_stop(); | |
235 | } | |
236 | ||
237 | #ifdef CONFIG_PM | |
238 | ||
239 | static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
240 | { | |
241 | at91_wdt_stop(); | |
242 | return 0; | |
243 | } | |
244 | ||
245 | static int at91wdt_resume(struct platform_device *pdev) | |
246 | { | |
247 | if (at91wdt_busy) | |
248 | at91_wdt_start(); | |
95f62bdc | 249 | return 0; |
dfc7bd9c AV |
250 | } |
251 | ||
252 | #else | |
253 | #define at91wdt_suspend NULL | |
254 | #define at91wdt_resume NULL | |
255 | #endif | |
256 | ||
a6a1bcd3 JE |
257 | static const struct of_device_id at91_wdt_dt_ids[] = { |
258 | { .compatible = "atmel,at91rm9200-wdt" }, | |
259 | { /* sentinel */ } | |
260 | }; | |
261 | MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids); | |
262 | ||
dfc7bd9c AV |
263 | static struct platform_driver at91wdt_driver = { |
264 | .probe = at91wdt_probe, | |
82268714 | 265 | .remove = at91wdt_remove, |
dfc7bd9c AV |
266 | .shutdown = at91wdt_shutdown, |
267 | .suspend = at91wdt_suspend, | |
268 | .resume = at91wdt_resume, | |
269 | .driver = { | |
270 | .name = "at91_wdt", | |
85eee819 | 271 | .of_match_table = at91_wdt_dt_ids, |
dfc7bd9c AV |
272 | }, |
273 | }; | |
274 | ||
275 | static int __init at91_wdt_init(void) | |
276 | { | |
2760600d AC |
277 | /* Check that the heartbeat value is within range; |
278 | if not reset to the default */ | |
dfc7bd9c AV |
279 | if (at91_wdt_settimeout(wdt_time)) { |
280 | at91_wdt_settimeout(WDT_DEFAULT_TIME); | |
27c766aa JP |
281 | pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n", |
282 | wdt_time); | |
dfc7bd9c AV |
283 | } |
284 | ||
285 | return platform_driver_register(&at91wdt_driver); | |
286 | } | |
287 | ||
853807fb AV |
288 | static void __exit at91_wdt_exit(void) |
289 | { | |
dfc7bd9c | 290 | platform_driver_unregister(&at91wdt_driver); |
853807fb AV |
291 | } |
292 | ||
293 | module_init(at91_wdt_init); | |
294 | module_exit(at91_wdt_exit); | |
295 | ||
296 | MODULE_AUTHOR("Andrew Victor"); | |
297 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200"); | |
298 | MODULE_LICENSE("GPL"); | |
f37d193c | 299 | MODULE_ALIAS("platform:at91_wdt"); |