Commit | Line | Data |
---|---|---|
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 | ||
12 | #include <linux/config.h> | |
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> | |
20 | #include <linux/types.h> | |
21 | #include <linux/watchdog.h> | |
22 | #include <asm/bitops.h> | |
23 | #include <asm/uaccess.h> | |
24 | ||
25 | ||
26 | #define WDT_DEFAULT_TIME 5 /* 5 seconds */ | |
27 | #define WDT_MAX_TIME 256 /* 256 seconds */ | |
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 | ||
35 | module_param(nowayout, int, 0); | |
36 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
37 | ||
38 | ||
39 | static unsigned long at91wdt_busy; | |
40 | ||
41 | /* ......................................................................... */ | |
42 | ||
43 | /* | |
44 | * Disable the watchdog. | |
45 | */ | |
46 | static void inline at91_wdt_stop(void) | |
47 | { | |
48 | at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN); | |
49 | } | |
50 | ||
51 | /* | |
52 | * Enable and reset the watchdog. | |
53 | */ | |
54 | static void inline at91_wdt_start(void) | |
55 | { | |
56 | at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); | |
57 | at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); | |
58 | } | |
59 | ||
60 | /* | |
61 | * Reload the watchdog timer. (ie, pat the watchdog) | |
62 | */ | |
63 | static void inline at91_wdt_reload(void) | |
64 | { | |
65 | at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); | |
66 | } | |
67 | ||
68 | /* ......................................................................... */ | |
69 | ||
70 | /* | |
71 | * Watchdog device is opened, and watchdog starts running. | |
72 | */ | |
73 | static int at91_wdt_open(struct inode *inode, struct file *file) | |
74 | { | |
75 | if (test_and_set_bit(0, &at91wdt_busy)) | |
76 | return -EBUSY; | |
77 | ||
78 | at91_wdt_start(); | |
79 | return nonseekable_open(inode, file); | |
80 | } | |
81 | ||
82 | /* | |
83 | * Close the watchdog device. | |
84 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also | |
85 | * disabled. | |
86 | */ | |
87 | static int at91_wdt_close(struct inode *inode, struct file *file) | |
88 | { | |
89 | if (!nowayout) | |
90 | at91_wdt_stop(); /* Disable the watchdog when file is closed */ | |
91 | ||
92 | clear_bit(0, &at91wdt_busy); | |
93 | return 0; | |
94 | } | |
95 | ||
96 | /* | |
97 | * Change the watchdog time interval. | |
98 | */ | |
99 | static int at91_wdt_settimeout(int new_time) | |
100 | { | |
101 | /* | |
102 | * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz | |
103 | * | |
104 | * Since WDV is a 16-bit counter, the maximum period is | |
105 | * 65536 / 0.256 = 256 seconds. | |
106 | */ | |
107 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | |
108 | return -EINVAL; | |
109 | ||
110 | /* Set new watchdog time. It will be used when at91_wdt_start() is called. */ | |
111 | wdt_time = new_time; | |
112 | return 0; | |
113 | } | |
114 | ||
115 | static struct watchdog_info at91_wdt_info = { | |
116 | .identity = "at91 watchdog", | |
117 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
118 | }; | |
119 | ||
120 | /* | |
121 | * Handle commands from user-space. | |
122 | */ | |
123 | static int at91_wdt_ioctl(struct inode *inode, struct file *file, | |
124 | unsigned int cmd, unsigned long arg) | |
125 | { | |
126 | void __user *argp = (void __user *)arg; | |
127 | int __user *p = argp; | |
128 | int new_value; | |
129 | ||
130 | switch(cmd) { | |
131 | case WDIOC_KEEPALIVE: | |
132 | at91_wdt_reload(); /* pat the watchdog */ | |
133 | return 0; | |
134 | ||
135 | case WDIOC_GETSUPPORT: | |
136 | return copy_to_user(argp, &at91_wdt_info, sizeof(at91_wdt_info)) ? -EFAULT : 0; | |
137 | ||
138 | case WDIOC_SETTIMEOUT: | |
139 | if (get_user(new_value, p)) | |
140 | return -EFAULT; | |
141 | ||
142 | if (at91_wdt_settimeout(new_value)) | |
143 | return -EINVAL; | |
144 | ||
145 | /* Enable new time value */ | |
146 | at91_wdt_start(); | |
147 | ||
148 | /* Return current value */ | |
149 | return put_user(wdt_time, p); | |
150 | ||
151 | case WDIOC_GETTIMEOUT: | |
152 | return put_user(wdt_time, p); | |
153 | ||
154 | case WDIOC_GETSTATUS: | |
155 | case WDIOC_GETBOOTSTATUS: | |
156 | return put_user(0, p); | |
157 | ||
158 | case WDIOC_SETOPTIONS: | |
159 | if (get_user(new_value, p)) | |
160 | return -EFAULT; | |
161 | ||
162 | if (new_value & WDIOS_DISABLECARD) | |
163 | at91_wdt_stop(); | |
164 | if (new_value & WDIOS_ENABLECARD) | |
165 | at91_wdt_start(); | |
166 | return 0; | |
167 | ||
168 | default: | |
169 | return -ENOIOCTLCMD; | |
170 | } | |
171 | } | |
172 | ||
173 | /* | |
174 | * Pat the watchdog whenever device is written to. | |
175 | */ | |
176 | static ssize_t at91_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) | |
177 | { | |
178 | at91_wdt_reload(); /* pat the watchdog */ | |
179 | return len; | |
180 | } | |
181 | ||
182 | /* ......................................................................... */ | |
183 | ||
184 | static struct file_operations at91wdt_fops = { | |
185 | .owner = THIS_MODULE, | |
186 | .llseek = no_llseek, | |
187 | .ioctl = at91_wdt_ioctl, | |
188 | .open = at91_wdt_open, | |
189 | .release = at91_wdt_close, | |
190 | .write = at91_wdt_write, | |
191 | }; | |
192 | ||
193 | static struct miscdevice at91wdt_miscdev = { | |
194 | .minor = WATCHDOG_MINOR, | |
195 | .name = "watchdog", | |
196 | .fops = &at91wdt_fops, | |
197 | }; | |
198 | ||
199 | static int __init at91_wdt_init(void) | |
200 | { | |
201 | int res; | |
202 | ||
203 | /* Check that the heartbeat value is within range; if not reset to the default */ | |
204 | if (at91_wdt_settimeout(wdt_time)) { | |
205 | at91_wdt_settimeout(WDT_DEFAULT_TIME); | |
206 | printk(KERN_INFO "at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time); | |
207 | } | |
208 | ||
209 | res = misc_register(&at91wdt_miscdev); | |
210 | if (res) | |
211 | return res; | |
212 | ||
213 | printk("AT91 Watchdog Timer enabled (%d seconds, nowayout=%d)\n", wdt_time, nowayout); | |
214 | return 0; | |
215 | } | |
216 | ||
217 | static void __exit at91_wdt_exit(void) | |
218 | { | |
219 | misc_deregister(&at91wdt_miscdev); | |
220 | } | |
221 | ||
222 | module_init(at91_wdt_init); | |
223 | module_exit(at91_wdt_exit); | |
224 | ||
225 | MODULE_AUTHOR("Andrew Victor"); | |
226 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200"); | |
227 | MODULE_LICENSE("GPL"); | |
228 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |