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eed6565f CC |
1 | /* |
2 | * SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3 | |
3 | * single board computer | |
4 | * | |
5 | * (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights | |
6 | * Reserved. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License | |
10 | * as published by the Free Software Foundation; either version | |
11 | * 2 of the License, or (at your option) any later version. | |
12 | * | |
13 | * based on softdog.c by Alan Cox <alan@redhat.com> | |
14 | */ | |
15 | ||
16 | #include <linux/module.h> | |
17 | #include <linux/moduleparam.h> | |
18 | #include <linux/config.h> | |
19 | #include <linux/types.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/fs.h> | |
22 | #include <linux/mm.h> | |
23 | #include <linux/miscdevice.h> | |
24 | #include <linux/watchdog.h> | |
25 | #include <linux/notifier.h> | |
26 | #include <linux/reboot.h> | |
27 | #include <linux/init.h> | |
de6c642c | 28 | #include <linux/ioport.h> |
eed6565f CC |
29 | #include <asm/uaccess.h> |
30 | #include <asm/io.h> | |
31 | ||
32 | #define PFX "epx_c3: " | |
33 | static int epx_c3_alive; | |
34 | ||
35 | #define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */ | |
36 | ||
37 | static int nowayout = WATCHDOG_NOWAYOUT; | |
38 | module_param(nowayout, int, 0); | |
39 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | |
40 | ||
41 | #define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */ | |
42 | #define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */ | |
43 | ||
44 | static void epx_c3_start(void) | |
45 | { | |
46 | outb(1, EPXC3_WATCHDOG_CTL_REG); | |
47 | } | |
48 | ||
49 | static void epx_c3_stop(void) | |
50 | { | |
51 | ||
52 | outb(0, EPXC3_WATCHDOG_CTL_REG); | |
53 | ||
54 | printk(KERN_INFO PFX "Stopped watchdog timer.\n"); | |
55 | } | |
56 | ||
57 | static void epx_c3_pet(void) | |
58 | { | |
59 | outb(1, EPXC3_WATCHDOG_PET_REG); | |
60 | } | |
61 | ||
62 | /* | |
63 | * Allow only one person to hold it open | |
64 | */ | |
65 | static int epx_c3_open(struct inode *inode, struct file *file) | |
66 | { | |
67 | if (epx_c3_alive) | |
68 | return -EBUSY; | |
69 | ||
70 | if (nowayout) | |
71 | __module_get(THIS_MODULE); | |
72 | ||
73 | /* Activate timer */ | |
74 | epx_c3_start(); | |
75 | epx_c3_pet(); | |
76 | ||
77 | epx_c3_alive = 1; | |
78 | printk(KERN_INFO "Started watchdog timer.\n"); | |
79 | ||
80 | return nonseekable_open(inode, file); | |
81 | } | |
82 | ||
83 | static int epx_c3_release(struct inode *inode, struct file *file) | |
84 | { | |
85 | /* Shut off the timer. | |
86 | * Lock it in if it's a module and we defined ...NOWAYOUT */ | |
87 | if (!nowayout) | |
88 | epx_c3_stop(); /* Turn the WDT off */ | |
89 | ||
90 | epx_c3_alive = 0; | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | static ssize_t epx_c3_write(struct file *file, const char *data, | |
96 | size_t len, loff_t *ppos) | |
97 | { | |
98 | /* Refresh the timer. */ | |
99 | if (len) | |
100 | epx_c3_pet(); | |
101 | return len; | |
102 | } | |
103 | ||
104 | static int epx_c3_ioctl(struct inode *inode, struct file *file, | |
105 | unsigned int cmd, unsigned long arg) | |
106 | { | |
107 | int options, retval = -EINVAL; | |
108 | static struct watchdog_info ident = { | |
109 | .options = WDIOF_KEEPALIVEPING | | |
110 | WDIOF_MAGICCLOSE, | |
111 | .firmware_version = 0, | |
112 | .identity = "Winsystems EPX-C3 H/W Watchdog", | |
113 | }; | |
114 | ||
115 | switch (cmd) { | |
116 | case WDIOC_GETSUPPORT: | |
117 | if (copy_to_user((struct watchdog_info *)arg, | |
118 | &ident, sizeof(ident))) | |
119 | return -EFAULT; | |
120 | return 0; | |
121 | case WDIOC_GETSTATUS: | |
122 | case WDIOC_GETBOOTSTATUS: | |
123 | return put_user(0,(int *)arg); | |
124 | case WDIOC_KEEPALIVE: | |
125 | epx_c3_pet(); | |
126 | return 0; | |
127 | case WDIOC_GETTIMEOUT: | |
128 | return put_user(WATCHDOG_TIMEOUT,(int *)arg); | |
129 | case WDIOC_SETOPTIONS: { | |
130 | if (get_user(options, (int *)arg)) | |
131 | return -EFAULT; | |
132 | ||
133 | if (options & WDIOS_DISABLECARD) { | |
134 | epx_c3_stop(); | |
135 | retval = 0; | |
136 | } | |
137 | ||
138 | if (options & WDIOS_ENABLECARD) { | |
139 | epx_c3_start(); | |
140 | retval = 0; | |
141 | } | |
142 | ||
143 | return retval; | |
144 | } | |
145 | default: | |
146 | return -ENOIOCTLCMD; | |
147 | } | |
148 | } | |
149 | ||
150 | static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code, | |
151 | void *unused) | |
152 | { | |
153 | if (code == SYS_DOWN || code == SYS_HALT) | |
154 | epx_c3_stop(); /* Turn the WDT off */ | |
155 | ||
156 | return NOTIFY_DONE; | |
157 | } | |
158 | ||
159 | static struct file_operations epx_c3_fops = { | |
160 | .owner = THIS_MODULE, | |
161 | .llseek = no_llseek, | |
162 | .write = epx_c3_write, | |
163 | .ioctl = epx_c3_ioctl, | |
164 | .open = epx_c3_open, | |
165 | .release = epx_c3_release, | |
166 | }; | |
167 | ||
168 | static struct miscdevice epx_c3_miscdev = { | |
169 | .minor = WATCHDOG_MINOR, | |
170 | .name = "watchdog", | |
171 | .fops = &epx_c3_fops, | |
172 | }; | |
173 | ||
174 | static struct notifier_block epx_c3_notifier = { | |
175 | .notifier_call = epx_c3_notify_sys, | |
176 | }; | |
177 | ||
178 | static const char banner[] __initdata = | |
179 | KERN_INFO PFX "Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n"; | |
180 | ||
181 | static int __init watchdog_init(void) | |
182 | { | |
183 | int ret; | |
184 | ||
de6c642c AC |
185 | if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog")) |
186 | return -EBUSY; | |
187 | ||
eed6565f CC |
188 | ret = register_reboot_notifier(&epx_c3_notifier); |
189 | if (ret) { | |
190 | printk(KERN_ERR PFX "cannot register reboot notifier " | |
191 | "(err=%d)\n", ret); | |
de6c642c | 192 | goto out; |
eed6565f CC |
193 | } |
194 | ||
195 | ret = misc_register(&epx_c3_miscdev); | |
196 | if (ret) { | |
197 | printk(KERN_ERR PFX "cannot register miscdev on minor=%d " | |
198 | "(err=%d)\n", WATCHDOG_MINOR, ret); | |
199 | unregister_reboot_notifier(&epx_c3_notifier); | |
de6c642c | 200 | goto out; |
eed6565f CC |
201 | } |
202 | ||
203 | printk(banner); | |
204 | ||
205 | return 0; | |
de6c642c AC |
206 | |
207 | out: | |
208 | release_region(EPXC3_WATCHDOG_CTL_REG, 2); | |
209 | return ret; | |
eed6565f CC |
210 | } |
211 | ||
212 | static void __exit watchdog_exit(void) | |
213 | { | |
214 | misc_deregister(&epx_c3_miscdev); | |
215 | unregister_reboot_notifier(&epx_c3_notifier); | |
de6c642c | 216 | release_region(EPXC3_WATCHDOG_CTL_REG, 2); |
eed6565f CC |
217 | } |
218 | ||
219 | module_init(watchdog_init); | |
220 | module_exit(watchdog_exit); | |
221 | ||
222 | MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>"); | |
223 | MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. Note that there is no way to probe for this device -- so only use it if you are *sure* you are runnning on this specific SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!"); | |
224 | MODULE_LICENSE("GPL"); | |
225 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |