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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> | |
28 | #include <asm/uaccess.h> | |
29 | #include <asm/io.h> | |
30 | ||
31 | #define PFX "epx_c3: " | |
32 | static int epx_c3_alive; | |
33 | ||
34 | #define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */ | |
35 | ||
36 | static int nowayout = WATCHDOG_NOWAYOUT; | |
37 | module_param(nowayout, int, 0); | |
38 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | |
39 | ||
40 | #define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */ | |
41 | #define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */ | |
42 | ||
43 | static void epx_c3_start(void) | |
44 | { | |
45 | outb(1, EPXC3_WATCHDOG_CTL_REG); | |
46 | } | |
47 | ||
48 | static void epx_c3_stop(void) | |
49 | { | |
50 | ||
51 | outb(0, EPXC3_WATCHDOG_CTL_REG); | |
52 | ||
53 | printk(KERN_INFO PFX "Stopped watchdog timer.\n"); | |
54 | } | |
55 | ||
56 | static void epx_c3_pet(void) | |
57 | { | |
58 | outb(1, EPXC3_WATCHDOG_PET_REG); | |
59 | } | |
60 | ||
61 | /* | |
62 | * Allow only one person to hold it open | |
63 | */ | |
64 | static int epx_c3_open(struct inode *inode, struct file *file) | |
65 | { | |
66 | if (epx_c3_alive) | |
67 | return -EBUSY; | |
68 | ||
69 | if (nowayout) | |
70 | __module_get(THIS_MODULE); | |
71 | ||
72 | /* Activate timer */ | |
73 | epx_c3_start(); | |
74 | epx_c3_pet(); | |
75 | ||
76 | epx_c3_alive = 1; | |
77 | printk(KERN_INFO "Started watchdog timer.\n"); | |
78 | ||
79 | return nonseekable_open(inode, file); | |
80 | } | |
81 | ||
82 | static int epx_c3_release(struct inode *inode, struct file *file) | |
83 | { | |
84 | /* Shut off the timer. | |
85 | * Lock it in if it's a module and we defined ...NOWAYOUT */ | |
86 | if (!nowayout) | |
87 | epx_c3_stop(); /* Turn the WDT off */ | |
88 | ||
89 | epx_c3_alive = 0; | |
90 | ||
91 | return 0; | |
92 | } | |
93 | ||
94 | static ssize_t epx_c3_write(struct file *file, const char *data, | |
95 | size_t len, loff_t *ppos) | |
96 | { | |
97 | /* Refresh the timer. */ | |
98 | if (len) | |
99 | epx_c3_pet(); | |
100 | return len; | |
101 | } | |
102 | ||
103 | static int epx_c3_ioctl(struct inode *inode, struct file *file, | |
104 | unsigned int cmd, unsigned long arg) | |
105 | { | |
106 | int options, retval = -EINVAL; | |
107 | static struct watchdog_info ident = { | |
108 | .options = WDIOF_KEEPALIVEPING | | |
109 | WDIOF_MAGICCLOSE, | |
110 | .firmware_version = 0, | |
111 | .identity = "Winsystems EPX-C3 H/W Watchdog", | |
112 | }; | |
113 | ||
114 | switch (cmd) { | |
115 | case WDIOC_GETSUPPORT: | |
116 | if (copy_to_user((struct watchdog_info *)arg, | |
117 | &ident, sizeof(ident))) | |
118 | return -EFAULT; | |
119 | return 0; | |
120 | case WDIOC_GETSTATUS: | |
121 | case WDIOC_GETBOOTSTATUS: | |
122 | return put_user(0,(int *)arg); | |
123 | case WDIOC_KEEPALIVE: | |
124 | epx_c3_pet(); | |
125 | return 0; | |
126 | case WDIOC_GETTIMEOUT: | |
127 | return put_user(WATCHDOG_TIMEOUT,(int *)arg); | |
128 | case WDIOC_SETOPTIONS: { | |
129 | if (get_user(options, (int *)arg)) | |
130 | return -EFAULT; | |
131 | ||
132 | if (options & WDIOS_DISABLECARD) { | |
133 | epx_c3_stop(); | |
134 | retval = 0; | |
135 | } | |
136 | ||
137 | if (options & WDIOS_ENABLECARD) { | |
138 | epx_c3_start(); | |
139 | retval = 0; | |
140 | } | |
141 | ||
142 | return retval; | |
143 | } | |
144 | default: | |
145 | return -ENOIOCTLCMD; | |
146 | } | |
147 | } | |
148 | ||
149 | static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code, | |
150 | void *unused) | |
151 | { | |
152 | if (code == SYS_DOWN || code == SYS_HALT) | |
153 | epx_c3_stop(); /* Turn the WDT off */ | |
154 | ||
155 | return NOTIFY_DONE; | |
156 | } | |
157 | ||
158 | static struct file_operations epx_c3_fops = { | |
159 | .owner = THIS_MODULE, | |
160 | .llseek = no_llseek, | |
161 | .write = epx_c3_write, | |
162 | .ioctl = epx_c3_ioctl, | |
163 | .open = epx_c3_open, | |
164 | .release = epx_c3_release, | |
165 | }; | |
166 | ||
167 | static struct miscdevice epx_c3_miscdev = { | |
168 | .minor = WATCHDOG_MINOR, | |
169 | .name = "watchdog", | |
170 | .fops = &epx_c3_fops, | |
171 | }; | |
172 | ||
173 | static struct notifier_block epx_c3_notifier = { | |
174 | .notifier_call = epx_c3_notify_sys, | |
175 | }; | |
176 | ||
177 | static const char banner[] __initdata = | |
178 | KERN_INFO PFX "Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n"; | |
179 | ||
180 | static int __init watchdog_init(void) | |
181 | { | |
182 | int ret; | |
183 | ||
184 | ret = register_reboot_notifier(&epx_c3_notifier); | |
185 | if (ret) { | |
186 | printk(KERN_ERR PFX "cannot register reboot notifier " | |
187 | "(err=%d)\n", ret); | |
188 | return ret; | |
189 | } | |
190 | ||
191 | ret = misc_register(&epx_c3_miscdev); | |
192 | if (ret) { | |
193 | printk(KERN_ERR PFX "cannot register miscdev on minor=%d " | |
194 | "(err=%d)\n", WATCHDOG_MINOR, ret); | |
195 | unregister_reboot_notifier(&epx_c3_notifier); | |
196 | return ret; | |
197 | } | |
198 | ||
199 | printk(banner); | |
200 | ||
201 | return 0; | |
202 | } | |
203 | ||
204 | static void __exit watchdog_exit(void) | |
205 | { | |
206 | misc_deregister(&epx_c3_miscdev); | |
207 | unregister_reboot_notifier(&epx_c3_notifier); | |
208 | } | |
209 | ||
210 | module_init(watchdog_init); | |
211 | module_exit(watchdog_exit); | |
212 | ||
213 | MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>"); | |
214 | 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!"); | |
215 | MODULE_LICENSE("GPL"); | |
216 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |