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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 | * | |
29fa0586 | 13 | * based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk> |
eed6565f CC |
14 | */ |
15 | ||
27c766aa JP |
16 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
17 | ||
eed6565f CC |
18 | #include <linux/module.h> |
19 | #include <linux/moduleparam.h> | |
eed6565f CC |
20 | #include <linux/types.h> |
21 | #include <linux/kernel.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/mm.h> | |
24 | #include <linux/miscdevice.h> | |
25 | #include <linux/watchdog.h> | |
26 | #include <linux/notifier.h> | |
27 | #include <linux/reboot.h> | |
28 | #include <linux/init.h> | |
de6c642c | 29 | #include <linux/ioport.h> |
f4f6f65a AC |
30 | #include <linux/uaccess.h> |
31 | #include <linux/io.h> | |
eed6565f | 32 | |
eed6565f CC |
33 | static int epx_c3_alive; |
34 | ||
35 | #define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */ | |
36 | ||
86a1e189 WVS |
37 | static bool nowayout = WATCHDOG_NOWAYOUT; |
38 | module_param(nowayout, bool, 0); | |
143a2e54 WVS |
39 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
40 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
eed6565f CC |
41 | |
42 | #define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */ | |
43 | #define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */ | |
44 | ||
45 | static void epx_c3_start(void) | |
46 | { | |
47 | outb(1, EPXC3_WATCHDOG_CTL_REG); | |
48 | } | |
49 | ||
50 | static void epx_c3_stop(void) | |
51 | { | |
52 | ||
53 | outb(0, EPXC3_WATCHDOG_CTL_REG); | |
54 | ||
27c766aa | 55 | pr_info("Stopped watchdog timer\n"); |
eed6565f CC |
56 | } |
57 | ||
58 | static void epx_c3_pet(void) | |
59 | { | |
60 | outb(1, EPXC3_WATCHDOG_PET_REG); | |
61 | } | |
62 | ||
63 | /* | |
64 | * Allow only one person to hold it open | |
65 | */ | |
66 | static int epx_c3_open(struct inode *inode, struct file *file) | |
67 | { | |
68 | if (epx_c3_alive) | |
69 | return -EBUSY; | |
70 | ||
71 | if (nowayout) | |
72 | __module_get(THIS_MODULE); | |
73 | ||
74 | /* Activate timer */ | |
75 | epx_c3_start(); | |
76 | epx_c3_pet(); | |
77 | ||
78 | epx_c3_alive = 1; | |
27c766aa | 79 | pr_info("Started watchdog timer\n"); |
eed6565f CC |
80 | |
81 | return nonseekable_open(inode, file); | |
82 | } | |
83 | ||
84 | static int epx_c3_release(struct inode *inode, struct file *file) | |
85 | { | |
86 | /* Shut off the timer. | |
87 | * Lock it in if it's a module and we defined ...NOWAYOUT */ | |
88 | if (!nowayout) | |
89 | epx_c3_stop(); /* Turn the WDT off */ | |
90 | ||
91 | epx_c3_alive = 0; | |
92 | ||
93 | return 0; | |
94 | } | |
95 | ||
73a09e62 | 96 | static ssize_t epx_c3_write(struct file *file, const char __user *data, |
eed6565f CC |
97 | size_t len, loff_t *ppos) |
98 | { | |
99 | /* Refresh the timer. */ | |
100 | if (len) | |
101 | epx_c3_pet(); | |
102 | return len; | |
103 | } | |
104 | ||
f4f6f65a AC |
105 | static long epx_c3_ioctl(struct file *file, unsigned int cmd, |
106 | unsigned long arg) | |
eed6565f CC |
107 | { |
108 | int options, retval = -EINVAL; | |
73a09e62 | 109 | int __user *argp = (void __user *)arg; |
f4f6f65a | 110 | static const struct watchdog_info ident = { |
e73a7802 | 111 | .options = WDIOF_KEEPALIVEPING, |
eed6565f CC |
112 | .firmware_version = 0, |
113 | .identity = "Winsystems EPX-C3 H/W Watchdog", | |
114 | }; | |
115 | ||
116 | switch (cmd) { | |
117 | case WDIOC_GETSUPPORT: | |
73a09e62 | 118 | if (copy_to_user(argp, &ident, sizeof(ident))) |
eed6565f CC |
119 | return -EFAULT; |
120 | return 0; | |
121 | case WDIOC_GETSTATUS: | |
122 | case WDIOC_GETBOOTSTATUS: | |
73a09e62 | 123 | return put_user(0, argp); |
73a09e62 AV |
124 | case WDIOC_SETOPTIONS: |
125 | if (get_user(options, argp)) | |
eed6565f CC |
126 | return -EFAULT; |
127 | ||
128 | if (options & WDIOS_DISABLECARD) { | |
129 | epx_c3_stop(); | |
130 | retval = 0; | |
131 | } | |
132 | ||
133 | if (options & WDIOS_ENABLECARD) { | |
134 | epx_c3_start(); | |
135 | retval = 0; | |
136 | } | |
137 | ||
138 | return retval; | |
0c06090c WVS |
139 | case WDIOC_KEEPALIVE: |
140 | epx_c3_pet(); | |
141 | return 0; | |
142 | case WDIOC_GETTIMEOUT: | |
143 | return put_user(WATCHDOG_TIMEOUT, argp); | |
eed6565f | 144 | default: |
795b89d2 | 145 | return -ENOTTY; |
eed6565f CC |
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 | ||
62322d25 | 158 | static const struct file_operations epx_c3_fops = { |
eed6565f CC |
159 | .owner = THIS_MODULE, |
160 | .llseek = no_llseek, | |
161 | .write = epx_c3_write, | |
f4f6f65a | 162 | .unlocked_ioctl = epx_c3_ioctl, |
eed6565f CC |
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 | ||
eed6565f CC |
177 | static int __init watchdog_init(void) |
178 | { | |
179 | int ret; | |
180 | ||
de6c642c AC |
181 | if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog")) |
182 | return -EBUSY; | |
183 | ||
eed6565f CC |
184 | ret = register_reboot_notifier(&epx_c3_notifier); |
185 | if (ret) { | |
27c766aa | 186 | pr_err("cannot register reboot notifier (err=%d)\n", ret); |
de6c642c | 187 | goto out; |
eed6565f CC |
188 | } |
189 | ||
190 | ret = misc_register(&epx_c3_miscdev); | |
191 | if (ret) { | |
27c766aa JP |
192 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
193 | WATCHDOG_MINOR, ret); | |
eed6565f | 194 | unregister_reboot_notifier(&epx_c3_notifier); |
de6c642c | 195 | goto out; |
eed6565f CC |
196 | } |
197 | ||
27c766aa | 198 | pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n"); |
eed6565f CC |
199 | |
200 | return 0; | |
de6c642c AC |
201 | |
202 | out: | |
203 | release_region(EPXC3_WATCHDOG_CTL_REG, 2); | |
204 | return ret; | |
eed6565f CC |
205 | } |
206 | ||
207 | static void __exit watchdog_exit(void) | |
208 | { | |
209 | misc_deregister(&epx_c3_miscdev); | |
210 | unregister_reboot_notifier(&epx_c3_notifier); | |
de6c642c | 211 | release_region(EPXC3_WATCHDOG_CTL_REG, 2); |
eed6565f CC |
212 | } |
213 | ||
214 | module_init(watchdog_init); | |
215 | module_exit(watchdog_exit); | |
216 | ||
217 | MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>"); | |
a77dba7e WVS |
218 | MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. " |
219 | "Note that there is no way to probe for this device -- " | |
ae0e47f0 | 220 | "so only use it if you are *sure* you are running on this specific " |
a77dba7e | 221 | "SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!"); |
eed6565f | 222 | MODULE_LICENSE("GPL"); |