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1 | /* |
2 | * Watchdog driver for SBC-FITPC2 board |
3 | * |
4 | * Author: Denis Turischev <denis@compulab.co.il> |
5 | * |
6 | * Adapted from the IXP2000 watchdog driver by Deepak Saxena. |
7 | * |
8 | * This file is licensed under the terms of the GNU General Public |
9 | * License version 2. This program is licensed "as is" without any |
10 | * warranty of any kind, whether express or implied. |
11 | */ |
12 | |
13 | #define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt |
14 | |
15 | #include <linux/module.h> |
16 | #include <linux/types.h> |
17 | #include <linux/miscdevice.h> |
18 | #include <linux/watchdog.h> |
19 | #include <linux/ioport.h> |
20 | #include <linux/delay.h> |
21 | #include <linux/fs.h> |
22 | #include <linux/init.h> |
23 | #include <linux/moduleparam.h> |
24 | #include <linux/dmi.h> |
25 | #include <linux/io.h> |
26 | #include <linux/uaccess.h> |
27 | |
28 | #include <asm/system.h> |
29 | |
30 | static int nowayout = WATCHDOG_NOWAYOUT; |
31 | static unsigned int margin = 60; /* (secs) Default is 1 minute */ |
32 | static unsigned long wdt_status; |
33 | static DEFINE_MUTEX(wdt_lock); |
34 | |
35 | #define WDT_IN_USE 0 |
36 | #define WDT_OK_TO_CLOSE 1 |
37 | |
38 | #define COMMAND_PORT 0x4c |
39 | #define DATA_PORT 0x48 |
40 | |
41 | #define IFACE_ON_COMMAND 1 |
42 | #define REBOOT_COMMAND 2 |
43 | |
44 | #define WATCHDOG_NAME "SBC-FITPC2 Watchdog" |
45 | |
46 | static void wdt_send_data(unsigned char command, unsigned char data) |
47 | { |
48 | outb(data, DATA_PORT); |
49 | msleep(200); |
50 | outb(command, COMMAND_PORT); |
51 | msleep(100); |
52 | } |
53 | |
54 | static void wdt_enable(void) |
55 | { |
56 | mutex_lock(&wdt_lock); |
57 | wdt_send_data(IFACE_ON_COMMAND, 1); |
58 | wdt_send_data(REBOOT_COMMAND, margin); |
59 | mutex_unlock(&wdt_lock); |
60 | } |
61 | |
62 | static void wdt_disable(void) |
63 | { |
64 | mutex_lock(&wdt_lock); |
65 | wdt_send_data(IFACE_ON_COMMAND, 0); |
66 | wdt_send_data(REBOOT_COMMAND, 0); |
67 | mutex_unlock(&wdt_lock); |
68 | } |
69 | |
70 | static int fitpc2_wdt_open(struct inode *inode, struct file *file) |
71 | { |
72 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
73 | return -EBUSY; |
74 | |
75 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
76 | |
77 | wdt_enable(); |
78 | |
79 | return nonseekable_open(inode, file); |
80 | } |
81 | |
82 | static ssize_t fitpc2_wdt_write(struct file *file, const char *data, |
83 | size_t len, loff_t *ppos) |
84 | { |
85 | size_t i; |
86 | |
87 | if (!len) |
88 | return 0; |
89 | |
90 | if (nowayout) { |
91 | len = 0; |
92 | goto out; |
93 | } |
94 | |
95 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
96 | |
97 | for (i = 0; i != len; i++) { |
98 | char c; |
99 | |
100 | if (get_user(c, data + i)) |
101 | return -EFAULT; |
102 | |
103 | if (c == 'V') |
104 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
105 | } |
106 | |
107 | out: |
108 | wdt_enable(); |
109 | |
110 | return len; |
111 | } |
112 | |
113 | |
114 | static const struct watchdog_info ident = { |
115 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
116 | WDIOF_KEEPALIVEPING, |
117 | .identity = WATCHDOG_NAME, |
118 | }; |
119 | |
120 | |
121 | static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd, |
122 | unsigned long arg) |
123 | { |
124 | int ret = -ENOTTY; |
125 | int time; |
126 | |
127 | switch (cmd) { |
128 | case WDIOC_GETSUPPORT: |
129 | ret = copy_to_user((struct watchdog_info *)arg, &ident, |
130 | sizeof(ident)) ? -EFAULT : 0; |
131 | break; |
132 | |
133 | case WDIOC_GETSTATUS: |
134 | ret = put_user(0, (int *)arg); |
135 | break; |
136 | |
137 | case WDIOC_GETBOOTSTATUS: |
138 | ret = put_user(0, (int *)arg); |
139 | break; |
140 | |
141 | case WDIOC_KEEPALIVE: |
142 | wdt_enable(); |
143 | ret = 0; |
144 | break; |
145 | |
146 | case WDIOC_SETTIMEOUT: |
147 | ret = get_user(time, (int *)arg); |
148 | if (ret) |
149 | break; |
150 | |
151 | if (time < 31 || time > 255) { |
152 | ret = -EINVAL; |
153 | break; |
154 | } |
155 | |
156 | margin = time; |
157 | wdt_enable(); |
158 | /* Fall through */ |
159 | |
160 | case WDIOC_GETTIMEOUT: |
161 | ret = put_user(margin, (int *)arg); |
162 | break; |
163 | } |
164 | |
165 | return ret; |
166 | } |
167 | |
168 | static int fitpc2_wdt_release(struct inode *inode, struct file *file) |
169 | { |
170 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { |
171 | wdt_disable(); |
172 | pr_info("Device disabled\n"); |
173 | } else { |
174 | pr_warning("Device closed unexpectedly -" |
175 | " timer will not stop\n"); |
176 | wdt_enable(); |
177 | } |
178 | |
179 | clear_bit(WDT_IN_USE, &wdt_status); |
180 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
181 | |
182 | return 0; |
183 | } |
184 | |
185 | |
186 | static const struct file_operations fitpc2_wdt_fops = { |
187 | .owner = THIS_MODULE, |
188 | .llseek = no_llseek, |
189 | .write = fitpc2_wdt_write, |
190 | .unlocked_ioctl = fitpc2_wdt_ioctl, |
191 | .open = fitpc2_wdt_open, |
192 | .release = fitpc2_wdt_release, |
193 | }; |
194 | |
195 | static struct miscdevice fitpc2_wdt_miscdev = { |
196 | .minor = WATCHDOG_MINOR, |
197 | .name = "watchdog", |
198 | .fops = &fitpc2_wdt_fops, |
199 | }; |
200 | |
201 | static int __init fitpc2_wdt_init(void) |
202 | { |
203 | int err; |
204 | |
205 | if (!strstr(dmi_get_system_info(DMI_BOARD_NAME), "SBC-FITPC2")) |
206 | return -ENODEV; |
207 | |
208 | pr_info("%s found\n", dmi_get_system_info(DMI_BOARD_NAME)); |
209 | |
210 | if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) { |
211 | pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT); |
212 | return -EIO; |
213 | } |
214 | |
215 | if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) { |
216 | pr_err("I/O address 0x%04x already in use\n", DATA_PORT); |
217 | err = -EIO; |
218 | goto err_data_port; |
219 | } |
220 | |
221 | if (margin < 31 || margin > 255) { |
222 | pr_err("margin must be in range 31 - 255" |
223 | " seconds, you tried to set %d\n", margin); |
224 | err = -EINVAL; |
225 | goto err_margin; |
226 | } |
227 | |
228 | err = misc_register(&fitpc2_wdt_miscdev); |
229 | if (err) { |
230 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
231 | WATCHDOG_MINOR, err); |
232 | goto err_margin; |
233 | } |
234 | |
235 | return 0; |
236 | |
237 | err_margin: |
238 | release_region(DATA_PORT, 1); |
239 | err_data_port: |
240 | release_region(COMMAND_PORT, 1); |
241 | |
242 | return err; |
243 | } |
244 | |
245 | static void __exit fitpc2_wdt_exit(void) |
246 | { |
247 | misc_deregister(&fitpc2_wdt_miscdev); |
248 | release_region(DATA_PORT, 1); |
249 | release_region(COMMAND_PORT, 1); |
250 | } |
251 | |
252 | module_init(fitpc2_wdt_init); |
253 | module_exit(fitpc2_wdt_exit); |
254 | |
255 | MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>"); |
256 | MODULE_DESCRIPTION("SBC-FITPC2 Watchdog"); |
257 | |
258 | module_param(margin, int, 0); |
259 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); |
260 | |
261 | module_param(nowayout, int, 0); |
262 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
263 | |
264 | MODULE_LICENSE("GPL"); |
265 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
266 | |
267 |
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