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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 | |
29 | static bool nowayout = WATCHDOG_NOWAYOUT; |
30 | static unsigned int margin = 60; /* (secs) Default is 1 minute */ |
31 | static unsigned long wdt_status; |
32 | static DEFINE_MUTEX(wdt_lock); |
33 | |
34 | #define WDT_IN_USE 0 |
35 | #define WDT_OK_TO_CLOSE 1 |
36 | |
37 | #define COMMAND_PORT 0x4c |
38 | #define DATA_PORT 0x48 |
39 | |
40 | #define IFACE_ON_COMMAND 1 |
41 | #define REBOOT_COMMAND 2 |
42 | |
43 | #define WATCHDOG_NAME "SBC-FITPC2 Watchdog" |
44 | |
45 | static void wdt_send_data(unsigned char command, unsigned char data) |
46 | { |
47 | outb(data, DATA_PORT); |
48 | msleep(200); |
49 | outb(command, COMMAND_PORT); |
50 | msleep(100); |
51 | } |
52 | |
53 | static void wdt_enable(void) |
54 | { |
55 | mutex_lock(&wdt_lock); |
56 | wdt_send_data(IFACE_ON_COMMAND, 1); |
57 | wdt_send_data(REBOOT_COMMAND, margin); |
58 | mutex_unlock(&wdt_lock); |
59 | } |
60 | |
61 | static void wdt_disable(void) |
62 | { |
63 | mutex_lock(&wdt_lock); |
64 | wdt_send_data(IFACE_ON_COMMAND, 0); |
65 | wdt_send_data(REBOOT_COMMAND, 0); |
66 | mutex_unlock(&wdt_lock); |
67 | } |
68 | |
69 | static int fitpc2_wdt_open(struct inode *inode, struct file *file) |
70 | { |
71 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
72 | return -EBUSY; |
73 | |
74 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
75 | |
76 | wdt_enable(); |
77 | |
78 | return nonseekable_open(inode, file); |
79 | } |
80 | |
81 | static ssize_t fitpc2_wdt_write(struct file *file, const char *data, |
82 | size_t len, loff_t *ppos) |
83 | { |
84 | size_t i; |
85 | |
86 | if (!len) |
87 | return 0; |
88 | |
89 | if (nowayout) { |
90 | len = 0; |
91 | goto out; |
92 | } |
93 | |
94 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
95 | |
96 | for (i = 0; i != len; i++) { |
97 | char c; |
98 | |
99 | if (get_user(c, data + i)) |
100 | return -EFAULT; |
101 | |
102 | if (c == 'V') |
103 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
104 | } |
105 | |
106 | out: |
107 | wdt_enable(); |
108 | |
109 | return len; |
110 | } |
111 | |
112 | |
113 | static const struct watchdog_info ident = { |
114 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
115 | WDIOF_KEEPALIVEPING, |
116 | .identity = WATCHDOG_NAME, |
117 | }; |
118 | |
119 | |
120 | static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd, |
121 | unsigned long arg) |
122 | { |
123 | int ret = -ENOTTY; |
124 | int time; |
125 | |
126 | switch (cmd) { |
127 | case WDIOC_GETSUPPORT: |
128 | ret = copy_to_user((struct watchdog_info *)arg, &ident, |
129 | sizeof(ident)) ? -EFAULT : 0; |
130 | break; |
131 | |
132 | case WDIOC_GETSTATUS: |
133 | ret = put_user(0, (int *)arg); |
134 | break; |
135 | |
136 | case WDIOC_GETBOOTSTATUS: |
137 | ret = put_user(0, (int *)arg); |
138 | break; |
139 | |
140 | case WDIOC_KEEPALIVE: |
141 | wdt_enable(); |
142 | ret = 0; |
143 | break; |
144 | |
145 | case WDIOC_SETTIMEOUT: |
146 | ret = get_user(time, (int *)arg); |
147 | if (ret) |
148 | break; |
149 | |
150 | if (time < 31 || time > 255) { |
151 | ret = -EINVAL; |
152 | break; |
153 | } |
154 | |
155 | margin = time; |
156 | wdt_enable(); |
157 | /* Fall through */ |
158 | |
159 | case WDIOC_GETTIMEOUT: |
160 | ret = put_user(margin, (int *)arg); |
161 | break; |
162 | } |
163 | |
164 | return ret; |
165 | } |
166 | |
167 | static int fitpc2_wdt_release(struct inode *inode, struct file *file) |
168 | { |
169 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { |
170 | wdt_disable(); |
171 | pr_info("Device disabled\n"); |
172 | } else { |
173 | pr_warn("Device closed unexpectedly - timer will not stop\n"); |
174 | wdt_enable(); |
175 | } |
176 | |
177 | clear_bit(WDT_IN_USE, &wdt_status); |
178 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
179 | |
180 | return 0; |
181 | } |
182 | |
183 | |
184 | static const struct file_operations fitpc2_wdt_fops = { |
185 | .owner = THIS_MODULE, |
186 | .llseek = no_llseek, |
187 | .write = fitpc2_wdt_write, |
188 | .unlocked_ioctl = fitpc2_wdt_ioctl, |
189 | .open = fitpc2_wdt_open, |
190 | .release = fitpc2_wdt_release, |
191 | }; |
192 | |
193 | static struct miscdevice fitpc2_wdt_miscdev = { |
194 | .minor = WATCHDOG_MINOR, |
195 | .name = "watchdog", |
196 | .fops = &fitpc2_wdt_fops, |
197 | }; |
198 | |
199 | static int __init fitpc2_wdt_init(void) |
200 | { |
201 | int err; |
202 | const char *brd_name; |
203 | |
204 | brd_name = dmi_get_system_info(DMI_BOARD_NAME); |
205 | |
206 | if (!brd_name || !strstr(brd_name, "SBC-FITPC2")) |
207 | return -ENODEV; |
208 | |
209 | pr_info("%s found\n", brd_name); |
210 | |
211 | if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) { |
212 | pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT); |
213 | return -EIO; |
214 | } |
215 | |
216 | if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) { |
217 | pr_err("I/O address 0x%04x already in use\n", DATA_PORT); |
218 | err = -EIO; |
219 | goto err_data_port; |
220 | } |
221 | |
222 | if (margin < 31 || margin > 255) { |
223 | pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n", |
224 | margin); |
225 | err = -EINVAL; |
226 | goto err_margin; |
227 | } |
228 | |
229 | err = misc_register(&fitpc2_wdt_miscdev); |
230 | if (err) { |
231 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
232 | WATCHDOG_MINOR, err); |
233 | goto err_margin; |
234 | } |
235 | |
236 | return 0; |
237 | |
238 | err_margin: |
239 | release_region(DATA_PORT, 1); |
240 | err_data_port: |
241 | release_region(COMMAND_PORT, 1); |
242 | |
243 | return err; |
244 | } |
245 | |
246 | static void __exit fitpc2_wdt_exit(void) |
247 | { |
248 | misc_deregister(&fitpc2_wdt_miscdev); |
249 | release_region(DATA_PORT, 1); |
250 | release_region(COMMAND_PORT, 1); |
251 | } |
252 | |
253 | module_init(fitpc2_wdt_init); |
254 | module_exit(fitpc2_wdt_exit); |
255 | |
256 | MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>"); |
257 | MODULE_DESCRIPTION("SBC-FITPC2 Watchdog"); |
258 | |
259 | module_param(margin, int, 0); |
260 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); |
261 | |
262 | module_param(nowayout, bool, 0); |
263 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
264 | |
265 | MODULE_LICENSE("GPL"); |
266 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
267 | |
268 |
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