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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
30static int nowayout = WATCHDOG_NOWAYOUT;
31static unsigned int margin = 60;
32static unsigned long wdt_status;
33static 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
46static 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
54static 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
62static 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
70static 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
82static 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
107out:
108 wdt_enable();
109
110 return len;
111}
112
113
114static const struct watchdog_info ident = {
115 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
116 WDIOF_KEEPALIVEPING,
117 .identity = WATCHDOG_NAME,
118};
119
120
121static 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
159
160 case WDIOC_GETTIMEOUT:
161 ret = put_user(margin, (int *)arg);
162 break;
163 }
164
165 return ret;
166}
167
168static 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
186static 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
195static struct miscdevice fitpc2_wdt_miscdev = {
196 .minor = WATCHDOG_MINOR,
197 .name = "watchdog",
198 .fops = &fitpc2_wdt_fops,
199};
200
201static int __init fitpc2_wdt_init(void)
202{
203 int err;
204 const char *brd_name;
205
206 brd_name = dmi_get_system_info(DMI_BOARD_NAME);
207
208 if (!brd_name || !strstr(brd_name, "SBC-FITPC2"))
209 return -ENODEV;
210
211 pr_info("%s found\n", brd_name);
212
213 if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) {
214 pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT);
215 return -EIO;
216 }
217
218 if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) {
219 pr_err("I/O address 0x%04x already in use\n", DATA_PORT);
220 err = -EIO;
221 goto err_data_port;
222 }
223
224 if (margin < 31 || margin > 255) {
225 pr_err("margin must be in range 31 - 255"
226 " seconds, you tried to set %d\n", margin);
227 err = -EINVAL;
228 goto err_margin;
229 }
230
231 err = misc_register(&fitpc2_wdt_miscdev);
232 if (err) {
233 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
234 WATCHDOG_MINOR, err);
235 goto err_margin;
236 }
237
238 return 0;
239
240err_margin:
241 release_region(DATA_PORT, 1);
242err_data_port:
243 release_region(COMMAND_PORT, 1);
244
245 return err;
246}
247
248static void __exit fitpc2_wdt_exit(void)
249{
250 misc_deregister(&fitpc2_wdt_miscdev);
251 release_region(DATA_PORT, 1);
252 release_region(COMMAND_PORT, 1);
253}
254
255module_init(fitpc2_wdt_init);
256module_exit(fitpc2_wdt_exit);
257
258MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
259MODULE_DESCRIPTION("SBC-FITPC2 Watchdog");
260
261module_param(margin, int, 0);
262MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
263
264module_param(nowayout, int, 0);
265MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
266
267MODULE_LICENSE("GPL");
268MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
269
270
