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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
29static bool nowayout = WATCHDOG_NOWAYOUT;
30static unsigned int margin = 60;
31static unsigned long wdt_status;
32static 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
45static 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
53static 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
61static 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
69static 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 stream_open(inode, file);
79}
80
81static ssize_t fitpc2_wdt_write(struct file *file, const char __user *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
106out:
107 wdt_enable();
108
109 return len;
110}
111
112
113static const struct watchdog_info ident = {
114 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
115 WDIOF_KEEPALIVEPING,
116 .identity = WATCHDOG_NAME,
117};
118
119
120static 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 __user *)arg, &ident,
129 sizeof(ident)) ? -EFAULT : 0;
130 break;
131
132 case WDIOC_GETSTATUS:
133 ret = put_user(0, (int __user *)arg);
134 break;
135
136 case WDIOC_GETBOOTSTATUS:
137 ret = put_user(0, (int __user *)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 __user *)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 fallthrough;
158
159 case WDIOC_GETTIMEOUT:
160 ret = put_user(margin, (int __user *)arg);
161 break;
162 }
163
164 return ret;
165}
166
167static 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
184static 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 .compat_ioctl = compat_ptr_ioctl,
190 .open = fitpc2_wdt_open,
191 .release = fitpc2_wdt_release,
192};
193
194static struct miscdevice fitpc2_wdt_miscdev = {
195 .minor = WATCHDOG_MINOR,
196 .name = "watchdog",
197 .fops = &fitpc2_wdt_fops,
198};
199
200static int __init fitpc2_wdt_init(void)
201{
202 int err;
203 const char *brd_name;
204
205 brd_name = dmi_get_system_info(DMI_BOARD_NAME);
206
207 if (!brd_name || !strstr(brd_name, "SBC-FITPC2"))
208 return -ENODEV;
209
210 pr_info("%s found\n", brd_name);
211
212 if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) {
213 pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT);
214 return -EIO;
215 }
216
217 if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) {
218 pr_err("I/O address 0x%04x already in use\n", DATA_PORT);
219 err = -EIO;
220 goto err_data_port;
221 }
222
223 if (margin < 31 || margin > 255) {
224 pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n",
225 margin);
226 err = -EINVAL;
227 goto err_margin;
228 }
229
230 err = misc_register(&fitpc2_wdt_miscdev);
231 if (err) {
232 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
233 WATCHDOG_MINOR, err);
234 goto err_margin;
235 }
236
237 return 0;
238
239err_margin:
240 release_region(DATA_PORT, 1);
241err_data_port:
242 release_region(COMMAND_PORT, 1);
243
244 return err;
245}
246
247static void __exit fitpc2_wdt_exit(void)
248{
249 misc_deregister(&fitpc2_wdt_miscdev);
250 release_region(DATA_PORT, 1);
251 release_region(COMMAND_PORT, 1);
252}
253
254module_init(fitpc2_wdt_init);
255module_exit(fitpc2_wdt_exit);
256
257MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
258MODULE_DESCRIPTION("SBC-FITPC2 Watchdog");
259
260module_param(margin, int, 0);
261MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
262
263module_param(nowayout, bool, 0);
264MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
265
266MODULE_LICENSE("GPL");
267
