2 * Watchdog driver for SBC-FITPC2 board
4 * Author: Denis Turischev <denis@compulab.co.il>
6 * Adapted from the IXP2000 watchdog driver by Deepak Saxena.
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.
13 #define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt
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>
22 #include <linux/init.h>
23 #include <linux/moduleparam.h>
24 #include <linux/dmi.h>
26 #include <linux/uaccess.h>
28 #include <asm/system.h>
30 static bool 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);
36 #define WDT_OK_TO_CLOSE 1
38 #define COMMAND_PORT 0x4c
39 #define DATA_PORT 0x48
41 #define IFACE_ON_COMMAND 1
42 #define REBOOT_COMMAND 2
44 #define WATCHDOG_NAME "SBC-FITPC2 Watchdog"
46 static void wdt_send_data(unsigned char command, unsigned char data)
48 outb(data, DATA_PORT);
50 outb(command, COMMAND_PORT);
54 static void wdt_enable(void)
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);
62 static void wdt_disable(void)
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);
70 static int fitpc2_wdt_open(struct inode *inode, struct file *file)
72 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
75 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
79 return nonseekable_open(inode, file);
82 static ssize_t fitpc2_wdt_write(struct file *file, const char *data,
83 size_t len, loff_t *ppos)
95 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
97 for (i = 0; i != len; i++) {
100 if (get_user(c, data + i))
104 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
114 static const struct watchdog_info ident = {
115 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
117 .identity = WATCHDOG_NAME,
121 static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
128 case WDIOC_GETSUPPORT:
129 ret = copy_to_user((struct watchdog_info *)arg, &ident,
130 sizeof(ident)) ? -EFAULT : 0;
133 case WDIOC_GETSTATUS:
134 ret = put_user(0, (int *)arg);
137 case WDIOC_GETBOOTSTATUS:
138 ret = put_user(0, (int *)arg);
141 case WDIOC_KEEPALIVE:
146 case WDIOC_SETTIMEOUT:
147 ret = get_user(time, (int *)arg);
151 if (time < 31 || time > 255) {
160 case WDIOC_GETTIMEOUT:
161 ret = put_user(margin, (int *)arg);
168 static int fitpc2_wdt_release(struct inode *inode, struct file *file)
170 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
172 pr_info("Device disabled\n");
174 pr_warn("Device closed unexpectedly - timer will not stop\n");
178 clear_bit(WDT_IN_USE, &wdt_status);
179 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
185 static const struct file_operations fitpc2_wdt_fops = {
186 .owner = THIS_MODULE,
188 .write = fitpc2_wdt_write,
189 .unlocked_ioctl = fitpc2_wdt_ioctl,
190 .open = fitpc2_wdt_open,
191 .release = fitpc2_wdt_release,
194 static struct miscdevice fitpc2_wdt_miscdev = {
195 .minor = WATCHDOG_MINOR,
197 .fops = &fitpc2_wdt_fops,
200 static int __init fitpc2_wdt_init(void)
203 const char *brd_name;
205 brd_name = dmi_get_system_info(DMI_BOARD_NAME);
207 if (!brd_name || !strstr(brd_name, "SBC-FITPC2"))
210 pr_info("%s found\n", brd_name);
212 if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) {
213 pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT);
217 if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) {
218 pr_err("I/O address 0x%04x already in use\n", DATA_PORT);
223 if (margin < 31 || margin > 255) {
224 pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n",
230 err = misc_register(&fitpc2_wdt_miscdev);
232 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
233 WATCHDOG_MINOR, err);
240 release_region(DATA_PORT, 1);
242 release_region(COMMAND_PORT, 1);
247 static void __exit fitpc2_wdt_exit(void)
249 misc_deregister(&fitpc2_wdt_miscdev);
250 release_region(DATA_PORT, 1);
251 release_region(COMMAND_PORT, 1);
254 module_init(fitpc2_wdt_init);
255 module_exit(fitpc2_wdt_exit);
257 MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
258 MODULE_DESCRIPTION("SBC-FITPC2 Watchdog");
260 module_param(margin, int, 0);
261 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
263 module_param(nowayout, bool, 0);
264 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
266 MODULE_LICENSE("GPL");
267 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);