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Calin A. Culianueed65652006-01-14 13:20:46 -08001/*
2 * SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3
3 * single board computer
4 *
5 * (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
6 * Reserved.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 *
Alan Cox29fa0582008-10-27 15:17:56 +000013 * based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
Calin A. Culianueed65652006-01-14 13:20:46 -080014 */
15
Joe Perches27c766a2012-02-15 15:06:19 -080016#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
Calin A. Culianueed65652006-01-14 13:20:46 -080018#include <linux/module.h>
19#include <linux/moduleparam.h>
Calin A. Culianueed65652006-01-14 13:20:46 -080020#include <linux/types.h>
21#include <linux/kernel.h>
22#include <linux/fs.h>
23#include <linux/mm.h>
24#include <linux/miscdevice.h>
25#include <linux/watchdog.h>
26#include <linux/notifier.h>
27#include <linux/reboot.h>
28#include <linux/init.h>
Alan Coxde6c6422006-02-03 03:03:58 -080029#include <linux/ioport.h>
Alan Coxf4f6f652008-05-19 14:08:27 +010030#include <linux/uaccess.h>
31#include <linux/io.h>
Calin A. Culianueed65652006-01-14 13:20:46 -080032
Calin A. Culianueed65652006-01-14 13:20:46 -080033static int epx_c3_alive;
34
35#define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */
36
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010037static bool nowayout = WATCHDOG_NOWAYOUT;
38module_param(nowayout, bool, 0);
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +000039MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Calin A. Culianueed65652006-01-14 13:20:46 -080041
42#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
43#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
44
45static void epx_c3_start(void)
46{
47 outb(1, EPXC3_WATCHDOG_CTL_REG);
48}
49
50static void epx_c3_stop(void)
51{
52
53 outb(0, EPXC3_WATCHDOG_CTL_REG);
54
Joe Perches27c766a2012-02-15 15:06:19 -080055 pr_info("Stopped watchdog timer\n");
Calin A. Culianueed65652006-01-14 13:20:46 -080056}
57
58static void epx_c3_pet(void)
59{
60 outb(1, EPXC3_WATCHDOG_PET_REG);
61}
62
63/*
64 * Allow only one person to hold it open
65 */
66static int epx_c3_open(struct inode *inode, struct file *file)
67{
68 if (epx_c3_alive)
69 return -EBUSY;
70
71 if (nowayout)
72 __module_get(THIS_MODULE);
73
74 /* Activate timer */
75 epx_c3_start();
76 epx_c3_pet();
77
78 epx_c3_alive = 1;
Joe Perches27c766a2012-02-15 15:06:19 -080079 pr_info("Started watchdog timer\n");
Calin A. Culianueed65652006-01-14 13:20:46 -080080
81 return nonseekable_open(inode, file);
82}
83
84static int epx_c3_release(struct inode *inode, struct file *file)
85{
86 /* Shut off the timer.
87 * Lock it in if it's a module and we defined ...NOWAYOUT */
88 if (!nowayout)
89 epx_c3_stop(); /* Turn the WDT off */
90
91 epx_c3_alive = 0;
92
93 return 0;
94}
95
Al Viro73a09e62006-02-01 06:04:15 -050096static ssize_t epx_c3_write(struct file *file, const char __user *data,
Calin A. Culianueed65652006-01-14 13:20:46 -080097 size_t len, loff_t *ppos)
98{
99 /* Refresh the timer. */
100 if (len)
101 epx_c3_pet();
102 return len;
103}
104
Alan Coxf4f6f652008-05-19 14:08:27 +0100105static long epx_c3_ioctl(struct file *file, unsigned int cmd,
106 unsigned long arg)
Calin A. Culianueed65652006-01-14 13:20:46 -0800107{
108 int options, retval = -EINVAL;
Al Viro73a09e62006-02-01 06:04:15 -0500109 int __user *argp = (void __user *)arg;
Alan Coxf4f6f652008-05-19 14:08:27 +0100110 static const struct watchdog_info ident = {
Wim Van Sebroecke73a7802009-05-11 18:33:00 +0000111 .options = WDIOF_KEEPALIVEPING,
Calin A. Culianueed65652006-01-14 13:20:46 -0800112 .firmware_version = 0,
113 .identity = "Winsystems EPX-C3 H/W Watchdog",
114 };
115
116 switch (cmd) {
117 case WDIOC_GETSUPPORT:
Al Viro73a09e62006-02-01 06:04:15 -0500118 if (copy_to_user(argp, &ident, sizeof(ident)))
Calin A. Culianueed65652006-01-14 13:20:46 -0800119 return -EFAULT;
120 return 0;
121 case WDIOC_GETSTATUS:
122 case WDIOC_GETBOOTSTATUS:
Al Viro73a09e62006-02-01 06:04:15 -0500123 return put_user(0, argp);
Al Viro73a09e62006-02-01 06:04:15 -0500124 case WDIOC_SETOPTIONS:
125 if (get_user(options, argp))
Calin A. Culianueed65652006-01-14 13:20:46 -0800126 return -EFAULT;
127
128 if (options & WDIOS_DISABLECARD) {
129 epx_c3_stop();
130 retval = 0;
131 }
132
133 if (options & WDIOS_ENABLECARD) {
134 epx_c3_start();
135 retval = 0;
136 }
137
138 return retval;
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000139 case WDIOC_KEEPALIVE:
140 epx_c3_pet();
141 return 0;
142 case WDIOC_GETTIMEOUT:
143 return put_user(WATCHDOG_TIMEOUT, argp);
Calin A. Culianueed65652006-01-14 13:20:46 -0800144 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200145 return -ENOTTY;
Calin A. Culianueed65652006-01-14 13:20:46 -0800146 }
147}
148
149static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
150 void *unused)
151{
152 if (code == SYS_DOWN || code == SYS_HALT)
153 epx_c3_stop(); /* Turn the WDT off */
154
155 return NOTIFY_DONE;
156}
157
Arjan van de Ven62322d22006-07-03 00:24:21 -0700158static const struct file_operations epx_c3_fops = {
Calin A. Culianueed65652006-01-14 13:20:46 -0800159 .owner = THIS_MODULE,
160 .llseek = no_llseek,
161 .write = epx_c3_write,
Alan Coxf4f6f652008-05-19 14:08:27 +0100162 .unlocked_ioctl = epx_c3_ioctl,
Calin A. Culianueed65652006-01-14 13:20:46 -0800163 .open = epx_c3_open,
164 .release = epx_c3_release,
165};
166
167static struct miscdevice epx_c3_miscdev = {
168 .minor = WATCHDOG_MINOR,
169 .name = "watchdog",
170 .fops = &epx_c3_fops,
171};
172
173static struct notifier_block epx_c3_notifier = {
174 .notifier_call = epx_c3_notify_sys,
175};
176
Calin A. Culianueed65652006-01-14 13:20:46 -0800177static int __init watchdog_init(void)
178{
179 int ret;
180
Alan Coxde6c6422006-02-03 03:03:58 -0800181 if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
182 return -EBUSY;
183
Calin A. Culianueed65652006-01-14 13:20:46 -0800184 ret = register_reboot_notifier(&epx_c3_notifier);
185 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800186 pr_err("cannot register reboot notifier (err=%d)\n", ret);
Alan Coxde6c6422006-02-03 03:03:58 -0800187 goto out;
Calin A. Culianueed65652006-01-14 13:20:46 -0800188 }
189
190 ret = misc_register(&epx_c3_miscdev);
191 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800192 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
193 WATCHDOG_MINOR, ret);
Calin A. Culianueed65652006-01-14 13:20:46 -0800194 unregister_reboot_notifier(&epx_c3_notifier);
Alan Coxde6c6422006-02-03 03:03:58 -0800195 goto out;
Calin A. Culianueed65652006-01-14 13:20:46 -0800196 }
197
Joe Perches27c766a2012-02-15 15:06:19 -0800198 pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n");
Calin A. Culianueed65652006-01-14 13:20:46 -0800199
200 return 0;
Alan Coxde6c6422006-02-03 03:03:58 -0800201
202out:
203 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
204 return ret;
Calin A. Culianueed65652006-01-14 13:20:46 -0800205}
206
207static void __exit watchdog_exit(void)
208{
209 misc_deregister(&epx_c3_miscdev);
210 unregister_reboot_notifier(&epx_c3_notifier);
Alan Coxde6c6422006-02-03 03:03:58 -0800211 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
Calin A. Culianueed65652006-01-14 13:20:46 -0800212}
213
214module_init(watchdog_init);
215module_exit(watchdog_exit);
216
217MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000218MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. "
219 "Note that there is no way to probe for this device -- "
Justin P. Mattockae0e47f2011-03-01 15:06:02 +0100220 "so only use it if you are *sure* you are running on this specific "
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000221 "SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
Calin A. Culianueed65652006-01-14 13:20:46 -0800222MODULE_LICENSE("GPL");
223MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);