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Thomas Gleixner2874c5f2019-05-27 08:55:01 +02001// SPDX-License-Identifier: GPL-2.0-or-later
Calin A. Culianueed65652006-01-14 13:20:46 -08002/*
3 * SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3
4 * single board computer
5 *
6 * (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
7 * Reserved.
8 *
Alan Cox29fa0582008-10-27 15:17:56 +00009 * based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
Calin A. Culianueed65652006-01-14 13:20:46 -080010 */
11
Joe Perches27c766a2012-02-15 15:06:19 -080012#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
Calin A. Culianueed65652006-01-14 13:20:46 -080014#include <linux/module.h>
15#include <linux/moduleparam.h>
Calin A. Culianueed65652006-01-14 13:20:46 -080016#include <linux/types.h>
17#include <linux/kernel.h>
18#include <linux/fs.h>
19#include <linux/mm.h>
20#include <linux/miscdevice.h>
21#include <linux/watchdog.h>
22#include <linux/notifier.h>
23#include <linux/reboot.h>
24#include <linux/init.h>
Alan Coxde6c6422006-02-03 03:03:58 -080025#include <linux/ioport.h>
Alan Coxf4f6f652008-05-19 14:08:27 +010026#include <linux/uaccess.h>
27#include <linux/io.h>
Calin A. Culianueed65652006-01-14 13:20:46 -080028
Calin A. Culianueed65652006-01-14 13:20:46 -080029static int epx_c3_alive;
30
31#define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */
32
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010033static bool nowayout = WATCHDOG_NOWAYOUT;
34module_param(nowayout, bool, 0);
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +000035MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
36 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Calin A. Culianueed65652006-01-14 13:20:46 -080037
38#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
39#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
40
41static void epx_c3_start(void)
42{
43 outb(1, EPXC3_WATCHDOG_CTL_REG);
44}
45
46static void epx_c3_stop(void)
47{
48
49 outb(0, EPXC3_WATCHDOG_CTL_REG);
50
Joe Perches27c766a2012-02-15 15:06:19 -080051 pr_info("Stopped watchdog timer\n");
Calin A. Culianueed65652006-01-14 13:20:46 -080052}
53
54static void epx_c3_pet(void)
55{
56 outb(1, EPXC3_WATCHDOG_PET_REG);
57}
58
59/*
60 * Allow only one person to hold it open
61 */
62static int epx_c3_open(struct inode *inode, struct file *file)
63{
64 if (epx_c3_alive)
65 return -EBUSY;
66
67 if (nowayout)
68 __module_get(THIS_MODULE);
69
70 /* Activate timer */
71 epx_c3_start();
72 epx_c3_pet();
73
74 epx_c3_alive = 1;
Joe Perches27c766a2012-02-15 15:06:19 -080075 pr_info("Started watchdog timer\n");
Calin A. Culianueed65652006-01-14 13:20:46 -080076
Kirill Smelkovc5bf68f2019-03-26 23:51:19 +030077 return stream_open(inode, file);
Calin A. Culianueed65652006-01-14 13:20:46 -080078}
79
80static int epx_c3_release(struct inode *inode, struct file *file)
81{
82 /* Shut off the timer.
83 * Lock it in if it's a module and we defined ...NOWAYOUT */
84 if (!nowayout)
85 epx_c3_stop(); /* Turn the WDT off */
86
87 epx_c3_alive = 0;
88
89 return 0;
90}
91
Al Viro73a09e62006-02-01 06:04:15 -050092static ssize_t epx_c3_write(struct file *file, const char __user *data,
Calin A. Culianueed65652006-01-14 13:20:46 -080093 size_t len, loff_t *ppos)
94{
95 /* Refresh the timer. */
96 if (len)
97 epx_c3_pet();
98 return len;
99}
100
Alan Coxf4f6f652008-05-19 14:08:27 +0100101static long epx_c3_ioctl(struct file *file, unsigned int cmd,
102 unsigned long arg)
Calin A. Culianueed65652006-01-14 13:20:46 -0800103{
104 int options, retval = -EINVAL;
Al Viro73a09e62006-02-01 06:04:15 -0500105 int __user *argp = (void __user *)arg;
Alan Coxf4f6f652008-05-19 14:08:27 +0100106 static const struct watchdog_info ident = {
Wim Van Sebroecke73a7802009-05-11 18:33:00 +0000107 .options = WDIOF_KEEPALIVEPING,
Calin A. Culianueed65652006-01-14 13:20:46 -0800108 .firmware_version = 0,
109 .identity = "Winsystems EPX-C3 H/W Watchdog",
110 };
111
112 switch (cmd) {
113 case WDIOC_GETSUPPORT:
Al Viro73a09e62006-02-01 06:04:15 -0500114 if (copy_to_user(argp, &ident, sizeof(ident)))
Calin A. Culianueed65652006-01-14 13:20:46 -0800115 return -EFAULT;
116 return 0;
117 case WDIOC_GETSTATUS:
118 case WDIOC_GETBOOTSTATUS:
Al Viro73a09e62006-02-01 06:04:15 -0500119 return put_user(0, argp);
Al Viro73a09e62006-02-01 06:04:15 -0500120 case WDIOC_SETOPTIONS:
121 if (get_user(options, argp))
Calin A. Culianueed65652006-01-14 13:20:46 -0800122 return -EFAULT;
123
124 if (options & WDIOS_DISABLECARD) {
125 epx_c3_stop();
126 retval = 0;
127 }
128
129 if (options & WDIOS_ENABLECARD) {
130 epx_c3_start();
131 retval = 0;
132 }
133
134 return retval;
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000135 case WDIOC_KEEPALIVE:
136 epx_c3_pet();
137 return 0;
138 case WDIOC_GETTIMEOUT:
139 return put_user(WATCHDOG_TIMEOUT, argp);
Calin A. Culianueed65652006-01-14 13:20:46 -0800140 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200141 return -ENOTTY;
Calin A. Culianueed65652006-01-14 13:20:46 -0800142 }
143}
144
145static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
146 void *unused)
147{
148 if (code == SYS_DOWN || code == SYS_HALT)
149 epx_c3_stop(); /* Turn the WDT off */
150
151 return NOTIFY_DONE;
152}
153
Arjan van de Ven62322d22006-07-03 00:24:21 -0700154static const struct file_operations epx_c3_fops = {
Calin A. Culianueed65652006-01-14 13:20:46 -0800155 .owner = THIS_MODULE,
156 .llseek = no_llseek,
157 .write = epx_c3_write,
Alan Coxf4f6f652008-05-19 14:08:27 +0100158 .unlocked_ioctl = epx_c3_ioctl,
Arnd Bergmannb6dfb242019-06-03 14:23:09 +0200159 .compat_ioctl = compat_ptr_ioctl,
Calin A. Culianueed65652006-01-14 13:20:46 -0800160 .open = epx_c3_open,
161 .release = epx_c3_release,
162};
163
164static struct miscdevice epx_c3_miscdev = {
165 .minor = WATCHDOG_MINOR,
166 .name = "watchdog",
167 .fops = &epx_c3_fops,
168};
169
170static struct notifier_block epx_c3_notifier = {
171 .notifier_call = epx_c3_notify_sys,
172};
173
Calin A. Culianueed65652006-01-14 13:20:46 -0800174static int __init watchdog_init(void)
175{
176 int ret;
177
Alan Coxde6c6422006-02-03 03:03:58 -0800178 if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
179 return -EBUSY;
180
Calin A. Culianueed65652006-01-14 13:20:46 -0800181 ret = register_reboot_notifier(&epx_c3_notifier);
182 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800183 pr_err("cannot register reboot notifier (err=%d)\n", ret);
Alan Coxde6c6422006-02-03 03:03:58 -0800184 goto out;
Calin A. Culianueed65652006-01-14 13:20:46 -0800185 }
186
187 ret = misc_register(&epx_c3_miscdev);
188 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800189 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
190 WATCHDOG_MINOR, ret);
Calin A. Culianueed65652006-01-14 13:20:46 -0800191 unregister_reboot_notifier(&epx_c3_notifier);
Alan Coxde6c6422006-02-03 03:03:58 -0800192 goto out;
Calin A. Culianueed65652006-01-14 13:20:46 -0800193 }
194
Joe Perches27c766a2012-02-15 15:06:19 -0800195 pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n");
Calin A. Culianueed65652006-01-14 13:20:46 -0800196
197 return 0;
Alan Coxde6c6422006-02-03 03:03:58 -0800198
199out:
200 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
201 return ret;
Calin A. Culianueed65652006-01-14 13:20:46 -0800202}
203
204static void __exit watchdog_exit(void)
205{
206 misc_deregister(&epx_c3_miscdev);
207 unregister_reboot_notifier(&epx_c3_notifier);
Alan Coxde6c6422006-02-03 03:03:58 -0800208 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
Calin A. Culianueed65652006-01-14 13:20:46 -0800209}
210
211module_init(watchdog_init);
212module_exit(watchdog_exit);
213
214MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000215MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. "
216 "Note that there is no way to probe for this device -- "
Justin P. Mattockae0e47f2011-03-01 15:06:02 +0100217 "so only use it if you are *sure* you are running on this specific "
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000218 "SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
Calin A. Culianueed65652006-01-14 13:20:46 -0800219MODULE_LICENSE("GPL");