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16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#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>
29#include <linux/ioport.h>
30#include <linux/uaccess.h>
31#include <linux/io.h>
32
33static int epx_c3_alive;
34
35#define WATCHDOG_TIMEOUT 1
36
37static bool nowayout = WATCHDOG_NOWAYOUT;
38module_param(nowayout, bool, 0);
39MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
41
42#define EPXC3_WATCHDOG_CTL_REG 0x1ee
43#define EPXC3_WATCHDOG_PET_REG 0x1ef
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
55 pr_info("Stopped watchdog timer\n");
56}
57
58static void epx_c3_pet(void)
59{
60 outb(1, EPXC3_WATCHDOG_PET_REG);
61}
62
63
64
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
75 epx_c3_start();
76 epx_c3_pet();
77
78 epx_c3_alive = 1;
79 pr_info("Started watchdog timer\n");
80
81 return nonseekable_open(inode, file);
82}
83
84static int epx_c3_release(struct inode *inode, struct file *file)
85{
86
87
88 if (!nowayout)
89 epx_c3_stop();
90
91 epx_c3_alive = 0;
92
93 return 0;
94}
95
96static ssize_t epx_c3_write(struct file *file, const char __user *data,
97 size_t len, loff_t *ppos)
98{
99
100 if (len)
101 epx_c3_pet();
102 return len;
103}
104
105static long epx_c3_ioctl(struct file *file, unsigned int cmd,
106 unsigned long arg)
107{
108 int options, retval = -EINVAL;
109 int __user *argp = (void __user *)arg;
110 static const struct watchdog_info ident = {
111 .options = WDIOF_KEEPALIVEPING,
112 .firmware_version = 0,
113 .identity = "Winsystems EPX-C3 H/W Watchdog",
114 };
115
116 switch (cmd) {
117 case WDIOC_GETSUPPORT:
118 if (copy_to_user(argp, &ident, sizeof(ident)))
119 return -EFAULT;
120 return 0;
121 case WDIOC_GETSTATUS:
122 case WDIOC_GETBOOTSTATUS:
123 return put_user(0, argp);
124 case WDIOC_SETOPTIONS:
125 if (get_user(options, argp))
126 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;
139 case WDIOC_KEEPALIVE:
140 epx_c3_pet();
141 return 0;
142 case WDIOC_GETTIMEOUT:
143 return put_user(WATCHDOG_TIMEOUT, argp);
144 default:
145 return -ENOTTY;
146 }
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();
154
155 return NOTIFY_DONE;
156}
157
158static const struct file_operations epx_c3_fops = {
159 .owner = THIS_MODULE,
160 .llseek = no_llseek,
161 .write = epx_c3_write,
162 .unlocked_ioctl = epx_c3_ioctl,
163 .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
177static int __init watchdog_init(void)
178{
179 int ret;
180
181 if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
182 return -EBUSY;
183
184 ret = register_reboot_notifier(&epx_c3_notifier);
185 if (ret) {
186 pr_err("cannot register reboot notifier (err=%d)\n", ret);
187 goto out;
188 }
189
190 ret = misc_register(&epx_c3_miscdev);
191 if (ret) {
192 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
193 WATCHDOG_MINOR, ret);
194 unregister_reboot_notifier(&epx_c3_notifier);
195 goto out;
196 }
197
198 pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n");
199
200 return 0;
201
202out:
203 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
204 return ret;
205}
206
207static void __exit watchdog_exit(void)
208{
209 misc_deregister(&epx_c3_miscdev);
210 unregister_reboot_notifier(&epx_c3_notifier);
211 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
212}
213
214module_init(watchdog_init);
215module_exit(watchdog_exit);
216
217MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
218MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. "
219 "Note that there is no way to probe for this device -- "
220 "so only use it if you are *sure* you are running on this specific "
221 "SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
222MODULE_LICENSE("GPL");
223MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
224
