1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/fs.h>
22#include <linux/init.h>
23#include <linux/ioport.h>
24#include <linux/jiffies.h>
25#include <linux/module.h>
26#include <linux/moduleparam.h>
27#include <linux/miscdevice.h>
28#include <linux/notifier.h>
29#include <linux/reboot.h>
30#include <linux/types.h>
31#include <linux/watchdog.h>
32#include <linux/io.h>
33#include <linux/uaccess.h>
34#include <linux/atomic.h>
35
36#define SBC7240_ENABLE_PORT 0x443
37#define SBC7240_DISABLE_PORT 0x043
38#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
39#define SBC7240_MAGIC_CHAR 'V'
40
41#define SBC7240_TIMEOUT 30
42#define SBC7240_MAX_TIMEOUT 255
43static int timeout = SBC7240_TIMEOUT;
44module_param(timeout, int, 0);
45MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
46 __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
47 __MODULE_STRING(SBC7240_TIMEOUT) ")");
48
49static bool nowayout = WATCHDOG_NOWAYOUT;
50module_param(nowayout, bool, 0);
51MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
52
53#define SBC7240_OPEN_STATUS_BIT 0
54#define SBC7240_ENABLED_STATUS_BIT 1
55#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
56static unsigned long wdt_status;
57
58
59
60
61
62static void wdt_disable(void)
63{
64
65 if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
66 inb_p(SBC7240_DISABLE_PORT);
67 pr_info("Watchdog timer is now disabled\n");
68 }
69}
70
71static void wdt_enable(void)
72{
73
74 if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
75 inb_p(SBC7240_ENABLE_PORT);
76 pr_info("Watchdog timer is now enabled\n");
77 }
78}
79
80static int wdt_set_timeout(int t)
81{
82 if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
83 pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT);
84 return -1;
85 }
86
87 outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
88 timeout = t;
89 pr_info("timeout set to %d seconds\n", t);
90 return 0;
91}
92
93
94static inline void wdt_keepalive(void)
95{
96 if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
97 inb_p(SBC7240_ENABLE_PORT);
98}
99
100
101
102
103static ssize_t fop_write(struct file *file, const char __user *buf,
104 size_t count, loff_t *ppos)
105{
106 size_t i;
107 char c;
108
109 if (count) {
110 if (!nowayout) {
111 clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
112 &wdt_status);
113
114
115 for (i = 0; i != count; i++) {
116 if (get_user(c, buf + i))
117 return -EFAULT;
118 if (c == SBC7240_MAGIC_CHAR) {
119 set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
120 &wdt_status);
121 break;
122 }
123 }
124 }
125
126 wdt_keepalive();
127 }
128
129 return count;
130}
131
132static int fop_open(struct inode *inode, struct file *file)
133{
134 if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
135 return -EBUSY;
136
137 wdt_enable();
138
139 return nonseekable_open(inode, file);
140}
141
142static int fop_close(struct inode *inode, struct file *file)
143{
144 if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
145 || !nowayout) {
146 wdt_disable();
147 } else {
148 pr_crit("Unexpected close, not stopping watchdog!\n");
149 wdt_keepalive();
150 }
151
152 clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
153 return 0;
154}
155
156static const struct watchdog_info ident = {
157 .options = WDIOF_KEEPALIVEPING|
158 WDIOF_SETTIMEOUT|
159 WDIOF_MAGICCLOSE,
160 .firmware_version = 1,
161 .identity = "SBC7240",
162};
163
164
165static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
166{
167 switch (cmd) {
168 case WDIOC_GETSUPPORT:
169 return copy_to_user((void __user *)arg, &ident, sizeof(ident))
170 ? -EFAULT : 0;
171 case WDIOC_GETSTATUS:
172 case WDIOC_GETBOOTSTATUS:
173 return put_user(0, (int __user *)arg);
174 case WDIOC_SETOPTIONS:
175 {
176 int options;
177 int retval = -EINVAL;
178
179 if (get_user(options, (int __user *)arg))
180 return -EFAULT;
181
182 if (options & WDIOS_DISABLECARD) {
183 wdt_disable();
184 retval = 0;
185 }
186
187 if (options & WDIOS_ENABLECARD) {
188 wdt_enable();
189 retval = 0;
190 }
191
192 return retval;
193 }
194 case WDIOC_KEEPALIVE:
195 wdt_keepalive();
196 return 0;
197 case WDIOC_SETTIMEOUT:
198 {
199 int new_timeout;
200
201 if (get_user(new_timeout, (int __user *)arg))
202 return -EFAULT;
203
204 if (wdt_set_timeout(new_timeout))
205 return -EINVAL;
206
207
208 }
209 case WDIOC_GETTIMEOUT:
210 return put_user(timeout, (int __user *)arg);
211 default:
212 return -ENOTTY;
213 }
214}
215
216static const struct file_operations wdt_fops = {
217 .owner = THIS_MODULE,
218 .llseek = no_llseek,
219 .write = fop_write,
220 .open = fop_open,
221 .release = fop_close,
222 .unlocked_ioctl = fop_ioctl,
223};
224
225static struct miscdevice wdt_miscdev = {
226 .minor = WATCHDOG_MINOR,
227 .name = "watchdog",
228 .fops = &wdt_fops,
229};
230
231
232
233
234
235static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
236 void *unused)
237{
238 if (code == SYS_DOWN || code == SYS_HALT)
239 wdt_disable();
240 return NOTIFY_DONE;
241}
242
243static struct notifier_block wdt_notifier = {
244 .notifier_call = wdt_notify_sys,
245};
246
247static void __exit sbc7240_wdt_unload(void)
248{
249 pr_info("Removing watchdog\n");
250 misc_deregister(&wdt_miscdev);
251
252 unregister_reboot_notifier(&wdt_notifier);
253 release_region(SBC7240_ENABLE_PORT, 1);
254}
255
256static int __init sbc7240_wdt_init(void)
257{
258 int rc = -EBUSY;
259
260 if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
261 pr_err("I/O address 0x%04x already in use\n",
262 SBC7240_ENABLE_PORT);
263 rc = -EIO;
264 goto err_out;
265 }
266
267
268
269
270
271 if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
272 timeout = SBC7240_TIMEOUT;
273 pr_info("timeout value must be 1<=x<=%d, using %d\n",
274 SBC7240_MAX_TIMEOUT, timeout);
275 }
276 wdt_set_timeout(timeout);
277 wdt_disable();
278
279 rc = register_reboot_notifier(&wdt_notifier);
280 if (rc) {
281 pr_err("cannot register reboot notifier (err=%d)\n", rc);
282 goto err_out_region;
283 }
284
285 rc = misc_register(&wdt_miscdev);
286 if (rc) {
287 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
288 wdt_miscdev.minor, rc);
289 goto err_out_reboot_notifier;
290 }
291
292 pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
293 nowayout);
294
295 return 0;
296
297err_out_reboot_notifier:
298 unregister_reboot_notifier(&wdt_notifier);
299err_out_region:
300 release_region(SBC7240_ENABLE_PORT, 1);
301err_out:
302 return rc;
303}
304
305module_init(sbc7240_wdt_init);
306module_exit(sbc7240_wdt_unload);
307
308MODULE_AUTHOR("Gilles Gigan");
309MODULE_DESCRIPTION("Watchdog device driver for single board"
310 " computers EPIC Nano 7240 from iEi");
311MODULE_LICENSE("GPL");
312
