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19#include <linux/fs.h>
20#include <linux/init.h>
21#include <linux/ioport.h>
22#include <linux/jiffies.h>
23#include <linux/module.h>
24#include <linux/moduleparam.h>
25#include <linux/miscdevice.h>
26#include <linux/notifier.h>
27#include <linux/reboot.h>
28#include <linux/types.h>
29#include <linux/watchdog.h>
30#include <asm/atomic.h>
31#include <asm/io.h>
32#include <asm/system.h>
33#include <asm/uaccess.h>
34
35#define SBC7240_PREFIX "sbc7240_wdt: "
36
37#define SBC7240_ENABLE_PORT 0x443
38#define SBC7240_DISABLE_PORT 0x043
39#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
40#define SBC7240_MAGIC_CHAR 'V'
41
42#define SBC7240_TIMEOUT 30
43#define SBC7240_MAX_TIMEOUT 255
44static int timeout = SBC7240_TIMEOUT;
45module_param(timeout, int, 0);
46MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
47 __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
48 __MODULE_STRING(SBC7240_TIMEOUT) ")");
49
50static int nowayout = WATCHDOG_NOWAYOUT;
51module_param(nowayout, int, 0);
52MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
53
54#define SBC7240_OPEN_STATUS_BIT 0
55#define SBC7240_ENABLED_STATUS_BIT 1
56#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
57static unsigned long wdt_status;
58
59
60
61
62
63static void wdt_disable(void)
64{
65
66 if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
67 inb_p(SBC7240_DISABLE_PORT);
68 printk(KERN_INFO SBC7240_PREFIX
69 "Watchdog timer is now disabled.\n");
70 }
71}
72
73static void wdt_enable(void)
74{
75
76 if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
77 inb_p(SBC7240_ENABLE_PORT);
78 printk(KERN_INFO SBC7240_PREFIX
79 "Watchdog timer is now enabled.\n");
80 }
81}
82
83static int wdt_set_timeout(int t)
84{
85 if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
86 printk(KERN_ERR SBC7240_PREFIX
87 "timeout value must be 1<=x<=%d\n",
88 SBC7240_MAX_TIMEOUT);
89 return -1;
90 }
91
92 outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
93 timeout = t;
94 printk(KERN_INFO SBC7240_PREFIX "timeout set to %d seconds\n", t);
95 return 0;
96}
97
98
99static inline void wdt_keepalive(void)
100{
101 if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
102 inb_p(SBC7240_ENABLE_PORT);
103}
104
105
106
107
108static ssize_t fop_write(struct file *file, const char __user *buf,
109 size_t count, loff_t *ppos)
110{
111 size_t i;
112 char c;
113
114 if (count) {
115 if (!nowayout) {
116 clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
117 &wdt_status);
118
119
120 for (i = 0; i != count; i++) {
121 if (get_user(c, buf + i))
122 return -EFAULT;
123 if (c == SBC7240_MAGIC_CHAR) {
124 set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
125 &wdt_status);
126 break;
127 }
128 }
129 }
130
131 wdt_keepalive();
132 }
133
134 return count;
135}
136
137static int fop_open(struct inode *inode, struct file *file)
138{
139 if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
140 return -EBUSY;
141
142 wdt_enable();
143
144 return nonseekable_open(inode, file);
145}
146
147static int fop_close(struct inode *inode, struct file *file)
148{
149 if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
150 || !nowayout) {
151 wdt_disable();
152 } else {
153 printk(KERN_CRIT SBC7240_PREFIX
154 "Unexpected close, not stopping watchdog!\n");
155 wdt_keepalive();
156 }
157
158 clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
159 return 0;
160}
161
162static struct watchdog_info ident = {
163 .options = WDIOF_KEEPALIVEPING|
164 WDIOF_SETTIMEOUT|
165 WDIOF_MAGICCLOSE,
166 .firmware_version = 1,
167 .identity = "SBC7240",
168};
169
170
171static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
172 unsigned long arg)
173{
174 switch (cmd) {
175 case WDIOC_GETSUPPORT:
176 return copy_to_user
177 ((void __user *)arg, &ident, sizeof(ident))
178 ? -EFAULT : 0;
179 case WDIOC_GETSTATUS:
180 case WDIOC_GETBOOTSTATUS:
181 return put_user(0, (int __user *)arg);
182 case WDIOC_KEEPALIVE:
183 wdt_keepalive();
184 return 0;
185 case WDIOC_SETOPTIONS:{
186 int options;
187 int retval = -EINVAL;
188
189 if (get_user(options, (int __user *)arg))
190 return -EFAULT;
191
192 if (options & WDIOS_DISABLECARD) {
193 wdt_disable();
194 retval = 0;
195 }
196
197 if (options & WDIOS_ENABLECARD) {
198 wdt_enable();
199 retval = 0;
200 }
201
202 return retval;
203 }
204 case WDIOC_SETTIMEOUT:{
205 int new_timeout;
206
207 if (get_user(new_timeout, (int __user *)arg))
208 return -EFAULT;
209
210 if (wdt_set_timeout(new_timeout))
211 return -EINVAL;
212
213
214 }
215 case WDIOC_GETTIMEOUT:
216 return put_user(timeout, (int __user *)arg);
217 default:
218 return -ENOTTY;
219 }
220}
221
222static const struct file_operations wdt_fops = {
223 .owner = THIS_MODULE,
224 .llseek = no_llseek,
225 .write = fop_write,
226 .open = fop_open,
227 .release = fop_close,
228 .ioctl = fop_ioctl,
229};
230
231static struct miscdevice wdt_miscdev = {
232 .minor = WATCHDOG_MINOR,
233 .name = "watchdog",
234 .fops = &wdt_fops,
235};
236
237
238
239
240
241static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
242 void *unused)
243{
244 if (code == SYS_DOWN || code == SYS_HALT)
245 wdt_disable();
246 return NOTIFY_DONE;
247}
248
249static struct notifier_block wdt_notifier = {
250 .notifier_call = wdt_notify_sys,
251};
252
253static void __exit sbc7240_wdt_unload(void)
254{
255 printk(KERN_INFO SBC7240_PREFIX "Removing watchdog\n");
256 misc_deregister(&wdt_miscdev);
257
258 unregister_reboot_notifier(&wdt_notifier);
259 release_region(SBC7240_ENABLE_PORT, 1);
260}
261
262static int __init sbc7240_wdt_init(void)
263{
264 int rc = -EBUSY;
265
266 if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
267 printk(KERN_ERR SBC7240_PREFIX
268 "I/O address 0x%04x already in use\n",
269 SBC7240_ENABLE_PORT);
270 rc = -EIO;
271 goto err_out;
272 }
273
274
275
276
277
278 if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
279 timeout = SBC7240_TIMEOUT;
280 printk(KERN_INFO SBC7240_PREFIX
281 "timeout value must be 1<=x<=%d, using %d\n",
282 SBC7240_MAX_TIMEOUT, timeout);
283 }
284 wdt_set_timeout(timeout);
285 wdt_disable();
286
287 rc = register_reboot_notifier(&wdt_notifier);
288 if (rc) {
289 printk(KERN_ERR SBC7240_PREFIX
290 "cannot register reboot notifier (err=%d)\n", rc);
291 goto err_out_region;
292 }
293
294 rc = misc_register(&wdt_miscdev);
295 if (rc) {
296 printk(KERN_ERR SBC7240_PREFIX
297 "cannot register miscdev on minor=%d (err=%d)\n",
298 wdt_miscdev.minor, rc);
299 goto err_out_reboot_notifier;
300 }
301
302 printk(KERN_INFO SBC7240_PREFIX
303 "Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
304 nowayout);
305
306 return 0;
307
308err_out_reboot_notifier:
309 unregister_reboot_notifier(&wdt_notifier);
310err_out_region:
311 release_region(SBC7240_ENABLE_PORT, 1);
312err_out:
313 return rc;
314}
315
316module_init(sbc7240_wdt_init);
317module_exit(sbc7240_wdt_unload);
318
319MODULE_AUTHOR("Gilles Gigan");
320MODULE_DESCRIPTION("Watchdog device driver for single board"
321 " computers EPIC Nano 7240 from iEi");
322MODULE_LICENSE("GPL");
323MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
324
325
