1 /*
2 * sma cpu5 watchdog driver
3 *
4 * Copyright (C) 2003 Heiko Ronsdorf <hero@ihg.uni-duisburg.de>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 *
20 */
21
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/types.h>
25 #include <linux/errno.h>
26 #include <linux/miscdevice.h>
27 #include <linux/fs.h>
28 #include <linux/init.h>
29 #include <linux/ioport.h>
30 #include <linux/timer.h>
31 #include <asm/io.h>
32 #include <asm/uaccess.h>
33
34 #include <linux/watchdog.h>
35
36 /* adjustable parameters */
37
38 static int verbose = 0;
39 static int port = 0x91;
40 static int ticks = 10000;
41
42 #define PFX "cpu5wdt: "
43
44 #define CPU5WDT_EXTENT 0x0A
45
46 #define CPU5WDT_STATUS_REG 0x00
47 #define CPU5WDT_TIME_A_REG 0x02
48 #define CPU5WDT_TIME_B_REG 0x03
49 #define CPU5WDT_MODE_REG 0x04
50 #define CPU5WDT_TRIGGER_REG 0x07
51 #define CPU5WDT_ENABLE_REG 0x08
52 #define CPU5WDT_RESET_REG 0x09
53
54 #define CPU5WDT_INTERVAL (HZ/10+1)
55
56 /* some device data */
57
58 static struct {
59 struct semaphore stop;
60 volatile int running;
61 struct timer_list timer;
62 volatile int queue;
63 int default_ticks;
64 unsigned long inuse;
65 } cpu5wdt_device;
66
67 /* generic helper functions */
68
69 static void cpu5wdt_trigger(unsigned long unused)
70 {
71 if ( verbose > 2 )
72 printk(KERN_DEBUG PFX "trigger at %i ticks\n", ticks);
73
74 if( cpu5wdt_device.running )
75 ticks--;
76
77 /* keep watchdog alive */
78 outb(1, port + CPU5WDT_TRIGGER_REG);
79
80 /* requeue?? */
81 if( cpu5wdt_device.queue && ticks ) {
82 cpu5wdt_device.timer.expires = jiffies + CPU5WDT_INTERVAL;
83 add_timer(&cpu5wdt_device.timer);
84 }
85 else {
86 /* ticks doesn't matter anyway */
87 up(&cpu5wdt_device.stop);
88 }
89
90 }
91
92 static void cpu5wdt_reset(void)
93 {
94 ticks = cpu5wdt_device.default_ticks;
95
96 if ( verbose )
97 printk(KERN_DEBUG PFX "reset (%i ticks)\n", (int) ticks);
98
99 }
100
101 static void cpu5wdt_start(void)
102 {
103 if ( !cpu5wdt_device.queue ) {
104 cpu5wdt_device.queue = 1;
105 outb(0, port + CPU5WDT_TIME_A_REG);
106 outb(0, port + CPU5WDT_TIME_B_REG);
107 outb(1, port + CPU5WDT_MODE_REG);
108 outb(0, port + CPU5WDT_RESET_REG);
109 outb(0, port + CPU5WDT_ENABLE_REG);
110 cpu5wdt_device.timer.expires = jiffies + CPU5WDT_INTERVAL;
111 add_timer(&cpu5wdt_device.timer);
112 }
113 /* if process dies, counter is not decremented */
114 cpu5wdt_device.running++;
115 }
116
117 static int cpu5wdt_stop(void)
118 {
119 if ( cpu5wdt_device.running )
120 cpu5wdt_device.running = 0;
121
122 ticks = cpu5wdt_device.default_ticks;
123
124 if ( verbose )
125 printk(KERN_CRIT PFX "stop not possible\n");
126
127 return -EIO;
128 }
129
130 /* filesystem operations */
131
132 static int cpu5wdt_open(struct inode *inode, struct file *file)
133 {
134 if ( test_and_set_bit(0, &cpu5wdt_device.inuse) )
135 return -EBUSY;
136
137 return nonseekable_open(inode, file);
138 }
139
140 static int cpu5wdt_release(struct inode *inode, struct file *file)
141 {
142 clear_bit(0, &cpu5wdt_device.inuse);
143 return 0;
144 }
145
146 static int cpu5wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
147 {
148 void __user *argp = (void __user *)arg;
149 unsigned int value;
150 static struct watchdog_info ident =
151 {
152 .options = WDIOF_CARDRESET,
153 .identity = "CPU5 WDT",
154 };
155
156 switch(cmd) {
157 case WDIOC_KEEPALIVE:
158 cpu5wdt_reset();
159 break;
160 case WDIOC_GETSTATUS:
161 value = inb(port + CPU5WDT_STATUS_REG);
162 value = (value >> 2) & 1;
163 if ( copy_to_user(argp, &value, sizeof(int)) )
164 return -EFAULT;
165 break;
166 case WDIOC_GETSUPPORT:
167 if ( copy_to_user(argp, &ident, sizeof(ident)) )
168 return -EFAULT;
169 break;
170 case WDIOC_SETOPTIONS:
171 if ( copy_from_user(&value, argp, sizeof(int)) )
172 return -EFAULT;
173 switch(value) {
174 case WDIOS_ENABLECARD:
175 cpu5wdt_start();
176 break;
177 case WDIOS_DISABLECARD:
178 return cpu5wdt_stop();
179 default:
180 return -EINVAL;
181 }
182 break;
183 default:
184 return -ENOIOCTLCMD;
185 }
186 return 0;
187 }
188
189 static ssize_t cpu5wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
190 {
191 if ( !count )
192 return -EIO;
193
194 cpu5wdt_reset();
195
196 return count;
197 }
198
199 static struct file_operations cpu5wdt_fops = {
200 .owner = THIS_MODULE,
201 .llseek = no_llseek,
202 .ioctl = cpu5wdt_ioctl,
203 .open = cpu5wdt_open,
204 .write = cpu5wdt_write,
205 .release = cpu5wdt_release,
206 };
207
208 static struct miscdevice cpu5wdt_misc = {
209 .minor = WATCHDOG_MINOR,
210 .name = "watchdog",
211 .fops = &cpu5wdt_fops,
212 };
213
214 /* init/exit function */
215
216 static int __devinit cpu5wdt_init(void)
217 {
218 unsigned int val;
219 int err;
220
221 if ( verbose )
222 printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose);
223
224 if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) {
225 printk(KERN_ERR PFX "misc_register failed\n");
226 goto no_misc;
227 }
228
229 if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) {
230 printk(KERN_ERR PFX "request_region failed\n");
231 err = -EBUSY;
232 goto no_port;
233 }
234
235 /* watchdog reboot? */
236 val = inb(port + CPU5WDT_STATUS_REG);
237 val = (val >> 2) & 1;
238 if ( !val )
239 printk(KERN_INFO PFX "sorry, was my fault\n");
240
241 init_MUTEX_LOCKED(&cpu5wdt_device.stop);
242 cpu5wdt_device.queue = 0;
243
244 clear_bit(0, &cpu5wdt_device.inuse);
245
246 init_timer(&cpu5wdt_device.timer);
247 cpu5wdt_device.timer.function = cpu5wdt_trigger;
248 cpu5wdt_device.timer.data = 0;
249
250 cpu5wdt_device.default_ticks = ticks;
251
252 printk(KERN_INFO PFX "init success\n");
253
254 return 0;
255
256 no_port:
257 misc_deregister(&cpu5wdt_misc);
258 no_misc:
259 return err;
260 }
261
262 static int __devinit cpu5wdt_init_module(void)
263 {
264 return cpu5wdt_init();
265 }
266
267 static void __devexit cpu5wdt_exit(void)
268 {
269 if ( cpu5wdt_device.queue ) {
270 cpu5wdt_device.queue = 0;
271 down(&cpu5wdt_device.stop);
272 }
273
274 misc_deregister(&cpu5wdt_misc);
275
276 release_region(port, CPU5WDT_EXTENT);
277
278 }
279
280 static void __devexit cpu5wdt_exit_module(void)
281 {
282 cpu5wdt_exit();
283 }
284
285 /* module entry points */
286
287 module_init(cpu5wdt_init_module);
288 module_exit(cpu5wdt_exit_module);
289
290 MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
291 MODULE_DESCRIPTION("sma cpu5 watchdog driver");
292 MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
293 MODULE_LICENSE("GPL");
294 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
295
296 module_param(port, int, 0);
297 MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
298
299 module_param(verbose, int, 0);
300 MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
301
302 module_param(ticks, int, 0);
303 MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");
304
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