cpu5wdt.c revision 996d62d449a7d5e691b0da22b7c877df08c2b0a4 
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 <linux/completion.h>
32#include <linux/jiffies.h>
33#include <asm/io.h>
34#include <asm/uaccess.h>
35
36#include <linux/watchdog.h>
37
38/* adjustable parameters */
39
40static int verbose = 0;
41static int port = 0x91;
42static int ticks = 10000;
43
44#define PFX			"cpu5wdt: "
45
46#define CPU5WDT_EXTENT          0x0A
47
48#define CPU5WDT_STATUS_REG      0x00
49#define CPU5WDT_TIME_A_REG      0x02
50#define CPU5WDT_TIME_B_REG      0x03
51#define CPU5WDT_MODE_REG        0x04
52#define CPU5WDT_TRIGGER_REG     0x07
53#define CPU5WDT_ENABLE_REG      0x08
54#define CPU5WDT_RESET_REG       0x09
55
56#define CPU5WDT_INTERVAL	(HZ/10+1)
57
58/* some device data */
59
60static struct {
61	struct completion stop;
62	int running;
63	struct timer_list timer;
64	int queue;
65	int default_ticks;
66	unsigned long inuse;
67} cpu5wdt_device;
68
69/* generic helper functions */
70
71static void cpu5wdt_trigger(unsigned long unused)
72{
73	if ( verbose > 2 )
74		printk(KERN_DEBUG PFX "trigger at %i ticks\n", ticks);
75
76	if( cpu5wdt_device.running )
77		ticks--;
78
79	/* keep watchdog alive */
80	outb(1, port + CPU5WDT_TRIGGER_REG);
81
82	/* requeue?? */
83	if (cpu5wdt_device.queue && ticks)
84		mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
85	else {
86		/* ticks doesn't matter anyway */
87		complete(&cpu5wdt_device.stop);
88	}
89
90}
91
92static 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
101static 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		mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
111	}
112	/* if process dies, counter is not decremented */
113	cpu5wdt_device.running++;
114}
115
116static int cpu5wdt_stop(void)
117{
118	if ( cpu5wdt_device.running )
119		cpu5wdt_device.running = 0;
120
121	ticks = cpu5wdt_device.default_ticks;
122
123	if ( verbose )
124		printk(KERN_CRIT PFX "stop not possible\n");
125
126	return -EIO;
127}
128
129/* filesystem operations */
130
131static int cpu5wdt_open(struct inode *inode, struct file *file)
132{
133	if ( test_and_set_bit(0, &cpu5wdt_device.inuse) )
134		return -EBUSY;
135
136	return nonseekable_open(inode, file);
137}
138
139static int cpu5wdt_release(struct inode *inode, struct file *file)
140{
141	clear_bit(0, &cpu5wdt_device.inuse);
142	return 0;
143}
144
145static int cpu5wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
146{
147	void __user *argp = (void __user *)arg;
148	unsigned int value;
149	static struct watchdog_info ident =
150	{
151		.options = WDIOF_CARDRESET,
152		.identity = "CPU5 WDT",
153	};
154
155	switch(cmd) {
156		case WDIOC_KEEPALIVE:
157			cpu5wdt_reset();
158			break;
159		case WDIOC_GETSTATUS:
160			value = inb(port + CPU5WDT_STATUS_REG);
161			value = (value >> 2) & 1;
162			if ( copy_to_user(argp, &value, sizeof(int)) )
163				return -EFAULT;
164			break;
165		case WDIOC_GETBOOTSTATUS:
166			if ( copy_to_user(argp, &value, sizeof(int)) )
167				return -EFAULT;
168			break;
169		case WDIOC_GETSUPPORT:
170			if ( copy_to_user(argp, &ident, sizeof(ident)) )
171				return -EFAULT;
172			break;
173		case WDIOC_SETOPTIONS:
174			if ( copy_from_user(&value, argp, sizeof(int)) )
175				return -EFAULT;
176			switch(value) {
177				case WDIOS_ENABLECARD:
178					cpu5wdt_start();
179					break;
180				case WDIOS_DISABLECARD:
181					return cpu5wdt_stop();
182				default:
183					return -EINVAL;
184			}
185			break;
186		default:
187    			return -ENOTTY;
188	}
189	return 0;
190}
191
192static ssize_t cpu5wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
193{
194	if ( !count )
195		return -EIO;
196
197	cpu5wdt_reset();
198
199	return count;
200}
201
202static const struct file_operations cpu5wdt_fops = {
203	.owner		= THIS_MODULE,
204	.llseek		= no_llseek,
205	.ioctl		= cpu5wdt_ioctl,
206	.open		= cpu5wdt_open,
207	.write		= cpu5wdt_write,
208	.release	= cpu5wdt_release,
209};
210
211static struct miscdevice cpu5wdt_misc = {
212	.minor	= WATCHDOG_MINOR,
213	.name	= "watchdog",
214	.fops	= &cpu5wdt_fops,
215};
216
217/* init/exit function */
218
219static int __devinit cpu5wdt_init(void)
220{
221	unsigned int val;
222	int err;
223
224	if ( verbose )
225		printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose);
226
227	if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) {
228		printk(KERN_ERR PFX "request_region failed\n");
229		err = -EBUSY;
230		goto no_port;
231	}
232
233	if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) {
234		printk(KERN_ERR PFX "misc_register failed\n");
235		goto no_misc;
236	}
237
238	/* watchdog reboot? */
239	val = inb(port + CPU5WDT_STATUS_REG);
240	val = (val >> 2) & 1;
241	if ( !val )
242		printk(KERN_INFO PFX "sorry, was my fault\n");
243
244	init_completion(&cpu5wdt_device.stop);
245	cpu5wdt_device.queue = 0;
246
247	clear_bit(0, &cpu5wdt_device.inuse);
248
249	setup_timer(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);
250
251	cpu5wdt_device.default_ticks = ticks;
252
253	printk(KERN_INFO PFX "init success\n");
254
255	return 0;
256
257no_misc:
258	release_region(port, CPU5WDT_EXTENT);
259no_port:
260	return err;
261}
262
263static int __devinit cpu5wdt_init_module(void)
264{
265	return cpu5wdt_init();
266}
267
268static void __devexit cpu5wdt_exit(void)
269{
270	if ( cpu5wdt_device.queue ) {
271		cpu5wdt_device.queue = 0;
272		wait_for_completion(&cpu5wdt_device.stop);
273	}
274
275	misc_deregister(&cpu5wdt_misc);
276
277	release_region(port, CPU5WDT_EXTENT);
278
279}
280
281static void __devexit cpu5wdt_exit_module(void)
282{
283	cpu5wdt_exit();
284}
285
286/* module entry points */
287
288module_init(cpu5wdt_init_module);
289module_exit(cpu5wdt_exit_module);
290
291MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
292MODULE_DESCRIPTION("sma cpu5 watchdog driver");
293MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
294MODULE_LICENSE("GPL");
295MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
296
297module_param(port, int, 0);
298MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
299
300module_param(verbose, int, 0);
301MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
302
303module_param(ticks, int, 0);
304MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");
305