cpu5wdt.c revision 6f932f18de7f0e22a1bdae5d0040eb5d8e4a6777 
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 <linux/io.h>
34#include <linux/uaccess.h>
35#include <linux/watchdog.h>
36
37/* adjustable parameters */
38
39static int verbose;
40static int port = 0x91;
41static int ticks = 10000;
42static spinlock_t cpu5wdt_lock;
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	spin_lock(&cpu5wdt_lock);
80	/* keep watchdog alive */
81	outb(1, port + CPU5WDT_TRIGGER_REG);
82
83	/* requeue?? */
84	if (cpu5wdt_device.queue && ticks)
85		mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
86	else {
87		/* ticks doesn't matter anyway */
88		complete(&cpu5wdt_device.stop);
89	}
90	spin_unlock(&cpu5wdt_lock);
91
92}
93
94static void cpu5wdt_reset(void)
95{
96	ticks = cpu5wdt_device.default_ticks;
97
98	if (verbose)
99		printk(KERN_DEBUG PFX "reset (%i ticks)\n", (int) ticks);
100
101}
102
103static void cpu5wdt_start(void)
104{
105	unsigned long flags;
106
107	spin_lock_irqsave(&cpu5wdt_lock, flags);
108	if (!cpu5wdt_device.queue) {
109		cpu5wdt_device.queue = 1;
110		outb(0, port + CPU5WDT_TIME_A_REG);
111		outb(0, port + CPU5WDT_TIME_B_REG);
112		outb(1, port + CPU5WDT_MODE_REG);
113		outb(0, port + CPU5WDT_RESET_REG);
114		outb(0, port + CPU5WDT_ENABLE_REG);
115		mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
116	}
117	/* if process dies, counter is not decremented */
118	cpu5wdt_device.running++;
119	spin_unlock_irqrestore(&cpu5wdt_lock, flags);
120}
121
122static int cpu5wdt_stop(void)
123{
124	unsigned long flags;
125
126	spin_lock_irqsave(&cpu5wdt_lock, flags);
127	if (cpu5wdt_device.running)
128		cpu5wdt_device.running = 0;
129	ticks = cpu5wdt_device.default_ticks;
130	spin_unlock_irqrestore(&cpu5wdt_lock, flags);
131	if (verbose)
132		printk(KERN_CRIT PFX "stop not possible\n");
133	return -EIO;
134}
135
136/* filesystem operations */
137
138static int cpu5wdt_open(struct inode *inode, struct file *file)
139{
140	if (test_and_set_bit(0, &cpu5wdt_device.inuse))
141		return -EBUSY;
142	return nonseekable_open(inode, file);
143}
144
145static int cpu5wdt_release(struct inode *inode, struct file *file)
146{
147	clear_bit(0, &cpu5wdt_device.inuse);
148	return 0;
149}
150
151static long cpu5wdt_ioctl(struct file *file, unsigned int cmd,
152						unsigned long arg)
153{
154	void __user *argp = (void __user *)arg;
155	int __user *p = argp;
156	unsigned int value;
157	static struct watchdog_info ident = {
158		.options = WDIOF_CARDRESET,
159		.identity = "CPU5 WDT",
160	};
161
162	switch (cmd) {
163	case WDIOC_KEEPALIVE:
164		cpu5wdt_reset();
165		break;
166	case WDIOC_GETSTATUS:
167		value = inb(port + CPU5WDT_STATUS_REG);
168		value = (value >> 2) & 1;
169		return put_user(value, p);
170	case WDIOC_GETBOOTSTATUS:
171		return put_user(0, p);
172	case WDIOC_GETSUPPORT:
173		if (copy_to_user(argp, &ident, sizeof(ident)))
174			return -EFAULT;
175		break;
176	case WDIOC_SETOPTIONS:
177		if (get_user(value, p))
178			return -EFAULT;
179		if (value & WDIOS_ENABLECARD)
180			cpu5wdt_start();
181		if (value & WDIOS_DISABLECARD)
182			cpu5wdt_stop();
183		break;
184	default:
185		return -ENOTTY;
186	}
187	return 0;
188}
189
190static ssize_t cpu5wdt_write(struct file *file, const char __user *buf,
191						size_t count, loff_t *ppos)
192{
193	if (!count)
194		return -EIO;
195	cpu5wdt_reset();
196	return count;
197}
198
199static const struct file_operations cpu5wdt_fops = {
200	.owner		= THIS_MODULE,
201	.llseek		= no_llseek,
202	.unlocked_ioctl	= cpu5wdt_ioctl,
203	.open		= cpu5wdt_open,
204	.write		= cpu5wdt_write,
205	.release	= cpu5wdt_release,
206};
207
208static struct miscdevice cpu5wdt_misc = {
209	.minor	= WATCHDOG_MINOR,
210	.name	= "watchdog",
211	.fops	= &cpu5wdt_fops,
212};
213
214/* init/exit function */
215
216static int __devinit cpu5wdt_init(void)
217{
218	unsigned int val;
219	int err;
220
221	if (verbose)
222		printk(KERN_DEBUG PFX
223				"port=0x%x, verbose=%i\n", port, verbose);
224
225	init_completion(&cpu5wdt_device.stop);
226	spin_lock_init(&cpu5wdt_lock);
227	cpu5wdt_device.queue = 0;
228	setup_timer(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);
229	cpu5wdt_device.default_ticks = ticks;
230
231	if (!request_region(port, CPU5WDT_EXTENT, PFX)) {
232		printk(KERN_ERR PFX "request_region failed\n");
233		err = -EBUSY;
234		goto no_port;
235	}
236
237	/* watchdog reboot? */
238	val = inb(port + CPU5WDT_STATUS_REG);
239	val = (val >> 2) & 1;
240	if (!val)
241		printk(KERN_INFO PFX "sorry, was my fault\n");
242
243	err = misc_register(&cpu5wdt_misc);
244	if (err < 0) {
245		printk(KERN_ERR PFX "misc_register failed\n");
246		goto no_misc;
247	}
248
249
250	printk(KERN_INFO PFX "init success\n");
251	return 0;
252
253no_misc:
254	release_region(port, CPU5WDT_EXTENT);
255no_port:
256	return err;
257}
258
259static int __devinit cpu5wdt_init_module(void)
260{
261	return cpu5wdt_init();
262}
263
264static void __devexit cpu5wdt_exit(void)
265{
266	if (cpu5wdt_device.queue) {
267		cpu5wdt_device.queue = 0;
268		wait_for_completion(&cpu5wdt_device.stop);
269	}
270
271	misc_deregister(&cpu5wdt_misc);
272
273	release_region(port, CPU5WDT_EXTENT);
274
275}
276
277static void __devexit cpu5wdt_exit_module(void)
278{
279	cpu5wdt_exit();
280}
281
282/* module entry points */
283
284module_init(cpu5wdt_init_module);
285module_exit(cpu5wdt_exit_module);
286
287MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
288MODULE_DESCRIPTION("sma cpu5 watchdog driver");
289MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
290MODULE_LICENSE("GPL");
291MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
292
293module_param(port, int, 0);
294MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
295
296module_param(verbose, int, 0);
297MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
298
299module_param(ticks, int, 0);
300MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");
301