mtx-1_wdt.c revision f80e919bb42c191bbe60ab078a59b30336d11d3b 
1/*
2 *      Driver for the MTX-1 Watchdog.
3 *
4 *      (C) Copyright 2005 4G Systems <info@4g-systems.biz>,
5 *							All Rights Reserved.
6 *                              http://www.4g-systems.biz
7 *
8 * 	(C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
9 *
10 *      This program is free software; you can redistribute it and/or
11 *      modify it under the terms of the GNU General Public License
12 *      as published by the Free Software Foundation; either version
13 *      2 of the License, or (at your option) any later version.
14 *
15 *      Neither Michael Stickel nor 4G Systems admit liability nor provide
16 *      warranty for any of this software. This material is provided
17 *      "AS-IS" and at no charge.
18 *
19 *      (c) Copyright 2005    4G Systems <info@4g-systems.biz>
20 *
21 *      Release 0.01.
22 *      Author: Michael Stickel  michael.stickel@4g-systems.biz
23 *
24 *      Release 0.02.
25 *	Author: Florian Fainelli florian@openwrt.org
26 *		use the Linux watchdog/timer APIs
27 *
28 *      The Watchdog is configured to reset the MTX-1
29 *      if it is not triggered for 100 seconds.
30 *      It should not be triggered more often than 1.6 seconds.
31 *
32 *      A timer triggers the watchdog every 5 seconds, until
33 *      it is opened for the first time. After the first open
34 *      it MUST be triggered every 2..95 seconds.
35 */
36
37#include <linux/module.h>
38#include <linux/moduleparam.h>
39#include <linux/types.h>
40#include <linux/errno.h>
41#include <linux/miscdevice.h>
42#include <linux/fs.h>
43#include <linux/init.h>
44#include <linux/ioport.h>
45#include <linux/timer.h>
46#include <linux/completion.h>
47#include <linux/jiffies.h>
48#include <linux/watchdog.h>
49#include <linux/platform_device.h>
50#include <linux/io.h>
51#include <linux/uaccess.h>
52#include <linux/gpio.h>
53
54#include <asm/mach-au1x00/au1000.h>
55
56#define MTX1_WDT_INTERVAL	(5 * HZ)
57
58static int ticks = 100 * HZ;
59
60static struct {
61	struct completion stop;
62	spinlock_t lock;
63	int running;
64	struct timer_list timer;
65	int queue;
66	int default_ticks;
67	unsigned long inuse;
68	unsigned gpio;
69} mtx1_wdt_device;
70
71static void mtx1_wdt_trigger(unsigned long unused)
72{
73	u32 tmp;
74
75	spin_lock(&mtx1_wdt_device.lock);
76	if (mtx1_wdt_device.running)
77		ticks--;
78	/*
79	 * toggle GPIO2_15
80	 */
81	tmp = au_readl(GPIO2_DIR);
82	tmp = (tmp & ~(1 << mtx1_wdt_device.gpio)) |
83	      ((~tmp) & (1 << mtx1_wdt_device.gpio));
84	au_writel(tmp, GPIO2_DIR);
85
86	if (mtx1_wdt_device.queue && ticks)
87		mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
88	else
89		complete(&mtx1_wdt_device.stop);
90	spin_unlock(&mtx1_wdt_device.lock);
91}
92
93static void mtx1_wdt_reset(void)
94{
95	ticks = mtx1_wdt_device.default_ticks;
96}
97
98
99static void mtx1_wdt_start(void)
100{
101	unsigned long flags;
102
103	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
104	if (!mtx1_wdt_device.queue) {
105		mtx1_wdt_device.queue = 1;
106		gpio_set_value(mtx1_wdt_device.gpio, 1);
107		mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
108	}
109	mtx1_wdt_device.running++;
110	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
111}
112
113static int mtx1_wdt_stop(void)
114{
115	unsigned long flags;
116
117	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
118	if (mtx1_wdt_device.queue) {
119		mtx1_wdt_device.queue = 0;
120		gpio_set_value(mtx1_wdt_device.gpio, 0);
121	}
122	ticks = mtx1_wdt_device.default_ticks;
123	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
124	return 0;
125}
126
127/* Filesystem functions */
128
129static int mtx1_wdt_open(struct inode *inode, struct file *file)
130{
131	if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
132		return -EBUSY;
133	return nonseekable_open(inode, file);
134}
135
136
137static int mtx1_wdt_release(struct inode *inode, struct file *file)
138{
139	clear_bit(0, &mtx1_wdt_device.inuse);
140	return 0;
141}
142
143static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
144							unsigned long arg)
145{
146	void __user *argp = (void __user *)arg;
147	int __user *p = (int __user *)argp;
148	unsigned int value;
149	static const struct watchdog_info ident = {
150		.options = WDIOF_CARDRESET,
151		.identity = "MTX-1 WDT",
152	};
153
154	switch (cmd) {
155	case WDIOC_GETSUPPORT:
156		if (copy_to_user(argp, &ident, sizeof(ident)))
157			return -EFAULT;
158		break;
159	case WDIOC_GETSTATUS:
160	case WDIOC_GETBOOTSTATUS:
161		put_user(0, p);
162		break;
163	case WDIOC_SETOPTIONS:
164		if (get_user(value, p))
165			return -EFAULT;
166		if (value & WDIOS_ENABLECARD)
167			mtx1_wdt_start();
168		else if (value & WDIOS_DISABLECARD)
169			mtx1_wdt_stop();
170		else
171			return -EINVAL;
172		return 0;
173	case WDIOC_KEEPALIVE:
174		mtx1_wdt_reset();
175		break;
176	default:
177		return -ENOTTY;
178	}
179	return 0;
180}
181
182
183static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
184						size_t count, loff_t *ppos)
185{
186	if (!count)
187		return -EIO;
188	mtx1_wdt_reset();
189	return count;
190}
191
192static const struct file_operations mtx1_wdt_fops = {
193	.owner 		= THIS_MODULE,
194	.llseek		= no_llseek,
195	.unlocked_ioctl	= mtx1_wdt_ioctl,
196	.open 		= mtx1_wdt_open,
197	.write 		= mtx1_wdt_write,
198	.release 	= mtx1_wdt_release,
199};
200
201
202static struct miscdevice mtx1_wdt_misc = {
203	.minor 	= WATCHDOG_MINOR,
204	.name 	= "watchdog",
205	.fops 	= &mtx1_wdt_fops,
206};
207
208
209static int mtx1_wdt_probe(struct platform_device *pdev)
210{
211	int ret;
212
213	mtx1_wdt_device.gpio = pdev->resource[0].start;
214
215	spin_lock_init(&mtx1_wdt_device.lock);
216	init_completion(&mtx1_wdt_device.stop);
217	mtx1_wdt_device.queue = 0;
218	clear_bit(0, &mtx1_wdt_device.inuse);
219	setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
220	mtx1_wdt_device.default_ticks = ticks;
221
222	ret = misc_register(&mtx1_wdt_misc);
223	if (ret < 0) {
224		printk(KERN_ERR " mtx-1_wdt : failed to register\n");
225		return ret;
226	}
227	mtx1_wdt_start();
228	printk(KERN_INFO "MTX-1 Watchdog driver\n");
229	return 0;
230}
231
232static int mtx1_wdt_remove(struct platform_device *pdev)
233{
234	/* FIXME: do we need to lock this test ? */
235	if (mtx1_wdt_device.queue) {
236		mtx1_wdt_device.queue = 0;
237		wait_for_completion(&mtx1_wdt_device.stop);
238	}
239	misc_deregister(&mtx1_wdt_misc);
240	return 0;
241}
242
243static struct platform_driver mtx1_wdt = {
244	.probe = mtx1_wdt_probe,
245	.remove = mtx1_wdt_remove,
246	.driver.name = "mtx1-wdt",
247	.driver.owner = THIS_MODULE,
248};
249
250static int __init mtx1_wdt_init(void)
251{
252	return platform_driver_register(&mtx1_wdt);
253}
254
255static void __exit mtx1_wdt_exit(void)
256{
257	platform_driver_unregister(&mtx1_wdt);
258}
259
260module_init(mtx1_wdt_init);
261module_exit(mtx1_wdt_exit);
262
263MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
264MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
265MODULE_LICENSE("GPL");
266MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
267MODULE_ALIAS("platform:mtx1-wdt");
268