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