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	unsigned int gstate;
70} mtx1_wdt_device;
71
72static void mtx1_wdt_trigger(unsigned long unused)
73{
74	spin_lock(&mtx1_wdt_device.lock);
75	if (mtx1_wdt_device.running)
76		ticks--;
77
78	/* toggle wdt gpio */
79	mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
80	gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
81
82	if (mtx1_wdt_device.queue && ticks)
83		mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
84	else
85		complete(&mtx1_wdt_device.stop);
86	spin_unlock(&mtx1_wdt_device.lock);
87}
88
89static void mtx1_wdt_reset(void)
90{
91	ticks = mtx1_wdt_device.default_ticks;
92}
93
94
95static void mtx1_wdt_start(void)
96{
97	unsigned long flags;
98
99	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
100	if (!mtx1_wdt_device.queue) {
101		mtx1_wdt_device.queue = 1;
102		mtx1_wdt_device.gstate = 1;
103		gpio_set_value(mtx1_wdt_device.gpio, 1);
104		mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
105	}
106	mtx1_wdt_device.running++;
107	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
108}
109
110static int mtx1_wdt_stop(void)
111{
112	unsigned long flags;
113
114	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
115	if (mtx1_wdt_device.queue) {
116		mtx1_wdt_device.queue = 0;
117		mtx1_wdt_device.gstate = 0;
118		gpio_set_value(mtx1_wdt_device.gpio, 0);
119	}
120	ticks = mtx1_wdt_device.default_ticks;
121	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
122	return 0;
123}
124
125/* Filesystem functions */
126
127static int mtx1_wdt_open(struct inode *inode, struct file *file)
128{
129	if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
130		return -EBUSY;
131	return nonseekable_open(inode, file);
132}
133
134
135static int mtx1_wdt_release(struct inode *inode, struct file *file)
136{
137	clear_bit(0, &mtx1_wdt_device.inuse);
138	return 0;
139}
140
141static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
142							unsigned long arg)
143{
144	void __user *argp = (void __user *)arg;
145	int __user *p = (int __user *)argp;
146	unsigned int value;
147	static const struct watchdog_info ident = {
148		.options = WDIOF_CARDRESET,
149		.identity = "MTX-1 WDT",
150	};
151
152	switch (cmd) {
153	case WDIOC_GETSUPPORT:
154		if (copy_to_user(argp, &ident, sizeof(ident)))
155			return -EFAULT;
156		break;
157	case WDIOC_GETSTATUS:
158	case WDIOC_GETBOOTSTATUS:
159		put_user(0, p);
160		break;
161	case WDIOC_SETOPTIONS:
162		if (get_user(value, p))
163			return -EFAULT;
164		if (value & WDIOS_ENABLECARD)
165			mtx1_wdt_start();
166		else if (value & WDIOS_DISABLECARD)
167			mtx1_wdt_stop();
168		else
169			return -EINVAL;
170		return 0;
171	case WDIOC_KEEPALIVE:
172		mtx1_wdt_reset();
173		break;
174	default:
175		return -ENOTTY;
176	}
177	return 0;
178}
179
180
181static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
182						size_t count, loff_t *ppos)
183{
184	if (!count)
185		return -EIO;
186	mtx1_wdt_reset();
187	return count;
188}
189
190static const struct file_operations mtx1_wdt_fops = {
191	.owner		= THIS_MODULE,
192	.llseek		= no_llseek,
193	.unlocked_ioctl	= mtx1_wdt_ioctl,
194	.open		= mtx1_wdt_open,
195	.write		= mtx1_wdt_write,
196	.release	= mtx1_wdt_release,
197};
198
199
200static struct miscdevice mtx1_wdt_misc = {
201	.minor	= WATCHDOG_MINOR,
202	.name	= "watchdog",
203	.fops	= &mtx1_wdt_fops,
204};
205
206
207static int __devinit mtx1_wdt_probe(struct platform_device *pdev)
208{
209	int ret;
210
211	mtx1_wdt_device.gpio = pdev->resource[0].start;
212	ret = gpio_request_one(mtx1_wdt_device.gpio,
213				GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
214	if (ret < 0) {
215		dev_err(&pdev->dev, "failed to request gpio");
216		return ret;
217	}
218
219	spin_lock_init(&mtx1_wdt_device.lock);
220	init_completion(&mtx1_wdt_device.stop);
221	mtx1_wdt_device.queue = 0;
222	clear_bit(0, &mtx1_wdt_device.inuse);
223	setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
224	mtx1_wdt_device.default_ticks = ticks;
225
226	ret = misc_register(&mtx1_wdt_misc);
227	if (ret < 0) {
228		dev_err(&pdev->dev, "failed to register\n");
229		return ret;
230	}
231	mtx1_wdt_start();
232	dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
233	return 0;
234}
235
236static int __devexit mtx1_wdt_remove(struct platform_device *pdev)
237{
238	/* FIXME: do we need to lock this test ? */
239	if (mtx1_wdt_device.queue) {
240		mtx1_wdt_device.queue = 0;
241		wait_for_completion(&mtx1_wdt_device.stop);
242	}
243
244	gpio_free(mtx1_wdt_device.gpio);
245	misc_deregister(&mtx1_wdt_misc);
246	return 0;
247}
248
249static struct platform_driver mtx1_wdt_driver = {
250	.probe = mtx1_wdt_probe,
251	.remove = __devexit_p(mtx1_wdt_remove),
252	.driver.name = "mtx1-wdt",
253	.driver.owner = THIS_MODULE,
254};
255
256module_platform_driver(mtx1_wdt_driver);
257
258MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
259MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
260MODULE_LICENSE("GPL");
261MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
262MODULE_ALIAS("platform:mtx1-wdt");
263