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/ioport.h>
44#include <linux/timer.h>
45#include <linux/completion.h>
46#include <linux/jiffies.h>
47#include <linux/watchdog.h>
48#include <linux/platform_device.h>
49#include <linux/io.h>
50#include <linux/uaccess.h>
51#include <linux/gpio.h>
52
53#include <asm/mach-au1x00/au1000.h>
54
55#define MTX1_WDT_INTERVAL	(5 * HZ)
56
57static int ticks = 100 * HZ;
58
59static struct {
60	struct completion stop;
61	spinlock_t lock;
62	int running;
63	struct timer_list timer;
64	int queue;
65	int default_ticks;
66	unsigned long inuse;
67	unsigned gpio;
68	unsigned int gstate;
69} mtx1_wdt_device;
70
71static void mtx1_wdt_trigger(unsigned long unused)
72{
73	spin_lock(&mtx1_wdt_device.lock);
74	if (mtx1_wdt_device.running)
75		ticks--;
76
77	/* toggle wdt gpio */
78	mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
79	gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
80
81	if (mtx1_wdt_device.queue && ticks)
82		mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
83	else
84		complete(&mtx1_wdt_device.stop);
85	spin_unlock(&mtx1_wdt_device.lock);
86}
87
88static void mtx1_wdt_reset(void)
89{
90	ticks = mtx1_wdt_device.default_ticks;
91}
92
93
94static void mtx1_wdt_start(void)
95{
96	unsigned long flags;
97
98	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
99	if (!mtx1_wdt_device.queue) {
100		mtx1_wdt_device.queue = 1;
101		mtx1_wdt_device.gstate = 1;
102		gpio_set_value(mtx1_wdt_device.gpio, 1);
103		mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
104	}
105	mtx1_wdt_device.running++;
106	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
107}
108
109static int mtx1_wdt_stop(void)
110{
111	unsigned long flags;
112
113	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
114	if (mtx1_wdt_device.queue) {
115		mtx1_wdt_device.queue = 0;
116		mtx1_wdt_device.gstate = 0;
117		gpio_set_value(mtx1_wdt_device.gpio, 0);
118	}
119	ticks = mtx1_wdt_device.default_ticks;
120	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
121	return 0;
122}
123
124/* Filesystem functions */
125
126static int mtx1_wdt_open(struct inode *inode, struct file *file)
127{
128	if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
129		return -EBUSY;
130	return nonseekable_open(inode, file);
131}
132
133
134static int mtx1_wdt_release(struct inode *inode, struct file *file)
135{
136	clear_bit(0, &mtx1_wdt_device.inuse);
137	return 0;
138}
139
140static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
141							unsigned long arg)
142{
143	void __user *argp = (void __user *)arg;
144	int __user *p = (int __user *)argp;
145	unsigned int value;
146	static const struct watchdog_info ident = {
147		.options = WDIOF_CARDRESET,
148		.identity = "MTX-1 WDT",
149	};
150
151	switch (cmd) {
152	case WDIOC_GETSUPPORT:
153		if (copy_to_user(argp, &ident, sizeof(ident)))
154			return -EFAULT;
155		break;
156	case WDIOC_GETSTATUS:
157	case WDIOC_GETBOOTSTATUS:
158		put_user(0, p);
159		break;
160	case WDIOC_SETOPTIONS:
161		if (get_user(value, p))
162			return -EFAULT;
163		if (value & WDIOS_ENABLECARD)
164			mtx1_wdt_start();
165		else if (value & WDIOS_DISABLECARD)
166			mtx1_wdt_stop();
167		else
168			return -EINVAL;
169		return 0;
170	case WDIOC_KEEPALIVE:
171		mtx1_wdt_reset();
172		break;
173	default:
174		return -ENOTTY;
175	}
176	return 0;
177}
178
179
180static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
181						size_t count, loff_t *ppos)
182{
183	if (!count)
184		return -EIO;
185	mtx1_wdt_reset();
186	return count;
187}
188
189static const struct file_operations mtx1_wdt_fops = {
190	.owner		= THIS_MODULE,
191	.llseek		= no_llseek,
192	.unlocked_ioctl	= mtx1_wdt_ioctl,
193	.open		= mtx1_wdt_open,
194	.write		= mtx1_wdt_write,
195	.release	= mtx1_wdt_release,
196};
197
198
199static struct miscdevice mtx1_wdt_misc = {
200	.minor	= WATCHDOG_MINOR,
201	.name	= "watchdog",
202	.fops	= &mtx1_wdt_fops,
203};
204
205
206static int mtx1_wdt_probe(struct platform_device *pdev)
207{
208	int ret;
209
210	mtx1_wdt_device.gpio = pdev->resource[0].start;
211	ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
212				GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
213	if (ret < 0) {
214		dev_err(&pdev->dev, "failed to request gpio");
215		return ret;
216	}
217
218	spin_lock_init(&mtx1_wdt_device.lock);
219	init_completion(&mtx1_wdt_device.stop);
220	mtx1_wdt_device.queue = 0;
221	clear_bit(0, &mtx1_wdt_device.inuse);
222	setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
223	mtx1_wdt_device.default_ticks = ticks;
224
225	ret = misc_register(&mtx1_wdt_misc);
226	if (ret < 0) {
227		dev_err(&pdev->dev, "failed to register\n");
228		return ret;
229	}
230	mtx1_wdt_start();
231	dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
232	return 0;
233}
234
235static int mtx1_wdt_remove(struct platform_device *pdev)
236{
237	/* FIXME: do we need to lock this test ? */
238	if (mtx1_wdt_device.queue) {
239		mtx1_wdt_device.queue = 0;
240		wait_for_completion(&mtx1_wdt_device.stop);
241	}
242
243	misc_deregister(&mtx1_wdt_misc);
244	return 0;
245}
246
247static struct platform_driver mtx1_wdt_driver = {
248	.probe = mtx1_wdt_probe,
249	.remove = mtx1_wdt_remove,
250	.driver.name = "mtx1-wdt",
251	.driver.owner = THIS_MODULE,
252};
253
254module_platform_driver(mtx1_wdt_driver);
255
256MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
257MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
258MODULE_LICENSE("GPL");
259MODULE_ALIAS("platform:mtx1-wdt");
260