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
58 static int ticks = 100 * HZ;
59
60 static 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
mtx1_wdt_trigger(unsigned long unused)71 static 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
mtx1_wdt_reset(void)93 static void mtx1_wdt_reset(void)
94 {
95 ticks = mtx1_wdt_device.default_ticks;
96 }
97
98
mtx1_wdt_start(void)99 static 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
mtx1_wdt_stop(void)113 static 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
mtx1_wdt_open(struct inode * inode,struct file * file)129 static 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
mtx1_wdt_release(struct inode * inode,struct file * file)137 static int mtx1_wdt_release(struct inode *inode, struct file *file)
138 {
139 clear_bit(0, &mtx1_wdt_device.inuse);
140 return 0;
141 }
142
mtx1_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)143 static 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
mtx1_wdt_write(struct file * file,const char * buf,size_t count,loff_t * ppos)183 static 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
192 static 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
202 static struct miscdevice mtx1_wdt_misc = {
203 .minor = WATCHDOG_MINOR,
204 .name = "watchdog",
205 .fops = &mtx1_wdt_fops,
206 };
207
208
mtx1_wdt_probe(struct platform_device * pdev)209 static int __devinit 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
mtx1_wdt_remove(struct platform_device * pdev)232 static int __devexit 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
243 static struct platform_driver mtx1_wdt = {
244 .probe = mtx1_wdt_probe,
245 .remove = __devexit_p(mtx1_wdt_remove),
246 .driver.name = "mtx1-wdt",
247 .driver.owner = THIS_MODULE,
248 };
249
mtx1_wdt_init(void)250 static int __init mtx1_wdt_init(void)
251 {
252 return platform_driver_register(&mtx1_wdt);
253 }
254
mtx1_wdt_exit(void)255 static void __exit mtx1_wdt_exit(void)
256 {
257 platform_driver_unregister(&mtx1_wdt);
258 }
259
260 module_init(mtx1_wdt_init);
261 module_exit(mtx1_wdt_exit);
262
263 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
264 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
265 MODULE_LICENSE("GPL");
266 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
267 MODULE_ALIAS("platform:mtx1-wdt");
268