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 <linux/platform_device.h>
49
50 #include <asm/io.h>
51 #include <asm/uaccess.h>
52
53 #include <asm/mach-au1x00/au1000.h>
54 #include <asm/gpio.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 int running;
63 struct timer_list timer;
64 int queue;
65 int default_ticks;
66 unsigned long inuse;
67 unsigned gpio;
68 } mtx1_wdt_device;
69
70 static void mtx1_wdt_trigger(unsigned long unused)
71 {
72 u32 tmp;
73
74 if (mtx1_wdt_device.running)
75 ticks--;
76 /*
77 * toggle GPIO2_15
78 */
79 tmp = au_readl(GPIO2_DIR);
80 tmp = (tmp & ~(1 << mtx1_wdt_device.gpio)) |
81 ((~tmp) & (1 << mtx1_wdt_device.gpio));
82 au_writel (tmp, GPIO2_DIR);
83
84 if (mtx1_wdt_device.queue && ticks)
85 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
86 else {
87 complete(&mtx1_wdt_device.stop);
88 }
89 }
90
91 static void mtx1_wdt_reset(void)
92 {
93 ticks = mtx1_wdt_device.default_ticks;
94 }
95
96
97 static void mtx1_wdt_start(void)
98 {
99 if (!mtx1_wdt_device.queue) {
100 mtx1_wdt_device.queue = 1;
101 gpio_set_value(mtx1_wdt_device.gpio, 1);
102 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
103 }
104 mtx1_wdt_device.running++;
105 }
106
107 static int mtx1_wdt_stop(void)
108 {
109 if (mtx1_wdt_device.queue) {
110 mtx1_wdt_device.queue = 0;
111 gpio_set_value(mtx1_wdt_device.gpio, 0);
112 }
113
114 ticks = mtx1_wdt_device.default_ticks;
115
116 return 0;
117 }
118
119 /* Filesystem functions */
120
121 static int mtx1_wdt_open(struct inode *inode, struct file *file)
122 {
123 if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
124 return -EBUSY;
125
126 return nonseekable_open(inode, file);
127 }
128
129
130 static int mtx1_wdt_release(struct inode *inode, struct file *file)
131 {
132 clear_bit(0, &mtx1_wdt_device.inuse);
133 return 0;
134 }
135
136 static int mtx1_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
137 {
138 void __user *argp = (void __user *)arg;
139 unsigned int value;
140 static struct watchdog_info ident =
141 {
142 .options = WDIOF_CARDRESET,
143 .identity = "MTX-1 WDT",
144 };
145
146 switch(cmd) {
147 case WDIOC_KEEPALIVE:
148 mtx1_wdt_reset();
149 break;
150 case WDIOC_GETSTATUS:
151 case WDIOC_GETBOOTSTATUS:
152 if ( copy_to_user(argp, &value, sizeof(int)) )
153 return -EFAULT;
154 break;
155 case WDIOC_GETSUPPORT:
156 if ( copy_to_user(argp, &ident, sizeof(ident)) )
157 return -EFAULT;
158 break;
159 case WDIOC_SETOPTIONS:
160 if ( copy_from_user(&value, argp, sizeof(int)) )
161 return -EFAULT;
162 switch(value) {
163 case WDIOS_ENABLECARD:
164 mtx1_wdt_start();
165 break;
166 case WDIOS_DISABLECARD:
167 return mtx1_wdt_stop();
168 default:
169 return -EINVAL;
170 }
171 break;
172 default:
173 return -ENOTTY;
174 }
175 return 0;
176 }
177
178
179 static ssize_t mtx1_wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
180 {
181 if (!count)
182 return -EIO;
183
184 mtx1_wdt_reset();
185 return count;
186 }
187
188 static const struct file_operations mtx1_wdt_fops = {
189 .owner = THIS_MODULE,
190 .llseek = no_llseek,
191 .ioctl = mtx1_wdt_ioctl,
192 .open = mtx1_wdt_open,
193 .write = mtx1_wdt_write,
194 .release = mtx1_wdt_release
195 };
196
197
198 static struct miscdevice mtx1_wdt_misc = {
199 .minor = WATCHDOG_MINOR,
200 .name = "watchdog",
201 .fops = &mtx1_wdt_fops
202 };
203
204
205 static int mtx1_wdt_probe(struct platform_device *pdev)
206 {
207 int ret;
208
209 mtx1_wdt_device.gpio = pdev->resource[0].start;
210
211 if ((ret = misc_register(&mtx1_wdt_misc)) < 0) {
212 printk(KERN_ERR " mtx-1_wdt : failed to register\n");
213 return ret;
214 }
215
216 init_completion(&mtx1_wdt_device.stop);
217 mtx1_wdt_device.queue = 0;
218
219 clear_bit(0, &mtx1_wdt_device.inuse);
220
221 setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
222
223 mtx1_wdt_device.default_ticks = ticks;
224
225 mtx1_wdt_start();
226
227 printk(KERN_INFO "MTX-1 Watchdog driver\n");
228
229 return 0;
230 }
231
232 static int mtx1_wdt_remove(struct platform_device *pdev)
233 {
234 if (mtx1_wdt_device.queue) {
235 mtx1_wdt_device.queue = 0;
236 wait_for_completion(&mtx1_wdt_device.stop);
237 }
238 misc_deregister(&mtx1_wdt_misc);
239 return 0;
240 }
241
242 static struct platform_driver mtx1_wdt = {
243 .probe = mtx1_wdt_probe,
244 .remove = mtx1_wdt_remove,
245 .driver.name = "mtx1-wdt",
246 .driver.owner = THIS_MODULE,
247 };
248
249 static int __init mtx1_wdt_init(void)
250 {
251 return platform_driver_register(&mtx1_wdt);
252 }
253
254 static void __exit mtx1_wdt_exit(void)
255 {
256 platform_driver_unregister(&mtx1_wdt);
257 }
258
259 module_init(mtx1_wdt_init);
260 module_exit(mtx1_wdt_exit);
261
262 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
263 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
264 MODULE_LICENSE("GPL");
265 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
266 MODULE_ALIAS("platform:mtx1-wdt");
267
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