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1 office 1 /*
2 * avila-wdt.c
3 * Copyright (C) 2009 Felix Fietkau <nbd@nbd.name>
4 *
5 * based on:
6 * drivers/char/watchdog/ixp4xx_wdt.c
7 *
8 * Watchdog driver for Intel IXP4xx network processors
9 *
10 * Author: Deepak Saxena <dsaxena@plexity.net>
11 *
12 * Copyright 2004 (c) MontaVista, Software, Inc.
13 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
14 *
15 * This file is licensed under the terms of the GNU General Public
16 * License version 2. This program is licensed "as is" without any
17 * warranty of any kind, whether express or implied.
18 */
19  
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/jiffies.h>
25 #include <linux/timer.h>
26 #include <linux/fs.h>
27 #include <linux/miscdevice.h>
28 #include <linux/watchdog.h>
29 #include <linux/init.h>
30 #include <linux/bitops.h>
31 #include <linux/uaccess.h>
32 #include <mach/hardware.h>
33  
34 static int nowayout = WATCHDOG_NOWAYOUT;
35 static int heartbeat = 20; /* (secs) Default is 20 seconds */
36 static unsigned long wdt_status;
37 static atomic_t wdt_counter;
38 struct timer_list wdt_timer;
39  
40 #define WDT_IN_USE 0
41 #define WDT_OK_TO_CLOSE 1
42 #define WDT_RUNNING 2
43  
44 static void wdt_refresh(unsigned long data)
45 {
46 if (test_bit(WDT_RUNNING, &wdt_status)) {
47 if (atomic_dec_and_test(&wdt_counter)) {
48 printk(KERN_WARNING "Avila watchdog expired, expect a reboot soon!\n");
49 clear_bit(WDT_RUNNING, &wdt_status);
50 return;
51 }
52 }
53  
54 /* strobe to the watchdog */
55 gpio_line_set(14, IXP4XX_GPIO_HIGH);
56 gpio_line_set(14, IXP4XX_GPIO_LOW);
57  
58 mod_timer(&wdt_timer, jiffies + msecs_to_jiffies(500));
59 }
60  
61 static void wdt_enable(void)
62 {
63 atomic_set(&wdt_counter, heartbeat * 2);
64  
65 /* Disable clock generator output on GPIO 14/15 */
66 *IXP4XX_GPIO_GPCLKR &= ~(1 << 8);
67  
68 /* activate GPIO 14 out */
69 gpio_line_config(14, IXP4XX_GPIO_OUT);
70 gpio_line_set(14, IXP4XX_GPIO_LOW);
71  
72 if (!test_bit(WDT_RUNNING, &wdt_status))
73 wdt_refresh(0);
74 set_bit(WDT_RUNNING, &wdt_status);
75 }
76  
77 static void wdt_disable(void)
78 {
79 /* Re-enable clock generator output on GPIO 14/15 */
80 *IXP4XX_GPIO_GPCLKR |= (1 << 8);
81 }
82  
83 static int avila_wdt_open(struct inode *inode, struct file *file)
84 {
85 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
86 return -EBUSY;
87  
88 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
89 wdt_enable();
90 return nonseekable_open(inode, file);
91 }
92  
93 static ssize_t
94 avila_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
95 {
96 if (len) {
97 if (!nowayout) {
98 size_t i;
99  
100 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
101  
102 for (i = 0; i != len; i++) {
103 char c;
104  
105 if (get_user(c, data + i))
106 return -EFAULT;
107 if (c == 'V')
108 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
109 }
110 }
111 wdt_enable();
112 }
113 return len;
114 }
115  
116 static struct watchdog_info ident = {
117 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
118 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
119 .identity = "Avila Watchdog",
120 };
121  
122  
123 static long avila_wdt_ioctl(struct file *file, unsigned int cmd,
124 unsigned long arg)
125 {
126 int ret = -ENOTTY;
127 int time;
128  
129 switch (cmd) {
130 case WDIOC_GETSUPPORT:
131 ret = copy_to_user((struct watchdog_info *)arg, &ident,
132 sizeof(ident)) ? -EFAULT : 0;
133 break;
134  
135 case WDIOC_GETSTATUS:
136 ret = put_user(0, (int *)arg);
137 break;
138  
139 case WDIOC_KEEPALIVE:
140 wdt_enable();
141 ret = 0;
142 break;
143  
144 case WDIOC_SETTIMEOUT:
145 ret = get_user(time, (int *)arg);
146 if (ret)
147 break;
148  
149 if (time <= 0 || time > 60) {
150 ret = -EINVAL;
151 break;
152 }
153  
154 heartbeat = time;
155 wdt_enable();
156 /* Fall through */
157  
158 case WDIOC_GETTIMEOUT:
159 ret = put_user(heartbeat, (int *)arg);
160 break;
161 }
162 return ret;
163 }
164  
165 static int avila_wdt_release(struct inode *inode, struct file *file)
166 {
167 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
168 wdt_disable();
169 else
170 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
171 "timer will not stop\n");
172 clear_bit(WDT_IN_USE, &wdt_status);
173 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
174  
175 return 0;
176 }
177  
178  
179 static const struct file_operations avila_wdt_fops = {
180 .owner = THIS_MODULE,
181 .llseek = no_llseek,
182 .write = avila_wdt_write,
183 .unlocked_ioctl = avila_wdt_ioctl,
184 .open = avila_wdt_open,
185 .release = avila_wdt_release,
186 };
187  
188 static struct miscdevice avila_wdt_miscdev = {
189 .minor = WATCHDOG_MINOR + 1,
190 .name = "avila_watchdog",
191 .fops = &avila_wdt_fops,
192 };
193  
194 static int __init avila_wdt_init(void)
195 {
196 int ret;
197  
198 init_timer(&wdt_timer);
199 wdt_timer.expires = 0;
200 wdt_timer.data = 0;
201 wdt_timer.function = wdt_refresh;
202 ret = misc_register(&avila_wdt_miscdev);
203 if (ret == 0)
204 printk(KERN_INFO "Avila Watchdog Timer: heartbeat %d sec\n",
205 heartbeat);
206 return ret;
207 }
208  
209 static void __exit avila_wdt_exit(void)
210 {
211 misc_deregister(&avila_wdt_miscdev);
212 del_timer(&wdt_timer);
213 wdt_disable();
214 }
215  
216  
217 module_init(avila_wdt_init);
218 module_exit(avila_wdt_exit);
219  
220 MODULE_AUTHOR("Felix Fietkau <nbd@nbd.name>");
221 MODULE_DESCRIPTION("Gateworks Avila Hardware Watchdog");
222  
223 module_param(heartbeat, int, 0);
224 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 20s)");
225  
226 module_param(nowayout, int, 0);
227 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
228  
229 MODULE_LICENSE("GPL");
230 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
231