Root/package/avila-wdt/src/avila-wdt.c

1/*
2 * avila-wdt.c
3 * Copyright (C) 2009 Felix Fietkau <nbd@openwrt.org>
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
34static int nowayout = WATCHDOG_NOWAYOUT;
35static int heartbeat = 20; /* (secs) Default is 20 seconds */
36static unsigned long wdt_status;
37static atomic_t wdt_counter;
38struct timer_list wdt_timer;
39
40#define WDT_IN_USE 0
41#define WDT_OK_TO_CLOSE 1
42#define WDT_RUNNING 2
43
44static 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
61static 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
77static void wdt_disable(void)
78{
79    /* Re-enable clock generator output on GPIO 14/15 */
80    *IXP4XX_GPIO_GPCLKR |= (1 << 8);
81}
82
83static 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
93static ssize_t
94avila_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
116static struct watchdog_info ident = {
117    .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
118              WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
119    .identity = "Avila Watchdog",
120};
121
122
123static 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
165static 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
179static 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
188static struct miscdevice avila_wdt_miscdev = {
189    .minor = WATCHDOG_MINOR + 1,
190    .name = "avila_watchdog",
191    .fops = &avila_wdt_fops,
192};
193
194static 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
209static void __exit avila_wdt_exit(void)
210{
211    misc_deregister(&avila_wdt_miscdev);
212    del_timer(&wdt_timer);
213    wdt_disable();
214}
215
216
217module_init(avila_wdt_init);
218module_exit(avila_wdt_exit);
219
220MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
221MODULE_DESCRIPTION("Gateworks Avila Hardware Watchdog");
222
223module_param(heartbeat, int, 0);
224MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 20s)");
225
226module_param(nowayout, int, 0);
227MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
228
229MODULE_LICENSE("GPL");
230MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
231
232

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