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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02002 * drivers/char/watchdog/ixp2000_wdt.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Watchdog driver for Intel IXP2000 network processors
5 *
6 * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
7 * The original version carries these notices:
8 *
9 * Author: Deepak Saxena <dsaxena@plexity.net>
10 *
11 * Copyright 2004 (c) MontaVista, Software, Inc.
12 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
13 *
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
17 */
18
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/module.h>
20#include <linux/moduleparam.h>
21#include <linux/types.h>
22#include <linux/kernel.h>
23#include <linux/fs.h>
24#include <linux/miscdevice.h>
25#include <linux/watchdog.h>
26#include <linux/init.h>
27#include <linux/bitops.h>
28
29#include <asm/hardware.h>
30#include <asm/uaccess.h>
31
Andrey Panin4bfdf372005-07-27 11:43:58 -070032static int nowayout = WATCHDOG_NOWAYOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070033static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
34static unsigned long wdt_status;
35
36#define WDT_IN_USE 0
37#define WDT_OK_TO_CLOSE 1
38
39static unsigned long wdt_tick_rate;
40
41static void
42wdt_enable(void)
43{
44 ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
45 ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
46 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
47 ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
48}
49
50static void
51wdt_disable(void)
52{
53 ixp2000_reg_write(IXP2000_T4_CTL, 0);
54}
55
56static void
57wdt_keepalive(void)
58{
59 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
60}
61
62static int
63ixp2000_wdt_open(struct inode *inode, struct file *file)
64{
65 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
66 return -EBUSY;
67
68 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
69
70 wdt_enable();
71
72 return nonseekable_open(inode, file);
73}
74
75static ssize_t
76ixp2000_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
77{
78 if (len) {
79 if (!nowayout) {
80 size_t i;
81
82 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
83
84 for (i = 0; i != len; i++) {
85 char c;
86
87 if (get_user(c, data + i))
88 return -EFAULT;
89 if (c == 'V')
90 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
91 }
92 }
93 wdt_keepalive();
94 }
95
96 return len;
97}
98
99
100static struct watchdog_info ident = {
101 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
102 WDIOF_KEEPALIVEPING,
103 .identity = "IXP2000 Watchdog",
104};
105
106static int
107ixp2000_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
108 unsigned long arg)
109{
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200110 int ret = -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 int time;
112
113 switch (cmd) {
114 case WDIOC_GETSUPPORT:
115 ret = copy_to_user((struct watchdog_info *)arg, &ident,
116 sizeof(ident)) ? -EFAULT : 0;
117 break;
118
119 case WDIOC_GETSTATUS:
120 ret = put_user(0, (int *)arg);
121 break;
122
123 case WDIOC_GETBOOTSTATUS:
124 ret = put_user(0, (int *)arg);
125 break;
126
127 case WDIOC_SETTIMEOUT:
128 ret = get_user(time, (int *)arg);
129 if (ret)
130 break;
131
132 if (time <= 0 || time > 60) {
133 ret = -EINVAL;
134 break;
135 }
136
137 heartbeat = time;
138 wdt_keepalive();
139 /* Fall through */
140
141 case WDIOC_GETTIMEOUT:
142 ret = put_user(heartbeat, (int *)arg);
143 break;
144
145 case WDIOC_KEEPALIVE:
146 wdt_enable();
147 ret = 0;
148 break;
149 }
150
151 return ret;
152}
153
154static int
155ixp2000_wdt_release(struct inode *inode, struct file *file)
156{
157 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
158 wdt_disable();
159 } else {
Lennert Buytenhekb36bbb62005-06-28 20:44:46 -0700160 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 "timer will not stop\n");
162 }
163
164 clear_bit(WDT_IN_USE, &wdt_status);
165 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
166
167 return 0;
168}
169
170
Arjan van de Ven62322d22006-07-03 00:24:21 -0700171static const struct file_operations ixp2000_wdt_fops =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172{
173 .owner = THIS_MODULE,
174 .llseek = no_llseek,
175 .write = ixp2000_wdt_write,
176 .ioctl = ixp2000_wdt_ioctl,
177 .open = ixp2000_wdt_open,
178 .release = ixp2000_wdt_release,
179};
180
181static struct miscdevice ixp2000_wdt_miscdev =
182{
183 .minor = WATCHDOG_MINOR,
Olaf Hering2dab3ca2005-08-17 08:58:34 +0200184 .name = "watchdog",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 .fops = &ixp2000_wdt_fops,
186};
187
188static int __init ixp2000_wdt_init(void)
189{
Lennert Buytenheke4fe1982005-06-20 18:51:07 +0100190 if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
191 printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
192 return -EIO;
193 }
194
195 wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
197 return misc_register(&ixp2000_wdt_miscdev);
198}
199
200static void __exit ixp2000_wdt_exit(void)
201{
202 misc_deregister(&ixp2000_wdt_miscdev);
203}
204
205module_init(ixp2000_wdt_init);
206module_exit(ixp2000_wdt_exit);
207
208MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net">);
209MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
210
211module_param(heartbeat, int, 0);
212MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
213
214module_param(nowayout, int, 0);
215MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
216
217MODULE_LICENSE("GPL");
218MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
219