1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
/*
* mpc83xx_wdt.c - MPC83xx watchdog userspace interface
*
* Authors: Dave Updegraff <dave@cray.org>
* Kumar Gala <galak@kernel.crashing.org>
* Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
* ..and from sc520_wdt
*
* Note: it appears that you can only actually ENABLE or DISABLE the thing
* once after POR. Once enabled, you cannot disable, and vice versa.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <asm/io.h>
#include <asm/uaccess.h>
struct mpc83xx_wdt {
__be32 res0;
__be32 swcrr; /* System watchdog control register */
#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
__be32 swcnr; /* System watchdog count register */
u8 res1[2];
__be16 swsrr; /* System watchdog service register */
u8 res2[0xF0];
};
static struct mpc83xx_wdt __iomem *wd_base;
static u16 timeout = 0xffff;
module_param(timeout, ushort, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in ticks. (0<timeout<65536, default=65535");
static int reset = 1;
module_param(reset, bool, 0);
MODULE_PARM_DESC(reset, "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
/*
* We always prescale, but if someone really doesn't want to they can set this
* to 0
*/
static int prescale = 1;
static unsigned int timeout_sec;
static unsigned long wdt_is_open;
static spinlock_t wdt_spinlock;
static void mpc83xx_wdt_keepalive(void)
{
/* Ping the WDT */
spin_lock(&wdt_spinlock);
out_be16(&wd_base->swsrr, 0x556c);
out_be16(&wd_base->swsrr, 0xaa39);
spin_unlock(&wdt_spinlock);
}
static ssize_t mpc83xx_wdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count)
mpc83xx_wdt_keepalive();
return count;
}
static int mpc83xx_wdt_open(struct inode *inode, struct file *file)
{
u32 tmp = SWCRR_SWEN;
if (test_and_set_bit(0, &wdt_is_open))
return -EBUSY;
/* Once we start the watchdog we can't stop it */
__module_get(THIS_MODULE);
/* Good, fire up the show */
if (prescale)
tmp |= SWCRR_SWPR;
if (reset)
tmp |= SWCRR_SWRI;
tmp |= timeout << 16;
out_be32(&wd_base->swcrr, tmp);
return nonseekable_open(inode, file);
}
static int mpc83xx_wdt_release(struct inode *inode, struct file *file)
{
printk(KERN_CRIT "Unexpected close, not stopping watchdog!\n");
mpc83xx_wdt_keepalive();
clear_bit(0, &wdt_is_open);
return 0;
}
static int mpc83xx_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
static struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING,
.firmware_version = 1,
.identity = "MPC83xx",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
case WDIOC_KEEPALIVE:
mpc83xx_wdt_keepalive();
return 0;
case WDIOC_GETTIMEOUT:
return put_user(timeout_sec, p);
default:
return -ENOTTY;
}
}
static const struct file_operations mpc83xx_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = mpc83xx_wdt_write,
.ioctl = mpc83xx_wdt_ioctl,
.open = mpc83xx_wdt_open,
.release = mpc83xx_wdt_release,
};
static struct miscdevice mpc83xx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &mpc83xx_wdt_fops,
};
static int __devinit mpc83xx_wdt_probe(struct platform_device *dev)
{
struct resource *r;
int ret;
unsigned int *freq = dev->dev.platform_data;
/* get a pointer to the register memory */
r = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (!r) {
ret = -ENODEV;
goto err_out;
}
wd_base = ioremap(r->start, sizeof (struct mpc83xx_wdt));
if (wd_base == NULL) {
ret = -ENOMEM;
goto err_out;
}
ret = misc_register(&mpc83xx_wdt_miscdev);
if (ret) {
printk(KERN_ERR "cannot register miscdev on minor=%d "
"(err=%d)\n",
WATCHDOG_MINOR, ret);
goto err_unmap;
}
/* Calculate the timeout in seconds */
if (prescale)
timeout_sec = (timeout * 0x10000) / (*freq);
else
timeout_sec = timeout / (*freq);
printk(KERN_INFO "WDT driver for MPC83xx initialized. "
"mode:%s timeout=%d (%d seconds)\n",
reset ? "reset":"interrupt", timeout, timeout_sec);
spin_lock_init(&wdt_spinlock);
return 0;
err_unmap:
iounmap(wd_base);
err_out:
return ret;
}
static int __devexit mpc83xx_wdt_remove(struct platform_device *dev)
{
misc_deregister(&mpc83xx_wdt_miscdev);
iounmap(wd_base);
return 0;
}
static struct platform_driver mpc83xx_wdt_driver = {
.probe = mpc83xx_wdt_probe,
.remove = __devexit_p(mpc83xx_wdt_remove),
.driver = {
.name = "mpc83xx_wdt",
},
};
static int __init mpc83xx_wdt_init(void)
{
return platform_driver_register(&mpc83xx_wdt_driver);
}
static void __exit mpc83xx_wdt_exit(void)
{
platform_driver_unregister(&mpc83xx_wdt_driver);
}
module_init(mpc83xx_wdt_init);
module_exit(mpc83xx_wdt_exit);
MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
MODULE_DESCRIPTION("Driver for watchdog timer in MPC83xx uProcessor");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|
