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authorKumar Gala <galak@gate.crashing.org>2006-01-14 16:20:50 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-14 21:27:07 -0500
commitfabbfb9e8c53416eaa4f62b957430211376c9c82 (patch)
treea17bd86d02975f724471dbc8ed23f4b38005b739 /drivers/char/watchdog/mpc83xx_wdt.c
parent7339ff8302fd70aabf5f1ae26e0c4905fa74a495 (diff)
[PATCH] powerpc: Add support for the MPC83xx watchdog
Add support for the PowerPC MPC83xx watchdog. The MPC83xx has a simple watchdog that once enabled it can not be stopped, has some simple timeout range selection, and the ability to either reset the processor or take a machine check. Signed-off-by: Dave Updegraff <dave@cray.org> Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Cc: Wim Van Sebroeck <wim@iguana.be> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/char/watchdog/mpc83xx_wdt.c')
-rw-r--r--drivers/char/watchdog/mpc83xx_wdt.c229
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/char/watchdog/mpc83xx_wdt.c b/drivers/char/watchdog/mpc83xx_wdt.c
new file mode 100644
index 000000000000..5d6f5061603a
--- /dev/null
+++ b/drivers/char/watchdog/mpc83xx_wdt.c
@@ -0,0 +1,229 @@
1/*
2 * mpc83xx_wdt.c - MPC83xx watchdog userspace interface
3 *
4 * Authors: Dave Updegraff <dave@cray.org>
5 * Kumar Gala <galak@kernel.crashing.org>
6 * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
7 * ..and from sc520_wdt
8 *
9 * Note: it appears that you can only actually ENABLE or DISABLE the thing
10 * once after POR. Once enabled, you cannot disable, and vice versa.
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License as published by the
14 * Free Software Foundation; either version 2 of the License, or (at your
15 * option) any later version.
16 */
17
18#include <linux/config.h>
19#include <linux/fs.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/miscdevice.h>
23#include <linux/platform_device.h>
24#include <linux/module.h>
25#include <linux/watchdog.h>
26#include <asm/io.h>
27#include <asm/uaccess.h>
28
29struct mpc83xx_wdt {
30 __be32 res0;
31 __be32 swcrr; /* System watchdog control register */
32#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
33#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
34#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
35#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
36 __be32 swcnr; /* System watchdog count register */
37 u8 res1[2];
38 __be16 swsrr; /* System watchdog service register */
39 u8 res2[0xF0];
40};
41
42static struct mpc83xx_wdt __iomem *wd_base;
43
44static u16 timeout = 0xffff;
45module_param(timeout, ushort, 0);
46MODULE_PARM_DESC(timeout, "Watchdog timeout in ticks. (0<timeout<65536, default=65535");
47
48static int reset = 1;
49module_param(reset, bool, 0);
50MODULE_PARM_DESC(reset, "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
51
52/*
53 * We always prescale, but if someone really doesn't want to they can set this
54 * to 0
55 */
56static int prescale = 1;
57static unsigned int timeout_sec;
58
59static unsigned long wdt_is_open;
60static spinlock_t wdt_spinlock;
61
62static void mpc83xx_wdt_keepalive(void)
63{
64 /* Ping the WDT */
65 spin_lock(&wdt_spinlock);
66 out_be16(&wd_base->swsrr, 0x556c);
67 out_be16(&wd_base->swsrr, 0xaa39);
68 spin_unlock(&wdt_spinlock);
69}
70
71static ssize_t mpc83xx_wdt_write(struct file *file, const char __user *buf,
72 size_t count, loff_t *ppos)
73{
74 if (count)
75 mpc83xx_wdt_keepalive();
76 return count;
77}
78
79static int mpc83xx_wdt_open(struct inode *inode, struct file *file)
80{
81 u32 tmp = SWCRR_SWEN;
82 if (test_and_set_bit(0, &wdt_is_open))
83 return -EBUSY;
84
85 /* Once we start the watchdog we can't stop it */
86 __module_get(THIS_MODULE);
87
88 /* Good, fire up the show */
89 if (prescale)
90 tmp |= SWCRR_SWPR;
91 if (reset)
92 tmp |= SWCRR_SWRI;
93
94 tmp |= timeout << 16;
95
96 out_be32(&wd_base->swcrr, tmp);
97
98 return nonseekable_open(inode, file);
99}
100
101static int mpc83xx_wdt_release(struct inode *inode, struct file *file)
102{
103 printk(KERN_CRIT "Unexpected close, not stopping watchdog!\n");
104 mpc83xx_wdt_keepalive();
105 clear_bit(0, &wdt_is_open);
106 return 0;
107}
108
109static int mpc83xx_wdt_ioctl(struct inode *inode, struct file *file,
110 unsigned int cmd, unsigned long arg)
111{
112 void __user *argp = (void __user *)arg;
113 int __user *p = argp;
114 static struct watchdog_info ident = {
115 .options = WDIOF_KEEPALIVEPING,
116 .firmware_version = 1,
117 .identity = "MPC83xx",
118 };
119
120 switch (cmd) {
121 case WDIOC_GETSUPPORT:
122 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
123 case WDIOC_KEEPALIVE:
124 mpc83xx_wdt_keepalive();
125 return 0;
126 case WDIOC_GETTIMEOUT:
127 return put_user(timeout_sec, p);
128 default:
129 return -ENOIOCTLCMD;
130 }
131}
132
133static struct file_operations mpc83xx_wdt_fops = {
134 .owner = THIS_MODULE,
135 .llseek = no_llseek,
136 .write = mpc83xx_wdt_write,
137 .ioctl = mpc83xx_wdt_ioctl,
138 .open = mpc83xx_wdt_open,
139 .release = mpc83xx_wdt_release,
140};
141
142static struct miscdevice mpc83xx_wdt_miscdev = {
143 .minor = WATCHDOG_MINOR,
144 .name = "watchdog",
145 .fops = &mpc83xx_wdt_fops,
146};
147
148static int __devinit mpc83xx_wdt_probe(struct platform_device *dev)
149{
150 struct resource *r;
151 int ret;
152 unsigned int *freq = dev->dev.platform_data;
153
154 /* get a pointer to the register memory */
155 r = platform_get_resource(dev, IORESOURCE_MEM, 0);
156
157 if (!r) {
158 ret = -ENODEV;
159 goto err_out;
160 }
161
162 wd_base = ioremap(r->start, sizeof (struct mpc83xx_wdt));
163
164 if (wd_base == NULL) {
165 ret = -ENOMEM;
166 goto err_out;
167 }
168
169 ret = misc_register(&mpc83xx_wdt_miscdev);
170 if (ret) {
171 printk(KERN_ERR "cannot register miscdev on minor=%d "
172 "(err=%d)\n",
173 WATCHDOG_MINOR, ret);
174 goto err_unmap;
175 }
176
177 /* Calculate the timeout in seconds */
178 if (prescale)
179 timeout_sec = (timeout * 0x10000) / (*freq);
180 else
181 timeout_sec = timeout / (*freq);
182
183 printk(KERN_INFO "WDT driver for MPC83xx initialized. "
184 "mode:%s timeout=%d (%d seconds)\n",
185 reset ? "reset":"interrupt", timeout, timeout_sec);
186
187 spin_lock_init(&wdt_spinlock);
188
189 return 0;
190
191err_unmap:
192 iounmap(wd_base);
193err_out:
194 return ret;
195}
196
197static int __devexit mpc83xx_wdt_remove(struct platform_device *dev)
198{
199 misc_deregister(&mpc83xx_wdt_miscdev);
200 iounmap(wd_base);
201
202 return 0;
203}
204
205static struct platform_driver mpc83xx_wdt_driver = {
206 .probe = mpc83xx_wdt_probe,
207 .remove = __devexit_p(mpc83xx_wdt_remove),
208 .driver = {
209 .name = "mpc83xx_wdt",
210 },
211};
212
213static int __init mpc83xx_wdt_init(void)
214{
215 return platform_driver_register(&mpc83xx_wdt_driver);
216}
217
218static void __exit mpc83xx_wdt_exit(void)
219{
220 platform_driver_unregister(&mpc83xx_wdt_driver);
221}
222
223module_init(mpc83xx_wdt_init);
224module_exit(mpc83xx_wdt_exit);
225
226MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
227MODULE_DESCRIPTION("Driver for watchdog timer in MPC83xx uProcessor");
228MODULE_LICENSE("GPL");
229MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);