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-rw-r--r--drivers/watchdog/booke_wdt.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c
new file mode 100644
index 000000000000..d362f5bf658a
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+++ b/drivers/watchdog/booke_wdt.c
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1/*
2 * drivers/char/watchdog/booke_wdt.c
3 *
4 * Watchdog timer for PowerPC Book-E systems
5 *
6 * Author: Matthew McClintock
7 * Maintainer: Kumar Gala <galak@kernel.crashing.org>
8 *
9 * Copyright 2005 Freescale Semiconductor Inc.
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2 of the License, or (at your
14 * option) any later version.
15 */
16
17#include <linux/module.h>
18#include <linux/fs.h>
19#include <linux/miscdevice.h>
20#include <linux/notifier.h>
21#include <linux/watchdog.h>
22
23#include <asm/reg_booke.h>
24#include <asm/uaccess.h>
25#include <asm/system.h>
26
27/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
28 * Also, the wdt_period sets the watchdog timer period timeout.
29 * For E500 cpus the wdt_period sets which bit changing from 0->1 will
30 * trigger a watchog timeout. This watchdog timeout will occur 3 times, the
31 * first time nothing will happen, the second time a watchdog exception will
32 * occur, and the final time the board will reset.
33 */
34
35#ifdef CONFIG_FSL_BOOKE
36#define WDT_PERIOD_DEFAULT 63 /* Ex. wdt_period=28 bus=333Mhz , reset=~40sec */
37#else
38#define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */
39#endif /* for timing information */
40
41u32 booke_wdt_enabled = 0;
42u32 booke_wdt_period = WDT_PERIOD_DEFAULT;
43
44#ifdef CONFIG_FSL_BOOKE
45#define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15))
46#else
47#define WDTP(x) (TCR_WP(x))
48#endif
49
50/*
51 * booke_wdt_ping:
52 */
53static __inline__ void booke_wdt_ping(void)
54{
55 mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
56}
57
58/*
59 * booke_wdt_enable:
60 */
61static __inline__ void booke_wdt_enable(void)
62{
63 u32 val;
64
65 /* clear status before enabling watchdog */
66 booke_wdt_ping();
67 val = mfspr(SPRN_TCR);
68 val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
69
70 mtspr(SPRN_TCR, val);
71}
72
73/*
74 * booke_wdt_write:
75 */
76static ssize_t booke_wdt_write (struct file *file, const char __user *buf,
77 size_t count, loff_t *ppos)
78{
79 booke_wdt_ping();
80 return count;
81}
82
83static struct watchdog_info ident = {
84 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
85 .firmware_version = 0,
86 .identity = "PowerPC Book-E Watchdog",
87};
88
89/*
90 * booke_wdt_ioctl:
91 */
92static int booke_wdt_ioctl (struct inode *inode, struct file *file,
93 unsigned int cmd, unsigned long arg)
94{
95 u32 tmp = 0;
96 u32 __user *p = (u32 __user *)arg;
97
98 switch (cmd) {
99 case WDIOC_GETSUPPORT:
100 if (copy_to_user ((struct watchdog_info __user *) arg, &ident,
101 sizeof(struct watchdog_info)))
102 return -EFAULT;
103 case WDIOC_GETSTATUS:
104 return put_user(ident.options, p);
105 case WDIOC_GETBOOTSTATUS:
106 /* XXX: something is clearing TSR */
107 tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
108 /* returns 1 if last reset was caused by the WDT */
109 return (tmp ? 1 : 0);
110 case WDIOC_KEEPALIVE:
111 booke_wdt_ping();
112 return 0;
113 case WDIOC_SETTIMEOUT:
114 if (get_user(booke_wdt_period, p))
115 return -EFAULT;
116 mtspr(SPRN_TCR, (mfspr(SPRN_TCR)&~WDTP(0))|WDTP(booke_wdt_period));
117 return 0;
118 case WDIOC_GETTIMEOUT:
119 return put_user(booke_wdt_period, p);
120 case WDIOC_SETOPTIONS:
121 if (get_user(tmp, p))
122 return -EINVAL;
123 if (tmp == WDIOS_ENABLECARD) {
124 booke_wdt_ping();
125 break;
126 } else
127 return -EINVAL;
128 return 0;
129 default:
130 return -ENOTTY;
131 }
132
133 return 0;
134}
135/*
136 * booke_wdt_open:
137 */
138static int booke_wdt_open (struct inode *inode, struct file *file)
139{
140 if (booke_wdt_enabled == 0) {
141 booke_wdt_enabled = 1;
142 booke_wdt_enable();
143 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
144 booke_wdt_period);
145 }
146
147 return nonseekable_open(inode, file);
148}
149
150static const struct file_operations booke_wdt_fops = {
151 .owner = THIS_MODULE,
152 .llseek = no_llseek,
153 .write = booke_wdt_write,
154 .ioctl = booke_wdt_ioctl,
155 .open = booke_wdt_open,
156};
157
158static struct miscdevice booke_wdt_miscdev = {
159 .minor = WATCHDOG_MINOR,
160 .name = "watchdog",
161 .fops = &booke_wdt_fops,
162};
163
164static void __exit booke_wdt_exit(void)
165{
166 misc_deregister(&booke_wdt_miscdev);
167}
168
169/*
170 * booke_wdt_init:
171 */
172static int __init booke_wdt_init(void)
173{
174 int ret = 0;
175
176 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n");
177 ident.firmware_version = cur_cpu_spec->pvr_value;
178
179 ret = misc_register(&booke_wdt_miscdev);
180 if (ret) {
181 printk (KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n",
182 WATCHDOG_MINOR, ret);
183 return ret;
184 }
185
186 if (booke_wdt_enabled == 1) {
187 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
188 booke_wdt_period);
189 booke_wdt_enable();
190 }
191
192 return ret;
193}
194device_initcall(booke_wdt_init);