Linux 2.6.20.7
[linux/fpc-iii.git] / drivers / char / watchdog / booke_wdt.c
blob488902231cc237ec24cd76568af57c186bc6d12d
1 /*
2 * drivers/char/watchdog/booke_wdt.c
4 * Watchdog timer for PowerPC Book-E systems
6 * Author: Matthew McClintock
7 * Maintainer: Kumar Gala <galak@kernel.crashing.org>
9 * Copyright 2005 Freescale Semiconductor Inc.
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.
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>
23 #include <asm/reg_booke.h>
24 #include <asm/uaccess.h>
25 #include <asm/system.h>
27 /* If the kernel parameter wdt_enable=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.
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 4 /* Refer to the PPC40x and PPC4xx manuals */
39 #endif /* for timing information */
41 u32 booke_wdt_enabled = 0;
42 u32 booke_wdt_period = WDT_PERIOD_DEFAULT;
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
51 * booke_wdt_enable:
53 static __inline__ void booke_wdt_enable(void)
55 u32 val;
57 val = mfspr(SPRN_TCR);
58 val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
60 mtspr(SPRN_TCR, val);
64 * booke_wdt_ping:
66 static __inline__ void booke_wdt_ping(void)
68 mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
72 * booke_wdt_write:
74 static ssize_t booke_wdt_write (struct file *file, const char __user *buf,
75 size_t count, loff_t *ppos)
77 booke_wdt_ping();
78 return count;
81 static struct watchdog_info ident = {
82 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
83 .firmware_version = 0,
84 .identity = "PowerPC Book-E Watchdog",
88 * booke_wdt_ioctl:
90 static int booke_wdt_ioctl (struct inode *inode, struct file *file,
91 unsigned int cmd, unsigned long arg)
93 u32 tmp = 0;
94 u32 __user *p = (u32 __user *)arg;
96 switch (cmd) {
97 case WDIOC_GETSUPPORT:
98 if (copy_to_user ((struct watchdog_info __user *) arg, &ident,
99 sizeof(struct watchdog_info)))
100 return -EFAULT;
101 case WDIOC_GETSTATUS:
102 return put_user(ident.options, p);
103 case WDIOC_GETBOOTSTATUS:
104 /* XXX: something is clearing TSR */
105 tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
106 /* returns 1 if last reset was caused by the WDT */
107 return (tmp ? 1 : 0);
108 case WDIOC_KEEPALIVE:
109 booke_wdt_ping();
110 return 0;
111 case WDIOC_SETTIMEOUT:
112 if (get_user(booke_wdt_period, p))
113 return -EFAULT;
114 mtspr(SPRN_TCR, (mfspr(SPRN_TCR)&~WDTP(0))|WDTP(booke_wdt_period));
115 return 0;
116 case WDIOC_GETTIMEOUT:
117 return put_user(booke_wdt_period, p);
118 case WDIOC_SETOPTIONS:
119 if (get_user(tmp, p))
120 return -EINVAL;
121 if (tmp == WDIOS_ENABLECARD) {
122 booke_wdt_ping();
123 break;
124 } else
125 return -EINVAL;
126 return 0;
127 default:
128 return -ENOTTY;
131 return 0;
134 * booke_wdt_open:
136 static int booke_wdt_open (struct inode *inode, struct file *file)
138 if (booke_wdt_enabled == 0) {
139 booke_wdt_enabled = 1;
140 booke_wdt_enable();
141 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
142 booke_wdt_period);
145 return 0;
148 static const struct file_operations booke_wdt_fops = {
149 .owner = THIS_MODULE,
150 .llseek = no_llseek,
151 .write = booke_wdt_write,
152 .ioctl = booke_wdt_ioctl,
153 .open = booke_wdt_open,
156 static struct miscdevice booke_wdt_miscdev = {
157 .minor = WATCHDOG_MINOR,
158 .name = "watchdog",
159 .fops = &booke_wdt_fops,
162 static void __exit booke_wdt_exit(void)
164 misc_deregister(&booke_wdt_miscdev);
168 * booke_wdt_init:
170 static int __init booke_wdt_init(void)
172 int ret = 0;
174 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n");
175 ident.firmware_version = cur_cpu_spec->pvr_value;
177 ret = misc_register(&booke_wdt_miscdev);
178 if (ret) {
179 printk (KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n",
180 WATCHDOG_MINOR, ret);
181 return ret;
184 if (booke_wdt_enabled == 1) {
185 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
186 booke_wdt_period);
187 booke_wdt_enable();
190 return ret;
192 device_initcall(booke_wdt_init);