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/*
* Watchdog timer for PowerPC Book-E systems
*
* Author: Matthew McClintock
* Maintainer: Kumar Gala <galak@kernel.crashing.org>
*
* Copyright 2005, 2008 Freescale Semiconductor Inc.
*
* 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/module.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/miscdevice.h>
#include <linux/notifier.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <asm/reg_booke.h>
#include <asm/system.h>
/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
* Also, the wdt_period sets the watchdog timer period timeout.
* For E500 cpus the wdt_period sets which bit changing from 0->1 will
* trigger a watchog timeout. This watchdog timeout will occur 3 times, the
* first time nothing will happen, the second time a watchdog exception will
* occur, and the final time the board will reset.
*/
#ifdef CONFIG_FSL_BOOKE
#define WDT_PERIOD_DEFAULT 63 /* Ex. wdt_period=28 bus=333Mhz,reset=~40sec */
#else
#define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */
#endif /* for timing information */
u32 booke_wdt_enabled;
u32 booke_wdt_period = WDT_PERIOD_DEFAULT;
#ifdef CONFIG_FSL_BOOKE
#define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15))
#else
#define WDTP(x) (TCR_WP(x))
#endif
static DEFINE_SPINLOCK(booke_wdt_lock);
static void __booke_wdt_ping(void *data)
{
mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
}
static void booke_wdt_ping(void)
{
on_each_cpu(__booke_wdt_ping, NULL, 0, 0);
}
static void __booke_wdt_enable(void *data)
{
u32 val;
/* clear status before enabling watchdog */
__booke_wdt_ping(NULL);
val = mfspr(SPRN_TCR);
val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
mtspr(SPRN_TCR, val);
}
static ssize_t booke_wdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
booke_wdt_ping();
return count;
}
static struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "PowerPC Book-E Watchdog",
};
static long booke_wdt_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
u32 tmp = 0;
u32 __user *p = (u32 __user *)arg;
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(arg, &ident, sizeof(struct watchdog_info)))
return -EFAULT;
case WDIOC_GETSTATUS:
return put_user(ident.options, p);
case WDIOC_GETBOOTSTATUS:
/* XXX: something is clearing TSR */
tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
/* returns 1 if last reset was caused by the WDT */
return (tmp ? 1 : 0);
case WDIOC_KEEPALIVE:
booke_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(booke_wdt_period, p))
return -EFAULT;
mtspr(SPRN_TCR, (mfspr(SPRN_TCR) & ~WDTP(0)) |
WDTP(booke_wdt_period));
return 0;
case WDIOC_GETTIMEOUT:
return put_user(booke_wdt_period, p);
case WDIOC_SETOPTIONS:
if (get_user(tmp, p))
return -EINVAL;
if (tmp == WDIOS_ENABLECARD) {
booke_wdt_ping();
break;
} else
return -EINVAL;
return 0;
default:
return -ENOTTY;
}
return 0;
}
static int booke_wdt_open(struct inode *inode, struct file *file)
{
spin_lock(&booke_wdt_lock);
if (booke_wdt_enabled == 0) {
booke_wdt_enabled = 1;
on_each_cpu(__booke_wdt_enable, NULL, 0, 0);
printk(KERN_INFO
"PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
booke_wdt_period);
}
spin_unlock(&booke_wdt_lock);
return nonseekable_open(inode, file);
}
static const struct file_operations booke_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = booke_wdt_write,
.unlocked_ioctl = booke_wdt_ioctl,
.open = booke_wdt_open,
};
static struct miscdevice booke_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &booke_wdt_fops,
};
static void __exit booke_wdt_exit(void)
{
misc_deregister(&booke_wdt_miscdev);
}
static int __init booke_wdt_init(void)
{
int ret = 0;
printk(KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n");
ident.firmware_version = cur_cpu_spec->pvr_value;
ret = misc_register(&booke_wdt_miscdev);
if (ret) {
printk(KERN_CRIT "Cannot register miscdev on minor=%d: %d\n",
WATCHDOG_MINOR, ret);
return ret;
}
spin_lock(&booke_wdt_lock);
if (booke_wdt_enabled == 1) {
printk(KERN_INFO
"PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
booke_wdt_period);
on_each_cpu(__booke_wdt_enable, NULL, 0, 0);
}
spin_unlock(&booke_wdt_lock);
return ret;
}
device_initcall(booke_wdt_init);
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