linux/drivers/watchdog/booke_wdt.c
Chen Gong f172ddc61a [WATCHDOG] Fix booke_wdt.c on MPC85xx SMP system's
On Book-E SMP systems each core has its own private watchdog.  If only one
watchdog is enabled, when the core that doesn't enable the watchdog is hung,
system can't reset because no watchdog is running on it.  That's bad.  It
means we must enable watchdogs on both cores.

We can use smp_call_function() to send appropriate messages to all the other
cores to enable and update the watchdog.

Signed-off-by: Chen Gong <g.chen@freescale.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2008-05-25 09:43:06 +00:00

187 lines
4.6 KiB
C

/*
* 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 <asm/reg_booke.h>
#include <asm/uaccess.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 int booke_wdt_ioctl(struct inode *inode, 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((struct watchdog_info __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,
.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);