241 lines
6.0 KiB
C
241 lines
6.0 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 <linux/uaccess.h>
|
|
|
|
#include <asm/reg_booke.h>
|
|
#include <asm/system.h>
|
|
#include <asm/time.h>
|
|
#include <asm/div64.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 38 /* 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) ((((x)&0x3)<<30)|(((x)&0x3c)<<15))
|
|
#define WDTP_MASK (WDTP(0x3f))
|
|
#else
|
|
#define WDTP(x) (TCR_WP(x))
|
|
#define WDTP_MASK (TCR_WP_MASK)
|
|
#endif
|
|
|
|
static DEFINE_SPINLOCK(booke_wdt_lock);
|
|
|
|
/* For the specified period, determine the number of seconds
|
|
* corresponding to the reset time. There will be a watchdog
|
|
* exception at approximately 3/5 of this time.
|
|
*
|
|
* The formula to calculate this is given by:
|
|
* 2.5 * (2^(63-period+1)) / timebase_freq
|
|
*
|
|
* In order to simplify things, we assume that period is
|
|
* at least 1. This will still result in a very long timeout.
|
|
*/
|
|
static unsigned long long period_to_sec(unsigned int period)
|
|
{
|
|
unsigned long long tmp = 1ULL << (64 - period);
|
|
unsigned long tmp2 = ppc_tb_freq;
|
|
|
|
/* tmp may be a very large number and we don't want to overflow,
|
|
* so divide the timebase freq instead of multiplying tmp
|
|
*/
|
|
tmp2 = tmp2 / 5 * 2;
|
|
|
|
do_div(tmp, tmp2);
|
|
return tmp;
|
|
}
|
|
|
|
/*
|
|
* This procedure will find the highest period which will give a timeout
|
|
* greater than the one required. e.g. for a bus speed of 66666666 and
|
|
* and a parameter of 2 secs, then this procedure will return a value of 38.
|
|
*/
|
|
static unsigned int sec_to_period(unsigned int secs)
|
|
{
|
|
unsigned int period;
|
|
for (period = 63; period > 0; period--) {
|
|
if (period_to_sec(period) >= secs)
|
|
return period;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
static void __booke_wdt_enable(void *data)
|
|
{
|
|
u32 val;
|
|
|
|
/* clear status before enabling watchdog */
|
|
__booke_wdt_ping(NULL);
|
|
val = mfspr(SPRN_TCR);
|
|
val &= ~WDTP_MASK;
|
|
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((void *)arg, &ident, sizeof(ident)))
|
|
return -EFAULT;
|
|
case WDIOC_GETSTATUS:
|
|
return put_user(0, p);
|
|
case WDIOC_GETBOOTSTATUS:
|
|
/* XXX: something is clearing TSR */
|
|
tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
|
|
/* returns CARDRESET if last reset was caused by the WDT */
|
|
return (tmp ? WDIOF_CARDRESET : 0);
|
|
case WDIOC_SETOPTIONS:
|
|
if (get_user(tmp, p))
|
|
return -EINVAL;
|
|
if (tmp == WDIOS_ENABLECARD) {
|
|
booke_wdt_ping();
|
|
break;
|
|
} else
|
|
return -EINVAL;
|
|
return 0;
|
|
case WDIOC_KEEPALIVE:
|
|
booke_wdt_ping();
|
|
return 0;
|
|
case WDIOC_SETTIMEOUT:
|
|
if (get_user(tmp, p))
|
|
return -EFAULT;
|
|
#ifdef CONFIG_FSL_BOOKE
|
|
/* period of 1 gives the largest possible timeout */
|
|
if (tmp > period_to_sec(1))
|
|
return -EINVAL;
|
|
booke_wdt_period = sec_to_period(tmp);
|
|
#else
|
|
booke_wdt_period = tmp;
|
|
#endif
|
|
mtspr(SPRN_TCR, (mfspr(SPRN_TCR) & ~WDTP_MASK) |
|
|
WDTP(booke_wdt_period));
|
|
return 0;
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(booke_wdt_period, p);
|
|
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);
|
|
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);
|
|
}
|
|
spin_unlock(&booke_wdt_lock);
|
|
|
|
return ret;
|
|
}
|
|
device_initcall(booke_wdt_init);
|