linux/drivers/watchdog/booke_wdt.c
Dmitry Artamonow 741b9c7da1 watchdog: fix GETTIMEOUT ioctl in booke_wdt
Commit dcfb748422 ([WATCHDOG] fix book E watchdog to take
WDIOC_SETTIMEOUT arg in seconds) fixed SETTIMEOUT ioctl
to use seconds as a parameter instead of some hardware-specific
"period", but missed to apply similar changes to GETTIMEOUT,
so it still returns "period" value. Let's fix it!
Also, while at it, make SETTIMEOUT ioctl return real timeout
value as it should do according to the documentation.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-02-29 09:46:13 +01:00

303 lines
7.4 KiB
C

/*
* Watchdog timer for PowerPC Book-E systems
*
* Author: Matthew McClintock
* Maintainer: Kumar Gala <galak@kernel.crashing.org>
*
* Copyright 2005, 2008, 2010-2011 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.
*/
u32 booke_wdt_enabled;
u32 booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT;
#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_set(void *data)
{
u32 val;
val = mfspr(SPRN_TCR);
val &= ~WDTP_MASK;
val |= WDTP(booke_wdt_period);
mtspr(SPRN_TCR, val);
}
static void booke_wdt_set(void)
{
on_each_cpu(__booke_wdt_set, NULL, 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);
}
/**
* booke_wdt_disable - disable the watchdog on the given CPU
*
* This function is called on each CPU. It disables the watchdog on that CPU.
*
* TCR[WRC] cannot be changed once it has been set to non-zero, but we can
* effectively disable the watchdog by setting its period to the maximum value.
*/
static void __booke_wdt_disable(void *data)
{
u32 val;
val = mfspr(SPRN_TCR);
val &= ~(TCR_WIE | WDTP_MASK);
mtspr(SPRN_TCR, val);
/* clear status to make sure nothing is pending */
__booke_wdt_ping(NULL);
}
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
booke_wdt_set();
/* Fall */
case WDIOC_GETTIMEOUT:
#ifdef CONFIG_FSL_BOOKE
return put_user(period_to_sec(booke_wdt_period), p);
#else
return put_user(booke_wdt_period, p);
#endif
default:
return -ENOTTY;
}
return 0;
}
/* wdt_is_active stores wether or not the /dev/watchdog device is opened */
static unsigned long wdt_is_active;
static int booke_wdt_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &wdt_is_active))
return -EBUSY;
spin_lock(&booke_wdt_lock);
if (booke_wdt_enabled == 0) {
booke_wdt_enabled = 1;
on_each_cpu(__booke_wdt_enable, NULL, 0);
pr_debug("booke_wdt: watchdog enabled (timeout = %llu sec)\n",
period_to_sec(booke_wdt_period));
}
spin_unlock(&booke_wdt_lock);
return nonseekable_open(inode, file);
}
static int booke_wdt_release(struct inode *inode, struct file *file)
{
#ifndef CONFIG_WATCHDOG_NOWAYOUT
/* Normally, the watchdog is disabled when /dev/watchdog is closed, but
* if CONFIG_WATCHDOG_NOWAYOUT is defined, then it means that the
* watchdog should remain enabled. So we disable it only if
* CONFIG_WATCHDOG_NOWAYOUT is not defined.
*/
on_each_cpu(__booke_wdt_disable, NULL, 0);
booke_wdt_enabled = 0;
pr_debug("booke_wdt: watchdog disabled\n");
#endif
clear_bit(0, &wdt_is_active);
return 0;
}
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,
.release = booke_wdt_release,
};
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;
pr_info("booke_wdt: powerpc book-e watchdog driver loaded\n");
ident.firmware_version = cur_cpu_spec->pvr_value;
ret = misc_register(&booke_wdt_miscdev);
if (ret) {
pr_err("booke_wdt: cannot register device (minor=%u, ret=%i)\n",
WATCHDOG_MINOR, ret);
return ret;
}
spin_lock(&booke_wdt_lock);
if (booke_wdt_enabled == 1) {
pr_info("booke_wdt: watchdog enabled (timeout = %llu sec)\n",
period_to_sec(booke_wdt_period));
on_each_cpu(__booke_wdt_enable, NULL, 0);
}
spin_unlock(&booke_wdt_lock);
return ret;
}
module_init(booke_wdt_init);
module_exit(booke_wdt_exit);
MODULE_DESCRIPTION("PowerPC Book-E watchdog driver");
MODULE_LICENSE("GPL");