/*
* mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
*
* Authors: Dave Updegraff <dave@cray.org>
* Kumar Gala <galak@kernel.crashing.org>
* Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
* ..and from sc520_wdt
* Copyright (c) 2008 MontaVista Software, Inc.
* Anton Vorontsov <avorontsov@ru.mvista.com>
*
* Note: it appears that you can only actually ENABLE or DISABLE the thing
* once after POR. Once enabled, you cannot disable, and vice versa.
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/miscdevice.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <sysdev/fsl_soc.h>
struct mpc8xxx_wdt {
__be32 res0;
__be32 swcrr; /* System watchdog control register */
#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
__be32 swcnr; /* System watchdog count register */
u8 res1[2];
__be16 swsrr; /* System watchdog service register */
u8 res2[0xF0];
};
struct mpc8xxx_wdt_type {
int prescaler;
bool hw_enabled;
};
static struct mpc8xxx_wdt __iomem *wd_base;
static int mpc8xxx_wdt_init_late(void);
static u16 timeout = 0xffff;
module_param(timeout, ushort, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in ticks. (0<timeout<65536, default=65535)");
static bool reset = 1;
module_param(reset, bool, 0);
MODULE_PARM_DESC(reset,
"Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* We always prescale, but if someone really doesn't want to they can set this
* to 0
*/
static int prescale = 1;
static DEFINE_SPINLOCK(wdt_spinlock);
static void mpc8xxx_wdt_keepalive(void)
{
/* Ping the WDT */
spin_lock(&wdt_spinlock);
out_be16(&wd_base->swsrr, 0x556c);
out_be16(&wd_base->swsrr, 0xaa39);
spin_unlock(&wdt_spinlock);
}
static struct watchdog_device mpc8xxx_wdt_dev;
static void mpc8xxx_wdt_timer_ping(unsigned long arg);
static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0,
(unsigned long)&mpc8xxx_wdt_dev);
static void mpc8xxx_wdt_timer_ping(unsigned long arg)
{
struct watchdog_device *w = (struct watchdog_device *)arg;
mpc8xxx_wdt_keepalive();
/* We're pinging it twice faster than needed, just to be sure. */
mod_timer(&wdt_timer, jiffies + HZ * w->timeout / 2);
}
static int mpc8xxx_wdt_start(struct watchdog_device *w)
{
u32 tmp = SWCRR_SWEN;
/* Good, fire up the show */
if (prescale)
tmp |= SWCRR_SWPR;
if (reset)
tmp |= SWCRR_SWRI;
tmp |= timeout << 16;
out_be32(&wd_base->swcrr, tmp);
del_timer_sync(&wdt_timer);
return 0;
}
static int mpc8xxx_wdt_ping(struct watchdog_device *w)
{
mpc8xxx_wdt_keepalive();
return 0;
}
static int mpc8xxx_wdt_stop(struct watchdog_device *w)
{
mod_timer(&wdt_timer, jiffies);
return 0;
}
static struct watchdog_info mpc8xxx_wdt_info = {
.options = WDIOF_KEEPALIVEPING,
.firmware_version = 1,
.identity = "MPC8xxx",
};
static struct watchdog_ops mpc8xxx_wdt_ops = {
.owner = THIS_MODULE,
.start = mpc8xxx_wdt_start,
.ping = mpc8xxx_wdt_ping,
.stop = mpc8xxx_wdt_stop,
};
static struct watchdog_device mpc8xxx_wdt_dev = {
.info = &mpc8xxx_wdt_info,
.ops = &mpc8xxx_wdt_ops,
};
static const struct of_device_id mpc8xxx_wdt_match[];
static int mpc8xxx_wdt_probe(struct platform_device *ofdev)
{
int ret;
const struct of_device_id *match;
struct device_node *np = ofdev->dev.of_node;
const struct mpc8xxx_wdt_type *wdt_type;
u32 freq = fsl_get_sys_freq();
bool enabled;
unsigned int timeout_sec;
match = of_match_device(mpc8xxx_wdt_match, &ofdev->dev);
if (!match)
return -EINVAL;
wdt_type = match->data;
if (!freq || freq == -1)
return -EINVAL;
wd_base = of_iomap(np, 0);
if (!wd_base)
return -ENOMEM;
enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
if (!enabled && wdt_type->hw_enabled) {
pr_info("could not be enabled in software\n");
ret = -ENOSYS;
goto err_unmap;
}
/* Calculate the timeout in seconds */
if (prescale)
timeout_sec = (timeout * wdt_type->prescaler) / freq;
else
timeout_sec = timeout / freq;
mpc8xxx_wdt_dev.timeout = timeout_sec;
#ifdef MODULE
ret = mpc8xxx_wdt_init_late();
if (ret)
goto err_unmap;
#endif
pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n",
reset ? "reset" : "interrupt", timeout, timeout_sec);
/*
* If the watchdog was previously enabled or we're running on
* MPC8xxx, we should ping the wdt from the kernel until the
* userspace handles it.
*/
if (enabled)
mod_timer(&wdt_timer, jiffies);
return 0;
err_unmap:
iounmap(wd_base);
wd_base = NULL;
return ret;
}
static int mpc8xxx_wdt_remove(struct platform_device *ofdev)
{
pr_crit("Watchdog removed, expect the %s soon!\n",
reset ? "reset" : "machine check exception");
del_timer_sync(&wdt_timer);
watchdog_unregister_device(&mpc8xxx_wdt_dev);
iounmap(wd_base);
return 0;
}
static const struct of_device_id mpc8xxx_wdt_match[] = {
{
.compatible = "mpc83xx_wdt",
.data = &(struct mpc8xxx_wdt_type) {
.prescaler = 0x10000,
},
},
{
.compatible = "fsl,mpc8610-wdt",
.data = &(struct mpc8xxx_wdt_type) {
.prescaler = 0x10000,
.hw_enabled = true,
},
},
{
.compatible = "fsl,mpc823-wdt",
.data = &(struct mpc8xxx_wdt_type) {
.prescaler = 0x800,
.hw_enabled = true,
},
},
{},
};
MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
static struct platform_driver mpc8xxx_wdt_driver = {
.probe = mpc8xxx_wdt_probe,
.remove = mpc8xxx_wdt_remove,
.driver = {
.name = "mpc8xxx_wdt",
.of_match_table = mpc8xxx_wdt_match,
},
};
/*
* We do wdt initialization in two steps: arch_initcall probes the wdt
* very early to start pinging the watchdog (misc devices are not yet
* available), and later module_init() just registers the misc device.
*/
static int mpc8xxx_wdt_init_late(void)
{
int ret;
if (!wd_base)
return -ENODEV;
watchdog_set_nowayout(&mpc8xxx_wdt_dev, nowayout);
ret = watchdog_register_device(&mpc8xxx_wdt_dev);
if (ret) {
pr_err("cannot register watchdog device (err=%d)\n", ret);
return ret;
}
return 0;
}
#ifndef MODULE
module_init(mpc8xxx_wdt_init_late);
#endif
static int __init mpc8xxx_wdt_init(void)
{
return platform_driver_register(&mpc8xxx_wdt_driver);
}
arch_initcall(mpc8xxx_wdt_init);
static void __exit mpc8xxx_wdt_exit(void)
{
platform_driver_unregister(&mpc8xxx_wdt_driver);
}
module_exit(mpc8xxx_wdt_exit);
MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
"uProcessors");
MODULE_LICENSE("GPL");
