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/*
* 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/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>
#define WATCHDOG_TIMEOUT 10
struct mpc8xxx_wdt {
__be32 res0;
__be32 swcrr; /* System watchdog control register */
#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
#define SWCRR_SWF 0x00000008 /* Software Watchdog Freeze (mpc8xx). */
#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;
};
struct mpc8xxx_wdt_ddata {
struct mpc8xxx_wdt __iomem *base;
struct watchdog_device wdd;
spinlock_t lock;
u16 swtc;
};
static u16 timeout;
module_param(timeout, ushort, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. (1<timeout<65535, default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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) ")");
static void mpc8xxx_wdt_keepalive(struct mpc8xxx_wdt_ddata *ddata)
{
/* Ping the WDT */
spin_lock(&ddata->lock);
out_be16(&ddata->base->swsrr, 0x556c);
out_be16(&ddata->base->swsrr, 0xaa39);
spin_unlock(&ddata->lock);
}
static int mpc8xxx_wdt_start(struct watchdog_device *w)
{
struct mpc8xxx_wdt_ddata *ddata =
container_of(w, struct mpc8xxx_wdt_ddata, wdd);
u32 tmp = in_be32(&ddata->base->swcrr);
/* Good, fire up the show */
tmp &= ~(SWCRR_SWTC | SWCRR_SWF | SWCRR_SWEN | SWCRR_SWRI | SWCRR_SWPR);
tmp |= SWCRR_SWEN | SWCRR_SWPR | (ddata->swtc << 16);
if (reset)
tmp |= SWCRR_SWRI;
out_be32(&ddata->base->swcrr, tmp);
tmp = in_be32(&ddata->base->swcrr);
if (!(tmp & SWCRR_SWEN))
return -EOPNOTSUPP;
ddata->swtc = tmp >> 16;
set_bit(WDOG_HW_RUNNING, &ddata->wdd.status);
return 0;
}
static int mpc8xxx_wdt_ping(struct watchdog_device *w)
{
struct mpc8xxx_wdt_ddata *ddata =
container_of(w, struct mpc8xxx_wdt_ddata, wdd);
mpc8xxx_wdt_keepalive(ddata);
return 0;
}
static struct watchdog_info mpc8xxx_wdt_info = {
.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT,
.firmware_version = 1,
.identity = "MPC8xxx",
};
static struct watchdog_ops mpc8xxx_wdt_ops = {
.owner = THIS_MODULE,
.start = mpc8xxx_wdt_start,
.ping = mpc8xxx_wdt_ping,
};
static int mpc8xxx_wdt_probe(struct platform_device *ofdev)
{
int ret;
struct resource *res;
const struct mpc8xxx_wdt_type *wdt_type;
struct mpc8xxx_wdt_ddata *ddata;
u32 freq = fsl_get_sys_freq();
bool enabled;
wdt_type = of_device_get_match_data(&ofdev->dev);
if (!wdt_type)
return -EINVAL;
if (!freq || freq == -1)
return -EINVAL;
ddata = devm_kzalloc(&ofdev->dev, sizeof(*ddata), GFP_KERNEL);
if (!ddata)
return -ENOMEM;
res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
ddata->base = devm_ioremap_resource(&ofdev->dev, res);
if (IS_ERR(ddata->base))
return PTR_ERR(ddata->base);
enabled = in_be32(&ddata->base->swcrr) & SWCRR_SWEN;
if (!enabled && wdt_type->hw_enabled) {
pr_info("could not be enabled in software\n");
return -ENODEV;
}
spin_lock_init(&ddata->lock);
ddata->wdd.info = &mpc8xxx_wdt_info,
ddata->wdd.ops = &mpc8xxx_wdt_ops,
ddata->wdd.timeout = WATCHDOG_TIMEOUT;
watchdog_init_timeout(&ddata->wdd, timeout, &ofdev->dev);
watchdog_set_nowayout(&ddata->wdd, nowayout);
ddata->swtc = min(ddata->wdd.timeout * freq / wdt_type->prescaler,
0xffffU);
/*
* 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)
mpc8xxx_wdt_start(&ddata->wdd);
ddata->wdd.max_hw_heartbeat_ms = (ddata->swtc * wdt_type->prescaler) /
(freq / 1000);
ddata->wdd.min_timeout = ddata->wdd.max_hw_heartbeat_ms / 1000;
if (ddata->wdd.timeout < ddata->wdd.min_timeout)
ddata->wdd.timeout = ddata->wdd.min_timeout;
ret = watchdog_register_device(&ddata->wdd);
if (ret) {
pr_err("cannot register watchdog device (err=%d)\n", ret);
return ret;
}
pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d sec\n",
reset ? "reset" : "interrupt", ddata->wdd.timeout);
platform_set_drvdata(ofdev, ddata);
return 0;
}
static int mpc8xxx_wdt_remove(struct platform_device *ofdev)
{
struct mpc8xxx_wdt_ddata *ddata = platform_get_drvdata(ofdev);
pr_crit("Watchdog removed, expect the %s soon!\n",
reset ? "reset" : "machine check exception");
watchdog_unregister_device(&ddata->wdd);
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,
},
};
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");
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