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// SPDX-License-Identifier: GPL-2.0-only
/*
* Ralink MT7621/MT7628 built-in hardware watchdog timer
*
* Copyright (C) 2014 John Crispin <john@phrozen.org>
*
* This driver was based on: drivers/watchdog/rt2880_wdt.c
*/
#include <linux/clk.h>
#include <linux/reset.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/watchdog.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#define SYSC_RSTSTAT 0x38
#define WDT_RST_CAUSE BIT(1)
#define RALINK_WDT_TIMEOUT 30
#define TIMER_REG_TMRSTAT 0x00
#define TIMER_REG_TMR1LOAD 0x24
#define TIMER_REG_TMR1CTL 0x20
#define TMR1CTL_ENABLE BIT(7)
#define TMR1CTL_RESTART BIT(9)
#define TMR1CTL_PRESCALE_SHIFT 16
struct mt7621_wdt_data {
void __iomem *base;
struct reset_control *rst;
struct regmap *sysc;
struct watchdog_device wdt;
};
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 inline void rt_wdt_w32(void __iomem *base, unsigned int reg, u32 val)
{
iowrite32(val, base + reg);
}
static inline u32 rt_wdt_r32(void __iomem *base, unsigned int reg)
{
return ioread32(base + reg);
}
static int mt7621_wdt_ping(struct watchdog_device *w)
{
struct mt7621_wdt_data *drvdata = watchdog_get_drvdata(w);
rt_wdt_w32(drvdata->base, TIMER_REG_TMRSTAT, TMR1CTL_RESTART);
return 0;
}
static int mt7621_wdt_set_timeout(struct watchdog_device *w, unsigned int t)
{
struct mt7621_wdt_data *drvdata = watchdog_get_drvdata(w);
w->timeout = t;
rt_wdt_w32(drvdata->base, TIMER_REG_TMR1LOAD, t * 1000);
mt7621_wdt_ping(w);
return 0;
}
static int mt7621_wdt_start(struct watchdog_device *w)
{
struct mt7621_wdt_data *drvdata = watchdog_get_drvdata(w);
u32 t;
/* set the prescaler to 1ms == 1000us */
rt_wdt_w32(drvdata->base, TIMER_REG_TMR1CTL, 1000 << TMR1CTL_PRESCALE_SHIFT);
mt7621_wdt_set_timeout(w, w->timeout);
t = rt_wdt_r32(drvdata->base, TIMER_REG_TMR1CTL);
t |= TMR1CTL_ENABLE;
rt_wdt_w32(drvdata->base, TIMER_REG_TMR1CTL, t);
return 0;
}
static int mt7621_wdt_stop(struct watchdog_device *w)
{
struct mt7621_wdt_data *drvdata = watchdog_get_drvdata(w);
u32 t;
mt7621_wdt_ping(w);
t = rt_wdt_r32(drvdata->base, TIMER_REG_TMR1CTL);
t &= ~TMR1CTL_ENABLE;
rt_wdt_w32(drvdata->base, TIMER_REG_TMR1CTL, t);
return 0;
}
static int mt7621_wdt_bootcause(struct mt7621_wdt_data *d)
{
u32 val;
regmap_read(d->sysc, SYSC_RSTSTAT, &val);
if (val & WDT_RST_CAUSE)
return WDIOF_CARDRESET;
return 0;
}
static int mt7621_wdt_is_running(struct watchdog_device *w)
{
struct mt7621_wdt_data *drvdata = watchdog_get_drvdata(w);
return !!(rt_wdt_r32(drvdata->base, TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE);
}
static const struct watchdog_info mt7621_wdt_info = {
.identity = "Mediatek Watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops mt7621_wdt_ops = {
.owner = THIS_MODULE,
.start = mt7621_wdt_start,
.stop = mt7621_wdt_stop,
.ping = mt7621_wdt_ping,
.set_timeout = mt7621_wdt_set_timeout,
};
static int mt7621_wdt_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct device *dev = &pdev->dev;
struct watchdog_device *mt7621_wdt;
struct mt7621_wdt_data *drvdata;
int err;
drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
if (!drvdata)
return -ENOMEM;
drvdata->sysc = syscon_regmap_lookup_by_phandle(np, "mediatek,sysctl");
if (IS_ERR(drvdata->sysc)) {
drvdata->sysc = syscon_regmap_lookup_by_compatible("mediatek,mt7621-sysc");
if (IS_ERR(drvdata->sysc))
return PTR_ERR(drvdata->sysc);
}
drvdata->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(drvdata->base))
return PTR_ERR(drvdata->base);
drvdata->rst = devm_reset_control_get_exclusive(dev, NULL);
if (!IS_ERR(drvdata->rst))
reset_control_deassert(drvdata->rst);
mt7621_wdt = &drvdata->wdt;
mt7621_wdt->info = &mt7621_wdt_info;
mt7621_wdt->ops = &mt7621_wdt_ops;
mt7621_wdt->min_timeout = 1;
mt7621_wdt->max_timeout = 0xfffful / 1000;
mt7621_wdt->parent = dev;
mt7621_wdt->bootstatus = mt7621_wdt_bootcause(drvdata);
watchdog_init_timeout(mt7621_wdt, mt7621_wdt->max_timeout, dev);
watchdog_set_nowayout(mt7621_wdt, nowayout);
watchdog_set_drvdata(mt7621_wdt, drvdata);
if (mt7621_wdt_is_running(mt7621_wdt)) {
/*
* Make sure to apply timeout from watchdog core, taking
* the prescaler of this driver here into account (the
* boot loader might be using a different prescaler).
*
* To avoid spurious resets because of different scaling,
* we first disable the watchdog, set the new prescaler
* and timeout, and then re-enable the watchdog.
*/
mt7621_wdt_stop(mt7621_wdt);
mt7621_wdt_start(mt7621_wdt);
set_bit(WDOG_HW_RUNNING, &mt7621_wdt->status);
}
err = devm_watchdog_register_device(dev, &drvdata->wdt);
if (err)
return err;
platform_set_drvdata(pdev, drvdata);
return 0;
}
static void mt7621_wdt_shutdown(struct platform_device *pdev)
{
struct mt7621_wdt_data *drvdata = platform_get_drvdata(pdev);
mt7621_wdt_stop(&drvdata->wdt);
}
static const struct of_device_id mt7621_wdt_match[] = {
{ .compatible = "mediatek,mt7621-wdt" },
{},
};
MODULE_DEVICE_TABLE(of, mt7621_wdt_match);
static struct platform_driver mt7621_wdt_driver = {
.probe = mt7621_wdt_probe,
.shutdown = mt7621_wdt_shutdown,
.driver = {
.name = KBUILD_MODNAME,
.of_match_table = mt7621_wdt_match,
},
};
module_platform_driver(mt7621_wdt_driver);
MODULE_DESCRIPTION("MediaTek MT762x hardware watchdog driver");
MODULE_AUTHOR("John Crispin <john@phrozen.org");
MODULE_LICENSE("GPL v2");
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