linux/drivers/watchdog/mt7621_wdt.c
Sergio Paracuellos ff8ec4ac39 watchdog: mt7621-wdt: avoid ralink architecture dependent code
MT7621 SoC has a system controller node. Watchdog need to access to reset
status register. Ralink architecture and related driver are old and from
the beggining they are using some architecture dependent operations for
accessing this shared registers through 'asm/mach-ralink/ralink_regs.h'
header file. However this is not ideal from a driver perspective which can
just access to the system controller registers in an arch independent way
using regmap syscon APIs. Update Kconfig accordingly to select new added
dependencies and allow driver to be compile tested.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230214103936.1061078-6-sergio.paracuellos@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-03-02 06:51:29 +01:00

230 lines
5.7 KiB
C

// 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");