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// SPDX-License-Identifier: GPL-2.0
/*
* Airoha Watchdog Driver
*
* Copyright (c) 2024, AIROHA All rights reserved.
*
* Mayur Kumar <mayur.kumar@airoha.com>
* Christian Marangi <ansuelsmth@gmail.com>
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/math.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
/* Base address of timer and watchdog registers */
#define TIMER_CTRL 0x0
#define WDT_ENABLE BIT(25)
#define WDT_TIMER_INTERRUPT BIT(21)
/* Timer3 is used as Watchdog Timer */
#define WDT_TIMER_ENABLE BIT(5)
#define WDT_TIMER_LOAD_VALUE 0x2c
#define WDT_TIMER_CUR_VALUE 0x30
#define WDT_TIMER_VAL GENMASK(31, 0)
#define WDT_RELOAD 0x38
#define WDT_RLD BIT(0)
/* Airoha watchdog structure description */
struct airoha_wdt_desc {
struct watchdog_device wdog_dev;
unsigned int wdt_freq;
void __iomem *base;
};
#define WDT_HEARTBEAT 24
static int heartbeat = WDT_HEARTBEAT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. (default="
__MODULE_STRING(WDT_HEARTBEAT) ")");
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 int airoha_wdt_start(struct watchdog_device *wdog_dev)
{
struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
u32 val;
val = readl(airoha_wdt->base + TIMER_CTRL);
val |= (WDT_TIMER_ENABLE | WDT_ENABLE | WDT_TIMER_INTERRUPT);
writel(val, airoha_wdt->base + TIMER_CTRL);
val = wdog_dev->timeout * airoha_wdt->wdt_freq;
writel(val, airoha_wdt->base + WDT_TIMER_LOAD_VALUE);
return 0;
}
static int airoha_wdt_stop(struct watchdog_device *wdog_dev)
{
struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
u32 val;
val = readl(airoha_wdt->base + TIMER_CTRL);
val &= (~WDT_ENABLE & ~WDT_TIMER_ENABLE);
writel(val, airoha_wdt->base + TIMER_CTRL);
return 0;
}
static int airoha_wdt_ping(struct watchdog_device *wdog_dev)
{
struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
u32 val;
val = readl(airoha_wdt->base + WDT_RELOAD);
val |= WDT_RLD;
writel(val, airoha_wdt->base + WDT_RELOAD);
return 0;
}
static int airoha_wdt_set_timeout(struct watchdog_device *wdog_dev, unsigned int timeout)
{
wdog_dev->timeout = timeout;
if (watchdog_active(wdog_dev)) {
airoha_wdt_stop(wdog_dev);
return airoha_wdt_start(wdog_dev);
}
return 0;
}
static unsigned int airoha_wdt_get_timeleft(struct watchdog_device *wdog_dev)
{
struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
u32 val;
val = readl(airoha_wdt->base + WDT_TIMER_CUR_VALUE);
return DIV_ROUND_UP(val, airoha_wdt->wdt_freq);
}
static const struct watchdog_info airoha_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
.identity = "Airoha Watchdog",
};
static const struct watchdog_ops airoha_wdt_ops = {
.owner = THIS_MODULE,
.start = airoha_wdt_start,
.stop = airoha_wdt_stop,
.ping = airoha_wdt_ping,
.set_timeout = airoha_wdt_set_timeout,
.get_timeleft = airoha_wdt_get_timeleft,
};
static int airoha_wdt_probe(struct platform_device *pdev)
{
struct airoha_wdt_desc *airoha_wdt;
struct watchdog_device *wdog_dev;
struct device *dev = &pdev->dev;
struct clk *bus_clk;
int ret;
airoha_wdt = devm_kzalloc(dev, sizeof(*airoha_wdt), GFP_KERNEL);
if (!airoha_wdt)
return -ENOMEM;
airoha_wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(airoha_wdt->base))
return PTR_ERR(airoha_wdt->base);
bus_clk = devm_clk_get_enabled(dev, "bus");
if (IS_ERR(bus_clk))
return dev_err_probe(dev, PTR_ERR(bus_clk),
"failed to enable bus clock\n");
/* Watchdog ticks at half the bus rate */
airoha_wdt->wdt_freq = clk_get_rate(bus_clk) / 2;
/* Initialize struct watchdog device */
wdog_dev = &airoha_wdt->wdog_dev;
wdog_dev->timeout = heartbeat;
wdog_dev->info = &airoha_wdt_info;
wdog_dev->ops = &airoha_wdt_ops;
/* Bus 300MHz, watchdog 150MHz, 28 seconds */
wdog_dev->max_timeout = FIELD_MAX(WDT_TIMER_VAL) / airoha_wdt->wdt_freq;
wdog_dev->parent = dev;
watchdog_set_drvdata(wdog_dev, airoha_wdt);
watchdog_set_nowayout(wdog_dev, nowayout);
watchdog_stop_on_unregister(wdog_dev);
ret = devm_watchdog_register_device(dev, wdog_dev);
if (ret)
return ret;
platform_set_drvdata(pdev, airoha_wdt);
return 0;
}
static int airoha_wdt_suspend(struct device *dev)
{
struct airoha_wdt_desc *airoha_wdt = dev_get_drvdata(dev);
if (watchdog_active(&airoha_wdt->wdog_dev))
airoha_wdt_stop(&airoha_wdt->wdog_dev);
return 0;
}
static int airoha_wdt_resume(struct device *dev)
{
struct airoha_wdt_desc *airoha_wdt = dev_get_drvdata(dev);
if (watchdog_active(&airoha_wdt->wdog_dev)) {
airoha_wdt_start(&airoha_wdt->wdog_dev);
airoha_wdt_ping(&airoha_wdt->wdog_dev);
}
return 0;
}
static const struct of_device_id airoha_wdt_of_match[] = {
{ .compatible = "airoha,en7581-wdt", },
{ },
};
MODULE_DEVICE_TABLE(of, airoha_wdt_of_match);
static DEFINE_SIMPLE_DEV_PM_OPS(airoha_wdt_pm_ops, airoha_wdt_suspend, airoha_wdt_resume);
static struct platform_driver airoha_wdt_driver = {
.probe = airoha_wdt_probe,
.driver = {
.name = "airoha-wdt",
.pm = pm_sleep_ptr(&airoha_wdt_pm_ops),
.of_match_table = airoha_wdt_of_match,
},
};
module_platform_driver(airoha_wdt_driver);
MODULE_AUTHOR("Mayur Kumar <mayur.kumar@airoha.com>");
MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
MODULE_DESCRIPTION("Airoha EN7581 Watchdog Driver");
MODULE_LICENSE("GPL");
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