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// SPDX-License-Identifier: GPL-2.0-only
/*
* sunplus Watchdog Driver
*
* Copyright (C) 2021 Sunplus Technology Co., Ltd.
*
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/watchdog.h>
#define WDT_CTRL 0x00
#define WDT_CNT 0x04
#define WDT_STOP 0x3877
#define WDT_RESUME 0x4A4B
#define WDT_CLRIRQ 0x7482
#define WDT_UNLOCK 0xAB00
#define WDT_LOCK 0xAB01
#define WDT_CONMAX 0xDEAF
/* TIMEOUT_MAX = ffff0/90kHz =11.65, so longer than 11 seconds will time out. */
#define SP_WDT_MAX_TIMEOUT 11U
#define SP_WDT_DEFAULT_TIMEOUT 10
#define STC_CLK 90000
#define DEVICE_NAME "sunplus-wdt"
static unsigned int timeout;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
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) ")");
struct sp_wdt_priv {
struct watchdog_device wdev;
void __iomem *base;
struct clk *clk;
struct reset_control *rstc;
};
static int sp_wdt_restart(struct watchdog_device *wdev,
unsigned long action, void *data)
{
struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
void __iomem *base = priv->base;
writel(WDT_STOP, base + WDT_CTRL);
writel(WDT_UNLOCK, base + WDT_CTRL);
writel(0x0001, base + WDT_CNT);
writel(WDT_LOCK, base + WDT_CTRL);
writel(WDT_RESUME, base + WDT_CTRL);
return 0;
}
static int sp_wdt_ping(struct watchdog_device *wdev)
{
struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
void __iomem *base = priv->base;
u32 count;
if (wdev->timeout > SP_WDT_MAX_TIMEOUT) {
/* WDT_CONMAX sets the count to the maximum (down-counting). */
writel(WDT_CONMAX, base + WDT_CTRL);
} else {
writel(WDT_UNLOCK, base + WDT_CTRL);
/*
* Watchdog timer is a 20-bit down-counting based on STC_CLK.
* This register bits[16:0] is from bit[19:4] of the watchdog
* timer counter.
*/
count = (wdev->timeout * STC_CLK) >> 4;
writel(count, base + WDT_CNT);
writel(WDT_LOCK, base + WDT_CTRL);
}
return 0;
}
static int sp_wdt_stop(struct watchdog_device *wdev)
{
struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
void __iomem *base = priv->base;
writel(WDT_STOP, base + WDT_CTRL);
return 0;
}
static int sp_wdt_start(struct watchdog_device *wdev)
{
struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
void __iomem *base = priv->base;
writel(WDT_RESUME, base + WDT_CTRL);
return 0;
}
static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev)
{
struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
void __iomem *base = priv->base;
u32 val;
val = readl(base + WDT_CNT);
val &= 0xffff;
val = val << 4;
return val;
}
static const struct watchdog_info sp_wdt_info = {
.identity = DEVICE_NAME,
.options = WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
};
static const struct watchdog_ops sp_wdt_ops = {
.owner = THIS_MODULE,
.start = sp_wdt_start,
.stop = sp_wdt_stop,
.ping = sp_wdt_ping,
.get_timeleft = sp_wdt_get_timeleft,
.restart = sp_wdt_restart,
};
static void sp_reset_control_assert(void *data)
{
reset_control_assert(data);
}
static int sp_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct sp_wdt_priv *priv;
int ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->clk = devm_clk_get_enabled(dev, NULL);
if (IS_ERR(priv->clk))
return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to enable clock\n");
/* The timer and watchdog shared the STC reset */
priv->rstc = devm_reset_control_get_shared(dev, NULL);
if (IS_ERR(priv->rstc))
return dev_err_probe(dev, PTR_ERR(priv->rstc), "Failed to get reset\n");
reset_control_deassert(priv->rstc);
ret = devm_add_action_or_reset(dev, sp_reset_control_assert, priv->rstc);
if (ret)
return ret;
priv->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
priv->wdev.info = &sp_wdt_info;
priv->wdev.ops = &sp_wdt_ops;
priv->wdev.timeout = SP_WDT_DEFAULT_TIMEOUT;
priv->wdev.max_hw_heartbeat_ms = SP_WDT_MAX_TIMEOUT * 1000;
priv->wdev.min_timeout = 1;
priv->wdev.parent = dev;
watchdog_set_drvdata(&priv->wdev, priv);
watchdog_init_timeout(&priv->wdev, timeout, dev);
watchdog_set_nowayout(&priv->wdev, nowayout);
watchdog_stop_on_reboot(&priv->wdev);
watchdog_set_restart_priority(&priv->wdev, 128);
return devm_watchdog_register_device(dev, &priv->wdev);
}
static const struct of_device_id sp_wdt_of_match[] = {
{.compatible = "sunplus,sp7021-wdt", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sp_wdt_of_match);
static struct platform_driver sp_wdt_driver = {
.probe = sp_wdt_probe,
.driver = {
.name = DEVICE_NAME,
.of_match_table = sp_wdt_of_match,
},
};
module_platform_driver(sp_wdt_driver);
MODULE_AUTHOR("Xiantao Hu <xt.hu@cqplus1.com>");
MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver");
MODULE_LICENSE("GPL");
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