linux/drivers/watchdog/msc313e_wdt.c
Daniel Palmer ffd264bd15 watchdog: msc313e: Check if the WDT was running at boot
Check if the WDT was running at boot and set the running
flag if it was. This prevents the system from getting
rebooted if the userland daemon doesn't take over soon enough
or there isn't a userland daemon at all.

Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Reviewed-by: Romain Perier <romain.perier@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20211228073427.2443174-1-daniel@0x0f.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2022-01-05 10:38:51 +01:00

171 lines
4.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* MStar WDT driver
*
* Copyright (C) 2019 - 2021 Daniel Palmer
* Copyright (C) 2021 Romain Perier
*
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define REG_WDT_CLR 0x0
#define REG_WDT_MAX_PRD_L 0x10
#define REG_WDT_MAX_PRD_H 0x14
#define MSC313E_WDT_MIN_TIMEOUT 1
#define MSC313E_WDT_DEFAULT_TIMEOUT 30
static unsigned int timeout;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
struct msc313e_wdt_priv {
void __iomem *base;
struct watchdog_device wdev;
struct clk *clk;
};
static int msc313e_wdt_start(struct watchdog_device *wdev)
{
struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);
u32 timeout;
int err;
err = clk_prepare_enable(priv->clk);
if (err)
return err;
timeout = wdev->timeout * clk_get_rate(priv->clk);
writew(timeout & 0xffff, priv->base + REG_WDT_MAX_PRD_L);
writew((timeout >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H);
writew(1, priv->base + REG_WDT_CLR);
return 0;
}
static int msc313e_wdt_ping(struct watchdog_device *wdev)
{
struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);
writew(1, priv->base + REG_WDT_CLR);
return 0;
}
static int msc313e_wdt_stop(struct watchdog_device *wdev)
{
struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);
writew(0, priv->base + REG_WDT_MAX_PRD_L);
writew(0, priv->base + REG_WDT_MAX_PRD_H);
writew(0, priv->base + REG_WDT_CLR);
clk_disable_unprepare(priv->clk);
return 0;
}
static int msc313e_wdt_settimeout(struct watchdog_device *wdev, unsigned int new_time)
{
wdev->timeout = new_time;
return msc313e_wdt_start(wdev);
}
static const struct watchdog_info msc313e_wdt_ident = {
.identity = "MSC313e watchdog",
.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
};
static const struct watchdog_ops msc313e_wdt_ops = {
.owner = THIS_MODULE,
.start = msc313e_wdt_start,
.stop = msc313e_wdt_stop,
.ping = msc313e_wdt_ping,
.set_timeout = msc313e_wdt_settimeout,
};
static const struct of_device_id msc313e_wdt_of_match[] = {
{ .compatible = "mstar,msc313e-wdt", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, msc313e_wdt_of_match);
static int msc313e_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct msc313e_wdt_priv *priv;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
priv->clk = devm_clk_get(dev, NULL);
if (IS_ERR(priv->clk)) {
dev_err(dev, "No input clock\n");
return PTR_ERR(priv->clk);
}
priv->wdev.info = &msc313e_wdt_ident,
priv->wdev.ops = &msc313e_wdt_ops,
priv->wdev.parent = dev;
priv->wdev.min_timeout = MSC313E_WDT_MIN_TIMEOUT;
priv->wdev.max_timeout = U32_MAX / clk_get_rate(priv->clk);
priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT;
/* If the period is non-zero the WDT is running */
if (readw(priv->base + REG_WDT_MAX_PRD_L) | (readw(priv->base + REG_WDT_MAX_PRD_H) << 16))
set_bit(WDOG_HW_RUNNING, &priv->wdev.status);
watchdog_set_drvdata(&priv->wdev, priv);
watchdog_init_timeout(&priv->wdev, timeout, dev);
watchdog_stop_on_reboot(&priv->wdev);
watchdog_stop_on_unregister(&priv->wdev);
return devm_watchdog_register_device(dev, &priv->wdev);
}
static int __maybe_unused msc313e_wdt_suspend(struct device *dev)
{
struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);
if (watchdog_active(&priv->wdev))
msc313e_wdt_stop(&priv->wdev);
return 0;
}
static int __maybe_unused msc313e_wdt_resume(struct device *dev)
{
struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);
if (watchdog_active(&priv->wdev))
msc313e_wdt_start(&priv->wdev);
return 0;
}
static SIMPLE_DEV_PM_OPS(msc313e_wdt_pm_ops, msc313e_wdt_suspend, msc313e_wdt_resume);
static struct platform_driver msc313e_wdt_driver = {
.driver = {
.name = "msc313e-wdt",
.of_match_table = msc313e_wdt_of_match,
.pm = &msc313e_wdt_pm_ops,
},
.probe = msc313e_wdt_probe,
};
module_platform_driver(msc313e_wdt_driver);
MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>");
MODULE_DESCRIPTION("Watchdog driver for MStar MSC313e");
MODULE_LICENSE("GPL v2");