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// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Copyright (c) 2016 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@baylibre.com>
*
*/
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#define DEFAULT_TIMEOUT 30 /* seconds */
#define GXBB_WDT_CTRL_REG 0x0
#define GXBB_WDT_TCNT_REG 0x8
#define GXBB_WDT_RSET_REG 0xc
#define GXBB_WDT_CTRL_CLKDIV_EN BIT(25)
#define GXBB_WDT_CTRL_CLK_EN BIT(24)
#define GXBB_WDT_CTRL_EE_RESET BIT(21)
#define GXBB_WDT_CTRL_EN BIT(18)
#define GXBB_WDT_CTRL_DIV_MASK (BIT(18) - 1)
#define GXBB_WDT_TCNT_SETUP_MASK (BIT(16) - 1)
#define GXBB_WDT_TCNT_CNT_SHIFT 16
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 unsigned int timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds="
__MODULE_STRING(DEFAULT_TIMEOUT) ")");
struct meson_gxbb_wdt {
void __iomem *reg_base;
struct watchdog_device wdt_dev;
struct clk *clk;
};
static int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
data->reg_base + GXBB_WDT_CTRL_REG);
return 0;
}
static int meson_gxbb_wdt_stop(struct watchdog_device *wdt_dev)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,
data->reg_base + GXBB_WDT_CTRL_REG);
return 0;
}
static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
writel(0, data->reg_base + GXBB_WDT_RSET_REG);
return 0;
}
static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
unsigned long tcnt = timeout * 1000;
if (tcnt > GXBB_WDT_TCNT_SETUP_MASK)
tcnt = GXBB_WDT_TCNT_SETUP_MASK;
wdt_dev->timeout = timeout;
meson_gxbb_wdt_ping(wdt_dev);
writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG);
return 0;
}
static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
unsigned long reg;
reg = readl(data->reg_base + GXBB_WDT_TCNT_REG);
return ((reg & GXBB_WDT_TCNT_SETUP_MASK) -
(reg >> GXBB_WDT_TCNT_CNT_SHIFT)) / 1000;
}
static const struct watchdog_ops meson_gxbb_wdt_ops = {
.start = meson_gxbb_wdt_start,
.stop = meson_gxbb_wdt_stop,
.ping = meson_gxbb_wdt_ping,
.set_timeout = meson_gxbb_wdt_set_timeout,
.get_timeleft = meson_gxbb_wdt_get_timeleft,
};
static const struct watchdog_info meson_gxbb_wdt_info = {
.identity = "Meson GXBB Watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};
static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev)
{
struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
if (watchdog_active(&data->wdt_dev))
meson_gxbb_wdt_start(&data->wdt_dev);
return 0;
}
static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev)
{
struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
if (watchdog_active(&data->wdt_dev))
meson_gxbb_wdt_stop(&data->wdt_dev);
return 0;
}
static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume)
};
static const struct of_device_id meson_gxbb_wdt_dt_ids[] = {
{ .compatible = "amlogic,meson-gxbb-wdt", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids);
static int meson_gxbb_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct meson_gxbb_wdt *data;
u32 ctrl_reg;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(data->reg_base))
return PTR_ERR(data->reg_base);
data->clk = devm_clk_get_enabled(dev, NULL);
if (IS_ERR(data->clk))
return PTR_ERR(data->clk);
platform_set_drvdata(pdev, data);
data->wdt_dev.parent = dev;
data->wdt_dev.info = &meson_gxbb_wdt_info;
data->wdt_dev.ops = &meson_gxbb_wdt_ops;
data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK;
data->wdt_dev.min_timeout = 1;
data->wdt_dev.timeout = DEFAULT_TIMEOUT;
watchdog_init_timeout(&data->wdt_dev, timeout, dev);
watchdog_set_nowayout(&data->wdt_dev, nowayout);
watchdog_set_drvdata(&data->wdt_dev, data);
ctrl_reg = readl(data->reg_base + GXBB_WDT_CTRL_REG) &
GXBB_WDT_CTRL_EN;
if (ctrl_reg) {
/* Watchdog is running - keep it running but extend timeout
* to the maximum while setting the timebase
*/
set_bit(WDOG_HW_RUNNING, &data->wdt_dev.status);
meson_gxbb_wdt_set_timeout(&data->wdt_dev,
GXBB_WDT_TCNT_SETUP_MASK / 1000);
}
/* Setup with 1ms timebase */
ctrl_reg |= ((clk_get_rate(data->clk) / 1000) &
GXBB_WDT_CTRL_DIV_MASK) |
GXBB_WDT_CTRL_EE_RESET |
GXBB_WDT_CTRL_CLK_EN |
GXBB_WDT_CTRL_CLKDIV_EN;
writel(ctrl_reg, data->reg_base + GXBB_WDT_CTRL_REG);
meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
return devm_watchdog_register_device(dev, &data->wdt_dev);
}
static struct platform_driver meson_gxbb_wdt_driver = {
.probe = meson_gxbb_wdt_probe,
.driver = {
.name = "meson-gxbb-wdt",
.pm = &meson_gxbb_wdt_pm_ops,
.of_match_table = meson_gxbb_wdt_dt_ids,
},
};
module_platform_driver(meson_gxbb_wdt_driver);
MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");
MODULE_LICENSE("Dual BSD/GPL");
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