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/*
* Copyright (C) 2015 Mans Rullgard <mans@mansr.com>
* SMP86xx/SMP87xx Watchdog driver
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define DEFAULT_TIMEOUT 30
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, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout");
/*
* Counter counts down from programmed value. Reset asserts when
* the counter reaches 1.
*/
#define WD_COUNTER 0
#define WD_CONFIG 4
#define WD_CONFIG_XTAL_IN BIT(0)
#define WD_CONFIG_DISABLE BIT(31)
struct tangox_wdt_device {
struct watchdog_device wdt;
void __iomem *base;
unsigned long clk_rate;
struct clk *clk;
};
static int tangox_wdt_set_timeout(struct watchdog_device *wdt,
unsigned int new_timeout)
{
wdt->timeout = new_timeout;
return 0;
}
static int tangox_wdt_start(struct watchdog_device *wdt)
{
struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
u32 ticks;
ticks = 1 + wdt->timeout * dev->clk_rate;
writel(ticks, dev->base + WD_COUNTER);
return 0;
}
static int tangox_wdt_stop(struct watchdog_device *wdt)
{
struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
writel(0, dev->base + WD_COUNTER);
return 0;
}
static unsigned int tangox_wdt_get_timeleft(struct watchdog_device *wdt)
{
struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
u32 count;
count = readl(dev->base + WD_COUNTER);
if (!count)
return 0;
return (count - 1) / dev->clk_rate;
}
static const struct watchdog_info tangox_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "tangox watchdog",
};
static int tangox_wdt_restart(struct watchdog_device *wdt,
unsigned long action, void *data)
{
struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
writel(1, dev->base + WD_COUNTER);
return 0;
}
static const struct watchdog_ops tangox_wdt_ops = {
.start = tangox_wdt_start,
.stop = tangox_wdt_stop,
.set_timeout = tangox_wdt_set_timeout,
.get_timeleft = tangox_wdt_get_timeleft,
.restart = tangox_wdt_restart,
};
static int tangox_wdt_probe(struct platform_device *pdev)
{
struct tangox_wdt_device *dev;
struct resource *res;
u32 config;
int err;
dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dev->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(dev->base))
return PTR_ERR(dev->base);
dev->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(dev->clk))
return PTR_ERR(dev->clk);
err = clk_prepare_enable(dev->clk);
if (err)
return err;
dev->clk_rate = clk_get_rate(dev->clk);
if (!dev->clk_rate) {
err = -EINVAL;
goto err;
}
dev->wdt.parent = &pdev->dev;
dev->wdt.info = &tangox_wdt_info;
dev->wdt.ops = &tangox_wdt_ops;
dev->wdt.timeout = DEFAULT_TIMEOUT;
dev->wdt.min_timeout = 1;
dev->wdt.max_hw_heartbeat_ms = (U32_MAX - 1) / dev->clk_rate;
watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev);
watchdog_set_nowayout(&dev->wdt, nowayout);
watchdog_set_drvdata(&dev->wdt, dev);
/*
* Deactivate counter if disable bit is set to avoid
* accidental reset.
*/
config = readl(dev->base + WD_CONFIG);
if (config & WD_CONFIG_DISABLE)
writel(0, dev->base + WD_COUNTER);
writel(WD_CONFIG_XTAL_IN, dev->base + WD_CONFIG);
/*
* Mark as active and restart with configured timeout if
* already running.
*/
if (readl(dev->base + WD_COUNTER)) {
set_bit(WDOG_HW_RUNNING, &dev->wdt.status);
tangox_wdt_start(&dev->wdt);
}
watchdog_set_restart_priority(&dev->wdt, 128);
err = watchdog_register_device(&dev->wdt);
if (err)
goto err;
platform_set_drvdata(pdev, dev);
dev_info(&pdev->dev, "SMP86xx/SMP87xx watchdog registered\n");
return 0;
err:
clk_disable_unprepare(dev->clk);
return err;
}
static int tangox_wdt_remove(struct platform_device *pdev)
{
struct tangox_wdt_device *dev = platform_get_drvdata(pdev);
tangox_wdt_stop(&dev->wdt);
clk_disable_unprepare(dev->clk);
watchdog_unregister_device(&dev->wdt);
return 0;
}
static const struct of_device_id tangox_wdt_dt_ids[] = {
{ .compatible = "sigma,smp8642-wdt" },
{ .compatible = "sigma,smp8759-wdt" },
{ }
};
MODULE_DEVICE_TABLE(of, tangox_wdt_dt_ids);
static struct platform_driver tangox_wdt_driver = {
.probe = tangox_wdt_probe,
.remove = tangox_wdt_remove,
.driver = {
.name = "tangox-wdt",
.of_match_table = tangox_wdt_dt_ids,
},
};
module_platform_driver(tangox_wdt_driver);
MODULE_AUTHOR("Mans Rullgard <mans@mansr.com>");
MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver");
MODULE_LICENSE("GPL");
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