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/*
* Mediatek Watchdog Driver
*
* Copyright (C) 2014 Matthias Brugger
*
* Matthias Brugger <matthias.bgg@gmail.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Based on sunxi_wdt.c
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/delay.h>
#define WDT_MAX_TIMEOUT 31
#define WDT_MIN_TIMEOUT 1
#define WDT_LENGTH_TIMEOUT(n) ((n) << 5)
#define WDT_LENGTH 0x04
#define WDT_LENGTH_KEY 0x8
#define WDT_RST 0x08
#define WDT_RST_RELOAD 0x1971
#define WDT_MODE 0x00
#define WDT_MODE_EN (1 << 0)
#define WDT_MODE_EXT_POL_LOW (0 << 1)
#define WDT_MODE_EXT_POL_HIGH (1 << 1)
#define WDT_MODE_EXRST_EN (1 << 2)
#define WDT_MODE_IRQ_EN (1 << 3)
#define WDT_MODE_AUTO_START (1 << 4)
#define WDT_MODE_DUAL_EN (1 << 6)
#define WDT_MODE_KEY 0x22000000
#define WDT_SWRST 0x14
#define WDT_SWRST_KEY 0x1209
#define DRV_NAME "mtk-wdt"
#define DRV_VERSION "1.0"
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int timeout = WDT_MAX_TIMEOUT;
struct mtk_wdt_dev {
struct watchdog_device wdt_dev;
void __iomem *wdt_base;
struct notifier_block restart_handler;
};
static int mtk_reset_handler(struct notifier_block *this, unsigned long mode,
void *cmd)
{
struct mtk_wdt_dev *mtk_wdt;
void __iomem *wdt_base;
mtk_wdt = container_of(this, struct mtk_wdt_dev, restart_handler);
wdt_base = mtk_wdt->wdt_base;
while (1) {
writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
mdelay(5);
}
return NOTIFY_DONE;
}
static int mtk_wdt_ping(struct watchdog_device *wdt_dev)
{
struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = mtk_wdt->wdt_base;
iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST);
return 0;
}
static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = mtk_wdt->wdt_base;
u32 reg;
wdt_dev->timeout = timeout;
/*
* One bit is the value of 512 ticks
* The clock has 32 KHz
*/
reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
iowrite32(reg, wdt_base + WDT_LENGTH);
mtk_wdt_ping(wdt_dev);
return 0;
}
static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
{
struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = mtk_wdt->wdt_base;
u32 reg;
reg = readl(wdt_base + WDT_MODE);
reg &= ~WDT_MODE_EN;
iowrite32(reg, wdt_base + WDT_MODE);
return 0;
}
static int mtk_wdt_start(struct watchdog_device *wdt_dev)
{
u32 reg;
struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = mtk_wdt->wdt_base;
u32 ret;
ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
if (ret < 0)
return ret;
reg = ioread32(wdt_base + WDT_MODE);
reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
reg |= (WDT_MODE_EN | WDT_MODE_KEY);
iowrite32(reg, wdt_base + WDT_MODE);
return 0;
}
static const struct watchdog_info mtk_wdt_info = {
.identity = DRV_NAME,
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops mtk_wdt_ops = {
.owner = THIS_MODULE,
.start = mtk_wdt_start,
.stop = mtk_wdt_stop,
.ping = mtk_wdt_ping,
.set_timeout = mtk_wdt_set_timeout,
};
static int mtk_wdt_probe(struct platform_device *pdev)
{
struct mtk_wdt_dev *mtk_wdt;
struct resource *res;
int err;
mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL);
if (!mtk_wdt)
return -ENOMEM;
platform_set_drvdata(pdev, mtk_wdt);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(mtk_wdt->wdt_base))
return PTR_ERR(mtk_wdt->wdt_base);
mtk_wdt->wdt_dev.info = &mtk_wdt_info;
mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
mtk_wdt->wdt_dev.parent = &pdev->dev;
watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev);
watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
mtk_wdt_stop(&mtk_wdt->wdt_dev);
err = watchdog_register_device(&mtk_wdt->wdt_dev);
if (unlikely(err))
return err;
mtk_wdt->restart_handler.notifier_call = mtk_reset_handler;
mtk_wdt->restart_handler.priority = 128;
err = register_restart_handler(&mtk_wdt->restart_handler);
if (err)
dev_warn(&pdev->dev,
"cannot register restart handler (err=%d)\n", err);
dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
mtk_wdt->wdt_dev.timeout, nowayout);
return 0;
}
static int mtk_wdt_remove(struct platform_device *pdev)
{
struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);
unregister_restart_handler(&mtk_wdt->restart_handler);
watchdog_unregister_device(&mtk_wdt->wdt_dev);
return 0;
}
static const struct of_device_id mtk_wdt_dt_ids[] = {
{ .compatible = "mediatek,mt6589-wdt" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);
static struct platform_driver mtk_wdt_driver = {
.probe = mtk_wdt_probe,
.remove = mtk_wdt_remove,
.driver = {
.name = DRV_NAME,
.of_match_table = mtk_wdt_dt_ids,
},
};
module_platform_driver(mtk_wdt_driver);
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>");
MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
MODULE_VERSION(DRV_VERSION);
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