linux/drivers/watchdog/mtk_wdt.c
Guenter Roeck a15f6e646b watchdog: mtk_wdt: Convert to use device managed functions and other improvements
Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.
Other improvements as listed below.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

- Drop assignments to otherwise unused variables
- Drop empty remove function
- Introduce local variable 'struct device *dev' and use it instead of
  dereferencing it repeatedly
- Use devm_watchdog_register_driver() to register watchdog device
- Replace shutdown function with call to watchdog_stop_on_reboot()

Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-05-05 21:02:25 +02:00

253 lines
5.8 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Mediatek Watchdog Driver
*
* Copyright (C) 2014 Matthias Brugger
*
* Matthias Brugger <matthias.bgg@gmail.com>
*
* 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/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;
struct mtk_wdt_dev {
struct watchdog_device wdt_dev;
void __iomem *wdt_base;
};
static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
unsigned long action, void *data)
{
struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base;
wdt_base = mtk_wdt->wdt_base;
while (1) {
writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
mdelay(5);
}
return 0;
}
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;
reg |= WDT_MODE_KEY;
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;
int 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,
.restart = mtk_wdt_restart,
};
static int mtk_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct mtk_wdt_dev *mtk_wdt;
int err;
mtk_wdt = devm_kzalloc(dev, sizeof(*mtk_wdt), GFP_KERNEL);
if (!mtk_wdt)
return -ENOMEM;
platform_set_drvdata(pdev, mtk_wdt);
mtk_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
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 = dev;
watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, dev);
watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128);
watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
mtk_wdt_stop(&mtk_wdt->wdt_dev);
watchdog_stop_on_reboot(&mtk_wdt->wdt_dev);
err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
if (unlikely(err))
return err;
dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
mtk_wdt->wdt_dev.timeout, nowayout);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int mtk_wdt_suspend(struct device *dev)
{
struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);
if (watchdog_active(&mtk_wdt->wdt_dev))
mtk_wdt_stop(&mtk_wdt->wdt_dev);
return 0;
}
static int mtk_wdt_resume(struct device *dev)
{
struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);
if (watchdog_active(&mtk_wdt->wdt_dev)) {
mtk_wdt_start(&mtk_wdt->wdt_dev);
mtk_wdt_ping(&mtk_wdt->wdt_dev);
}
return 0;
}
#endif
static const struct of_device_id mtk_wdt_dt_ids[] = {
{ .compatible = "mediatek,mt6589-wdt" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);
static const struct dev_pm_ops mtk_wdt_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(mtk_wdt_suspend,
mtk_wdt_resume)
};
static struct platform_driver mtk_wdt_driver = {
.probe = mtk_wdt_probe,
.driver = {
.name = DRV_NAME,
.pm = &mtk_wdt_pm_ops,
.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);