txx9wdt.c
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/*
* txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
*
* Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <asm/txx9tmr.h>
#define WD_TIMER_CCD 7 /* 1/256 */
#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
#define TIMER_MARGIN 60 /* Default is 60 seconds */
static unsigned int timeout = TIMER_MARGIN; /* in seconds */
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. "
"(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
"default=" __MODULE_STRING(TIMER_MARGIN) ")");
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 struct txx9_tmr_reg __iomem *txx9wdt_reg;
static struct clk *txx9_imclk;
static DEFINE_SPINLOCK(txx9_lock);
static int txx9wdt_ping(struct watchdog_device *wdt_dev)
{
spin_lock(&txx9_lock);
__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
spin_unlock(&txx9_lock);
return 0;
}
static int txx9wdt_start(struct watchdog_device *wdt_dev)
{
spin_lock(&txx9_lock);
__raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra);
__raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
__raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
__raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
&txx9wdt_reg->tcr);
__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
spin_unlock(&txx9_lock);
return 0;
}
static int txx9wdt_stop(struct watchdog_device *wdt_dev)
{
spin_lock(&txx9_lock);
__raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
__raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
&txx9wdt_reg->tcr);
spin_unlock(&txx9_lock);
return 0;
}
static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int new_timeout)
{
wdt_dev->timeout = new_timeout;
txx9wdt_stop(wdt_dev);
txx9wdt_start(wdt_dev);
return 0;
}
static const struct watchdog_info txx9wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "Hardware Watchdog for TXx9",
};
static const struct watchdog_ops txx9wdt_ops = {
.owner = THIS_MODULE,
.start = txx9wdt_start,
.stop = txx9wdt_stop,
.ping = txx9wdt_ping,
.set_timeout = txx9wdt_set_timeout,
};
static struct watchdog_device txx9wdt = {
.info = &txx9wdt_info,
.ops = &txx9wdt_ops,
};
static int __init txx9wdt_probe(struct platform_device *dev)
{
struct resource *res;
int ret;
txx9_imclk = clk_get(NULL, "imbus_clk");
if (IS_ERR(txx9_imclk)) {
ret = PTR_ERR(txx9_imclk);
txx9_imclk = NULL;
goto exit;
}
ret = clk_enable(txx9_imclk);
if (ret) {
clk_put(txx9_imclk);
txx9_imclk = NULL;
goto exit;
}
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
txx9wdt_reg = devm_ioremap_resource(&dev->dev, res);
if (IS_ERR(txx9wdt_reg)) {
ret = PTR_ERR(txx9wdt_reg);
goto exit;
}
if (timeout < 1 || timeout > WD_MAX_TIMEOUT)
timeout = TIMER_MARGIN;
txx9wdt.timeout = timeout;
txx9wdt.min_timeout = 1;
txx9wdt.max_timeout = WD_MAX_TIMEOUT;
watchdog_set_nowayout(&txx9wdt, nowayout);
ret = watchdog_register_device(&txx9wdt);
if (ret)
goto exit;
pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n",
timeout, WD_MAX_TIMEOUT, nowayout);
return 0;
exit:
if (txx9_imclk) {
clk_disable(txx9_imclk);
clk_put(txx9_imclk);
}
return ret;
}
static int __exit txx9wdt_remove(struct platform_device *dev)
{
watchdog_unregister_device(&txx9wdt);
clk_disable(txx9_imclk);
clk_put(txx9_imclk);
return 0;
}
static void txx9wdt_shutdown(struct platform_device *dev)
{
txx9wdt_stop(&txx9wdt);
}
static struct platform_driver txx9wdt_driver = {
.remove = __exit_p(txx9wdt_remove),
.shutdown = txx9wdt_shutdown,
.driver = {
.name = "txx9wdt",
.owner = THIS_MODULE,
},
};
module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe);
MODULE_DESCRIPTION("TXx9 Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:txx9wdt");