linux-imx

// SPDX-License-Identifier: GPL-2.0-only

/*

 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs

 *

 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>

 */

​

#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,