linux-imx

/*

 * Watchdog timer for PowerPC Book-E systems

 *

 * Author: Matthew McClintock

 * Maintainer: Kumar Gala <galak@kernel.crashing.org>

 *

 * Copyright 2005, 2008, 2010-2011 Freescale Semiconductor Inc.

 *

 * 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.

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/module.h>

#include <linux/smp.h>

#include <linux/watchdog.h>

​

#include <asm/reg_booke.h>

#include <asm/time.h>

#include <asm/div64.h>

​

/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.

 * Also, the wdt_period sets the watchdog timer period timeout.

 * For E500 cpus the wdt_period sets which bit changing from 0->1 will

 * trigger a watchdog timeout. This watchdog timeout will occur 3 times, the

 * first time nothing will happen, the second time a watchdog exception will

 * occur, and the final time the board will reset.

 */

​

​

#ifdef  CONFIG_PPC_FSL_BOOK3E

#define WDTP(x)     ((((x)&0x3)<<30)|(((x)&0x3c)<<15))

#define WDTP_MASK   (WDTP(0x3f))

#else

#define WDTP(x)     (TCR_WP(x))

#define WDTP_MASK   (TCR_WP_MASK)

#endif

​

static bool booke_wdt_enabled;

module_param(booke_wdt_enabled, bool, 0);

static int  booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT;

module_param(booke_wdt_period, int, 0);

​

#ifdef CONFIG_PPC_FSL_BOOK3E

​

/* For the specified period, determine the number of seconds

 * corresponding to the reset time.  There will be a watchdog

 * exception at approximately 3/5 of this time.

 *

 * The formula to calculate this is given by:

 * 2.5 * (2^(63-period+1)) / timebase_freq

 *

 * In order to simplify things, we assume that period is

 * at least 1.  This will still result in a very long timeout.

 */

static unsigned long long period_to_sec(unsigned int period)

{

    unsigned long long tmp = 1ULL << (64 - period);

    unsigned long tmp2 = ppc_tb_freq;

​