linux-imx

/*

 * ACPI watchdog table parsing support.

 *

 * Copyright (C) 2016, Intel Corporation

 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>

 *

 * 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) "ACPI: watchdog: " fmt

​

#include <linux/acpi.h>

#include <linux/ioport.h>

#include <linux/platform_device.h>

​

#include "internal.h"

​

#ifdef CONFIG_RTC_MC146818_LIB

#include <linux/mc146818rtc.h>

​

/*

 * There are several systems where the WDAT table is accessing RTC SRAM to

 * store persistent information. This does not work well with the Linux RTC

 * driver so on those systems we skip WDAT driver and prefer iTCO_wdt

 * instead.

 *

 * See also https://bugzilla.kernel.org/show_bug.cgi?id=199033.

 */

static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)

{

    const struct acpi_wdat_entry *entries;

    int i;

​

    entries = (struct acpi_wdat_entry *)(wdat + 1);

    for (i = 0; i < wdat->entries; i++) {

        const struct acpi_generic_address *gas;

​

        gas = &entries[i].register_region;

        if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {

            switch (gas->address) {

            case RTC_PORT(0):

            case RTC_PORT(1):

            case RTC_PORT(2):

            case RTC_PORT(3):

                return true;

            }

        }

    }

​

    return false;

}

#else

static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)

{

    return false;

}

#endif

​

static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void)

{

    const struct acpi_table_wdat *wdat = NULL;