linux-imx

/*

 * ACPI Hardware Watchdog (WDAT) driver.

 *

 * 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.

 */

​

#include <linux/acpi.h>

#include <linux/ioport.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/pm.h>

#include <linux/watchdog.h>

​

#define MAX_WDAT_ACTIONS ACPI_WDAT_ACTION_RESERVED

​

/**

 * struct wdat_instruction - Single ACPI WDAT instruction

 * @entry: Copy of the ACPI table instruction

 * @reg: Register the instruction is accessing

 * @node: Next instruction in action sequence

 */

struct wdat_instruction {

    struct acpi_wdat_entry entry;

    void __iomem *reg;

    struct list_head node;

};

​

/**

 * struct wdat_wdt - ACPI WDAT watchdog device

 * @pdev: Parent platform device

 * @wdd: Watchdog core device

 * @period: How long is one watchdog period in ms

 * @stopped_in_sleep: Is this watchdog stopped by the firmware in S1-S5

 * @stopped: Was the watchdog stopped by the driver in suspend

 * @actions: An array of instruction lists indexed by an action number from

 *           the WDAT table. There can be %NULL entries for not implemented

 *           actions.

 */

struct wdat_wdt {

    struct platform_device *pdev;

    struct watchdog_device wdd;

    unsigned int period;

    bool stopped_in_sleep;

    bool stopped;

    struct list_head *instructions[MAX_WDAT_ACTIONS];

};

​

#define to_wdat_wdt(wdd) container_of(wdd, struct wdat_wdt, wdd)

​

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 int wdat_wdt_read(struct wdat_wdt *wdat,

     const struct wdat_instruction *instr, u32 *value)

{

    const struct acpi_generic_address *gas = &instr->entry.register_region;