linux-imx

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

/*

 * Cadence WDT driver - Used by Xilinx Zynq

 *

 * Copyright (C) 2010 - 2014 Xilinx, Inc.

 *

 */

​

#include <linux/clk.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/irq.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/watchdog.h>

​

#define CDNS_WDT_DEFAULT_TIMEOUT    10

/* Supports 1 - 516 sec */

#define CDNS_WDT_MIN_TIMEOUT    1

#define CDNS_WDT_MAX_TIMEOUT    516

​

/* Restart key */

#define CDNS_WDT_RESTART_KEY 0x00001999

​

/* Counter register access key */

#define CDNS_WDT_REGISTER_ACCESS_KEY 0x00920000

​

/* Counter value divisor */

#define CDNS_WDT_COUNTER_VALUE_DIVISOR 0x1000

​

/* Clock prescaler value and selection */

#define CDNS_WDT_PRESCALE_64    64

#define CDNS_WDT_PRESCALE_512   512

#define CDNS_WDT_PRESCALE_4096  4096

#define CDNS_WDT_PRESCALE_SELECT_64 1

#define CDNS_WDT_PRESCALE_SELECT_512    2

#define CDNS_WDT_PRESCALE_SELECT_4096   3

​

/* Input clock frequency */

#define CDNS_WDT_CLK_10MHZ  10000000

#define CDNS_WDT_CLK_75MHZ  75000000

​

/* Counter maximum value */

#define CDNS_WDT_COUNTER_MAX 0xFFF

​

static int wdt_timeout;

static int nowayout = WATCHDOG_NOWAYOUT;

​

module_param(wdt_timeout, int, 0644);

MODULE_PARM_DESC(wdt_timeout,

         "Watchdog time in seconds. (default="

         __MODULE_STRING(CDNS_WDT_DEFAULT_TIMEOUT) ")");

​

module_param(nowayout, int, 0644);

MODULE_PARM_DESC(nowayout,

         "Watchdog cannot be stopped once started (default="

         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

​

/**

 * struct cdns_wdt - Watchdog device structure

 * @regs: baseaddress of device

 * @rst: reset flag

 * @clk: struct clk * of a clock source

 * @prescaler: for saving prescaler value

 * @ctrl_clksel: counter clock prescaler selection

 * @io_lock: spinlock for IO register access

 * @cdns_wdt_device: watchdog device structure

 *

 * Structure containing parameters specific to cadence watchdog.

 */

struct cdns_wdt {

    void __iomem        *regs;

    bool            rst;

    struct clk      *clk;

    u32         prescaler;

    u32         ctrl_clksel;

    spinlock_t      io_lock;

    struct watchdog_device  cdns_wdt_device;

};

​

/* Write access to Registers */

static inline void cdns_wdt_writereg(struct cdns_wdt *wdt, u32 offset, u32 val)

{

    writel_relaxed(val, wdt->regs + offset);

}

​

/*************************Register Map**************************************/

​

/* Register Offsets for the WDT */