linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Watchdog driver for IMX2 and later processors

 *

 *  Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de>

 *  Copyright (C) 2014 Freescale Semiconductor, Inc.

 *

 * some parts adapted by similar drivers from Darius Augulis and Vladimir

 * Zapolskiy, additional improvements by Wim Van Sebroeck.

 *

 * NOTE: MX1 has a slightly different Watchdog than MX2 and later:

 *

 *          MX1:        MX2+:

 *          ----        -----

 * Registers:       32-bit      16-bit

 * Stopable timer:  Yes     No

 * Need to enable clk:  No      Yes

 * Halt on suspend: Manual      Can be automatic

 */

​

#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/of_address.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/watchdog.h>

​

#define DRIVER_NAME "imx2-wdt"

​

#define IMX2_WDT_WCR        0x00        /* Control Register */

#define IMX2_WDT_WCR_WT     (0xFF << 8) /* -> Watchdog Timeout Field */

#define IMX2_WDT_WCR_WDA    BIT(5)      /* -> External Reset WDOG_B */

#define IMX2_WDT_WCR_SRS    BIT(4)      /* -> Software Reset Signal */

#define IMX2_WDT_WCR_WRE    BIT(3)      /* -> WDOG Reset Enable */

#define IMX2_WDT_WCR_WDE    BIT(2)      /* -> Watchdog Enable */

#define IMX2_WDT_WCR_WDZST  BIT(0)      /* -> Watchdog timer Suspend */

​

#define IMX2_WDT_WSR        0x02        /* Service Register */

#define IMX2_WDT_SEQ1       0x5555      /* -> service sequence 1 */

#define IMX2_WDT_SEQ2       0xAAAA      /* -> service sequence 2 */

​

#define IMX2_WDT_WRSR       0x04        /* Reset Status Register */

#define IMX2_WDT_WRSR_TOUT  BIT(1)      /* -> Reset due to Timeout */

​

#define IMX2_WDT_WICR       0x06        /* Interrupt Control Register */

#define IMX2_WDT_WICR_WIE   BIT(15)     /* -> Interrupt Enable */

#define IMX2_WDT_WICR_WTIS  BIT(14)     /* -> Interrupt Status */

#define IMX2_WDT_WICR_WICT  0xFF        /* -> Interrupt Count Timeout */

​

#define IMX2_WDT_WMCR       0x08        /* Misc Register */

​

#define IMX2_WDT_MAX_TIME   128

#define IMX2_WDT_DEFAULT_TIME   60      /* in seconds */

​

#define WDOG_SEC_TO_COUNT(s)    ((s * 2 - 1) << 8)

​

struct imx2_wdt_device {

    struct clk *clk;

    struct regmap *regmap;

    struct watchdog_device wdog;

    bool ext_reset;

};

​

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 unsigned timeout;

module_param(timeout, uint, 0);

MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="

                __MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")");

​

static const struct watchdog_info imx2_wdt_info = {

    .identity = "imx2+ watchdog",

    .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,

};

​

static const struct watchdog_info imx2_wdt_pretimeout_info = {

    .identity = "imx2+ watchdog",

    .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |

           WDIOF_PRETIMEOUT,

};

​

static int imx2_wdt_restart(struct watchdog_device *wdog, unsigned long action,