linux-imx

/*

 * Watchdog driver for CSR Atlas7

 *

 * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.

 *

 * Licensed under GPLv2.

 */

​

#include <linux/clk.h>

#include <linux/io.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/watchdog.h>

​

#define ATLAS7_TIMER_WDT_INDEX      5

#define ATLAS7_WDT_DEFAULT_TIMEOUT  20

​

#define ATLAS7_WDT_CNT_CTRL (0 + 4 * ATLAS7_TIMER_WDT_INDEX)

#define ATLAS7_WDT_CNT_MATCH    (0x18 + 4 * ATLAS7_TIMER_WDT_INDEX)

#define ATLAS7_WDT_CNT      (0x48 +  4 * ATLAS7_TIMER_WDT_INDEX)

#define ATLAS7_WDT_CNT_EN   (BIT(0) | BIT(1))

#define ATLAS7_WDT_EN       0x64

​

static unsigned int timeout = ATLAS7_WDT_DEFAULT_TIMEOUT;

static bool nowayout = WATCHDOG_NOWAYOUT;

​

module_param(timeout, uint, 0);

module_param(nowayout, bool, 0);

​

MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");

MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="

            __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

​

struct atlas7_wdog {

    struct device *dev;

    void __iomem *base;

    unsigned long tick_rate;

    struct clk *clk;

};

​

static unsigned int atlas7_wdt_gettimeleft(struct watchdog_device *wdd)

{

    struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);

    u32 counter, match, delta;

​

    counter = readl(wdt->base + ATLAS7_WDT_CNT);

    match = readl(wdt->base + ATLAS7_WDT_CNT_MATCH);

    delta = match - counter;

​

    return  delta / wdt->tick_rate;

}

​

static int atlas7_wdt_ping(struct watchdog_device *wdd)

{

    struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);

    u32 counter, match, delta;

​

    counter = readl(wdt->base + ATLAS7_WDT_CNT);

    delta = wdd->timeout * wdt->tick_rate;

    match = counter + delta;

​

    writel(match, wdt->base + ATLAS7_WDT_CNT_MATCH);

​

    return 0;

}

​

static int atlas7_wdt_enable(struct watchdog_device *wdd)

{

    struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);

​

    atlas7_wdt_ping(wdd);

​

    writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) | ATLAS7_WDT_CNT_EN,

          wdt->base + ATLAS7_WDT_CNT_CTRL);

    writel(1, wdt->base + ATLAS7_WDT_EN);

​

    return 0;

}

​

static int atlas7_wdt_disable(struct watchdog_device *wdd)

{

    struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);

​

    writel(0, wdt->base + ATLAS7_WDT_EN);

    writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) & ~ATLAS7_WDT_CNT_EN,

          wdt->base + ATLAS7_WDT_CNT_CTRL);

​

    return 0;

}

​