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Commit 05e487d9 authored by Josh Cartwright's avatar Josh Cartwright Committed by Wim Van Sebroeck
Browse files

watchdog: qcom: register a restart notifier 



The WDT's BITE_TIME warm-reset behavior can be leveraged as a last
resort mechanism for triggering chip reset.  Usually, other restart
methods (such as PS_HOLD) are preferrable for issuing a more complete
reset of the chip.  As such, keep the priority of the watchdog notifier
low.

Signed-off-by: default avatarJosh Cartwright <joshc@codeaurora.org>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent f286e133

drivers/watchdog/qcom-wdt.c

+38 −0
Original line number Diff line number Diff line
@@ -11,11 +11,13 @@ 
 *

 */

#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/reboot.h>

#include <linux/watchdog.h>



#define WDT_RST		0x0
@@ -26,6 +28,7 @@ struct qcom_wdt { 
	struct watchdog_device	wdd;

	struct clk		*clk;

	unsigned long		rate;

	struct notifier_block	restart_nb;

	void __iomem		*base;

};
@@ -84,6 +87,32 @@ static const struct watchdog_info qcom_wdt_info = { 
	.identity	= KBUILD_MODNAME,

};



static int qcom_wdt_restart(struct notifier_block *nb, unsigned long action,

			    void *data)

{

	struct qcom_wdt *wdt = container_of(nb, struct qcom_wdt, restart_nb);

	u32 timeout;



	/*

	 * Trigger watchdog bite:

	 *    Setup BITE_TIME to be 128ms, and enable WDT.

	 */

	timeout = 128 * wdt->rate / 1000;



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

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

	writel(timeout, wdt->base + WDT_BITE_TIME);

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



	/*

	 * Actually make sure the above sequence hits hardware before sleeping.

	 */

	wmb();



	msleep(150);

	return NOTIFY_DONE;

}



static int qcom_wdt_probe(struct platform_device *pdev)

{

	struct qcom_wdt *wdt;
@@ -147,6 +176,14 @@ static int qcom_wdt_probe(struct platform_device *pdev) 
		goto err_clk_unprepare;

	}



	/*

	 * WDT restart notifier has priority 0 (use as a last resort)

	 */

	wdt->restart_nb.notifier_call = qcom_wdt_restart;

	ret = register_restart_handler(&wdt->restart_nb);

	if (ret)

		dev_err(&pdev->dev, "failed to setup restart handler\n");



	platform_set_drvdata(pdev, wdt);

	return 0;
@@ -159,6 +196,7 @@ static int qcom_wdt_remove(struct platform_device *pdev) 
{

	struct qcom_wdt *wdt = platform_get_drvdata(pdev);



	unregister_restart_handler(&wdt->restart_nb);

	watchdog_unregister_device(&wdt->wdd);

	clk_disable_unprepare(wdt->clk);

	return 0;