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Commit a4658e57 authored by Tomasz Figa's avatar Tomasz Figa Committed by Kukjin Kim
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ARM: SAMSUNG: Add watchdog reset driver 



This patch adds a watchdog reset driver that can be used on Samsung SoCs
that do not provide dedicated reset method. It replaces the legacy
helper function that relies on static IO mapping.

Signed-off-by: default avatarTomasz Figa <tomasz.figa@gmail.com>
Tested-by: default avatarSylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: default avatarKukjin Kim <kgene.kim@samsung.com>
parent fa26c71a

arch/arm/plat-samsung/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -475,6 +475,12 @@ config SAMSUNG_WAKEMASK 
	  and above. This code allows a set of interrupt to wakeup-mask

	  mappings. See <plat/wakeup-mask.h>



config SAMSUNG_WDT_RESET

	bool

	help

	  Compile support for system restart by triggering watchdog reset.

	  Used on SoCs that do not provide dedicated reset control.



config S5P_PM

	bool

	help

arch/arm/plat-samsung/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ obj-$(CONFIG_PM) += pm-gpio.o 
obj-$(CONFIG_SAMSUNG_PM_CHECK)	+= pm-check.o



obj-$(CONFIG_SAMSUNG_WAKEMASK)	+= wakeup-mask.o

obj-$(CONFIG_SAMSUNG_WDT_RESET)	+= watchdog-reset.o



obj-$(CONFIG_S5P_PM)		+= s5p-pm.o s5p-irq-pm.o

obj-$(CONFIG_S5P_SLEEP)		+= s5p-sleep.o

arch/arm/plat-samsung/include/plat/watchdog-reset.h

+9 −0
Original line number Diff line number Diff line
@@ -10,6 +10,9 @@ 
 * published by the Free Software Foundation.

*/



#ifndef __PLAT_SAMSUNG_WATCHDOG_RESET_H

#define __PLAT_SAMSUNG_WATCHDOG_RESET_H



#include <plat/clock.h>

#include <plat/regs-watchdog.h>

#include <mach/map.h>
@@ -44,3 +47,9 @@ static inline void arch_wdt_reset(void) 
	/* delay to allow the serial port to show the message */

	mdelay(50);

}



extern void samsung_wdt_reset(void);

extern void samsung_wdt_reset_of_init(void);

extern void samsung_wdt_reset_init(void __iomem *base);



#endif /* __PLAT_SAMSUNG_WATCHDOG_RESET_H */

arch/arm/plat-samsung/watchdog-reset.c

0 → 100644
+97 −0
Original line number Diff line number Diff line 
/* arch/arm/plat-samsung/watchdog-reset.c

 *

 * Copyright (c) 2008 Simtec Electronics

 *	Ben Dooks <ben@simtec.co.uk>

 *

 * Coyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>

 *

 * Watchdog reset support for Samsung SoCs.

 *

 * 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/clk.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/delay.h>

#include <linux/of.h>

#include <linux/of_address.h>



#define S3C2410_WTCON			0x00

#define S3C2410_WTDAT			0x04

#define S3C2410_WTCNT			0x08



#define S3C2410_WTCON_ENABLE		(1 << 5)

#define S3C2410_WTCON_DIV16		(0 << 3)

#define S3C2410_WTCON_RSTEN		(1 << 0)

#define S3C2410_WTCON_PRESCALE(x)	((x) << 8)



static void __iomem *wdt_base;

static struct clk *wdt_clock;



void samsung_wdt_reset(void)

{

	if (!wdt_base) {

		pr_err("%s: wdt reset not initialized\n", __func__);

		/* delay to allow the serial port to show the message */

		mdelay(50);

		return;

	}



	if (!IS_ERR(wdt_clock))

		clk_prepare_enable(wdt_clock);



	/* disable watchdog, to be safe  */

	__raw_writel(0, wdt_base + S3C2410_WTCON);



	/* put initial values into count and data */

	__raw_writel(0x80, wdt_base + S3C2410_WTCNT);

	__raw_writel(0x80, wdt_base + S3C2410_WTDAT);



	/* set the watchdog to go and reset... */

	__raw_writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 |

			S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20),

			wdt_base + S3C2410_WTCON);



	/* wait for reset to assert... */

	mdelay(500);



	pr_err("Watchdog reset failed to assert reset\n");



	/* delay to allow the serial port to show the message */

	mdelay(50);

}



#ifdef CONFIG_OF

static const struct of_device_id s3c2410_wdt_match[] = {

	{ .compatible = "samsung,s3c2410-wdt" },

	{},

};



void __init samsung_wdt_reset_of_init(void)

{

	struct device_node *np;



	np = of_find_matching_node(NULL, s3c2410_wdt_match);

	if (!np) {

		pr_err("%s: failed to find watchdog node\n", __func__);

		return;

	}



	wdt_base = of_iomap(np, 0);

	if (!wdt_base) {

		pr_err("%s: failed to map watchdog registers\n", __func__);

		return;

	}



	wdt_clock = of_clk_get(np, 0);

}

#endif



void __init samsung_wdt_reset_init(void __iomem *base)

{

	wdt_base = base;

	wdt_clock = clk_get(NULL, "watchdog");

}