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ARM: SAMSUNG: Add watchdog reset driver

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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: Tomasz Figa <tomasz.figa@gmail.com>
Tested-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
This commit is contained in:
Tomasz Figa 2013-06-17 23:45:33 +09:00 committed by Kukjin Kim
parent fa26c71aaf
commit a4658e57a7
4 changed files with 113 additions and 0 deletions
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6
arch/arm/plat-samsung/Kconfig
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@ -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

1
arch/arm/plat-samsung/Makefile
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@ -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

9
arch/arm/plat-samsung/include/plat/watchdog-reset.h
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@ -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 */

97
arch/arm/plat-samsung/watchdog-reset.c Normal file
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@ -0,0 +1,97 @@
/* 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");
}