watchdog-reset.c
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/* 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");
}