wd_timer.c
/*
* OMAP2+ MPU WD_TIMER-specific code
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/err.h>
#include <plat/omap_hwmod.h>
#include "wd_timer.h"
/*
* In order to avoid any assumptions from bootloader regarding WDT
* settings, WDT module is reset during init. This enables the watchdog
* timer. Hence it is required to disable the watchdog after the WDT reset
* during init. Otherwise the system would reboot as per the default
* watchdog timer registers settings.
*/
#define OMAP_WDT_WPS 0x34
#define OMAP_WDT_SPR 0x48
int omap2_wd_timer_disable(struct omap_hwmod *oh)
{
void __iomem *base;
if (!oh) {
pr_err("%s: Could not look up wdtimer_hwmod\n", __func__);
return -EINVAL;
}
base = omap_hwmod_get_mpu_rt_va(oh);
if (!base) {
pr_err("%s: Could not get the base address for %s\n",
oh->name, __func__);
return -EINVAL;
}
/* sequence required to disable watchdog */
__raw_writel(0xAAAA, base + OMAP_WDT_SPR);
while (__raw_readl(base + OMAP_WDT_WPS) & 0x10)
cpu_relax();
__raw_writel(0x5555, base + OMAP_WDT_SPR);
while (__raw_readl(base + OMAP_WDT_WPS) & 0x10)
cpu_relax();
return 0;
}