/*
* OMAP2+ MPU WD_TIMER-specific code
*
* Copyright (C) 2012 Texas Instruments, Inc.
*
* 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 <linux/platform_data/omap-wd-timer.h>
#include "omap_hwmod.h"
#include "omap_device.h"
#include "wd_timer.h"
#include "common.h"
#include "prm.h"
#include "soc.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;
}
/**
* omap2_wdtimer_reset - reset and disable the WDTIMER IP block
* @oh: struct omap_hwmod *
*
* After the WDTIMER IP blocks are reset on OMAP2/3, we must also take
* care to execute the special watchdog disable sequence. This is
* because the watchdog is re-armed upon OCP softreset. (On OMAP4,
* this behavior was apparently changed and the watchdog is no longer
* re-armed after an OCP soft-reset.) Returns -ETIMEDOUT if the reset
* did not complete, or 0 upon success.
*
* XXX Most of this code should be moved to the omap_hwmod.c layer
* during a normal merge window. omap_hwmod_softreset() should be
* renamed to omap_hwmod_set_ocp_softreset(), and omap_hwmod_softreset()
* should call the hwmod _ocp_softreset() code.
*/
int omap2_wd_timer_reset(struct omap_hwmod *oh)
{
int c = 0;
/* Write to the SOFTRESET bit */
omap_hwmod_softreset(oh);
/* Poll on RESETDONE bit */
omap_test_timeout((omap_hwmod_read(oh,
oh->class->sysc->syss_offs)
& SYSS_RESETDONE_MASK),
MAX_MODULE_SOFTRESET_WAIT, c);
if (oh->class->sysc->srst_udelay)
udelay(oh->class->sysc->srst_udelay);
if (c == MAX_MODULE_SOFTRESET_WAIT)
pr_warning("%s: %s: softreset failed (waited %d usec)\n",
__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
else
pr_debug("%s: %s: softreset in %d usec\n", __func__,
oh->name, c);
return (c == MAX_MODULE_SOFTRESET_WAIT) ? -ETIMEDOUT :
omap2_wd_timer_disable(oh);
}
static int __init omap_init_wdt(void)
{
int id = -1;
struct platform_device *pdev;
struct omap_hwmod *oh;
char *oh_name = "wd_timer2";
char *dev_name = "omap_wdt";
struct omap_wd_timer_platform_data pdata;
if (!cpu_class_is_omap2() || of_have_populated_dt())
return 0;
oh = omap_hwmod_lookup(oh_name);
if (!oh) {
pr_err("Could not look up wd_timer%d hwmod\n", id);
return -EINVAL;
}
pdata.read_reset_sources = prm_read_reset_sources;
pdev = omap_device_build(dev_name, id, oh, &pdata,
sizeof(struct omap_wd_timer_platform_data));
WARN(IS_ERR(pdev), "Can't build omap_device for %s:%s.\n",
dev_name, oh->name);
return 0;
}
omap_subsys_initcall(omap_init_wdt);
