133 lines
3.6 KiB
C
133 lines
3.6 KiB
C
/*
|
|
* 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);
|