freebsd-dev/sys/boot/arm/at91/libat91/reset.c

58 lines
2.0 KiB
C

/*-
* Copyright (c) 2006 M. Warner Losh. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#include "at91rm9200.h"
#include "lib.h"
/*
* void reset()
*
* Forces a reset of the system. Uses watchdog timer of '1', which
* corresponds to 128 / SLCK seconds (SLCK is 32,768 Hz, so 128/32768 is
* 1 / 256 ~= 5.4ms
*/
void
reset(void)
{
// The following should effect a reset.
AT91C_BASE_ST->ST_WDMR = 1 | AT91C_ST_RSTEN;
AT91C_BASE_ST->ST_CR = AT91C_ST_WDRST;
}
/*
* void start_wdog()
*
* Starts a watchdog timer. We force the boot process to get to the point
* it can kick the watch dog part of the ST part for the OS's driver.
*/
void
start_wdog(int n)
{
// The following should effect a reset after N seconds.
AT91C_BASE_ST->ST_WDMR = (n * (32768 / 128)) | AT91C_ST_RSTEN;
AT91C_BASE_ST->ST_CR = AT91C_ST_WDRST;
}