zephyr/arch/arm/bsp/rand32.c

79 lines
2.7 KiB
C

/* rand32.c - random number generator */
/*
* Copyright (c) 2013-2015 Wind River Systems, Inc.
*
* 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.
*
* 3) Neither the name of Wind River Systems nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
*/
/*
DESCRIPTION
This module provides a non-random implementation of _Rand32Get(), which is not
meant to be used in a final product as a truly random number generator. It
was provided to allow testing of kernel stack canaries on a BSP that does not
(yet) provide a random number generator.
*/
#include <drivers/rand32.h>
#include <drivers/system_timer.h>
#if defined(CONFIG_TEST_RANDOM_GENERATOR)
#if defined(__GNUC__)
/*******************************************************************************
*
* _Rand32Init - initialize the random number generator
*
* The non-random number generator does not require any initialization.
*
* RETURNS: N/A
*/
void _Rand32Init(void)
{
}
/*******************************************************************************
*
* _Rand32Get - get a 32 bit random number
*
* The non-random number generator returns values that are based off the
* target's clock counter, which means that successive calls will normally
* display ever-increasing values.
*
* RETURNS: a 32-bit number
*/
uint32_t _Rand32Get(void)
{
return timer_read();
}
#endif /* __GNUC__ */
#endif /* CONFIG_TEST_RANDOM_GENERATOR */