forked from Imagelibrary/rtems
d735d4459c
This BSP supports a custom STM32U5 based board. It uses a similar structure like the existing STM32H7 BSP and therefore should be well adaptable to other boards. Co-authored-by: Christian Mauderer <christian.mauderer@embedded-brains.de>
89 lines
2.5 KiB
C
89 lines
2.5 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/**
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* @file
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*
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* @ingroup RTEMSBSPsARMSTM32U5
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*
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* @brief Implementation of an entropy source for STM32U5.
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*/
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/*
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* Copyright (C) 2024 embedded brains GmbH & Co. KG
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stm32u5/hal.h>
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#include <rtems.h>
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#include <rtems/sysinit.h>
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#include <string.h>
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#include <sys/param.h>
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#include <unistd.h>
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static RNG_HandleTypeDef stm32u5_rng_instance = {
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.Instance = RNG,
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.Init.ClockErrorDetection = RNG_CED_DISABLE
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};
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static void stm32u5_rng_enable( void )
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{
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stm32u5_clk_enable( STM32U5_MODULE_RNG );
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HAL_RNG_Init( &stm32u5_rng_instance );
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}
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int getentropy( void *ptr, size_t n )
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{
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while ( n > 0 ) {
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rtems_interrupt_level level;
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uint32_t random;
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bool ok;
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size_t copy;
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do {
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rtems_interrupt_disable( level );
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ok = ( RNG->SR & RNG_FLAG_DRDY ) != 0;
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if ( ok ) {
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random = RNG->DR;
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}
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rtems_interrupt_enable( level );
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} while ( !ok );
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copy = MIN( sizeof( random ), n );
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ptr = memcpy( ptr, &random, copy );
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n -= copy;
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ptr += copy;
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}
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return 0;
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}
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RTEMS_SYSINIT_ITEM(
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stm32u5_rng_enable,
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RTEMS_SYSINIT_DEVICE_DRIVERS,
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RTEMS_SYSINIT_ORDER_LAST_BUT_5
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);
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