122 lines
4.1 KiB
C++
122 lines
4.1 KiB
C++
/***************************************************************************
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* Copyright (C) 2013 by Terraneo Federico *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* As a special exception, if other files instantiate templates or use *
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* macros or inline functions from this file, or you compile this file *
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* and link it with other works to produce a work based on this file, *
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* this file does not by itself cause the resulting work to be covered *
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* by the GNU General Public License. However the source code for this *
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* file must still be made available in accordance with the GNU General *
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* Public License. This exception does not invalidate any other reasons *
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* why a work based on this file might be covered by the GNU General *
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* Public License. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, see <http://www.gnu.org/licenses/> *
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***************************************************************************/
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#include <stdexcept>
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#include "interfaces/delays.h"
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#include "stm32_hardware_rng.h"
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using namespace std;
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namespace miosix {
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//
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// class HardwareRng
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//
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HardwareRng& HardwareRng::instance()
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{
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static HardwareRng singleton;
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return singleton;
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}
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unsigned int HardwareRng::get()
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{
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miosix::Lock<miosix::FastMutex> l(mutex);
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PeripheralEnable pe;
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return getImpl();
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}
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void HardwareRng::get(void* buf, unsigned int size)
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{
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unsigned char *buffer=reinterpret_cast<unsigned char*>(buf);
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Lock<FastMutex> l(mutex);
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PeripheralEnable pe;
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union Cast
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{
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unsigned int theInt;
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unsigned char theChar[4];
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};
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if(reinterpret_cast<unsigned int>(buffer) & 0x3)
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{
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Cast cast;
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cast.theInt=getImpl();
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int i=0;
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while(reinterpret_cast<unsigned int>(buffer) & 0x3)
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{
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if(size--==0) return; //May happen if buffer is small and unaligned
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*buffer++=cast.theChar[i++];
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}
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}
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unsigned int *aligned=reinterpret_cast<unsigned int*>(buffer);
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for(unsigned int i=0;i<size/4;i++) aligned[i]=getImpl();
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if(size & 0x3)
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{
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buffer+=(size/4)*4;
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Cast cast;
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cast.theInt=getImpl();
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int i=0;
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while(size & 0x3)
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{
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size--;
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*buffer++=cast.theChar[i++];
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}
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}
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}
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unsigned int HardwareRng::getImpl()
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{
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#ifndef __NO_EXCEPTIONS
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for(int i=0;i<16;i++) //Try up to a reasonable # of times, then throw
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#else
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for(;;) //Can't return an error, keep retrying
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#endif
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{
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int timeout=1000000;
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unsigned int sr;
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while(--timeout>0) { sr=RNG->SR; if(sr & RNG_SR_DRDY) break; }
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if((sr & RNG_SR_SECS) || (sr & RNG_SR_CECS) || timeout<=0)
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{
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RNG->CR=0;
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delayUs(1);
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RNG->CR=RNG_CR_RNGEN;
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continue;
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}
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unsigned int result=RNG->DR;
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if(result==old) continue;
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old=result;
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return result;
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}
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#ifndef __NO_EXCEPTIONS
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throw runtime_error("RNG Fault detected");
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#endif //__NO_EXCEPTIONS
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}
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} //namespace miosix
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