137 lines
4.5 KiB
C
137 lines
4.5 KiB
C
/*
|
|
* Copyright (c) 2012, Texas Instruments Incorporated - http://www.ti.com/
|
|
* 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.
|
|
*
|
|
* 3. Neither the name of the copyright holder 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.
|
|
*/
|
|
/**
|
|
* \addtogroup cc2538
|
|
* @{
|
|
*
|
|
* \defgroup cc2538-random cc2538 Random Number Generator
|
|
*
|
|
* Driver for the cc2538 Hardware Random Number Generator
|
|
* @{
|
|
*
|
|
* \file
|
|
* Random number generator routines exploiting the cc2538 hardware
|
|
* capabilities.
|
|
*
|
|
* This file overrides core/lib/random.c.
|
|
*/
|
|
#include "contiki.h"
|
|
#include "dev/rfcore.h"
|
|
#include "dev/cc2538-rf.h"
|
|
#include "dev/soc-adc.h"
|
|
#include "dev/sys-ctrl.h"
|
|
#include "reg.h"
|
|
/*---------------------------------------------------------------------------*/
|
|
/**
|
|
* \brief Generates a new random number using the cc2538 RNG.
|
|
* \return The random number.
|
|
*/
|
|
unsigned short
|
|
random_rand(void)
|
|
{
|
|
uint32_t rv;
|
|
|
|
/* Clock the RNG LSFR once */
|
|
REG(SOC_ADC_ADCCON1) |= SOC_ADC_ADCCON1_RCTRL0;
|
|
|
|
rv = REG(SOC_ADC_RNDL) | (REG(SOC_ADC_RNDH) << 8);
|
|
return ((unsigned short)rv);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
/**
|
|
* \brief Seed the cc2538 random number generator.
|
|
* \param seed Ignored. It's here because the function prototype is in core.
|
|
*
|
|
* We form a seed for the RNG by sampling IF_ADC as
|
|
* discussed in the user guide.
|
|
* Seeding with this method should not be done during
|
|
* normal radio operation. Thus, use this function before
|
|
* initialising the network.
|
|
*
|
|
* \note Must not be called after the RF driver has been initialised and is
|
|
* in normal operation. If it is absolutely necessary to do so, the
|
|
* radio will need re-initialised.
|
|
*/
|
|
void
|
|
random_init(unsigned short seed)
|
|
{
|
|
int i;
|
|
unsigned short s = 0;
|
|
|
|
/* Make sure the RNG is on */
|
|
REG(SOC_ADC_ADCCON1) &= ~(SOC_ADC_ADCCON1_RCTRL1 | SOC_ADC_ADCCON1_RCTRL0);
|
|
|
|
/* Enable clock for the RF Core */
|
|
REG(SYS_CTRL_RCGCRFC) = 1;
|
|
|
|
/* Wait for the clock ungating to take effect */
|
|
while(REG(SYS_CTRL_RCGCRFC) != 1);
|
|
|
|
/* Infinite RX - FRMCTRL0[3:2] = 10
|
|
* This will mess with radio operation - see note above */
|
|
REG(RFCORE_XREG_FRMCTRL0) = 0x00000008;
|
|
|
|
/* Turn RF on */
|
|
CC2538_RF_CSP_ISRXON();
|
|
|
|
/*
|
|
* Wait until "the chip has been in RX long enough for the transients to
|
|
* have died out. A convenient way to do this is to wait for the RSSI-valid
|
|
* signal to go high."
|
|
*/
|
|
while(!(REG(RFCORE_XREG_RSSISTAT) & RFCORE_XREG_RSSISTAT_RSSI_VALID));
|
|
|
|
/*
|
|
* Form the seed by concatenating bits from IF_ADC in the RF receive path.
|
|
* Keep sampling until we have read at least 16 bits AND the seed is valid
|
|
*
|
|
* Invalid seeds are 0x0000 and 0x8003 and should not be used.
|
|
*/
|
|
while(s == 0x0000 || s == 0x8003) {
|
|
for(i = 0; i < 16; i++) {
|
|
s |= (REG(RFCORE_XREG_RFRND) & RFCORE_XREG_RFRND_IRND);
|
|
s <<= 1;
|
|
}
|
|
}
|
|
|
|
/* High byte first */
|
|
REG(SOC_ADC_RNDL) = (s >> 8) & 0x00FF;
|
|
REG(SOC_ADC_RNDL) = s & 0xFF;
|
|
|
|
/* RF Off. NETSTACK_RADIO.init() will sort out normal RF operation */
|
|
CC2538_RF_CSP_ISRFOFF();
|
|
}
|
|
|
|
/**
|
|
* @}
|
|
* @}
|
|
*/
|