eed1352282
Contiki sometimes fails to boot correctly and locks up in random_init() This problem only manifests itself for specific versions of the arm-gcc toolchain and then again only for specific levels of optimisation (-Os vs -O2, depending on the value of the SMALL make variable) The lockup is caused when we write an RFCORE XREG before the RF clock ungating has taken effect, which in turn only occurs depending on the assembly generated for those two instructions: REG(SYS_CTRL_RCGCRFC) = 1; REG(RFCORE_XREG_FRMCTRL0) = 0x00000008; This commit makes the RNG wait for the ungating to take effect before attempting to write the register
136 lines
4.5 KiB
C
136 lines
4.5 KiB
C
/*
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* Copyright (c) 2012, Texas Instruments Incorporated - http://www.ti.com/
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* All rights reserved.
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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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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* 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
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \addtogroup cc2538
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* @{
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*
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* \defgroup cc2538-random cc2538 Random Number Generator
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*
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* Driver for the cc2538 Hardware Random Number Generator
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* @{
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*
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* \file
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* Random number generator routines exploiting the cc2538 hardware
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* capabilities.
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*
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* This file overrides core/lib/random.c.
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*/
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#include "contiki.h"
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#include "dev/rfcore.h"
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#include "dev/cc2538-rf.h"
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#include "dev/soc-adc.h"
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#include "dev/sys-ctrl.h"
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#include "reg.h"
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/*---------------------------------------------------------------------------*/
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/**
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* \brief Generates a new random number using the cc2538 RNG.
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* \return The random number.
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*/
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unsigned short
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random_rand(void)
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{
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uint32_t rv;
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/* Clock the RNG LSFR once */
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REG(SOC_ADC_ADCCON1) |= SOC_ADC_ADCCON1_RCTRL0;
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rv = REG(SOC_ADC_RNDL) | (REG(SOC_ADC_RNDH) << 8);
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return ((unsigned short)rv);
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}
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/*---------------------------------------------------------------------------*/
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/**
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* \brief Seed the cc2538 random number generator.
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* \param seed Ignored. It's here because the function prototype is in core.
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*
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* We form a seed for the RNG by sampling IF_ADC as
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* discussed in the user guide.
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* Seeding with this method should not be done during
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* normal radio operation. Thus, use this function before
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* initialising the network.
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*
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* \note Must not be called after the RF driver has been initialised and is
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* in normal operation. If it is absolutely necessary to do so, the
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* radio will need re-initialised.
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*/
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void
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random_init(unsigned short seed)
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{
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int i;
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unsigned short s = 0;
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/* Make sure the RNG is on */
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REG(SOC_ADC_ADCCON1) &= ~(SOC_ADC_ADCCON1_RCTRL1 | SOC_ADC_ADCCON1_RCTRL0);
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/* Enable clock for the RF Core */
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REG(SYS_CTRL_RCGCRFC) = 1;
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/* Wait for the clock ungating to take effect */
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while(REG(SYS_CTRL_RCGCRFC) != 1);
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/* Infinite RX - FRMCTRL0[3:2] = 10
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* This will mess with radio operation - see note above */
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REG(RFCORE_XREG_FRMCTRL0) = 0x00000008;
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/* Turn RF on */
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CC2538_RF_CSP_ISRXON();
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/*
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* Wait until "the chip has been in RX long enough for the transients to
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* have died out. A convenient way to do this is to wait for the RSSI-valid
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* signal to go high."
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*/
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while(!(REG(RFCORE_XREG_RSSISTAT) & RFCORE_XREG_RSSISTAT_RSSI_VALID));
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/*
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* Form the seed by concatenating bits from IF_ADC in the RF receive path.
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* Keep sampling until we have read at least 16 bits AND the seed is valid
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*
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* Invalid seeds are 0x0000 and 0x8003 and should not be used.
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*/
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while(s == 0x0000 || s == 0x8003) {
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for(i = 0; i < 16; i++) {
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s |= (REG(RFCORE_XREG_RFRND) & RFCORE_XREG_RFRND_IRND);
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s <<= 1;
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}
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}
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/* High byte first */
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REG(SOC_ADC_RNDL) = (s >> 8) & 0x00FF;
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REG(SOC_ADC_RNDL) = s & 0xFF;
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/* RF Off. NETSTACK_RADIO.init() will sort out normal RF operation */
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CC2538_RF_CSP_ISRFOFF();
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}
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/**
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* @}
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* @}
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*/
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