Add CC13xx/CC26xx TRNG driver
This commit is contained in:
George Oikonomou
parent
adfeaa5500
commit
bb4056903c
315
cpu/cc26xx-cc13xx/dev/soc-trng.c
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315
cpu/cc26xx-cc13xx/dev/soc-trng.c
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/*
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* Copyright (c) 2016, University of Bristol - http://www.bristol.ac.uk
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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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* 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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/**
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* \addtogroup cc26xx-trng
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* @{
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*
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* \file
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*
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* Implementation of the CC13xx/CC26xx RNG driver
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*/
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/*---------------------------------------------------------------------------*/
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#include "contiki.h"
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#include "lpm.h"
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#include "sys/process.h"
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#include "dev/soc-trng.h"
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#include "ti-lib.h"
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#include <stdbool.h>
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#include <stdint.h>
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#include <stddef.h>
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/*---------------------------------------------------------------------------*/
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#ifdef SOC_TRNG_CONF_CACHE_LEN
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#define SOC_TRNG_CACHE_LEN SOC_TRNG_CONF_CACHE_LEN
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#else
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/** Size of the random number cache. Each slot holds 4 16-bit numbers */
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#define SOC_TRNG_CACHE_LEN 4
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#endif
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/*---------------------------------------------------------------------------*/
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#define MIN_REFILL_CYCLES_MAX 0x00000000
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/*---------------------------------------------------------------------------*/
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PROCESS(soc_trng_process, "CC13xx/CC26xx TRNG process");
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/*---------------------------------------------------------------------------*/
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static process_event_t rng_ready_event = PROCESS_EVENT_NONE;
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/*---------------------------------------------------------------------------*/
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static soc_trng_callback_t notify_cb = NULL;
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/*---------------------------------------------------------------------------*/
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#define soc_trng_isr TRNGIntHandler
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/*---------------------------------------------------------------------------*/
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static uint64_t rands_cache[SOC_TRNG_CACHE_LEN];
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static bool rands_mask[SOC_TRNG_CACHE_LEN];
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/*---------------------------------------------------------------------------*/
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static void
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disable_number_ready_interrupt(void)
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{
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ti_lib_trng_int_disable(TRNG_NUMBER_READY);
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ti_lib_rom_int_disable(INT_TRNG);
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}
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/*---------------------------------------------------------------------------*/
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static void
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enable_number_ready_interrupt(void)
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{
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ti_lib_trng_int_clear(TRNG_NUMBER_READY);
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ti_lib_trng_int_enable(TRNG_NUMBER_READY);
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ti_lib_rom_int_enable(INT_TRNG);
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}
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/*---------------------------------------------------------------------------*/
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static bool
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accessible(void)
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{
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/* First, check the PD */
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if(ti_lib_rom_prcm_power_domain_status(PRCM_DOMAIN_PERIPH)
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!= PRCM_DOMAIN_POWER_ON) {
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return false;
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}
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/* Then check the 'run mode' clock gate */
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if(!(HWREG(PRCM_BASE + PRCM_O_SECDMACLKGR) &
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PRCM_SECDMACLKGDS_TRNG_CLK_EN_M)) {
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return false;
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}
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return true;
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}
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/*---------------------------------------------------------------------------*/
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static void
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power_up(void)
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{
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/* First, make sure the PERIPH PD is on */
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ti_lib_rom_prcm_power_domain_on(PRCM_DOMAIN_PERIPH);
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while((ti_lib_rom_prcm_power_domain_status(PRCM_DOMAIN_PERIPH)
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!= PRCM_DOMAIN_POWER_ON));
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/* Enable clock in active mode */
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ti_lib_rom_prcm_peripheral_run_enable(PRCM_PERIPH_TRNG);
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ti_lib_prcm_load_set();
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while(!ti_lib_prcm_load_get());
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}
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/*---------------------------------------------------------------------------*/
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static void
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reset_synchronous(void)
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{
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ti_lib_trng_reset();
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while(HWREG(TRNG_BASE + TRNG_O_SWRESET));
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}
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/*---------------------------------------------------------------------------*/
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static uint8_t
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request(void)
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{
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if(notify_cb) {
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return LPM_MODE_SLEEP;
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}
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return LPM_MODE_MAX_SUPPORTED;
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}
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/*---------------------------------------------------------------------------*/
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LPM_MODULE(rng_module, request, NULL, NULL, LPM_DOMAIN_NONE);
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/*---------------------------------------------------------------------------*/
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static uint64_t
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read_number(void)
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{
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uint64_t ran = (uint64_t)HWREG(TRNG_BASE + TRNG_O_OUT1) << 32;
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ran += ti_lib_rom_trng_number_get(TRNG_LOW_WORD);
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return ran;
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}
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/*---------------------------------------------------------------------------*/
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uint64_t
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soc_trng_rand_synchronous()
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{
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uint64_t ran;
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bool interrupts_disabled;
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int i;
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/* If the TRNG is gathering entropy, return a cached value */
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if(notify_cb) {
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for(i = 0; i < SOC_TRNG_CACHE_LEN; i++) {
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if(rands_mask[i]) {
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rands_mask[i] = false;
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return rands_cache[i];
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}
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}
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return 0;
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}
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if(!accessible()) {
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power_up();
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}
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/*
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* If we were previously enabled, we either have a number already available,
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* or we need clock, which means we are calculating. If neither is true then
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* we need setup from scratch.
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*/
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if((ti_lib_trng_status_get() & (TRNG_NEED_CLOCK | TRNG_NUMBER_READY)) == 0) {
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reset_synchronous();
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ti_lib_trng_configure(MIN_REFILL_CYCLES_MAX, SOC_TRNG_REFILL_CYCLES_MIN, 0);
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ti_lib_trng_enable();
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}
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interrupts_disabled = ti_lib_int_master_disable();
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while((ti_lib_trng_status_get() & TRNG_NUMBER_READY) == 0);
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ran = read_number();
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if(!interrupts_disabled) {
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ti_lib_int_master_enable();
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}
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return ran;
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}
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/*---------------------------------------------------------------------------*/
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uint8_t
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soc_trng_rand_asynchronous(uint32_t samples, soc_trng_callback_t cb)
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{
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int i;
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bool interrupts_disabled;
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if(notify_cb != NULL) {
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return SOC_TRNG_RAND_ASYNC_REQUEST_ERROR;
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}
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if(!accessible()) {
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power_up();
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}
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/*
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* First we need to cache some random numbers for general use in case the
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* application requests them while we are calculating.
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*
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* If we were previously enabled, we either have a number already available,
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* or we need clock, which means we are calculating. If neither is true then
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* we need setup from scratch.
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*/
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if((ti_lib_trng_status_get() & (TRNG_NEED_CLOCK | TRNG_NUMBER_READY)) == 0) {
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reset_synchronous();
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}
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interrupts_disabled = ti_lib_int_master_disable();
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ti_lib_trng_disable();
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ti_lib_trng_configure(MIN_REFILL_CYCLES_MAX, SOC_TRNG_REFILL_CYCLES_MIN, 0);
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ti_lib_trng_enable();
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/* Cache SOC_TRNG_CACHE_LEN min-entropy rands */
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for(i = 0; i < SOC_TRNG_CACHE_LEN; i++) {
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while((ti_lib_trng_status_get() & TRNG_NUMBER_READY) == 0);
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rands_mask[i] = true;
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rands_cache[i] = read_number();
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}
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/* Configure the RNG to the required entropy */
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ti_lib_trng_disable();
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ti_lib_trng_configure(MIN_REFILL_CYCLES_MAX, samples, 0);
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/*
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* Clear the TRNG_NUMBER_READY flag. This will trigger a new calculation
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* as soon as the module gets enabled.
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*/
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ti_lib_trng_int_clear(TRNG_NUMBER_READY);
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/* Enable clock in sleep mode and register with LPM */
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ti_lib_rom_prcm_peripheral_sleep_enable(PRCM_PERIPH_TRNG);
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ti_lib_prcm_load_set();
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while(!ti_lib_prcm_load_get());
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lpm_register_module(&rng_module);
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notify_cb = cb;
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/* Enable the number ready interrupt and fire-up the module */
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enable_number_ready_interrupt();
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ti_lib_trng_enable();
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if(!interrupts_disabled) {
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ti_lib_int_master_enable();
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}
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return SOC_TRNG_RAND_ASYNC_REQUEST_OK;
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}
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/*---------------------------------------------------------------------------*/
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PROCESS_THREAD(soc_trng_process, ev, data)
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{
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PROCESS_BEGIN();
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while(1) {
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PROCESS_YIELD_UNTIL(ev == rng_ready_event);
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if(notify_cb) {
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uint64_t ran = read_number();
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notify_cb(ran);
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notify_cb = NULL;
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}
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/* Disable clock in sleep mode */
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ti_lib_rom_prcm_peripheral_sleep_disable(PRCM_PERIPH_TRNG);
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ti_lib_prcm_load_set();
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while(!ti_lib_prcm_load_get());
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lpm_unregister_module(&rng_module);
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}
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PROCESS_END();
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}
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/*---------------------------------------------------------------------------*/
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void
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soc_trng_isr(void)
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{
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ENERGEST_ON(ENERGEST_TYPE_IRQ);
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ti_lib_trng_disable();
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disable_number_ready_interrupt();
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ti_lib_trng_configure(MIN_REFILL_CYCLES_MAX, SOC_TRNG_REFILL_CYCLES_MIN, 0);
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ti_lib_trng_enable();
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process_post(&soc_trng_process, rng_ready_event, NULL);
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ENERGEST_OFF(ENERGEST_TYPE_IRQ);
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}
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/*---------------------------------------------------------------------------*/
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void
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soc_trng_init()
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{
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if(rng_ready_event != PROCESS_EVENT_NONE) {
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return;
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}
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/* Register the RNG ready event */
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rng_ready_event = process_alloc_event();
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process_start(&soc_trng_process, NULL);
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}
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/*---------------------------------------------------------------------------*/
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/**
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* @}
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*/
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135
cpu/cc26xx-cc13xx/dev/soc-trng.h
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135
cpu/cc26xx-cc13xx/dev/soc-trng.h
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@ -0,0 +1,135 @@
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/*
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* Copyright (c) 2016, University of Bristol - http://www.bristol.ac.uk
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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
|
||||
* 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
|
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* documentation and/or other materials provided with the distribution.
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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
|
||||
* ``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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/**
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* \addtogroup cc26xx
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* @{
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*
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* \defgroup cc26xx-trng CC13xx/CC26xx Random Number Generator
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*
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* Driver for the CC13xx/CC26xx Random Number Generator
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*
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* @{
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*
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* \file
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*
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* Header file for the CC13xx/CC26xx TRNG driver
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*/
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/*---------------------------------------------------------------------------*/
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#ifndef SOC_TRNG_H_
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#define SOC_TRNG_H_
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/*---------------------------------------------------------------------------*/
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#include <stdint.h>
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/*---------------------------------------------------------------------------*/
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#define SOC_TRNG_RAND_ASYNC_REQUEST_ERROR 0 /**< Async request rejected */
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#define SOC_TRNG_RAND_ASYNC_REQUEST_OK 1 /**< Async request accepted */
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/*---------------------------------------------------------------------------*/
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#define SOC_TRNG_REFILL_CYCLES_MIN 0x00000100
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#define SOC_TRNG_REFILL_CYCLES_MAX 0x00000000
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/*---------------------------------------------------------------------------*/
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/**
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* \brief Pointer to a callback to be provided as an argument to
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* soc_trng_rand_asynchronous()
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*/
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typedef void (*soc_trng_callback_t)(uint64_t rand);
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/*---------------------------------------------------------------------------*/
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/**
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* \name TRNG functions
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* @{
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*/
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/**
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* \brief Returns a minimum entropy random number
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* \return The random number
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*
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* This function is synchronous. This function will make sure the PERIPH PD is
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* powered and the TRNG is clocked. The function will then configure the TRNG
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* to generate a random number of minimum entropy. These numbers are not
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* suitable for cryptographic usage, but their generation is very fast.
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*
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* If a high-entropy random number is currently being generated, this function
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* will return a cached random number. The cache is of configurable size and
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* can hold a maximum SOC_TRNG_CONF_CACHE_LEN numbers. If the cache gets
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* emptied while high-entropy generation is in progress (e.g. because a
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* function requested many random numbers in a row), this function will return
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* 0. Care must therefore be taken when the return value is 0, which can also
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* be a valid random number.
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*
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* This function can be safely called from within an interrupt context.
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*/
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uint64_t soc_trng_rand_synchronous();
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/**
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* \brief Initialise the CC13xx/CC26xx TRNG driver
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*/
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void soc_trng_init(void);
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/**
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* \brief Request a 64-bit, configurable-entropy random number
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* \param samples Controls the entropy generated for the random number
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* \param cb A callback function to be called when the generation is complete
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* \retval SOC_TRNG_RAND_ASYNC_REQUEST_ERROR There was an error adding request.
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* \retval SOC_TRNG_RAND_ASYNC_REQUEST_OK Request successfully registered
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*
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* This function is asynchronous, it will start generation of a random number
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* and will return. The caller must provide a callback that will be called when
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* the generation is complete. This callback must either use the random number
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* immediately or store it, since it will not be possible to retrieve it again
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* later form the soc-trng module.
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*
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* Only one generation can be active at any given point in time. If this
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* function gets called when a generation is already in progress, it will
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* return SOC_TRNG_RAND_ASYNC_REQUEST_ERROR.
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*
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* The function will configure the TRNG to generate entropy by sampling the
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* FROs for a number clock cycles controlled by the samples argument. The 8 LS
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* bits of this argument will be truncated by CC13xxware/CC26xxware and the
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* resulting number of clock cycles will be (samples >> 8) * 2^8. Increasing
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* the value of this argument increases entropy, but it also increases latency.
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* Maximum entropy can be generated by passing SOC_TRNG_REFILL_CYCLES_MAX, but
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* this will take approximately 350ms. Consult the chip's technical reference
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* manual for advice on what would constitute sufficient entropy for random
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* numbers meant to be used for crypto.
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*
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* While this function is executing, calls to soc_trng_rand_synchronous() will
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* return cached random numbers.
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*
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* This function is not re-entrant and must not be called from an interrupt
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* context.
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*/
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uint8_t soc_trng_rand_asynchronous(uint32_t samples, soc_trng_callback_t cb);
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/** @} */
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/*---------------------------------------------------------------------------*/
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#endif /* SOC_TRNG_H_ */
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/*---------------------------------------------------------------------------*/
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/**
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* @}
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* @}
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*/
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