osd-contiki/cpu/cc2538/dev/aes.c
Benoît Thébaudeau 801315e819 cc2538: aes: Make it possible to have several keys stored at once
Several keys can be kept at the same time in the key store, and several
keys can be loaded at once. Give access to these features.

The ccm-test example is also improved to better demonstrate the use of
the key store.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau.dev@gmail.com>
2015-06-02 21:41:07 +02:00

138 lines
5 KiB
C

/*
* Original file:
* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
* All rights reserved.
*
* Port to Contiki:
* Copyright (c) 2013, ADVANSEE - http://www.advansee.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-aes
* @{
*
* \file
* Implementation of the cc2538 AES driver
*/
#include "contiki.h"
#include "dev/rom-util.h"
#include "dev/aes.h"
#include "reg.h"
#include <stdint.h>
/*---------------------------------------------------------------------------*/
uint8_t
aes_load_keys(const void *keys, uint8_t count, uint8_t start_area)
{
uint32_t aes_key_store_size;
uint32_t areas;
uint32_t aligned_keys[32];
if(REG(AES_CTRL_ALG_SEL) != 0x00000000) {
return CRYPTO_RESOURCE_IN_USE;
}
/* The keys base address needs to be 4-byte aligned */
rom_util_memcpy(aligned_keys, keys, count << 4);
/* Workaround for AES registers not retained after PM2 */
REG(AES_CTRL_INT_CFG) = AES_CTRL_INT_CFG_LEVEL;
REG(AES_CTRL_INT_EN) = AES_CTRL_INT_EN_DMA_IN_DONE |
AES_CTRL_INT_EN_RESULT_AV;
/* Configure master control module */
REG(AES_CTRL_ALG_SEL) = AES_CTRL_ALG_SEL_KEYSTORE;
/* Clear any outstanding events */
REG(AES_CTRL_INT_CLR) = AES_CTRL_INT_CLR_DMA_IN_DONE |
AES_CTRL_INT_CLR_RESULT_AV;
/* Configure key store module (areas, size): 128-bit key size
* Note that writing AES_KEY_STORE_SIZE deletes all stored keys */
aes_key_store_size = REG(AES_KEY_STORE_SIZE);
if((aes_key_store_size & AES_KEY_STORE_SIZE_KEY_SIZE_M) !=
AES_KEY_STORE_SIZE_KEY_SIZE_128) {
REG(AES_KEY_STORE_SIZE) = (aes_key_store_size &
~AES_KEY_STORE_SIZE_KEY_SIZE_M) |
AES_KEY_STORE_SIZE_KEY_SIZE_128;
}
/* Free possibly already occupied key areas */
areas = ((0x00000001 << count) - 1) << start_area;
REG(AES_KEY_STORE_WRITTEN_AREA) = areas;
/* Enable key areas to write */
REG(AES_KEY_STORE_WRITE_AREA) = areas;
/* Configure DMAC
* Enable DMA channel 0 */
REG(AES_DMAC_CH0_CTRL) = AES_DMAC_CH_CTRL_EN;
/* Base address of the keys in ext. memory */
REG(AES_DMAC_CH0_EXTADDR) = (uint32_t)aligned_keys;
/* Total keys length in bytes (e.g. 16 for 1 x 128-bit key) */
REG(AES_DMAC_CH0_DMALENGTH) = (REG(AES_DMAC_CH0_DMALENGTH) &
~AES_DMAC_CH_DMALENGTH_DMALEN_M) |
(count << (4 + AES_DMAC_CH_DMALENGTH_DMALEN_S));
/* Wait for operation to complete */
while(!(REG(AES_CTRL_INT_STAT) & AES_CTRL_INT_STAT_RESULT_AV));
/* Check for absence of errors in DMA and key store */
if(REG(AES_CTRL_INT_STAT) & AES_CTRL_INT_STAT_DMA_BUS_ERR) {
REG(AES_CTRL_INT_CLR) = AES_CTRL_INT_CLR_DMA_BUS_ERR;
/* Disable master control / DMA clock */
REG(AES_CTRL_ALG_SEL) = 0x00000000;
return CRYPTO_DMA_BUS_ERROR;
}
if(REG(AES_CTRL_INT_STAT) & AES_CTRL_INT_STAT_KEY_ST_WR_ERR) {
REG(AES_CTRL_INT_CLR) = AES_CTRL_INT_CLR_KEY_ST_WR_ERR;
/* Disable master control / DMA clock */
REG(AES_CTRL_ALG_SEL) = 0x00000000;
return AES_KEYSTORE_WRITE_ERROR;
}
/* Acknowledge the interrupt */
REG(AES_CTRL_INT_CLR) = AES_CTRL_INT_CLR_DMA_IN_DONE |
AES_CTRL_INT_CLR_RESULT_AV;
/* Disable master control / DMA clock */
REG(AES_CTRL_ALG_SEL) = 0x00000000;
/* Check status, if error return error code */
if((REG(AES_KEY_STORE_WRITTEN_AREA) & areas) != areas) {
return AES_KEYSTORE_WRITE_ERROR;
}
return CRYPTO_SUCCESS;
}
/** @} */