OVMS3-idf/components/mbedtls/port/esp32s2beta/sha.c

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2019-05-10 03:34:06 +00:00
/*
* ESP32 hardware accelerated SHA1/256/512 implementation
* based on mbedTLS FIPS-197 compliant version.
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* Additions Copyright (C) 2016, Espressif Systems (Shanghai) PTE Ltd
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/*
* The SHA-1 standard was published by NIST in 1993.
*
* http://www.itl.nist.gov/fipspubs/fip180-1.htm
*/
#include <string.h>
#include <stdio.h>
#include <sys/lock.h>
#include <byteswap.h>
#include <assert.h>
#include "esp32s2beta/sha.h"
#include "esp32s2beta/rom/ets_sys.h"
2019-05-10 03:34:06 +00:00
#include "soc/dport_reg.h"
#include "soc/hwcrypto_reg.h"
/* Single lock for SHA engine
*/
static _lock_t s_sha_lock;
/* This API was designed for ESP32, which has seperate
engines for SHA1,256,512. ESP32C has a single engine.
*/
/* Return block size (in bytes) for a given SHA type */
inline static size_t block_length(esp_sha_type type) {
switch(type) {
case SHA1:
case SHA2_224:
case SHA2_256:
return 64;
case SHA2_384:
case SHA2_512:
return 128;
default:
return 0;
}
}
/* Return state size (in bytes) for a given SHA type */
inline static size_t state_length(esp_sha_type type) {
switch(type) {
case SHA1:
return 160/8;
case SHA2_224:
case SHA2_256:
return 256/8;
case SHA2_384:
case SHA2_512:
return 512/8;
default:
return 0;
}
}
/* Copy words in memory (to/from a memory block), byte swapping as we go. */
static void memcpy_endianswap(void *to, const void *from, size_t num_bytes)
{
uint32_t *to_words = (uint32_t *)to;
const uint32_t *from_words = (const uint32_t *)from;
assert(num_bytes % 4 == 0);
for (int i = 0; i < num_bytes / 4; i++) {
to_words[i] = __bswap_32(from_words[i]);
}
asm volatile ("memw");
}
static void memcpy_swapwords(void *to, const void *from, size_t num_bytes)
{
uint32_t *to_words = (uint32_t *)to;
const uint32_t *from_words = (const uint32_t *)from;
assert(num_bytes % 8 == 0);
for (int i = 0; i < num_bytes / 4; i += 2) {
to_words[i] = from_words[i+1];
to_words[i+1] = from_words[i];
}
asm volatile ("memw");
}
static void esp_sha_lock_engine_inner(void);
bool esp_sha_try_lock_engine(esp_sha_type sha_type)
{
if(_lock_try_acquire(&s_sha_lock) != 0) {
/* SHA engine is already in use */
return false;
} else {
esp_sha_lock_engine_inner();
return true;
}
}
void esp_sha_lock_engine(esp_sha_type sha_type)
{
_lock_acquire(&s_sha_lock);
esp_sha_lock_engine_inner();
}
static void esp_sha_lock_engine_inner(void)
{
ets_sha_enable();
}
void esp_sha_unlock_engine(esp_sha_type sha_type)
{
ets_sha_disable();
_lock_release(&s_sha_lock);
}
void esp_sha_wait_idle(void)
{
while(DPORT_REG_READ(SHA_BUSY_REG) != 0) { }
}
void esp_sha_read_digest_state(esp_sha_type sha_type, void *digest_state)
{
/* engine should be locked */
esp_sha_wait_idle();
if (sha_type != SHA2_512 && sha_type != SHA2_384) {
/* <SHA-512, read out directly */
memcpy(digest_state, (void *)SHA_H_BASE, state_length(sha_type));
} else {
/* SHA-512, read out with each pair of words swapped */
memcpy_swapwords(digest_state, (void *)SHA_H_BASE, state_length(sha_type));
}
}
void esp_sha_block(esp_sha_type sha_type, const void *data_block, bool is_first_block)
{
/* engine should be locked */
REG_WRITE(SHA_MODE_REG, sha_type);
/* ESP32C SHA unit can be loaded while previous block is processing */
memcpy_endianswap((void *)SHA_M_BASE, data_block, block_length(sha_type));
esp_sha_wait_idle();
if (is_first_block) {
REG_WRITE(SHA_START_REG, 1);
} else {
REG_WRITE(SHA_CONTINUE_REG, 1);
}
/* Note: deliberately not waiting for this operation to complete,
as a performance tweak - delay waiting until the next time we need the SHA
unit, instead.
*/
}
void esp_sha(esp_sha_type sha_type, const unsigned char *input, size_t ilen, unsigned char *output)
{
SHA_CTX ctx;
esp_sha_lock_engine(sha_type);
ets_sha_init(&ctx, sha_type);
ets_sha_starts(&ctx, 0);
ets_sha_update(&ctx, input, ilen, false);
ets_sha_finish(&ctx, output);
esp_sha_unlock_engine(sha_type);
}