mbed-os/targets/TARGET_NUVOTON/TARGET_M261/trng_api.cpp

105 lines
3.1 KiB
C++

/*
* Copyright (c) 2019-2020 Nuvoton Technology Corporation
* 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.
*/
#if DEVICE_TRNG
#include "cmsis.h"
#include <limits.h>
#include "crypto-misc.h"
#include "hal/trng_api.h"
#include "platform/mbed_toolchain.h"
#include "platform/mbed_critical.h"
#include "platform/mbed_error.h"
#include "nu_modutil.h"
/* Module init definition: modname, clkidx, clksrc, clkdiv, rstidx, irqnum, misc */
static const struct nu_modinit_s trng_modinit = {TRNG_0, TRNG_MODULE, 0, 0, TRNG_RST, TRNG_IRQn, NULL};
/* TRNG init counter. TRNG is kept active as it is non-zero. */
static uint16_t trng_init_counter = 0U;
void trng_init(MBED_UNUSED trng_t *obj)
{
core_util_critical_section_enter();
if (trng_init_counter == USHRT_MAX) {
core_util_critical_section_exit();
MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_HAL, MBED_ERROR_CODE_OVERFLOW), \
"TRNG initialization counter would overflow");
}
++ trng_init_counter;
if (trng_init_counter == 1) {
/* Enable IP clock */
CLK_EnableModuleClock(trng_modinit.clkidx);
/* Reset IP */
SYS_ResetModule(trng_modinit.rsetidx);
TRNG_T *trng_base = (TRNG_T *) NU_MODBASE(trng_modinit.modname);
trng_base->ACT |= TRNG_ACT_ACT_Msk;
while (!(trng_base->CTL & TRNG_CTL_READY_Msk));
}
core_util_critical_section_exit();
}
void trng_free(MBED_UNUSED trng_t *obj)
{
core_util_critical_section_enter();
if (trng_init_counter == 0) {
core_util_critical_section_exit();
MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_HAL, MBED_ERROR_CODE_UNDERFLOW), \
"TRNG initialization counter would underflow");
}
-- trng_init_counter;
if (trng_init_counter == 0) {
TRNG_T *trng_base = (TRNG_T *) NU_MODBASE(trng_modinit.modname);
trng_base->ACT &= ~TRNG_ACT_ACT_Msk;
/* Disable IP clock */
CLK_DisableModuleClock(trng_modinit.clkidx);
}
core_util_critical_section_exit();
}
int trng_get_bytes(MBED_UNUSED trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
{
/* Check augument validity */
if (!output && length) {
return -1;
}
uint8_t *output_ind = output;
uint8_t *output_end = output + length;
TRNG_T *trng_base = (TRNG_T *) NU_MODBASE(trng_modinit.modname);
for (; output_ind != output_end; output_ind ++) {
trng_base->CTL |= TRNG_CTL_TRNGEN_Msk;
while (!(trng_base->CTL & TRNG_CTL_DVIF_Msk));
*output_ind = trng_base->DATA & 0xff;
}
if (output_length) {
*output_length = length;
}
return 0;
}
#endif