/* Copyright 2023 Dual Tachyon
 * https://github.com/DualTachyon
 *
 * 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.
 */

#include <stdbool.h>

#include "bsp/dp32g030/aes.h"
#include "driver/aes.h"

static void AES_Setup_ENC_CBC(bool IsDecrypt, const void *pKey, const void *pIv)
{
	const uint32_t *pK = (const uint32_t *)pKey;
	const uint32_t *pI = (const uint32_t *)pIv;

	(void)IsDecrypt;	// unused
	
	AES_CR = (AES_CR & ~AES_CR_EN_MASK) | AES_CR_EN_BITS_DISABLE;
	AES_CR = AES_CR_CHMOD_BITS_CBC;
	AES_KEYR3 = pK[0];
	AES_KEYR2 = pK[1];
	AES_KEYR1 = pK[2];
	AES_KEYR0 = pK[3];
	AES_IVR3 = pI[0];
	AES_IVR2 = pI[1];
	AES_IVR1 = pI[2];
	AES_IVR0 = pI[3];
	AES_CR = (AES_CR & ~AES_CR_EN_MASK) | AES_CR_EN_BITS_ENABLE;
}

static void AES_Transform(const void *pIn, void *pOut)
{
	const uint32_t *pI = (const uint32_t *)pIn;
	uint32_t *pO = (uint32_t *)pOut;

	AES_DINR = pI[0];
	AES_DINR = pI[1];
	AES_DINR = pI[2];
	AES_DINR = pI[3];

	while ((AES_SR & AES_SR_CCF_MASK) == AES_SR_CCF_BITS_NOT_COMPLETE) {
	}

	pO[0] = AES_DOUTR;
	pO[1] = AES_DOUTR;
	pO[2] = AES_DOUTR;
	pO[3] = AES_DOUTR;

	AES_CR |= AES_CR_CCFC_BITS_SET;
}

void AES_Encrypt(const void *pKey, const void *pIv, const void *pIn, void *pOut, uint8_t NumBlocks)
{
	const uint8_t *pI = (const uint8_t *)pIn;
	uint8_t *pO = (uint8_t *)pOut;
	uint8_t i;

	AES_Setup_ENC_CBC(0, pKey, pIv);
	for (i = 0; i < NumBlocks; i++) {
		AES_Transform(pI + (i * 16), pO + (i * 16));
	}
}

