/* esp32_sha.c
 *
 * Copyright (C) 2006-2020 wolfSSL Inc.
 *
 * This file is part of wolfSSL.
 *
 * wolfSSL is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * wolfSSL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
 */
#include <string.h>
#include <stdio.h>

#ifdef HAVE_CONFIG_H
    #include <config.h>
#endif
#include <wolfssl/wolfcrypt/settings.h>

#if !defined(NO_SHA) || !defined(NO_SHA256) || defined(WC_SHA384) || \
     defined(WC_SHA512)

#include "wolfssl/wolfcrypt/logging.h"


#if defined(WOLFSSL_ESP32WROOM32_CRYPT) && \
   !defined(NO_WOLFSSL_ESP32WROOM32_CRYPT_HASH)

#include <wolfssl/wolfcrypt/sha.h>
#include <wolfssl/wolfcrypt/sha256.h>
#include <wolfssl/wolfcrypt/sha512.h>

#include "wolfssl/wolfcrypt/port/Espressif/esp32-crypt.h"
#include "wolfssl/wolfcrypt/error-crypt.h"

#ifdef NO_INLINE
    #include <wolfssl/wolfcrypt/misc.h>
#else
    #define WOLFSSL_MISC_INCLUDED
    #include <wolfcrypt/src/misc.c>
#endif

static const char* TAG = "wolf_hw_sha";
/* continue register offset */
#define CONTINUE_REG_OFFSET    (0x04)     /* start_reg + 0x04 */

#ifdef NO_SHA
    #define WC_SHA_DIGEST_SIZE 20
#endif
/* mutex */
#if defined(SINGLE_THREADED)
static int InUse = 0;
#else
static wolfSSL_Mutex sha_mutex;
static int espsha_CryptHwMutexInit = 0;
#endif
/*
    enum SHA_TYPE {
        SHA1 = 0,
        SHA2_256,
        SHA2_384,
        SHA2_512,
        SHA_INVALID = -1,
    };
*/
static word32 esp_sha_digest_size(enum SHA_TYPE type)
{
    ESP_LOGV(TAG, "enter esp_sha_digest_size");

    switch(type){
#ifndef NO_SHA
        case SHA1:
            return WC_SHA_DIGEST_SIZE;
#endif
#ifndef NO_SHA256
        case SHA2_256:
            return WC_SHA256_DIGEST_SIZE;
#endif
#ifdef WOLFSSL_SHA384
        case SHA2_384:
            return WC_SHA384_DIGEST_SIZE;
#endif
#ifdef WOLFSSL_SHA512
        case SHA2_512:
            return WC_SHA512_DIGEST_SIZE;
#endif
        default:
            ESP_LOGE(TAG, "Bad sha type");
            return WC_SHA_DIGEST_SIZE;
    }
    ESP_LOGV(TAG, "leave esp_sha_digest_size");
}
/*
* wait until engines becomes idle
*/
static void esp_wait_until_idle()
{
    while((DPORT_REG_READ(SHA_1_BUSY_REG)  !=0) ||
          (DPORT_REG_READ(SHA_256_BUSY_REG)!=0) ||
          (DPORT_REG_READ(SHA_384_BUSY_REG)!=0) ||
          (DPORT_REG_READ(SHA_512_BUSY_REG)!=0)){ }
}
/*
* lock hw engine.
* this should be called before using engine.
*/
int esp_sha_try_hw_lock(WC_ESP32SHA* ctx)
{
    int ret = 0;

    ESP_LOGV(TAG, "enter esp_sha_hw_lock");

    /* Init mutex */
#if defined(SINGLE_THREADED)
    if(ctx->mode == ESP32_SHA_INIT) {
        if(!InUse) {
            ctx->mode = ESP32_SHA_HW;
            InUse = 1;
        } else {
            ctx->mode = ESP32_SHA_SW;
        }
    } else {
         /* this should not happens */
        ESP_LOGE(TAG, "unexpected error in esp_sha_try_hw_lock.");
        return -1;
    }
#else
    if(espsha_CryptHwMutexInit == 0){
        ret = esp_CryptHwMutexInit(&sha_mutex);
        if(ret == 0) {
            espsha_CryptHwMutexInit = 1;
        } else {
            ESP_LOGE(TAG, " mutex initialization failed.");
            ctx->mode = ESP32_SHA_SW;
            return 0;
        }
    }
    /* check if this sha has been operated as sw or hw, or not yet init */
    if(ctx->mode == ESP32_SHA_INIT){
        /* try to lock the hw engine */
        if(esp_CryptHwMutexLock(&sha_mutex, (TickType_t)0) == 0) {
            ctx->mode = ESP32_SHA_HW;
        } else {
            ESP_LOGI(TAG, "someone used. hw is locked.....");
            ESP_LOGI(TAG, "the rest of operation will use sw implementation for this sha");
            ctx->mode = ESP32_SHA_SW;
            return 0;
        }
    } else {
        /* this should not happens */
        ESP_LOGE(TAG, "unexpected error in esp_sha_try_hw_lock.");
        return -1;
    }
#endif
   /* Enable SHA hardware */
    periph_module_enable(PERIPH_SHA_MODULE);

    ESP_LOGV(TAG, "leave esp_sha_hw_lock");
    return ret;
}
/*
* release hw engine
*/
void esp_sha_hw_unlock( void )
{
    ESP_LOGV(TAG, "enter esp_sha_hw_unlock");

    /* Disable AES hardware */
    periph_module_disable(PERIPH_SHA_MODULE);
#if defined(SINGLE_THREADED)
    InUse = 0;
#else
    /* unlock hw engine for next use */
    esp_CryptHwMutexUnLock(&sha_mutex);
#endif
    ESP_LOGV(TAG, "leave esp_sha_hw_unlock");
}
/*
* start sha process by using hw engine
*/
static void esp_sha_start_process(WC_ESP32SHA* sha, word32 address)
{
    ESP_LOGV(TAG, "enter esp_sha_start_process");

    if(sha->isfirstblock){
        /* start first message block */
        DPORT_REG_WRITE(address, 1);
        sha->isfirstblock = 0;
    } else {
        /* CONTINU_REG */
        DPORT_REG_WRITE(address + CONTINUE_REG_OFFSET , 1);
   }

   ESP_LOGV(TAG, "leave esp_sha_start_process");
}
/*
* process message block
*/
static void esp_process_block(WC_ESP32SHA* ctx,  word32 address,
                                         const word32* data, word32 len)
{
    int i;

    ESP_LOGV(TAG, "enter esp_process_block");

    /* check if there are any busy engine */
    esp_wait_until_idle();
    /* load message data into hw */
    for(i=0;i<((len)/(sizeof(word32)));++i){
        DPORT_REG_WRITE(SHA_TEXT_BASE+(i*sizeof(word32)),*(data+i));
    }
    /* notify hw to start process */
    esp_sha_start_process(ctx, address);

    ESP_LOGV(TAG, "leave esp_process_block");
}
/*
* retrieve sha digest from memory
*/
static void esp_digest_state(WC_ESP32SHA* ctx, byte* hash, enum SHA_TYPE sha_type)
{
    /* registers */
    word32 SHA_LOAD_REG = SHA_1_LOAD_REG;
    word32 SHA_BUSY_REG = SHA_1_BUSY_REG;

    ESP_LOGV(TAG, "enter esp_digest_state");

    /* sanity check */
    if(sha_type == SHA_INVALID) {
        ESP_LOGE(TAG, "unexpected error. sha_type is invalid.");
        return;
    }

    SHA_LOAD_REG += (sha_type << 4);
    SHA_BUSY_REG += (sha_type << 4);

    if(ctx->isfirstblock == 1){
        /* no hardware use yet. Nothing to do yet */
        return ;
    }

    /* wait until idle */
    esp_wait_until_idle();

    /* LOAD final digest */
    DPORT_REG_WRITE(SHA_LOAD_REG, 1);
    /* wait until done */
    while(DPORT_REG_READ(SHA_BUSY_REG) == 1){ }

    esp_dport_access_read_buffer((word32*)(hash), SHA_TEXT_BASE,
                                 esp_sha_digest_size(sha_type)/sizeof(word32));

#if defined(WOLFSSL_SHA512) || defined(WOLFSSL_SHA384)
    if(sha_type==SHA2_384||sha_type==SHA2_512) {
        word32  i;
        word32* pwrd1 = (word32*)(hash);
        /* swap value */
        for(i = 0; i <WC_SHA512_DIGEST_SIZE/4; i+=2 ) {
            pwrd1[i]  ^= pwrd1[i+1];
            pwrd1[i+1]^= pwrd1[i];
            pwrd1[i]  ^= pwrd1[i+1];
        }
    }
#endif

    ESP_LOGV(TAG, "leave esp_digest_state");
}

#ifndef NO_SHA
/*
* sha1 process
*/
int esp_sha_process(struct wc_Sha* sha, const byte* data)
{
    int ret = 0;

    ESP_LOGV(TAG, "enter esp_sha_process");

    word32 SHA_START_REG = SHA_1_START_REG;

    esp_process_block(&sha->ctx, SHA_START_REG, (const word32*)data,
                                        WC_SHA_BLOCK_SIZE);

    ESP_LOGV(TAG, "leave esp_sha_process");
    return ret;
}
/*
* retrieve sha1 digest
*/
int esp_sha_digest_process(struct wc_Sha* sha, byte blockproc)
{
    int ret = 0;

    ESP_LOGV(TAG, "enter esp_sha_digest_process");

    if(blockproc) {
        word32 SHA_START_REG = SHA_1_START_REG;

        esp_process_block(&sha->ctx, SHA_START_REG, sha->buffer,
                                            WC_SHA_BLOCK_SIZE);
    }

    esp_digest_state(&sha->ctx, (byte*)sha->digest, SHA1);

    ESP_LOGV(TAG, "leave esp_sha_digest_process");

    return ret;
}
#endif /* NO_SHA */


#ifndef NO_SHA256
/*
* sha256 process
*/
int esp_sha256_process(struct wc_Sha256* sha, const byte* data)
{
    int ret = 0;
    word32 SHA_START_REG = SHA_1_START_REG;

    ESP_LOGV(TAG, "enter esp_sha256_process");

    /* start register offset */
    SHA_START_REG += (SHA2_256 << 4);

    esp_process_block(&sha->ctx, SHA_START_REG, (const word32*)data,
        WC_SHA256_BLOCK_SIZE);

    ESP_LOGV(TAG, "leave esp_sha256_process");

    return ret;
}
/*
* retrieve sha256 digest
*/
int esp_sha256_digest_process(struct wc_Sha256* sha, byte blockproc)
{
    int ret = 0;

    ESP_LOGV(TAG, "enter esp_sha256_digest_process");

    if(blockproc) {
        word32 SHA_START_REG = SHA_1_START_REG + (SHA2_256 << 4);

        esp_process_block(&sha->ctx, SHA_START_REG, sha->buffer,
                                           WC_SHA256_BLOCK_SIZE);
    }

    esp_digest_state(&sha->ctx, (byte*)sha->digest, SHA2_256);

    ESP_LOGV(TAG, "leave esp_sha256_digest_process");
    return ret;
}
#endif /* NO_SHA256 */

#if defined(WOLFSSL_SHA512) || defined(WOLFSSL_SHA384)
/*
* sha512 proess. this is used for sha384 too.
*/
void esp_sha512_block(struct wc_Sha512* sha, const word32* data, byte isfinal)
{
    enum SHA_TYPE sha_type = sha->ctx.sha_type;
    word32 SHA_START_REG = SHA_1_START_REG;

    ESP_LOGV(TAG, "enter esp_sha512_block");
    /* start register offset */
    SHA_START_REG += (sha_type << 4);

    if(sha->ctx.mode == ESP32_SHA_SW){
        ByteReverseWords64(sha->buffer, sha->buffer,
                               WC_SHA512_BLOCK_SIZE);
        if(isfinal){
            sha->buffer[WC_SHA512_BLOCK_SIZE / sizeof(word64) - 2] = sha->hiLen;
            sha->buffer[WC_SHA512_BLOCK_SIZE / sizeof(word64) - 1] = sha->loLen;
        }

    } else {
        ByteReverseWords((word32*)sha->buffer, (word32*)sha->buffer,
                                                        WC_SHA512_BLOCK_SIZE);
        if(isfinal){
            sha->buffer[WC_SHA512_BLOCK_SIZE / sizeof(word64) - 2] =
                                        rotlFixed64(sha->hiLen, 32U);
            sha->buffer[WC_SHA512_BLOCK_SIZE / sizeof(word64) - 1] =
                                        rotlFixed64(sha->loLen, 32U);
        }

        esp_process_block(&sha->ctx, SHA_START_REG, data, WC_SHA512_BLOCK_SIZE);
    }
    ESP_LOGV(TAG, "leave esp_sha512_block");
}
/*
* sha512 process. this is used for sha384 too.
*/
int esp_sha512_process(struct wc_Sha512* sha)
{
    word32 *data = (word32*)sha->buffer;

    ESP_LOGV(TAG, "enter esp_sha512_process");

    esp_sha512_block(sha, data, 0);

    ESP_LOGV(TAG, "leave esp_sha512_process");
    return 0;
}
/*
* retrieve sha512 digest. this is used for sha384 too.
*/
int esp_sha512_digest_process(struct wc_Sha512* sha, byte blockproc)
{
    ESP_LOGV(TAG, "enter esp_sha512_digest_process");

    if(blockproc) {
        word32* data = (word32*)sha->buffer;

        esp_sha512_block(sha, data, 1);
    }
    if(sha->ctx.mode != ESP32_SHA_SW)
        esp_digest_state(&sha->ctx, (byte*)sha->digest, sha->ctx.sha_type);

    ESP_LOGV(TAG, "leave esp_sha512_digest_process");
    return 0;
}
#endif /* WOLFSSL_SHA512 || WOLFSSL_SHA384 */
#endif /* WOLFSSL_ESP32WROOM32_CRYPT */
#endif /* !defined(NO_SHA) ||... */