/******************************************************************************
**
** FILE NAME    : ifxmips_sha1_hmac.c
** PROJECT      : IFX UEIP
** MODULES      : DEU Module for UEIP
** DATE         : September 8, 2009
** AUTHOR       : Mohammad Firdaus
** DESCRIPTION  : Data Encryption Unit Driver
** COPYRIGHT    :       Copyright (c) 2009
**                      Infineon Technologies AG
**                      Am Campeon 1-12, 85579 Neubiberg, Germany
**
**    This program 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.
**
** HISTORY
** $Date        $Author             $Comment
** 08,Sept 2009 Mohammad Firdaus    Initial UEIP release
** 21,March 2011 Mohammad Firdaus   Changes for Kernel 2.6.32 and IPSec integration
*******************************************************************************/
/*!
  \defgroup IFX_DEU IFX_DEU_DRIVERS
  \ingroup API
  \brief ifx deu driver module
*/

/*!
  \file	ifxmips_sha1_hmac.c
  \ingroup IFX_DEU
  \brief SHA1-HMAC deu driver file
*/

/*! 
  \defgroup IFX_SHA1_HMAC_FUNCTIONS IFX_SHA1_HMAC_FUNCTIONS
  \ingroup IFX_DEU
  \brief ifx sha1 hmac functions
*/

/* Project header */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/crypto.h>
#include <crypto/internal/hash.h>
#include <linux/version.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(5,11,0)
#include <crypto/sha.h>
#else
#include <crypto/sha1.h>
#endif
#include <linux/types.h>
#include <linux/scatterlist.h>
#include <asm/byteorder.h>
#include <linux/delay.h>

#if defined(CONFIG_AR9)
#include "ifxmips_deu_ar9.h"
#elif defined(CONFIG_VR9) || defined(CONFIG_AR10)
#include "ifxmips_deu_vr9.h"
#else
#error "Plaform Unknwon!"
#endif

#define SHA1_DIGEST_SIZE    20
#define SHA1_BLOCK_WORDS    16
#define SHA1_HASH_WORDS     5
#define SHA1_HMAC_BLOCK_SIZE    64
#define SHA1_HMAC_DBN_TEMP_SIZE 1024 // size in dword, needed for dbn workaround 
#define HASH_START   IFX_HASH_CON

#define SHA1_HMAC_MAX_KEYLEN 64

#ifdef CRYPTO_DEBUG
extern char debug_level;
#define DPRINTF(level, format, args...) if (level < debug_level) printk(KERN_INFO "[%s %s %d]: " format, __FILE__, __func__, __LINE__, ##args);
#else
#define DPRINTF(level, format, args...)
#endif

struct sha1_hmac_ctx {
    int keylen;

    u8 buffer[SHA1_HMAC_BLOCK_SIZE];
    u8 key[SHA1_HMAC_MAX_KEYLEN];
    u32 hash[SHA1_HASH_WORDS];
    u32 dbn;
    int started;
    u64 count;

    struct shash_desc *desc;
    u32 (*temp)[SHA1_BLOCK_WORDS];
};

extern int disable_deudma;

static int sha1_hmac_final_impl(struct shash_desc *desc, u8 *out, bool hash_final);

/*! \fn static void sha1_hmac_transform(struct crypto_tfm *tfm, u32 const *in)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief save input block to context   
 *  \param tfm linux crypto algo transform  
 *  \param in 64-byte block of input  
*/                                 
static int sha1_hmac_transform(struct shash_desc *desc, u32 const *in)
{
    struct sha1_hmac_ctx *sctx =  crypto_shash_ctx(desc->tfm);

    if ( ((sctx->dbn<<4)+1) > SHA1_HMAC_DBN_TEMP_SIZE )
    {
        //printk("SHA1_HMAC_DBN_TEMP_SIZE exceeded\n");
        sha1_hmac_final_impl(desc, (u8 *)sctx->hash, false);
    }

    memcpy(&sctx->temp[sctx->dbn], in, 64); //dbn workaround
    sctx->dbn += 1;

    return 0;
}

/*! \fn int sha1_hmac_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief sets sha1 hmac key   
 *  \param tfm linux crypto algo transform  
 *  \param key input key  
 *  \param keylen key length greater than 64 bytes IS NOT SUPPORTED  
*/                                 
static int sha1_hmac_setkey(struct crypto_shash *tfm, const u8 *key, unsigned int keylen)
{
    struct sha1_hmac_ctx *sctx = crypto_shash_ctx(tfm);
    int err;

    if (keylen > SHA1_HMAC_MAX_KEYLEN) {
        char *hash_alg_name = "sha1";

        sctx->desc->tfm = crypto_alloc_shash(hash_alg_name, 0, 0);
        if (IS_ERR(sctx->desc->tfm)) return PTR_ERR(sctx->desc->tfm);

        memset(sctx->key, 0, SHA1_HMAC_MAX_KEYLEN);
        err = crypto_shash_digest(sctx->desc, key, keylen, sctx->key);
        if (err) return err;

        sctx->keylen = SHA1_DIGEST_SIZE;

        crypto_free_shash(sctx->desc->tfm);
    } else {
        memcpy(sctx->key, key, keylen);
        sctx->keylen = keylen;
    }
    memset(sctx->key + sctx->keylen, 0, SHA1_HMAC_MAX_KEYLEN - sctx->keylen);

    //printk("Setting keys of len: %d\n", keylen);

    return 0;
}

/*! \fn int sha1_hmac_setkey_hw(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief sets sha1 hmac key  into hw registers 
 *  \param tfm linux crypto algo transform  
 *  \param key input key  
 *  \param keylen key length greater than 64 bytes IS NOT SUPPORTED  
*/                                 
static int sha1_hmac_setkey_hw(const u8 *key, unsigned int keylen)
{
    volatile struct deu_hash_t *hash = (struct deu_hash_t *) HASH_START;
    int i, j;
    u32 *in_key = (u32 *)key;        

    j = 0;

    hash->KIDX |= 0x80000000; //reset keys back to 0
    for (i = 0; i < keylen; i+=4)
    {
         hash->KIDX = j;
         asm("sync");
         hash->KEY = *((u32 *) in_key + j); 
         j++;
    }

    return 0;
}

/*! \fn void sha1_hmac_init(struct crypto_tfm *tfm)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief initialize sha1 hmac context   
 *  \param tfm linux crypto algo transform  
*/                                 
static int sha1_hmac_init(struct shash_desc *desc)
{
    struct sha1_hmac_ctx *sctx =  crypto_shash_ctx(desc->tfm);

    //printk("debug ln: %d, fn: %s\n", __LINE__, __func__);
    sctx->dbn = 0; //dbn workaround
    sctx->started = 0;
    sctx->count = 0;

    return 0;
}

/*! \fn static void sha1_hmac_update(struct crypto_tfm *tfm, const u8 *data, unsigned int len)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief on-the-fly sha1 hmac computation   
 *  \param tfm linux crypto algo transform  
 *  \param data input data  
 *  \param len size of input data 
*/                                 
static int sha1_hmac_update(struct shash_desc *desc, const u8 *data,
            unsigned int len)
{
    struct sha1_hmac_ctx *sctx =  crypto_shash_ctx(desc->tfm);
    unsigned int i, j;

    j = (sctx->count >> 3) & 0x3f;
    sctx->count += len << 3;
   // printk("sctx->count = %d\n", sctx->count);

    if ((j + len) > 63) {
        memcpy (&sctx->buffer[j], data, (i = 64 - j));
        sha1_hmac_transform (desc, (const u32 *)sctx->buffer);
        for (; i + 63 < len; i += 64) {
            sha1_hmac_transform (desc, (const u32 *)&data[i]);
        }

        j = 0;
    }
    else
        i = 0;

    memcpy (&sctx->buffer[j], &data[i], len - i);
    return 0;
}

/*! \fn static int sha1_hmac_final(struct crypto_tfm *tfm, u8 *out)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief call sha1_hmac_final_impl with hash_final true   
 *  \param tfm linux crypto algo transform  
 *  \param out final sha1 hmac output value  
*/                                 
static int sha1_hmac_final(struct shash_desc *desc, u8 *out)
{
    return sha1_hmac_final_impl(desc, out, true);
}

/*! \fn static int sha1_hmac_final_impl(struct crypto_tfm *tfm, u8 *out, bool hash_final)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief ompute final or intermediate sha1 hmac value   
 *  \param tfm linux crypto algo transform  
 *  \param out final sha1 hmac output value  
 *  \param in finalize or intermediate processing  
*/                                 
static int sha1_hmac_final_impl(struct shash_desc *desc, u8 *out, bool hash_final)
{
    struct sha1_hmac_ctx *sctx =  crypto_shash_ctx(desc->tfm);
    u32 index, padlen;
    u64 t;
    u8 bits[8] = { 0, };
    static const u8 padding[64] = { 0x80, };
    volatile struct deu_hash_t *hashs = (struct deu_hash_t *) HASH_START;
    unsigned long flag;
    int i = 0;
    int dbn;
    u32 *in = sctx->temp[0];

    if (hash_final) {
        t = sctx->count + 512; // need to add 512 bit of the IPAD operation
        bits[7] = 0xff & t;
        t >>= 8;
        bits[6] = 0xff & t;
        t >>= 8;
        bits[5] = 0xff & t;
        t >>= 8;
        bits[4] = 0xff & t;
        t >>= 8;
        bits[3] = 0xff & t;
        t >>= 8;
        bits[2] = 0xff & t;
        t >>= 8;
        bits[1] = 0xff & t;
        t >>= 8;
        bits[0] = 0xff & t;

        /* Pad out to 56 mod 64 */
        index = (sctx->count >> 3) & 0x3f;
        padlen = (index < 56) ? (56 - index) : ((64 + 56) - index);
        sha1_hmac_update (desc, padding, padlen);

        /* Append length */
        sha1_hmac_update (desc, bits, sizeof bits);
    }

    CRTCL_SECT_HASH_START;

    SHA_HASH_INIT;

    sha1_hmac_setkey_hw(sctx->key, sctx->keylen);

    if (hash_final) {
        hashs->DBN = sctx->dbn;
    } else {
        hashs->DBN = sctx->dbn + 5;
    }
    asm("sync");

    //for vr9 change, ENDI = 1
    *IFX_HASH_CON = HASH_CON_VALUE; 

    //wait for processing
    while (hashs->controlr.BSY) {
        // this will not take long
    }

    if (sctx->started) {
        hashs->D1R = *((u32 *) sctx->hash + 0);
        hashs->D2R = *((u32 *) sctx->hash + 1);
        hashs->D3R = *((u32 *) sctx->hash + 2);
        hashs->D4R = *((u32 *) sctx->hash + 3);
        hashs->D5R = *((u32 *) sctx->hash + 4);
    } else {
        sctx->started = 1;
    }

    for (dbn = 0; dbn < sctx->dbn; dbn++)
    {
        for (i = 0; i < 16; i++) {
            hashs->MR = in[i];
        };

        hashs->controlr.GO = 1;
        asm("sync");

        //wait for processing
        while (hashs->controlr.BSY) {
            // this will not take long
        }
    
        in += 16;
    }


#if 1
    if (hash_final) {
        //wait for digest ready
        while (! hashs->controlr.DGRY) {
            // this will not take long
        }
    }
#endif

    *((u32 *) out + 0) = hashs->D1R;
    *((u32 *) out + 1) = hashs->D2R;
    *((u32 *) out + 2) = hashs->D3R;
    *((u32 *) out + 3) = hashs->D4R;
    *((u32 *) out + 4) = hashs->D5R;

    CRTCL_SECT_HASH_END;

    if (hash_final) {
        sha1_hmac_init(desc);
    } else {
        sctx->dbn = 0;
    }
    //printk("debug ln: %d, fn: %s\n", __LINE__, __func__);

    return 0;

}

/*! \fn void sha1_hmac_init_tfm(struct crypto_tfm *tfm)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief initialize pointers in sha1_hmac_ctx
 *  \param tfm linux crypto algo transform
*/
static int sha1_hmac_init_tfm(struct crypto_tfm *tfm)
{
    struct sha1_hmac_ctx *sctx = crypto_tfm_ctx(tfm);
    sctx->temp = kzalloc(4 * SHA1_HMAC_DBN_TEMP_SIZE, GFP_KERNEL);
    if (IS_ERR(sctx->temp)) return PTR_ERR(sctx->temp);
    sctx->desc = kzalloc(sizeof(struct shash_desc), GFP_KERNEL);
    if (IS_ERR(sctx->desc)) return PTR_ERR(sctx->desc);

    return 0;
}

/*! \fn void sha1_hmac_exit_tfm(struct crypto_tfm *tfm)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief free pointers in sha1_hmac_ctx
 *  \param tfm linux crypto algo transform
*/
static void sha1_hmac_exit_tfm(struct crypto_tfm *tfm)
{
    struct sha1_hmac_ctx *sctx = crypto_tfm_ctx(tfm);
    kfree(sctx->temp);
    kfree(sctx->desc);
}

/* 
 * \brief SHA1_HMAC function mappings
*/

static struct shash_alg ifxdeu_sha1_hmac_alg = {
    .digestsize         =       SHA1_DIGEST_SIZE,
    .init               =       sha1_hmac_init,
    .update             =       sha1_hmac_update,
    .final              =       sha1_hmac_final,
    .setkey             =       sha1_hmac_setkey,
    .descsize           =       sizeof(struct sha1_hmac_ctx),
    .base               =       {
        .cra_name       =       "hmac(sha1)",
        .cra_driver_name=       "ifxdeu-sha1_hmac",
        .cra_priority   =       400,
        .cra_ctxsize    =       sizeof(struct sha1_hmac_ctx),
        .cra_flags      =       CRYPTO_ALG_TYPE_HASH | CRYPTO_ALG_KERN_DRIVER_ONLY,
        .cra_blocksize  =       SHA1_HMAC_BLOCK_SIZE,
        .cra_module     =       THIS_MODULE,
        .cra_init       =       sha1_hmac_init_tfm,
        .cra_exit       =       sha1_hmac_exit_tfm,
        }
};

/*! \fn int ifxdeu_init_sha1_hmac (void)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief initialize sha1 hmac driver    
*/                                 
int ifxdeu_init_sha1_hmac (void)
{
    int ret = -ENOSYS;



    if ((ret = crypto_register_shash(&ifxdeu_sha1_hmac_alg)))
        goto sha1_err;

    printk (KERN_NOTICE "IFX DEU SHA1_HMAC initialized%s.\n", disable_deudma ? "" : " (DMA)");
    return ret;

sha1_err:
    printk(KERN_ERR "IFX DEU SHA1_HMAC initialization failed!\n");
    return ret;
}

/*! \fn void ifxdeu_fini_sha1_hmac (void)
 *  \ingroup IFX_SHA1_HMAC_FUNCTIONS
 *  \brief unregister sha1 hmac driver    
*/                                 
void ifxdeu_fini_sha1_hmac (void)
{

    crypto_unregister_shash(&ifxdeu_sha1_hmac_alg);


}
