/*
 * Cryptographic API.
 *
 * Support for Infineon DEU hardware crypto engine.
 *
 * Copyright (c) 2005  Johannes Doering <info@com-style.de>, INFINEON
 *
 * modified from crypto/md5.c
 *
 * ---------------------------------------------------------------------------
 * Cryptographic API.
 *
 * MD5 Message Digest Algorithm (RFC1321).
 *
 * Derived from cryptoapi implementation, originally based on the
 * public domain implementation written by Colin Plumb in 1993.
 *
 * Copyright (c) Cryptoapi developers.
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 *
 * 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
 * ---------------------------------------------------------------------------
 */

/**
  \addtogroup AMAZON_S_DEU
  \ingroup AMAZON_S_BSP
  \brief amazon_s deu driver module
*/

/*!
  \file amazon_s_deu_md5_hmac.c
  \ingroup AMAZON_S_DEU
  \brief md5 hmac driver file
*/

/*!
  \addtogroup AMAZON_S_DEU_FUNCTIONS
  \ingroup AMAZON_S_DEU
  \brief amazon_s deu driver functions
*/

#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <linux/types.h>
#include <asm/byteorder.h>
#include <amazon_s_deu.h>

#define MD5_DIGEST_SIZE		16
#define MD5_HMAC_BLOCK_SIZE	64
#define MD5_BLOCK_WORDS		16
#define MD5_HASH_WORDS		4

#define MD5_HMAC_DBN_TEMP_SIZE	1024 // size in dword, needed for dbn workaround

#if 0
     #define CRTCL_SECT_INIT
     #define CRTCL_SECT_START       local_irq_save(flag)
     #define CRTCL_SECT_END         local_irq_restore(flag)
#else
     static spinlock_t lock;
     #define CRTCL_SECT_INIT        spin_lock_init(&lock)
     #define CRTCL_SECT_START       spin_lock_irqsave(&lock, flag)
     #define CRTCL_SECT_END         spin_unlock_irqrestore(&lock, flag)
#endif

//#define CRYPTO_DEBUG
#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

#ifdef CONFIG_CRYPTO_DEV_AMAZON_S_MD5_HMAC
#include <amazon_s.h>
#include <amazon_s_deu_structs.h>
#define HASH_START   AMAZON_S_HASH_CON
#endif
#ifdef CONFIG_CRYPTO_DEV_AMAZON_S_DMA
#include <amazon_s_deu_dma.h>
#include <amazon_s_dma.h>
#include <irq.h>
#endif

struct md5_hmac_ctx {
	u32 hash[MD5_HASH_WORDS];
	u32 block[MD5_BLOCK_WORDS];
	u64 byte_count;
	u32 dbn;
	u32 temp[MD5_HMAC_DBN_TEMP_SIZE];
};

extern int disable_deudma;

/*! \fn static u32 endian_swap(u32 input)
    \ingroup AMAZON_S_DEU_FUNCTIONS
    \brief perform dword level endian swap
    \param input value of dword that requires to be swapped
*/
static u32 endian_swap(u32 input)
{
    u8 *ptr = (u8 *)&input;

    return ((ptr[3] << 24) | (ptr[2] << 16) | (ptr[1] << 8) | ptr[0]);
}

/*! \fn static void md5_hmac_transform(struct crypto_tfm *tfm, u32 const *in)
    \ingroup AMAZON_S_DEU_FUNCTIONS
    \brief save input block to context
    \param tfm linux crypto algo transform
    \param in 64-byte block of input
*/
static void md5_hmac_transform(struct crypto_tfm *tfm, u32 const *in)
{
	struct md5_hmac_ctx *mctx = crypto_tfm_ctx(tfm);

	memcpy(&mctx->temp[mctx->dbn<<4], in, 64); //dbn workaround
        mctx->dbn += 1;

	if ( (mctx->dbn<<4) > MD5_HMAC_DBN_TEMP_SIZE )
	{
	    printk("MD5_HMAC_DBN_TEMP_SIZE exceeded\n");
	}

}

/*! \fn int md5_hmac_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
    \ingroup AMAZON_S_DEU_FUNCTIONS
    \brief sets md5 hmac key
    \param tfm linux crypto algo transform
    \param key input key
    \param keylen key length greater than 64 bytes IS NOT SUPPORTED
*/
int md5_hmac_setkey(struct crypto_tfm *tfm, 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;

    hash->KIDX = 0x80000000; // reset all 16 words of the key to '0'
    asm("sync");

    j = 0;
    for (i = 0; i < keylen; i+=4)
    {
         hash->KIDX = j;
         asm("sync");
         hash->KEY = *((u32 *) in_key + j);
         j++;
    }

    return 0;
}

/*! \fn void md5_hmac_init(struct crypto_tfm *tfm)
    \ingroup AMAZON_S_DEU_FUNCTIONS
    \brief initialize md5 hmac context
    \param tfm linux crypto algo transform
*/
void md5_hmac_init(struct crypto_tfm *tfm)
{
	struct md5_hmac_ctx *mctx = crypto_tfm_ctx(tfm);

        memset(mctx, 0, sizeof(struct md5_hmac_ctx));
	mctx->dbn = 0; //dbn workaround
}

/*! \fn void md5_hmac_update(struct crypto_tfm *tfm, const u8 *data, unsigned int len)
    \ingroup AMAZON_S_DEU_FUNCTIONS
    \brief on-the-fly md5 hmac computation
    \param tfm linux crypto algo transform
    \param data input data
    \param len size of input data
*/
void md5_hmac_update(struct crypto_tfm *tfm, const u8 *data, unsigned int len)
{
	struct md5_hmac_ctx *mctx = crypto_tfm_ctx(tfm);
	const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);

	mctx->byte_count += len;
        //printk("mctx->byte_count = %d\n", mctx->byte_count);

	if (avail > len) {
		memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
		       data, len);
		return;
	}

	memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
	       data, avail);

	md5_hmac_transform(tfm, mctx->block);
	data += avail;
	len -= avail;

	while (len >= sizeof(mctx->block)) {
		memcpy(mctx->block, data, sizeof(mctx->block));
		md5_hmac_transform(tfm, mctx->block);
		data += sizeof(mctx->block);
		len -= sizeof(mctx->block);
	}

	memcpy(mctx->block, data, len);

}

/*! \fn void md5_hmac_final(struct crypto_tfm *tfm, u8 *out)
    \ingroup AMAZON_S_DEU_FUNCTIONS
    \brief compute final md5 hmac value
    \param tfm linux crypto algo transform
    \param out final md5 hmac output value
*/
void md5_hmac_final(struct crypto_tfm *tfm, u8 *out)
{
	struct md5_hmac_ctx *mctx = crypto_tfm_ctx(tfm);
	const unsigned int offset = mctx->byte_count & 0x3f;
	char *p = (char *)mctx->block + offset;
	int padding = 56 - (offset + 1);
	volatile struct deu_hash_t *hashs = (struct deu_hash_t *) HASH_START;
	unsigned long flag;

	int i = 0;
    int dbn;
    u32 *in;

	*p++ = 0x80;
	if (padding < 0) {
		memset(p, 0x00, padding + sizeof (u64));
		md5_hmac_transform(tfm, mctx->block);
		p = (char *)mctx->block;
		padding = 56;
	}

	memset(p, 0, padding);
	mctx->block[14] = endian_swap((mctx->byte_count + 64) << 3); // need to add 512 bit of the IPAD operation
	mctx->block[15] = 0x00000000;

	md5_hmac_transform(tfm, mctx->block);

    in = &mctx->temp[0];

    CRTCL_SECT_START;


#if 0
    printk("dummy dbn = %d\n", 0xffff);
    hashs->DBN = 0xffff;
#else
    printk("dbn = %d\n", mctx->dbn);
    hashs->DBN = mctx->dbn;
#endif

    *AMAZON_S_HASH_CON = 0x0703002D; //khs, go, init, ndc, endi, kyue, hmen, md5

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

for (dbn = 0; dbn < mctx->dbn; dbn++)
{
#if 0
    if (dbn == (mctx->dbn - 1))
    {
         printk("dbn = %d\n", mctx->dbn);
         hashs->DBN = mctx->dbn;
    }
#endif

    for (i = 0; i < 16; i++) {
	    //printk("in[%d] = %08x\n", i, in[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
    //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_END;
}

static struct crypto_alg ifxdeu_md5_hmac_alg = {
	.cra_name	        =	"hmac(md5)",
	.cra_driver_name	=	"ifxdeu-md5_hmac",
	.cra_flags	        =	CRYPTO_ALG_TYPE_DIGEST,
	.cra_blocksize	        =	MD5_HMAC_BLOCK_SIZE,
	.cra_ctxsize	        =	sizeof(struct md5_hmac_ctx),
	.cra_module	        =	THIS_MODULE,
	.cra_list	        =	LIST_HEAD_INIT(ifxdeu_md5_hmac_alg.cra_list),
	.cra_u		        =	{ .digest = {
	.dia_digestsize	        =	MD5_DIGEST_SIZE,
        .dia_setkey             =       md5_hmac_setkey,
        .dia_init               =       md5_hmac_init,
        .dia_update             =       md5_hmac_update,
        .dia_final              =       md5_hmac_final } }
};

/*! \fn int __init ifxdeu_init_md5_hmac (void)
    \ingroup AMAZON_S_DEU_FUNCTIONS
    \brief initialize md5 hmac driver
*/
int __init ifxdeu_init_md5_hmac (void)
{
	int ret;

	if ((ret = crypto_register_alg(&ifxdeu_md5_hmac_alg)))
		goto md5_hmac_err;

	CRTCL_SECT_INIT;

	printk (KERN_NOTICE "IFX DEU MD5_HMAC initialized%s.\n", disable_deudma ? "" : " (DMA)");
	return ret;

md5_hmac_err:
	printk(KERN_ERR "IFX DEU MD5_HMAC initialization failed!\n");
	return ret;
}

/*! \fn void __exit ifxdeu_fini_md5_hmac (void)
    \ingroup AMAZON_S_DEU_FUNCTIONS
    \brief unregister md5 hmac driver
*/
void __exit ifxdeu_fini_md5_hmac (void)
{
	crypto_unregister_alg (&ifxdeu_md5_hmac_alg);
}