/*
 * Cryptographic API.
 *
 * MD5 Message Digest Algorithm (RFC1321).
 *
 * Adapted for OCTEON by Aaro Koskinen <aaro.koskinen@iki.fi>.
 *
 * Based on crypto/md5.c, which is:
 *
 * 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.
 */

#include <crypto/md5.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/string.h>
#include <asm/byteorder.h>
#include <asm/octeon/octeon.h>
#include <crypto/internal/hash.h>

#include "octeon-crypto.h"

/*
 * We pass everything as 64-bit. OCTEON can handle misaligned data.
 */

static void octeon_md5_store_hash(struct md5_state *ctx)
{
        u64 *hash = (u64 *)ctx->hash;

        write_octeon_64bit_hash_dword(hash[0], 0);
        write_octeon_64bit_hash_dword(hash[1], 1);
}

static void octeon_md5_read_hash(struct md5_state *ctx)
{
        u64 *hash = (u64 *)ctx->hash;

        hash[0] = read_octeon_64bit_hash_dword(0);
        hash[1] = read_octeon_64bit_hash_dword(1);
}

static void octeon_md5_transform(const void *_block)
{
        const u64 *block = _block;

        write_octeon_64bit_block_dword(block[0], 0);
        write_octeon_64bit_block_dword(block[1], 1);
        write_octeon_64bit_block_dword(block[2], 2);
        write_octeon_64bit_block_dword(block[3], 3);
        write_octeon_64bit_block_dword(block[4], 4);
        write_octeon_64bit_block_dword(block[5], 5);
        write_octeon_64bit_block_dword(block[6], 6);
        octeon_md5_start(block[7]);
}

static int octeon_md5_init(struct shash_desc *desc)
{
        struct md5_state *mctx = shash_desc_ctx(desc);

        mctx->hash[0] = MD5_H0;
        mctx->hash[1] = MD5_H1;
        mctx->hash[2] = MD5_H2;
        mctx->hash[3] = MD5_H3;
        cpu_to_le32_array(mctx->hash, 4);
        mctx->byte_count = 0;

        return 0;
}

static int octeon_md5_update(struct shash_desc *desc, const u8 *data,
                             unsigned int len)
{
        struct md5_state *mctx = shash_desc_ctx(desc);
        const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
        struct octeon_cop2_state state;
        unsigned long flags;

        mctx->byte_count += len;

        if (avail > len) {
                memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
                       data, len);
                return 0;
        }

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

        flags = octeon_crypto_enable(&state);
        octeon_md5_store_hash(mctx);

        octeon_md5_transform(mctx->block);
        data += avail;
        len -= avail;

        while (len >= sizeof(mctx->block)) {
                octeon_md5_transform(data);
                data += sizeof(mctx->block);
                len -= sizeof(mctx->block);
        }

        octeon_md5_read_hash(mctx);
        octeon_crypto_disable(&state, flags);

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

        return 0;
}

static int octeon_md5_final(struct shash_desc *desc, u8 *out)
{
        struct md5_state *mctx = shash_desc_ctx(desc);
        const unsigned int offset = mctx->byte_count & 0x3f;
        char *p = (char *)mctx->block + offset;
        int padding = 56 - (offset + 1);
        struct octeon_cop2_state state;
        unsigned long flags;

        *p++ = 0x80;

        flags = octeon_crypto_enable(&state);
        octeon_md5_store_hash(mctx);

        if (padding < 0) {
                memset(p, 0x00, padding + sizeof(u64));
                octeon_md5_transform(mctx->block);
                p = (char *)mctx->block;
                padding = 56;
        }

        memset(p, 0, padding);
        mctx->block[14] = mctx->byte_count << 3;
        mctx->block[15] = mctx->byte_count >> 29;
        cpu_to_le32_array(mctx->block + 14, 2);
        octeon_md5_transform(mctx->block);

        octeon_md5_read_hash(mctx);
        octeon_crypto_disable(&state, flags);

        memcpy(out, mctx->hash, sizeof(mctx->hash));
        memset(mctx, 0, sizeof(*mctx));

        return 0;
}

static int octeon_md5_export(struct shash_desc *desc, void *out)
{
        struct md5_state *ctx = shash_desc_ctx(desc);

        memcpy(out, ctx, sizeof(*ctx));
        return 0;
}

static int octeon_md5_import(struct shash_desc *desc, const void *in)
{
        struct md5_state *ctx = shash_desc_ctx(desc);

        memcpy(ctx, in, sizeof(*ctx));
        return 0;
}

static struct shash_alg alg = {
        .digestsize     =       MD5_DIGEST_SIZE,
        .init           =       octeon_md5_init,
        .update         =       octeon_md5_update,
        .final          =       octeon_md5_final,
        .export         =       octeon_md5_export,
        .import         =       octeon_md5_import,
        .descsize       =       sizeof(struct md5_state),
        .statesize      =       sizeof(struct md5_state),
        .base           =       {
                .cra_name       =       "md5",
                .cra_driver_name=       "octeon-md5",
                .cra_priority   =       OCTEON_CR_OPCODE_PRIORITY,
                .cra_blocksize  =       MD5_HMAC_BLOCK_SIZE,
                .cra_module     =       THIS_MODULE,
        }
};

static int __init md5_mod_init(void)
{
        if (!octeon_has_crypto())
                return -ENOTSUPP;
        return crypto_register_shash(&alg);
}

static void __exit md5_mod_fini(void)
{
        crypto_unregister_shash(&alg);
}

module_init(md5_mod_init);
module_exit(md5_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MD5 Message Digest Algorithm (OCTEON)");
MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");