/*
 * Cryptographic API.
 *
 * SHA-224 and SHA-256 Secure Hash Algorithm.
 *
 * Adapted for OCTEON by Aaro Koskinen <aaro.koskinen@iki.fi>.
 *
 * Based on crypto/sha256_generic.c, which is:
 *
 * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * SHA224 Support Copyright 2007 Intel Corporation <jonathan.lynch@intel.com>
 *
 * 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 <linux/mm.h>
#include <crypto/sha.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/module.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_sha256_store_hash(struct sha256_state *sctx)
{
        u64 *hash = (u64 *)sctx->state;

        write_octeon_64bit_hash_dword(hash[0], 0);
        write_octeon_64bit_hash_dword(hash[1], 1);
        write_octeon_64bit_hash_dword(hash[2], 2);
        write_octeon_64bit_hash_dword(hash[3], 3);
}

static void octeon_sha256_read_hash(struct sha256_state *sctx)
{
        u64 *hash = (u64 *)sctx->state;

        hash[0] = read_octeon_64bit_hash_dword(0);
        hash[1] = read_octeon_64bit_hash_dword(1);
        hash[2] = read_octeon_64bit_hash_dword(2);
        hash[3] = read_octeon_64bit_hash_dword(3);
}

static void octeon_sha256_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_sha256_start(block[7]);
}

static int octeon_sha224_init(struct shash_desc *desc)
{
        struct sha256_state *sctx = shash_desc_ctx(desc);

        sctx->state[0] = SHA224_H0;
        sctx->state[1] = SHA224_H1;
        sctx->state[2] = SHA224_H2;
        sctx->state[3] = SHA224_H3;
        sctx->state[4] = SHA224_H4;
        sctx->state[5] = SHA224_H5;
        sctx->state[6] = SHA224_H6;
        sctx->state[7] = SHA224_H7;
        sctx->count = 0;

        return 0;
}

static int octeon_sha256_init(struct shash_desc *desc)
{
        struct sha256_state *sctx = shash_desc_ctx(desc);

        sctx->state[0] = SHA256_H0;
        sctx->state[1] = SHA256_H1;
        sctx->state[2] = SHA256_H2;
        sctx->state[3] = SHA256_H3;
        sctx->state[4] = SHA256_H4;
        sctx->state[5] = SHA256_H5;
        sctx->state[6] = SHA256_H6;
        sctx->state[7] = SHA256_H7;
        sctx->count = 0;

        return 0;
}

static void __octeon_sha256_update(struct sha256_state *sctx, const u8 *data,
                                   unsigned int len)
{
        unsigned int partial;
        unsigned int done;
        const u8 *src;

        partial = sctx->count % SHA256_BLOCK_SIZE;
        sctx->count += len;
        done = 0;
        src = data;

        if ((partial + len) >= SHA256_BLOCK_SIZE) {
                if (partial) {
                        done = -partial;
                        memcpy(sctx->buf + partial, data,
                               done + SHA256_BLOCK_SIZE);
                        src = sctx->buf;
                }

                do {
                        octeon_sha256_transform(src);
                        done += SHA256_BLOCK_SIZE;
                        src = data + done;
                } while (done + SHA256_BLOCK_SIZE <= len);

                partial = 0;
        }
        memcpy(sctx->buf + partial, src, len - done);
}

static int octeon_sha256_update(struct shash_desc *desc, const u8 *data,
                                unsigned int len)
{
        struct sha256_state *sctx = shash_desc_ctx(desc);
        struct octeon_cop2_state state;
        unsigned long flags;

        /*
         * Small updates never reach the crypto engine, so the generic sha256 is
         * faster because of the heavyweight octeon_crypto_enable() /
         * octeon_crypto_disable().
         */
        if ((sctx->count % SHA256_BLOCK_SIZE) + len < SHA256_BLOCK_SIZE)
                return crypto_sha256_update(desc, data, len);

        flags = octeon_crypto_enable(&state);
        octeon_sha256_store_hash(sctx);

        __octeon_sha256_update(sctx, data, len);

        octeon_sha256_read_hash(sctx);
        octeon_crypto_disable(&state, flags);

        return 0;
}

static int octeon_sha256_final(struct shash_desc *desc, u8 *out)
{
        struct sha256_state *sctx = shash_desc_ctx(desc);
        static const u8 padding[64] = { 0x80, };
        struct octeon_cop2_state state;
        __be32 *dst = (__be32 *)out;
        unsigned int pad_len;
        unsigned long flags;
        unsigned int index;
        __be64 bits;
        int i;

        /* Save number of bits. */
        bits = cpu_to_be64(sctx->count << 3);

        /* Pad out to 56 mod 64. */
        index = sctx->count & 0x3f;
        pad_len = (index < 56) ? (56 - index) : ((64+56) - index);

        flags = octeon_crypto_enable(&state);
        octeon_sha256_store_hash(sctx);

        __octeon_sha256_update(sctx, padding, pad_len);

        /* Append length (before padding). */
        __octeon_sha256_update(sctx, (const u8 *)&bits, sizeof(bits));

        octeon_sha256_read_hash(sctx);
        octeon_crypto_disable(&state, flags);

        /* Store state in digest */
        for (i = 0; i < 8; i++)
                dst[i] = cpu_to_be32(sctx->state[i]);

        /* Zeroize sensitive information. */
        memset(sctx, 0, sizeof(*sctx));

        return 0;
}

static int octeon_sha224_final(struct shash_desc *desc, u8 *hash)
{
        u8 D[SHA256_DIGEST_SIZE];

        octeon_sha256_final(desc, D);

        memcpy(hash, D, SHA224_DIGEST_SIZE);
        memzero_explicit(D, SHA256_DIGEST_SIZE);

        return 0;
}

static int octeon_sha256_export(struct shash_desc *desc, void *out)
{
        struct sha256_state *sctx = shash_desc_ctx(desc);

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

static int octeon_sha256_import(struct shash_desc *desc, const void *in)
{
        struct sha256_state *sctx = shash_desc_ctx(desc);

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

static struct shash_alg octeon_sha256_algs[2] = { {
        .digestsize     =       SHA256_DIGEST_SIZE,
        .init           =       octeon_sha256_init,
        .update         =       octeon_sha256_update,
        .final          =       octeon_sha256_final,
        .export         =       octeon_sha256_export,
        .import         =       octeon_sha256_import,
        .descsize       =       sizeof(struct sha256_state),
        .statesize      =       sizeof(struct sha256_state),
        .base           =       {
                .cra_name       =       "sha256",
                .cra_driver_name=       "octeon-sha256",
                .cra_priority   =       OCTEON_CR_OPCODE_PRIORITY,
                .cra_flags      =       CRYPTO_ALG_TYPE_SHASH,
                .cra_blocksize  =       SHA256_BLOCK_SIZE,
                .cra_module     =       THIS_MODULE,
        }
}, {
        .digestsize     =       SHA224_DIGEST_SIZE,
        .init           =       octeon_sha224_init,
        .update         =       octeon_sha256_update,
        .final          =       octeon_sha224_final,
        .descsize       =       sizeof(struct sha256_state),
        .base           =       {
                .cra_name       =       "sha224",
                .cra_driver_name=       "octeon-sha224",
                .cra_flags      =       CRYPTO_ALG_TYPE_SHASH,
                .cra_blocksize  =       SHA224_BLOCK_SIZE,
                .cra_module     =       THIS_MODULE,
        }
} };

static int __init octeon_sha256_mod_init(void)
{
        if (!octeon_has_crypto())
                return -ENOTSUPP;
        return crypto_register_shashes(octeon_sha256_algs,
                                       ARRAY_SIZE(octeon_sha256_algs));
}

static void __exit octeon_sha256_mod_fini(void)
{
        crypto_unregister_shashes(octeon_sha256_algs,
                                  ARRAY_SIZE(octeon_sha256_algs));
}

module_init(octeon_sha256_mod_init);
module_exit(octeon_sha256_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA-224 and SHA-256 Secure Hash Algorithm (OCTEON)");
MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");