/**
 * AES CTR routines supporting the Power 7+ Nest Accelerators driver
 *
 * Copyright (C) 2011-2012 International Business Machines Inc.
 *
 * 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; version 2 only.
 *
 * This program 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Author: Kent Yoder <yoder1@us.ibm.com>
 */

#include <crypto/aes.h>
#include <crypto/ctr.h>
#include <crypto/algapi.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <asm/vio.h>

#include "nx_csbcpb.h"
#include "nx.h"


static int ctr_aes_nx_set_key(struct crypto_tfm *tfm,
			      const u8          *in_key,
			      unsigned int       key_len)
{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(tfm);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;

	nx_ctx_init(nx_ctx, HCOP_FC_AES);

	switch (key_len) {
	case AES_KEYSIZE_128:
		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_128);
		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_128];
		break;
	case AES_KEYSIZE_192:
		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_192);
		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_192];
		break;
	case AES_KEYSIZE_256:
		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_256);
		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_256];
		break;
	default:
		return -EINVAL;
	}

	csbcpb->cpb.hdr.mode = NX_MODE_AES_CTR;
	memcpy(csbcpb->cpb.aes_ctr.key, in_key, key_len);

	return 0;
}

static int ctr3686_aes_nx_set_key(struct crypto_tfm *tfm,
				  const u8          *in_key,
				  unsigned int       key_len)
{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(tfm);

	if (key_len < CTR_RFC3686_NONCE_SIZE)
		return -EINVAL;

	memcpy(nx_ctx->priv.ctr.nonce,
	       in_key + key_len - CTR_RFC3686_NONCE_SIZE,
	       CTR_RFC3686_NONCE_SIZE);

	key_len -= CTR_RFC3686_NONCE_SIZE;

	return ctr_aes_nx_set_key(tfm, in_key, key_len);
}

static int ctr_aes_nx_crypt(struct blkcipher_desc *desc,
			    struct scatterlist    *dst,
			    struct scatterlist    *src,
			    unsigned int           nbytes)
{
	struct nx_crypto_ctx *nx_ctx = crypto_blkcipher_ctx(desc->tfm);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
	unsigned long irq_flags;
	unsigned int processed = 0, to_process;
	int rc;

	spin_lock_irqsave(&nx_ctx->lock, irq_flags);

	do {
		to_process = nbytes - processed;

		rc = nx_build_sg_lists(nx_ctx, desc, dst, src, &to_process,
				       processed, csbcpb->cpb.aes_ctr.iv);
		if (rc)
			goto out;

		if (!nx_ctx->op.inlen || !nx_ctx->op.outlen) {
			rc = -EINVAL;
			goto out;
		}

		rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
				   desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP);
		if (rc)
			goto out;

		memcpy(desc->info, csbcpb->cpb.aes_cbc.cv, AES_BLOCK_SIZE);

		atomic_inc(&(nx_ctx->stats->aes_ops));
		atomic64_add(csbcpb->csb.processed_byte_count,
			     &(nx_ctx->stats->aes_bytes));

		processed += to_process;
	} while (processed < nbytes);
out:
	spin_unlock_irqrestore(&nx_ctx->lock, irq_flags);
	return rc;
}

static int ctr3686_aes_nx_crypt(struct blkcipher_desc *desc,
				struct scatterlist    *dst,
				struct scatterlist    *src,
				unsigned int           nbytes)
{
	struct nx_crypto_ctx *nx_ctx = crypto_blkcipher_ctx(desc->tfm);
	u8 iv[16];

	memcpy(iv, nx_ctx->priv.ctr.nonce, CTR_RFC3686_IV_SIZE);
	memcpy(iv + CTR_RFC3686_NONCE_SIZE,
	       desc->info, CTR_RFC3686_IV_SIZE);
	iv[12] = iv[13] = iv[14] = 0;
	iv[15] = 1;

	desc->info = iv;

	return ctr_aes_nx_crypt(desc, dst, src, nbytes);
}

struct crypto_alg nx_ctr3686_aes_alg = {
	.cra_name        = "rfc3686(ctr(aes))",
	.cra_driver_name = "rfc3686-ctr-aes-nx",
	.cra_priority    = 300,
	.cra_flags       = CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize   = 1,
	.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
	.cra_type        = &crypto_blkcipher_type,
	.cra_module      = THIS_MODULE,
	.cra_init        = nx_crypto_ctx_aes_ctr_init,
	.cra_exit        = nx_crypto_ctx_exit,
	.cra_blkcipher = {
		.min_keysize = AES_MIN_KEY_SIZE + CTR_RFC3686_NONCE_SIZE,
		.max_keysize = AES_MAX_KEY_SIZE + CTR_RFC3686_NONCE_SIZE,
		.ivsize      = CTR_RFC3686_IV_SIZE,
		.geniv       = "seqiv",
		.setkey      = ctr3686_aes_nx_set_key,
		.encrypt     = ctr3686_aes_nx_crypt,
		.decrypt     = ctr3686_aes_nx_crypt,
	}
};