/*
 * Copyright (c) 2014, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * 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.
 *
 */

#ifndef __MSM_CTR_DRBG_H__
#define __MSM_CTR_DRBG_H__

/* This is the module that is actually follows the details of NIST SP
 * 800-90 so it can claim to use a FIPS-approved algorithm.
 */

/* Added ctr_drbg_generate_w_data which supplies
 * additional input to the generate operation.
 */


#define CTR_DRBG_MAX_REQ_LEN_BITS	(1 << 19)
#define CTR_DRBG_SEED_LEN_BITS		256
#define CTR_DRBG_BLOCK_LEN_BITS		128
#define CTR_DRBG_BLOCK_LEN_BYTES	(CTR_DRBG_BLOCK_LEN_BITS/8)
#define CTR_DRBG_MAX_RESEED_INTERVAL	(1ULL << 48)

#define MSM_AES128_BLOCK_SIZE   (16)
#define MSM_ENTROPY_BUFFER_SIZE (16)
#define MSM_NONCE_BUFFER_SIZE   (8)

enum ctr_drbg_status_t {
	CTR_DRBG_SUCCESS = 0,
	CTR_DRBG_NEEDS_RESEED,
	CTR_DRBG_INVALID_ARG,
	CTR_DRBG_GENERAL_ERROR = 0xFF,
};

union ctr_drbg_seed_t {
	uint8_t as_bytes[32];
	uint32_t as_words[8];
	uint64_t as_64[4];
	struct {
		uint8_t key[16];
		uint8_t V[16];
	} key_V;
};

struct msm_ctr_tcrypt_result_s {
	struct completion completion;
	int err;
};

struct msm_ctr_buffer_s {
	unsigned char *virt_addr;
};

struct aes_struct_s {
	struct crypto_ablkcipher	*tfm;
	struct ablkcipher_request	*req;
	struct msm_ctr_buffer_s		input;
	struct msm_ctr_buffer_s		output;
	struct msm_ctr_tcrypt_result_s	result;
};

struct ctr_drbg_ctx_s {
	unsigned long long reseed_counter;  /* starts at 1 as per SP
					     * 800-90
					     */
	unsigned long long	reseed_interval;
	union ctr_drbg_seed_t	seed;
	struct aes_struct_s	aes_ctx;
	struct aes_struct_s	df_aes_ctx;
	uint8_t			prev_drn[MSM_AES128_BLOCK_SIZE];
	uint8_t			continuous_test_started;
};

enum ctr_drbg_status_t ctr_drbg_instantiate(struct ctr_drbg_ctx_s *ctx,
					const uint8_t *entropy,
					size_t entropy_len_bits,
					const uint8_t *nonce,
					size_t nonce_len_bits,
					unsigned long long reseed_interval);

enum ctr_drbg_status_t ctr_drbg_reseed(struct ctr_drbg_ctx_s *ctx,
				const void *entropy,
				size_t entropy_len);

enum ctr_drbg_status_t ctr_drbg_generate_w_data(struct ctr_drbg_ctx_s *ctx,
			void *additional_input,
			size_t additional_input_len_bits,
			void *buffer,
			size_t len_bits);

enum ctr_drbg_status_t ctr_drbg_generate(struct ctr_drbg_ctx_s *ctx,
				void *buffer,
				size_t len);

void ctr_drbg_uninstantiate(struct ctr_drbg_ctx_s *ctx);

enum ctr_drbg_status_t block_cipher_df(struct ctr_drbg_ctx_s *ctx,
				const uint8_t *input,
				uint32_t input_size,
				uint8_t *output,
				uint32_t output_size
				);
void ctr_aes_deinit(struct ctr_drbg_ctx_s *ctx);

#endif /* __MSM_CTR_DRBG_H__ */