linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * exynos-rng.c - Random Number Generator driver for the Exynos

 *

 * Copyright (c) 2017 Krzysztof Kozlowski <krzk@kernel.org>

 *

 * Loosely based on old driver from drivers/char/hw_random/exynos-rng.c:

 * Copyright (C) 2012 Samsung Electronics

 * Jonghwa Lee <jonghwa3.lee@samsung.com>

 */

​

#include <linux/clk.h>

#include <linux/crypto.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of_device.h>

#include <linux/platform_device.h>

​

#include <crypto/internal/rng.h>

​

#define EXYNOS_RNG_CONTROL      0x0

#define EXYNOS_RNG_STATUS       0x10

​

#define EXYNOS_RNG_SEED_CONF        0x14

#define EXYNOS_RNG_GEN_PRNG         BIT(1)

​

#define EXYNOS_RNG_SEED_BASE        0x140

#define EXYNOS_RNG_SEED(n)      (EXYNOS_RNG_SEED_BASE + (n * 0x4))

#define EXYNOS_RNG_OUT_BASE     0x160

#define EXYNOS_RNG_OUT(n)       (EXYNOS_RNG_OUT_BASE + (n * 0x4))

​

/* EXYNOS_RNG_CONTROL bit fields */

#define EXYNOS_RNG_CONTROL_START    0x18

/* EXYNOS_RNG_STATUS bit fields */

#define EXYNOS_RNG_STATUS_SEED_SETTING_DONE BIT(1)

#define EXYNOS_RNG_STATUS_RNG_DONE      BIT(5)

​

/* Five seed and output registers, each 4 bytes */

#define EXYNOS_RNG_SEED_REGS        5

#define EXYNOS_RNG_SEED_SIZE        (EXYNOS_RNG_SEED_REGS * 4)

​

enum exynos_prng_type {

    EXYNOS_PRNG_UNKNOWN = 0,

    EXYNOS_PRNG_EXYNOS4,

    EXYNOS_PRNG_EXYNOS5,

};

​

/*

 * Driver re-seeds itself with generated random numbers to hinder

 * backtracking of the original seed.

 *

 * Time for next re-seed in ms.

 */

#define EXYNOS_RNG_RESEED_TIME      1000

#define EXYNOS_RNG_RESEED_BYTES     65536

​

/*

 * In polling mode, do not wait infinitely for the engine to finish the work.

 */

#define EXYNOS_RNG_WAIT_RETRIES     100

​