TRNGXXF3HSM.h

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/*!****************************************************************************
 *  @file       TRNGXXF3HSM.h
 *
 *  @brief      TRNG driver implementation for CC27XX and CC35XX device families
 *
 *  This file should only be included in the board file to fill the TRNG_config
 *  struct.
 *
 *  # Hardware
 *
 *  The CC27XX and CC35XX device families have a dedicated hardware engine,
 *  the Hardware Security Module (HSM) that contains TRNG capabilities based on
 *  sampling multiple free running oscillators (FROs).
 *
 *  # Behaviour
 *
 *  The driver submits a get random number token to the HSM. The token will indicate the
 *  destination buffer and the request size.
 *
 *  The TRNG driver can be used as a True Random Number Generator (TRNG) or as a Cryptographically
 *  Secure Pseudo Random Number Generator (CRNG). CRNG is a deterministic (hence the pseudo)
 *  computational method to turn an input (FRO samples) into a sequence of bits that are
 *  indistinguishable from ideal randomness, with cryptographic certainty, for a computationally
 *  bounded adversary not knowing the input.
 *
 *  By default, the HSM HW is configured and initialized to be in CRNG mode. To switch to TRNG,
 *  the user must call TRNGXXF3HSM_switchNrbgMode() API and specify TRNG_MODE_TRNG as the
 *  NRBG Mode.
 *
 *  # Samples Per Cycle Vs. Mix Cycles
 *
 *  # Mix Cycles
 *
 *  When the HSM EIP-130 HW in CRNG mode, the Mix Cycles value represents the number of clock
 *  cycles before the output is sampled. The MixCycles value must be in the range [0...15].
 *  However, in the current implementation the value 0 is interpreted as not configured and
 *  therefore will be set to 15 internally, which is also the default value.
 *
 *  # Samples Per Cycle
 *
 *  When the HSM EIP-130 HW is in TRNG mode, the Samples Per Cycle value represents the number of
 *  (XOR-ed) FRO samples XOR-ed together to generate a single 'noise' bit. This value must be
 *  set such that the total amount of entropy in 8 'noise' bits equals at least 1 bit. The value
 *  to program here depends upon the jitter behavior of the FROs.
 *
 *  !!!!!!!!!!!!! WARNING !!!!!!!!!!!!!
 *  The HSM HW engine is configured and initialized with the Samples Per Cycle value set to 19390
 *  and Mix Cycles value set to 15. This value is not available for the customer to configure.
 */

#ifndef ti_drivers_TRNG_TRNGXXF3HSM__include
#define ti_drivers_TRNG_TRNGXXF3HSM__include

#include <stdint.h>
#include <stdbool.h>

#include <ti/drivers/Power.h>
#include <ti/drivers/TRNG.h>
#include <ti/drivers/cryptoutils/cryptokey/CryptoKey.h>

#include <ti/drivers/dpl/HwiP.h>
#include <ti/drivers/dpl/SemaphoreP.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 *
 *  !!!!!!!!!!!!! WARNING !!!!!!!!!!!!!
 *  ## TRNG Driver Limitation for CC27XX and CC35XX device families #
 *
 *  For CC27XX and CC35XX devices, the size of random data requested must be a 32-bit multiple. The
 *  appropriate error code, TRNG_STATUS_INVALID_INPUT_SIZE, will be returned to the user in
 *  the case this rule is not adhered to and the input size is not a multiple of 4 bytes, (32-bits).
 *
 */

#define TRNG_STATUS_ALREADY_IN_SPECIFIED_NRBG_TYPE ((int_fast16_t)(TRNG_STATUS_RESERVED - 0))

#define TRNG_STATUS_INVALID_INPUT_SIZE ((int_fast16_t)(TRNG_STATUS_RESERVED - 1))

#define TRNG_STATUS_INVALID_KEY_ENCODING ((int_fast16_t)(TRNG_STATUS_RESERVED - 2))

typedef enum
{
    TRNG_MODE_CRNG = 1,
    TRNG_MODE_TRNG = 2,
} TRNGXXF3HSM_NRBGMode;

typedef struct
{
    uint8_t reserved1;
} TRNGXXF3HSM_HWAttrs;

typedef struct
{
    TRNG_Handle handle;
    TRNG_CryptoKeyCallbackFxn cryptoKeyCallbackFxn;
    TRNG_RandomBytesCallbackFxn randomBytesCallbackFxn;
    CryptoKey *entropyKey;
    uint8_t *entropyBuffer;
    uint32_t semaphoreTimeout;
    size_t entropyGenerated;
    size_t entropyRequested;
    size_t rawEntropyBlocksRequested;
    int_fast16_t returnStatus;
    int_fast16_t hsmStatus;
    TRNG_ReturnBehavior returnBehavior;
    bool isOpen;
} TRNGXXF3HSM_Object;

#if (DeviceFamily_PARENT == DeviceFamily_PARENT_CC27XX)

extern int_fast16_t TRNGXXF3HSM_reseedHSM(TRNG_Handle handle);

extern int_fast16_t TRNGXXF3HSM_reseedHSMAsync();

extern int_fast16_t TRNGXXF3HSM_switchNrbgMode(TRNG_Handle handle, TRNGXXF3HSM_NRBGMode nrbgMode);
#endif /* (DeviceFamily_PARENT == DeviceFamily_PARENT_CC27XX) */

#ifdef __cplusplus
}
#endif

#endif /* ti_drivers_TRNG_TRNGXXF3HSM__include */