/**
 * \file timing_alt.h
 *
 * \brief Portable interface to the CPU cycle counter
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
#ifndef MBEDTLS_TIMING_ALT_H
#define MBEDTLS_TIMING_ALT_H

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_TIMING_ALT)
/* Iotelic timing implementation */

#include "encoding.h"
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          timer structure
 */
struct mbedtls_timing_hr_time
{
    unsigned char opaque[32];
};

/**
 * \brief          Context for mbedtls_timing_set/get_delay()
 */
typedef struct
{
    struct mbedtls_timing_hr_time   timer;
    uint32_t                        int_ms;
    uint32_t                        fin_ms;
} mbedtls_timing_delay_context;

extern volatile int mbedtls_timing_alarmed;

/**
 * \brief          Return the elapsed time in milliseconds
 *
 * \param val      points to a timer structure
 * \param reset    if set to 1, the timer is restarted
 */
unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset );

/**
 * \brief          Setup an alarm clock
 *
 * \param seconds  delay before the "mbedtls_timing_alarmed" flag is set
 *
 * \warning        Only one alarm at a time  is supported. In a threaded
 *                 context, this means one for the whole process, not one per
 *                 thread.
 */
void mbedtls_set_alarm( int seconds );

/**
 * \brief          Set a pair of delays to watch
 *                 (See \c mbedtls_timing_get_delay().)
 *
 * \param data     Pointer to timing data
 *                 Must point to a valid \c mbedtls_timing_delay_context struct.
 * \param int_ms   First (intermediate) delay in milliseconds.
 * \param fin_ms   Second (final) delay in milliseconds.
 *                 Pass 0 to cancel the current delay.
 */
void mbedtls_timing_set_delay( void *data, uint32_t int_ms, uint32_t fin_ms );

/**
 * \brief          Get the status of delays
 *                 (Memory helper: number of delays passed.)
 *
 * \param data     Pointer to timing data
 *                 Must point to a valid \c mbedtls_timing_delay_context struct.
 *
 * \return         -1 if cancelled (fin_ms = 0)
 *                  0 if none of the delays are passed,
 *                  1 if only the intermediate delay is passed,
 *                  2 if the final delay is passed.
 */
int mbedtls_timing_get_delay( void *data );

 // The mcycle counter is 64-bit counter, but since
 // Freedom E platforms use RV32, we must access it as
 // 2 32-bit registers. At 256MHz, the lower bits will
 // roll over approx. every 5 seconds, so we check for
 // rollover with this routine as suggested by the
 // RISC-V Priviledged Architecture Specification.

 #define rdmcycle(x)  {                     \
     uint32_t lo, hi, hi2;                  \
     __asm__ __volatile__ ("1:\n\t"             \
               "csrr %0, mcycleh\n\t"       \
               "csrr %1, mcycle\n\t"        \
               "csrr %2, mcycleh\n\t"       \
               "bne  %0, %2, 1b\n\t"         \
               : "=r" (hi), "=r" (lo), "=r" (hi2)) ; \
     *(x) = lo | ((uint64_t) hi << 32);              \
   }


/**
 * \brief          Return the CPU cycle counter value
 *
 */
static inline unsigned long mbedtls_timing_hardclock( void )
{
 	uint64_t mcycle;

	rdmcycle(&mcycle);

    return mcycle;
}


#ifdef __cplusplus
}
#endif

#endif /* MBEDTLS_TIMING_ALT */

#endif /* MBEDTLS_TIMING_ALT_H */