/* mbed Microcontroller Library
 * Copyright (c) 2018-2018 ARM Limited
 *
 * 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.
 */
#include "greentea-client/test_env.h"
#include "utest/utest.h"
#include "unity/unity.h"

#include "rtos/Kernel.h"
#include "mbed.h"


using utest::v1::Case;

#define TEST_REPEAT_COUNT   1000
#define NUM_WAIT_TICKS      1000

// all in [us]
#define ONE_SECOND          1000000
#define SMALL_DELTA         1500        // 0.15%
#define BIG_DELTA           15000       // 1.5%

/** Test if kernel ticker frequency is 1kHz

    Given a RTOS kernel ticker
    When check it frequency
    Then the the frequency is 1kHz
 */
void test_frequency()
{
    uint32_t freq = osKernelGetTickFreq();
    TEST_ASSERT_EQUAL_UINT32_MESSAGE(1000, freq, "Expected SysTick frequency is 1kHz");
}

/** Test if kernel ticker increments by one

    Given a RTOS kernel ticker
    When perform subsequent calls of @a rtos::Kernel::get_ms_count
    Then subsequent reads should not differ by more than one
 */
void test_increment(void)
{
    for (uint32_t i = 0; i < TEST_REPEAT_COUNT; i++) {
        const uint64_t start = rtos::Kernel::get_ms_count();
        while (true) {
            uint64_t diff = rtos::Kernel::get_ms_count() - start;
            if (diff != 0) {
                TEST_ASSERT_EQUAL_UINT64(1, diff);
                break;
            }
        }
    }
}

/** Test if kernel ticker interval is 1ms

    Given a RTOS kernel ticker
    When perform subsequent calls of @a rtos::Kernel::get_ms_count
    Then the ticker interval should be 1ms
 */
void test_interval()
{
    uint64_t start, stop;
    Timer timer;

    start = rtos::Kernel::get_ms_count();
    // wait for tick
    do {
        stop = rtos::Kernel::get_ms_count();
    } while ((stop - start) == 0);
    timer.start();
    start = stop;

    // wait for NUM_WAIT_TICKS ticks
    do {
        stop = rtos::Kernel::get_ms_count();
    } while ((stop - start) != NUM_WAIT_TICKS);
    timer.stop();
    TEST_ASSERT_EQUAL_UINT64(NUM_WAIT_TICKS, (stop - start));

#if defined(NO_SYSTICK) || defined(MBED_TICKLESS)
    // On targets with NO_SYSTICK/MBED_TICKLESS enabled, systick is emulated by lp_ticker what makes it less accurate
    // for more details https://os.mbed.com/docs/latest/reference/tickless.html
    TEST_ASSERT_UINT64_WITHIN(BIG_DELTA, ONE_SECOND, timer.read_high_resolution_us());
#else
    TEST_ASSERT_UINT64_WITHIN(SMALL_DELTA, ONE_SECOND, timer.read_high_resolution_us());
#endif
}

// Test cases
Case cases[] = {
    Case("Test kernel ticker frequency", test_frequency),
    Case("Test if kernel ticker increments by one", test_increment),
    Case("Test if kernel ticker interval is 1ms", test_interval)
};

utest::v1::status_t greentea_test_setup(const size_t number_of_cases)
{
    GREENTEA_SETUP(10, "timing_drift_auto");
    return utest::v1::greentea_test_setup_handler(number_of_cases);
}

utest::v1::Specification specification(greentea_test_setup, cases);

int main()
{
    return !utest::v1::Harness::run(specification);
}