phosphor-regulators/test/pmbus_utils_tests.cpp

/**
 * Copyright © 2020 IBM Corporation
 *
 * 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 "pmbus_utils.hpp"

#include <cstdint>

#include <gtest/gtest.h>

using namespace phosphor::power::regulators;

TEST(PMBusUtilsTests, ParseVoutMode)
{
    uint8_t voutModeValue;
    pmbus_utils::VoutDataFormat format;
    int8_t parameter;

    // Linear format: Exponent is negative: 0b1'1111
    voutModeValue = 0b0001'1111u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::linear);
    EXPECT_EQ(parameter, -1);

    // Linear format: Exponent is negative: 0b1'0000
    voutModeValue = 0b1001'0000u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::linear);
    EXPECT_EQ(parameter, -16);

    // Linear format: Exponent is positive: 0b0'1111
    voutModeValue = 0b1000'1111u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::linear);
    EXPECT_EQ(parameter, 15);

    // Linear format: Exponent is positive: 0b0'0001
    voutModeValue = 0b0000'0001u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::linear);
    EXPECT_EQ(parameter, 1);

    // Linear format: Exponent is zero: 0b0'0000
    voutModeValue = 0b0000'0000u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::linear);
    EXPECT_EQ(parameter, 0);

    // VID format: VID code is 0b1'1111
    voutModeValue = 0b0011'1111u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::vid);
    EXPECT_EQ(parameter, 31);

    // VID format: VID code is 0b1'0000
    voutModeValue = 0b1011'0000u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::vid);
    EXPECT_EQ(parameter, 16);

    // VID format: VID code is 0b0'1111
    voutModeValue = 0b1010'1111u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::vid);
    EXPECT_EQ(parameter, 15);

    // VID format: VID code is 0b0'0001
    voutModeValue = 0b0010'0001u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::vid);
    EXPECT_EQ(parameter, 1);

    // VID format: VID code is 0b0'0000
    voutModeValue = 0b1010'0000u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::vid);
    EXPECT_EQ(parameter, 0);

    // Direct format
    voutModeValue = 0b1100'0000u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::direct);
    EXPECT_EQ(parameter, 0);

    // IEEE format
    voutModeValue = 0b0110'0000u;
    pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
    EXPECT_EQ(format, pmbus_utils::VoutDataFormat::ieee);
    EXPECT_EQ(parameter, 0);
}

TEST(PMBusUtilsTests, ToString)
{
    // Sensor data format: SensorDataFormat::linear_11
    {
        pmbus_utils::SensorDataFormat format =
            pmbus_utils::SensorDataFormat::linear_11;
        EXPECT_EQ(pmbus_utils::toString(format), "linear_11");
    }

    // Sensor data format: SensorDataFormat::linear_16
    {
        pmbus_utils::SensorDataFormat format =
            pmbus_utils::SensorDataFormat::linear_16;
        EXPECT_EQ(pmbus_utils::toString(format), "linear_16");
    }

    // Vout data format: VoutDataFormat::linear
    {
        pmbus_utils::VoutDataFormat format =
            pmbus_utils::VoutDataFormat::linear;
        EXPECT_EQ(pmbus_utils::toString(format), "linear");
    }

    // Vout data format: VoutDataFormat::vid
    {
        pmbus_utils::VoutDataFormat format = pmbus_utils::VoutDataFormat::vid;
        EXPECT_EQ(pmbus_utils::toString(format), "vid");
    }

    // Vout data format: VoutDataFormat::direct
    {
        pmbus_utils::VoutDataFormat format =
            pmbus_utils::VoutDataFormat::direct;
        EXPECT_EQ(pmbus_utils::toString(format), "direct");
    }

    // Vout data format: VoutDataFormat::ieee
    {
        pmbus_utils::VoutDataFormat format = pmbus_utils::VoutDataFormat::ieee;
        EXPECT_EQ(pmbus_utils::toString(format), "ieee");
    }
}

TEST(PMBusUtilsTests, ConvertFromLinear)
{
    uint16_t value;

    // Minimum possible exponent value: -16
    // mantissa : 511, exponent : -16, decimal = 511 * 2^-16 =
    // 0.0077972412109375
    value = 0x81ff;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), 0.0077972412109375);

    // Maximum possible exponent value: 15
    // mantissa : 2, exponent : 15, decimal = 2 * 2^15 = 65536
    value = 0x7802;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), 65536);

    // Minimum possible mantissa value: -1024
    // mantissa : -1024, exponent : 1, decimal = -1024 * 2^1 = -2048
    value = 0x0c00;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), -2048);

    // Maximum possible mantissa value: 1023
    // mantissa : 1023, exponent : -11, decimal = 1023 * 2^-11 = 0.49951171875
    value = 0xabff;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), 0.49951171875);

    // Exponent = 0, mantissa > 0
    // mantissa : 1, exponent : 0, decimal = 1 * 2^0 = 1
    value = 0x0001;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), 1);

    // Exponent > 0, mantissa > 0
    // mantissa : 2, exponent : 1, decimal = 2 * 2^1 = 4
    value = 0x0802;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), 4);

    // Exponent < 0, mantissa > 0
    // mantissa : 15, exponent : -1, decimal = 15 * 2^-1 = 7.5
    value = 0xf80f;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), 7.5);

    // Exponent > 0, mantissa = 0
    // mantissa : 0, exponent : 3, decimal = 0 * 2^3 = 0
    value = 0x1800;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), 0);

    // Exponent > 0, mantissa < 0
    // mantissa : -2, exponent : 3, decimal = -2 * 2^3 = -16
    value = 0x1ffe;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromLinear(value), -16);
}

TEST(PMBusUtilsTests, ConvertFromVoutLinear)
{
    uint16_t value;
    int8_t exponent;

    // mantissa : 1, exponent : 2, decimal = 1 * 2^2 = 4
    value = 0x0001;
    exponent = 2;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromVoutLinear(value, exponent), 4);

    // mantissa : 15, exponent : 0, decimal = 15 * 2^0 = 15
    value = 0x000f;
    exponent = 0;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromVoutLinear(value, exponent), 15);

    // mantissa : 255, exponent : -3, decimal = 255 * 2^-3 = 31.875
    value = 0x00ff;
    exponent = -3;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromVoutLinear(value, exponent),
                     31.875);

    // mantissa : 0, exponent : 10, decimal = 0 * 2^10 = 0
    value = 0x0000;
    exponent = 10;
    EXPECT_DOUBLE_EQ(pmbus_utils::convertFromVoutLinear(value, exponent), 0);
}

TEST(PMBusUtilsTests, ConvertToVoutLinear)
{
    double volts;
    int8_t exponent;

    // Exponent > 0: Value is not rounded up
    volts = 13.9;
    exponent = 2;
    // 13.9 / 2^2 == 3.475 = 3
    EXPECT_EQ(pmbus_utils::convertToVoutLinear(volts, exponent), 3);

    // Exponent > 0: Value is rounded up
    volts = 14.0;
    exponent = 2;
    // 14.0 / 2^2 == 3.5 = 4
    EXPECT_EQ(pmbus_utils::convertToVoutLinear(volts, exponent), 4);

    // Exponent = 0: Value is not rounded up
    volts = 2.49;
    exponent = 0;
    // 2.49 / 2^0 == 2.49 = 2
    EXPECT_EQ(pmbus_utils::convertToVoutLinear(volts, exponent), 2);

    // Exponent = 0: Value is rounded up
    volts = 2.51;
    exponent = 0;
    // 2.51 / 2^0 == 2.51 = 3
    EXPECT_EQ(pmbus_utils::convertToVoutLinear(volts, exponent), 3);

    // Exponent < 0: Value is not rounded up
    volts = 1.32613;
    exponent = -8;
    // 1.32613 / 2^-8 == 339.48928 == 339
    EXPECT_EQ(pmbus_utils::convertToVoutLinear(volts, exponent), 339);

    // Exponent < 0: Value is rounded up
    volts = 1.32618;
    exponent = -8;
    // 1.32618 / 2^-8 == 339.50208 == 340
    EXPECT_EQ(pmbus_utils::convertToVoutLinear(volts, exponent), 340);
}