// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// Copyright (C) LibreHardwareMonitor and Contributors.
// Partial Copyright (C) Michael Möller <mmoeller@openhardwaremonitor.org> and Contributors.
// All Rights Reserved.

namespace LibreHardwareMonitor.Hardware.Motherboard.Lpc
{
    internal class LpcPort
    {
        public LpcPort(ushort registerPort, ushort valuePort)
        {
            RegisterPort = registerPort;
            ValuePort = valuePort;
        }

        public ushort RegisterPort { get; }

        public ushort ValuePort { get; }

        public byte ReadByte(byte register)
        {
            Ring0.WriteIoPort(RegisterPort, register);
            return Ring0.ReadIoPort(ValuePort);
        }

        public void WriteByte(byte register, byte value)
        {
            Ring0.WriteIoPort(RegisterPort, register);
            Ring0.WriteIoPort(ValuePort, value);
        }

        public ushort ReadWord(byte register)
        {
            return (ushort)((ReadByte(register) << 8) | ReadByte((byte)(register + 1)));
        }

        public void Select(byte logicalDeviceNumber)
        {
            Ring0.WriteIoPort(RegisterPort, DEVICE_SELECT_REGISTER);
            Ring0.WriteIoPort(ValuePort, logicalDeviceNumber);
        }

        public void WinbondNuvotonFintekEnter()
        {
            Ring0.WriteIoPort(RegisterPort, 0x87);
            Ring0.WriteIoPort(RegisterPort, 0x87);
        }

        public void WinbondNuvotonFintekExit()
        {
            Ring0.WriteIoPort(RegisterPort, 0xAA);
        }

        public void NuvotonDisableIOSpaceLock()
        {
            byte options = ReadByte(NUVOTON_HARDWARE_MONITOR_IO_SPACE_LOCK);
            // if the i/o space lock is enabled
            if ((options & 0x10) > 0)
            {
                // disable the i/o space lock
                WriteByte(NUVOTON_HARDWARE_MONITOR_IO_SPACE_LOCK, (byte)(options & ~0x10));
            }
        }

        public void IT87Enter()
        {
            Ring0.WriteIoPort(RegisterPort, 0x87);
            Ring0.WriteIoPort(RegisterPort, 0x01);
            Ring0.WriteIoPort(RegisterPort, 0x55);
            Ring0.WriteIoPort(RegisterPort, RegisterPort == 0x4E ? (byte)0xAA : (byte)0x55);
        }

        public void IT87Exit()
        {
            // Do not exit config mode for secondary super IO.
            if (RegisterPort != 0x4E)
            {
                Ring0.WriteIoPort(RegisterPort, CONFIGURATION_CONTROL_REGISTER);
                Ring0.WriteIoPort(ValuePort, 0x02);
            }
        }

        public void SmscEnter()
        {
            Ring0.WriteIoPort(RegisterPort, 0x55);
        }

        public void SmscExit()
        {
            Ring0.WriteIoPort(RegisterPort, 0xAA);
        }

        // ReSharper disable InconsistentNaming
        private const byte CONFIGURATION_CONTROL_REGISTER = 0x02;
        private const byte DEVICE_SELECT_REGISTER = 0x07;
        private const byte NUVOTON_HARDWARE_MONITOR_IO_SPACE_LOCK = 0x28;
        // ReSharper restore InconsistentNaming
    }
}