Aaru/SCSI/Modes/02.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : 02.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Device structures decoders.
//
// --[ Description ] ----------------------------------------------------------
//
//     Decodes SCSI MODE PAGE 02h: Disconnect-reconnect page.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General Public License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library is distributed in the hope that it will be useful, but
//     WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
//     Lesser General Public License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2023 Natalia Portillo
// ****************************************************************************/

using System.Diagnostics.CodeAnalysis;
using System.Text;

namespace Aaru.Decoders.SCSI;

[SuppressMessage("ReSharper", "InconsistentNaming")]
[SuppressMessage("ReSharper", "MemberCanBeInternal")]
[SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
public static partial class Modes
{
#region Mode Page 0x02: Disconnect-reconnect page

    /// <summary>Disconnect-reconnect page Page code 0x02 16 bytes in SCSI-2, SPC-1, SPC-2, SPC-3, SPC-4, SPC-5</summary>
    public struct ModePage_02
    {
        /// <summary>Parameters can be saved</summary>
        public bool PS;
        /// <summary>How full should be the buffer prior to attempting a reselection</summary>
        public byte BufferFullRatio;
        /// <summary>How empty should be the buffer prior to attempting a reselection</summary>
        public byte BufferEmptyRatio;
        /// <summary>Max. time in 100 µs increments that the target is permitted to assert BSY without a REQ/ACK</summary>
        public ushort BusInactivityLimit;
        /// <summary>Min. time in 100 µs increments to wait after releasing the bus before attempting reselection</summary>
        public ushort DisconnectTimeLimit;
        /// <summary>
        ///     Max. time in 100 µs increments allowed to use the bus before disconnecting, if granted the privilege and not
        ///     restricted by <see cref="DTDC" />
        /// </summary>
        public ushort ConnectTimeLimit;
        /// <summary>Maximum amount of data before disconnecting in 512 bytes increments</summary>
        public ushort MaxBurstSize;
        /// <summary>Data transfer disconnect control</summary>
        public byte DTDC;

        /// <summary>Target shall not transfer data for a command during the same interconnect tenancy</summary>
        public bool DIMM;
        /// <summary>Wether to use fair or unfair arbitration when requesting an interconnect tenancy</summary>
        public byte FairArbitration;
        /// <summary>Max. ammount of data in 512 bytes increments that may be transferred for a command along with the command</summary>
        public ushort FirstBurstSize;
        /// <summary>Target is allowed to re-order the data transfer</summary>
        public bool EMDP;
    }

    public static ModePage_02? DecodeModePage_02(byte[] pageResponse)
    {
        if((pageResponse?[0] & 0x40) == 0x40)
            return null;

        if((pageResponse?[0] & 0x3F) != 0x02)
            return null;

        if(pageResponse[1] + 2 != pageResponse.Length)
            return null;

        if(pageResponse.Length < 12)
            return null;

        var decoded = new ModePage_02();

        decoded.PS                  |= (pageResponse[0] & 0x80) == 0x80;
        decoded.BufferFullRatio     =  pageResponse[2];
        decoded.BufferEmptyRatio    =  pageResponse[3];
        decoded.BusInactivityLimit  =  (ushort)((pageResponse[4]  << 8) + pageResponse[5]);
        decoded.DisconnectTimeLimit =  (ushort)((pageResponse[6]  << 8) + pageResponse[7]);
        decoded.ConnectTimeLimit    =  (ushort)((pageResponse[8]  << 8) + pageResponse[9]);
        decoded.MaxBurstSize        =  (ushort)((pageResponse[10] << 8) + pageResponse[11]);

        if(pageResponse.Length >= 13)
        {
            decoded.EMDP            |= (pageResponse[12] & 0x80) == 0x80;
            decoded.DIMM            |= (pageResponse[12] & 0x08) == 0x08;
            decoded.FairArbitration =  (byte)((pageResponse[12] & 0x70) >> 4);
            decoded.DTDC            =  (byte)(pageResponse[12] & 0x07);
        }

        if(pageResponse.Length >= 16)
            decoded.FirstBurstSize = (ushort)((pageResponse[14] << 8) + pageResponse[15]);

        return decoded;
    }

    public static string PrettifyModePage_02(byte[] pageResponse) =>
        PrettifyModePage_02(DecodeModePage_02(pageResponse));

    public static string PrettifyModePage_02(ModePage_02? modePage)
    {
        if(!modePage.HasValue)
            return null;

        ModePage_02 page = modePage.Value;
        var         sb   = new StringBuilder();

        sb.AppendLine(Localization.SCSI_Disconnect_Reconnect_mode_page);

        if(page.PS)
            sb.AppendLine("\t" + Localization.Parameters_can_be_saved);

        if(page.BufferFullRatio > 0)
        {
            sb.AppendFormat("\t" + Localization._0_ratio_of_buffer_that_shall_be_full_prior_to_attempting_a_reselection,
                            page.BufferFullRatio).AppendLine();
        }

        if(page.BufferEmptyRatio > 0)
        {
            sb.
                AppendFormat(
                    "\t" + Localization._0_ratio_of_buffer_that_shall_be_empty_prior_to_attempting_a_reselection,
                    page.BufferEmptyRatio).AppendLine();
        }

        if(page.BusInactivityLimit > 0)
        {
            sb.AppendFormat("\t" + Localization._0_µs_maximum_permitted_to_assert_BSY_without_a_REQ_ACK_handshake,
                            page.BusInactivityLimit * 100).AppendLine();
        }

        if(page.DisconnectTimeLimit > 0)
        {
            sb.
                AppendFormat(
                    "\t" + Localization.
                        _0_µs_maximum_permitted_wait_after_releasing_the_bus_before_attempting_reselection,
                    page.DisconnectTimeLimit * 100).AppendLine();
        }

        if(page.ConnectTimeLimit > 0)
        {
            sb.
                AppendFormat(
                    "\t" + Localization.
                        _0_µs_allowed_to_use_the_bus_before_disconnecting_if_granted_the_privilege_and_not_restricted,
                    page.ConnectTimeLimit * 100).AppendLine();
        }

        if(page.MaxBurstSize > 0)
        {
            sb.AppendFormat("\t" + Localization._0_bytes_maximum_can_be_transferred_before_disconnecting,
                            page.MaxBurstSize * 512).AppendLine();
        }

        if(page.FirstBurstSize > 0)
        {
            sb.
                AppendFormat(
                    "\t" + Localization.
                        _0_bytes_maximum_can_be_transferred_for_a_command_along_with_the_disconnect_command,
                    page.FirstBurstSize * 512).AppendLine();
        }

        if(page.DIMM)
        {
            sb.AppendLine("\t" + Localization.
                              Target_shall_not_transfer_data_for_a_command_during_the_same_interconnect_tenancy);
        }

        if(page.EMDP)
            sb.AppendLine("\t" + Localization.Target_is_allowed_to_reorder_the_data_transfer);

        switch(page.DTDC)
        {
            case 0:
                sb.AppendLine("\t" + Localization.Data_transfer_disconnect_control_is_not_used);

                break;
            case 1:
                sb.AppendLine("\t" + Localization.
                                  All_data_for_a_command_shall_be_transferred_within_a_single_interconnect_tenancy);

                break;
            case 3:
                sb.AppendLine("\t" + Localization.
                                  All_data_and_the_response_for_a_command_shall_be_transferred_within_a_single_interconnect_tenancy);

                break;
            default:
                sb.AppendFormat("\t" + Localization.Reserved_data_transfer_disconnect_control_value_0, page.DTDC).
                   AppendLine();

                break;
        }

        return sb.ToString();
    }

#endregion Mode Page 0x02: Disconnect-reconnect page
}