Files
Aaru/SCSI/Modes/08.cs

294 lines
12 KiB
C#

// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename : 08.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Device structures decoders.
//
// --[ Description ] ----------------------------------------------------------
//
// Decodes SCSI MODE PAGE 08h: Caching 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 © 2011-2018 Natalia Portillo
// ****************************************************************************/
using System.Text;
namespace DiscImageChef.Decoders.SCSI
{
public static partial class Modes
{
#region Mode Page 0x08: Caching page
/// <summary>
/// Disconnect-reconnect page
/// Page code 0x08
/// 12 bytes in SCSI-2
/// 20 bytes in SBC-1, SBC-2, SBC-3
/// </summary>
public struct ModePage_08
{
/// <summary>
/// Parameters can be saved
/// </summary>
public bool PS;
/// <summary>
/// <c>true</c> if write cache is enabled
/// </summary>
public bool WCE;
/// <summary>
/// Multiplication factor
/// </summary>
public bool MF;
/// <summary>
/// <c>true</c> if read cache is enabled
/// </summary>
public bool RCD;
/// <summary>
/// Advices on reading-cache retention priority
/// </summary>
public byte DemandReadRetentionPrio;
/// <summary>
/// Advices on writing-cache retention priority
/// </summary>
public byte WriteRetentionPriority;
/// <summary>
/// If requested read blocks are more than this, no pre-fetch is done
/// </summary>
public ushort DisablePreFetch;
/// <summary>
/// Minimum pre-fetch
/// </summary>
public ushort MinimumPreFetch;
/// <summary>
/// Maximum pre-fetch
/// </summary>
public ushort MaximumPreFetch;
/// <summary>
/// Upper limit on maximum pre-fetch value
/// </summary>
public ushort MaximumPreFetchCeiling;
/// <summary>
/// Manual cache controlling
/// </summary>
public bool IC;
/// <summary>
/// Abort pre-fetch
/// </summary>
public bool ABPF;
/// <summary>
/// Caching analysis permitted
/// </summary>
public bool CAP;
/// <summary>
/// Pre-fetch over discontinuities
/// </summary>
public bool Disc;
/// <summary>
/// <see cref="CacheSegmentSize"/> is to be used to control caching segmentation
/// </summary>
public bool Size;
/// <summary>
/// Force sequential write
/// </summary>
public bool FSW;
/// <summary>
/// Logical block cache segment size
/// </summary>
public bool LBCSS;
/// <summary>
/// Disable read-ahead
/// </summary>
public bool DRA;
/// <summary>
/// How many segments should the cache be divided upon
/// </summary>
public byte CacheSegments;
/// <summary>
/// How many bytes should the cache be divided upon
/// </summary>
public ushort CacheSegmentSize;
/// <summary>
/// How many bytes should be used as a buffer when all other cached data cannot be evicted
/// </summary>
public uint NonCacheSegmentSize;
public bool NV_DIS;
}
public static ModePage_08? DecodeModePage_08(byte[] pageResponse)
{
if((pageResponse?[0] & 0x40) == 0x40) return null;
if((pageResponse?[0] & 0x3F) != 0x08) return null;
if(pageResponse[1] + 2 != pageResponse.Length) return null;
if(pageResponse.Length < 12) return null;
ModePage_08 decoded = new ModePage_08();
decoded.PS |= (pageResponse[0] & 0x80) == 0x80;
decoded.WCE |= (pageResponse[2] & 0x04) == 0x04;
decoded.MF |= (pageResponse[2] & 0x02) == 0x02;
decoded.RCD |= (pageResponse[2] & 0x01) == 0x01;
decoded.DemandReadRetentionPrio = (byte)((pageResponse[3] & 0xF0) >> 4);
decoded.WriteRetentionPriority = (byte)(pageResponse[3] & 0x0F);
decoded.DisablePreFetch = (ushort)((pageResponse[4] << 8) + pageResponse[5]);
decoded.MinimumPreFetch = (ushort)((pageResponse[6] << 8) + pageResponse[7]);
decoded.MaximumPreFetch = (ushort)((pageResponse[8] << 8) + pageResponse[9]);
decoded.MaximumPreFetchCeiling = (ushort)((pageResponse[10] << 8) + pageResponse[11]);
if(pageResponse.Length < 20) return decoded;
decoded.IC |= (pageResponse[2] & 0x80) == 0x80;
decoded.ABPF |= (pageResponse[2] & 0x40) == 0x40;
decoded.CAP |= (pageResponse[2] & 0x20) == 0x20;
decoded.Disc |= (pageResponse[2] & 0x10) == 0x10;
decoded.Size |= (pageResponse[2] & 0x08) == 0x08;
decoded.FSW |= (pageResponse[12] & 0x80) == 0x80;
decoded.LBCSS |= (pageResponse[12] & 0x40) == 0x40;
decoded.DRA |= (pageResponse[12] & 0x20) == 0x20;
decoded.CacheSegments = pageResponse[13];
decoded.CacheSegmentSize = (ushort)((pageResponse[14] << 8) + pageResponse[15]);
decoded.NonCacheSegmentSize = (uint)((pageResponse[17] << 16) + (pageResponse[18] << 8) + pageResponse[19]);
decoded.NV_DIS |= (pageResponse[12] & 0x01) == 0x01;
return decoded;
}
public static string PrettifyModePage_08(byte[] pageResponse)
{
return PrettifyModePage_08(DecodeModePage_08(pageResponse));
}
public static string PrettifyModePage_08(ModePage_08? modePage)
{
if(!modePage.HasValue) return null;
ModePage_08 page = modePage.Value;
StringBuilder sb = new StringBuilder();
sb.AppendLine("SCSI Caching mode page:");
if(page.PS) sb.AppendLine("\tParameters can be saved");
if(page.RCD) sb.AppendLine("\tRead-cache is enabled");
if(page.WCE) sb.AppendLine("\tWrite-cache is enabled");
switch(page.DemandReadRetentionPrio)
{
case 0:
sb.AppendLine("\tDrive does not distinguish between cached read data");
break;
case 1:
sb.AppendLine("\tData put by READ commands should be evicted from cache sooner than data put in read cache by other means");
break;
case 0xF:
sb.AppendLine("\tData put by READ commands should not be evicted if there is data cached by other means that can be evicted");
break;
default:
sb.AppendFormat("\tUnknown demand read retention priority value {0}", page.DemandReadRetentionPrio)
.AppendLine();
break;
}
switch(page.WriteRetentionPriority)
{
case 0:
sb.AppendLine("\tDrive does not distinguish between cached write data");
break;
case 1:
sb.AppendLine("\tData put by WRITE commands should be evicted from cache sooner than data put in write cache by other means");
break;
case 0xF:
sb.AppendLine("\tData put by WRITE commands should not be evicted if there is data cached by other means that can be evicted");
break;
default:
sb.AppendFormat("\tUnknown demand write retention priority value {0}", page.DemandReadRetentionPrio)
.AppendLine();
break;
}
if(page.DRA) sb.AppendLine("\tRead-ahead is disabled");
else
{
if(page.MF) sb.AppendLine("\tPre-fetch values indicate a block multiplier");
if(page.DisablePreFetch == 0) sb.AppendLine("\tNo pre-fetch will be done");
else
{
sb.AppendFormat("\tPre-fetch will be done for READ commands of {0} blocks or less",
page.DisablePreFetch).AppendLine();
if(page.MinimumPreFetch > 0)
sb.AppendFormat("At least {0} blocks will be always pre-fetched", page.MinimumPreFetch)
.AppendLine();
if(page.MaximumPreFetch > 0)
sb.AppendFormat("\tA maximum of {0} blocks will be pre-fetched", page.MaximumPreFetch)
.AppendLine();
if(page.MaximumPreFetchCeiling > 0)
sb
.AppendFormat("\tA maximum of {0} blocks will be pre-fetched even if it is commanded to pre-fetch more",
page.MaximumPreFetchCeiling).AppendLine();
if(page.IC)
sb.AppendLine("\tDevice should use number of cache segments or cache segment size for caching");
if(page.ABPF) sb.AppendLine("\tPre-fetch should be aborted upong receiving a new command");
if(page.CAP) sb.AppendLine("\tCaching analysis is permitted");
if(page.Disc)
sb.AppendLine("\tPre-fetch can continue across discontinuities (such as cylinders or tracks)");
}
}
if(page.FSW) sb.AppendLine("\tDrive should not reorder the sequence of write commands to be faster");
if(page.Size)
{
if(page.CacheSegmentSize > 0)
if(page.LBCSS)
sb.AppendFormat("\tDrive cache segments should be {0} blocks long", page.CacheSegmentSize)
.AppendLine();
else
sb.AppendFormat("\tDrive cache segments should be {0} bytes long", page.CacheSegmentSize)
.AppendLine();
}
else
{
if(page.CacheSegments > 0)
sb.AppendFormat("\tDrive should have {0} cache segments", page.CacheSegments).AppendLine();
}
if(page.NonCacheSegmentSize > 0)
sb
.AppendFormat("\tDrive shall allocate {0} bytes to buffer even when all cached data cannot be evicted",
page.NonCacheSegmentSize).AppendLine();
if(page.NV_DIS) sb.AppendLine("\tNon-Volatile cache is disabled");
return sb.ToString();
}
#endregion Mode Page 0x08: Caching page
}
}