[ros-diffs] [apriyadarshi] 71588: AHCI-SATA Interface almost ready. - tested on VM. - need to implement Interrupt Routine (MessagePerPort) and ATA/ATAPI Based SCSI Query.

Author: apriyadarshi
Date: Tue Jun  7 11:05:32 2016
New Revision: 71588

URL: http://svn.reactos.org/svn/reactos?rev=71588&view=rev
Log:
AHCI-SATA Interface almost ready.
- tested on VM.
- need to implement Interrupt Routine (MessagePerPort) and ATA/ATAPI Based SCSI Query.

Modified:
    branches/GSoC_2016/AHCI/drivers/storage/storahci/sources
    branches/GSoC_2016/AHCI/drivers/storage/storahci/storahci.c
    branches/GSoC_2016/AHCI/drivers/storage/storahci/storahci.h

Modified: branches/GSoC_2016/AHCI/drivers/storage/storahci/sources
URL:
http://svn.reactos.org/svn/reactos/branches/GSoC_2016/AHCI/drivers/storage/…
==============================================================================
--- branches/GSoC_2016/AHCI/drivers/storage/storahci/sources	[iso-8859-1] (original)
+++ branches/GSoC_2016/AHCI/drivers/storage/storahci/sources	[iso-8859-1] Tue Jun  7
11:05:32 2016
@@ -1,6 +1,7 @@
 TARGETNAME = storahci
 TARGETTYPE = MINIPORT
 
+MSC_WARNING_LEVEL=/W4
 TARGETLIBS=$(DDK_LIB_PATH)\storport.lib
 
 INCLUDES   = %BUILD%\inc

Modified: branches/GSoC_2016/AHCI/drivers/storage/storahci/storahci.c
URL:
http://svn.reactos.org/svn/reactos/branches/GSoC_2016/AHCI/drivers/storage/…
==============================================================================
--- branches/GSoC_2016/AHCI/drivers/storage/storahci/storahci.c	[iso-8859-1] (original)
+++ branches/GSoC_2016/AHCI/drivers/storage/storahci/storahci.c	[iso-8859-1] Tue Jun  7
11:05:32 2016
@@ -11,11 +11,18 @@
   __in      PAHCI_ADAPTER_EXTENSION             adapterExtension
 );
 
+__inline
 VOID AhciZeroMemory(
   __in      PCHAR                               buffer,
   __in      ULONG                               bufferSize
 );
 
+__inline
+BOOLEAN IsPortValid(
+  __in      PAHCI_ADAPTER_EXTENSION             adapterExtension,
+  __in      UCHAR                               pathId
+);
+
 /**
  * @name AhciPortInitialize
  * @implemented
@@ -40,6 +47,7 @@
 
     adapterExtension = portExtension->AdapterExtension;
     abar = adapterExtension->ABAR_Address;
+
     portExtension->Port = &abar->PortList[portExtension->PortNumber];
 
     commandListPhysical = StorPortGetPhysicalAddress(adapterExtension, NULL,
portExtension->CommandList, &mappedLength);
@@ -61,6 +69,14 @@
     StorPortWriteRegisterUlong(adapterExtension, &portExtension->Port->CLB,
commandListPhysical.LowPart);
     StorPortWriteRegisterUlong(adapterExtension, &portExtension->Port->FB,
receivedFISPhysical.LowPart);
 
+    // set device power state flag to D0
+    portExtension->DevicePowerState = StorPowerDeviceD0;
+
+    // clear pending interrupts
+    StorPortWriteRegisterUlong(adapterExtension, &portExtension->Port->SERR,
(ULONG)-1);
+    StorPortWriteRegisterUlong(adapterExtension, &portExtension->Port->IS,
(ULONG)-1);
+    StorPortWriteRegisterUlong(adapterExtension,
portExtension->AdapterExtension->IS, (1 << portExtension->PortNumber));
+
     return TRUE;
 }// -- AhciPortInitialize();
 
@@ -87,7 +103,7 @@
 
     StorPortDebugPrint(0, "AhciAllocateResourceForAdapter()\n");
 
-    // 3.1.1 NCS = CAP[12:08] -> Align 
+    // 3.1.1 NCS = CAP[12:08] -> Align
     NCS = (adapterExtension->CAP & 0xF00) >> 8;
     AlignedNCS = ((NCS/8) + 1) * 8;
 
@@ -116,33 +132,16 @@
     nonCachedExtension = (PCHAR)adapterExtension->NonCachedExtension;
 
     AhciZeroMemory(nonCachedExtension, nonCachedExtensionSize);
-    
-
-    // allocate memory for port extension
-    /* --> Allocate memory for port extension, but right now it is returning
STOR_STATUS_NOT_IMPLEMENTED
-    so, for testing purpose, I allocated during driver entry itself.
-    status = StorPortAllocatePool(
-                    adapterExtension, 
-                    portCount * sizeof(AHCI_PORT_EXTENSION),
-                    AHCI_POOL_TAG, 
-                    (PVOID*)&portsExtension);
-
-    if (status != STOR_STATUS_SUCCESS){
-        StorPortDebugPrint(0, "\tstatus : %x\n", status);
-        return FALSE;
-    }
-
-    AhciZeroMemory((PCHAR)portsExtension, portCount * sizeof(AHCI_PORT_EXTENSION));
-    */
+
     nonCachedExtensionSize /= portCount;
     currentCount = 0;
-    for (index = 0; index < 32; index++)
-    {
+    for (index = 0; index < MAXIMUM_AHCI_PORT_COUNT; index++)
+    {
+        adapterExtension->PortExtension[index].IsActive = FALSE;
         if ((adapterExtension->PortImplemented & (1<<index)) != 0)
         {
-            //adapterExtension->PortExtension[index] =
(PAHCI_PORT_EXTENSION)((PCHAR)portsExtension + sizeof(AHCI_PORT_EXTENSION) *
currentCount);
-
             adapterExtension->PortExtension[index].PortNumber = index;
+            adapterExtension->PortExtension[index].IsActive = TRUE;
             adapterExtension->PortExtension[index].AdapterExtension =
adapterExtension;
             adapterExtension->PortExtension[index].CommandList =
(PAHCI_COMMAND_HEADER)(nonCachedExtension + (currentCount*nonCachedExtensionSize));
             adapterExtension->PortExtension[index].ReceivedFIS =
(PAHCI_RECEIVED_FIS)((PCHAR)adapterExtension->PortExtension[index].CommandList +
sizeof(AHCI_COMMAND_HEADER) * AlignedNCS);
@@ -168,11 +167,26 @@
   __in      PVOID                               AdapterExtension
 )
 {
+    ULONG ghc, messageCount, status;
     PAHCI_ADAPTER_EXTENSION adapterExtension;
 
     StorPortDebugPrint(0, "AhciHwInitialize()\n");
 
     adapterExtension = (PAHCI_ADAPTER_EXTENSION)AdapterExtension;
+    adapterExtension->StateFlags.MessagePerPort = FALSE;
+
+    // First check what type of interrupt/synchronization device is using
+    ghc = StorPortReadRegisterUlong(adapterExtension,
&adapterExtension->ABAR_Address->GHC);
+
+    //When set to ‘1’ by hardware, indicates that the HBA requested more than one MSI
vector
+    //but has reverted to using the first vector only.  When this bit is cleared to
‘0’,
+    //the HBA has not reverted to single MSI mode (i.e. hardware is already in single MSI
mode,
+    //software has allocated the number of messages requested
+    if ((ghc & AHCI_Global_HBA_CONTROL_MRSM) == 0)
+    {
+        adapterExtension->StateFlags.MessagePerPort = TRUE;
+        StorPortDebugPrint(0, "\tMultiple MSI based message not supported\n");
+    }
 
     return TRUE;
 }// -- AhciHwInitialize();
@@ -199,7 +213,7 @@
 
     adapterExtension = (PAHCI_ADAPTER_EXTENSION)AdapterExtension;
 
-    return TRUE;
+    return FALSE;
 }// -- AhciHwInterrupt();
 
 /**
@@ -221,14 +235,87 @@
 
 )
 {
-    UCHAR function;
+    UCHAR function, pathId;
     PAHCI_ADAPTER_EXTENSION adapterExtension;
 
     StorPortDebugPrint(0, "AhciHwStartIo()\n");
 
+    pathId = Srb->PathId;
+    function = Srb->Function;
     adapterExtension = (PAHCI_ADAPTER_EXTENSION)AdapterExtension;
-    function = Srb->Function;
-
+
+    if (!IsPortValid(adapterExtension, pathId))
+    {
+        Srb->SrbStatus = SRB_STATUS_NO_DEVICE;
+        StorPortNotification(RequestComplete, adapterExtension, Srb);
+        return TRUE;
+    }
+
+    //
https://msdn.microsoft.com/windows/hardware/drivers/storage/handling-srb-fu…
+    // If the function member of an SRB is set to SRB_FUNCTION_PNP,
+    // the SRB is a structure of type SCSI_PNP_REQUEST_BLOCK.
+    if (function == SRB_FUNCTION_PNP)
+    {
+        PSCSI_PNP_REQUEST_BLOCK pnpRequest;
+
+        pnpRequest = (PSCSI_PNP_REQUEST_BLOCK)Srb;
+        if ((pnpRequest->SrbPnPFlags & SRB_PNP_FLAGS_ADAPTER_REQUEST) != 0)
+        {
+            if (pnpRequest->PnPAction == StorRemoveDevice ||
+                pnpRequest->PnPAction == StorSurpriseRemoval)
+            {
+                Srb->SrbStatus = SRB_STATUS_SUCCESS;
+                adapterExtension->StateFlags.Removed = 1;
+                StorPortDebugPrint(0, "\tadapter removed\n");
+            }
+            else if (pnpRequest->PnPAction == StorStopDevice)
+            {
+                Srb->SrbStatus = SRB_STATUS_SUCCESS;
+                StorPortDebugPrint(0, "\tRequested to Stop the adapter\n");
+            }
+            else
+                Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;
+            StorPortNotification(RequestComplete, adapterExtension, Srb);
+            return TRUE;
+        }
+    }
+
+    if (function == SRB_FUNCTION_EXECUTE_SCSI)
+    {
+        //
https://msdn.microsoft.com/en-us/windows/hardware/drivers/storage/handling-…
+        // On receipt of an SRB_FUNCTION_EXECUTE_SCSI request, a miniport driver's
HwScsiStartIo
+        // routine does the following:
+        //
+        // - Gets and/or sets up whatever context the miniport driver maintains in its
device,
+        //   logical unit, and/or SRB extensions
+        //   For example, a miniport driver might set up a logical unit extension with
pointers
+        //   to the SRB itself and the SRB DataBuffer pointer, the SRB DataTransferLength
value,
+        //   and a driver-defined value (or CDB SCSIOP_XXX value) indicating the
operation to be
+        //   carried out on the HBA.
+        //
+        // - Calls an internal routine to program the HBA, as partially directed by the
SrbFlags,
+        //   for the requested operation
+        //   For a device I/O operation, such an internal routine generally selects the
target device
+        //   and sends the CDB over the bus to the target logical unit.
+        if (Srb->CdbLength > 0)
+        {
+            PCDB cdb = (PCDB)&Srb->Cdb;
+            if (cdb->CDB10.OperationCode == SCSIOP_INQUIRY)
+            {
+                StorPortDebugPrint(0, "\tINQUIRY Called!\n");
+            }
+        }
+        else
+        {
+            Srb->SrbStatus = SRB_STATUS_BAD_FUNCTION;
+            StorPortNotification(RequestComplete, adapterExtension, Srb);
+            return TRUE;
+        }
+    }
+
+    StorPortDebugPrint(0, "\tUnknow function code recieved: %x\n", function);
+    Srb->SrbStatus = SRB_STATUS_BAD_FUNCTION;
+    StorPortNotification(RequestComplete, adapterExtension, Srb);
     return TRUE;
 }// -- AhciHwStartIo();
 
@@ -305,7 +392,7 @@
     ULONG portCount, portImplemented;
     ULONG pci_cfg_len;
     UCHAR pci_cfg_buf[0x30];
-    
+
     PAHCI_MEMORY_REGISTERS abar;
     PPCI_COMMON_CONFIG pciConfigData;
     PAHCI_ADAPTER_EXTENSION adapterExtension;
@@ -315,7 +402,7 @@
     adapterExtension = (PAHCI_ADAPTER_EXTENSION)AdapterExtension;
     adapterExtension->SlotNumber = ConfigInfo->SlotNumber;
     adapterExtension->SystemIoBusNumber = ConfigInfo->SystemIoBusNumber;
-    
+
     // get PCI configuration header
     pci_cfg_len = StorPortGetBusData(
                         adapterExtension,
@@ -374,7 +461,7 @@
     // 3.1.2 -- AE bit is read-write only if CAP.SAM is '0'
     ghc = StorPortReadRegisterUlong(adapterExtension, &abar->GHC);
     // AE := Highest Significant bit of GHC
-    if ((ghc & (0x1<<31)) == 1)//Hmm, controller was already in power state
+    if ((ghc & AHCI_Global_HBA_CONTROL_AE) == 1)//Hmm, controller was already in
power state
     {
         // reset controller to have it in know state
         StorPortDebugPrint(0, "\tAE Already set, Reset()\n");
@@ -384,10 +471,10 @@
         }
     }
 
-    ghc = 0x1<<31;// only AE=1
+    ghc = AHCI_Global_HBA_CONTROL_AE;// only AE=1
     StorPortWriteRegisterUlong(adapterExtension, &abar->GHC, ghc);
 
-    adapterExtension->IS = abar->IS;
+    adapterExtension->IS = &abar->IS;
     adapterExtension->PortImplemented = StorPortReadRegisterUlong(adapterExtension,
&abar->PI);
 
     if (adapterExtension->PortImplemented == 0){
@@ -400,23 +487,23 @@
     ConfigInfo->MaximumNumberOfTargets = 1;
     ConfigInfo->MaximumNumberOfLogicalUnits = 1;
     ConfigInfo->ResetTargetSupported = TRUE;
-    ConfigInfo->NumberOfBuses = 32;
+    ConfigInfo->NumberOfBuses = MAXIMUM_AHCI_PORT_COUNT;
     ConfigInfo->SynchronizationModel = StorSynchronizeFullDuplex;
     ConfigInfo->ScatterGather = TRUE;
 
     // Turn IE -- Interrupt Enabled
-    ghc |= 0x2;
+    ghc |= AHCI_Global_HBA_CONTROL_IE;
     StorPortWriteRegisterUlong(adapterExtension, &abar->GHC, ghc);
-    
+
     // allocate necessary resource for each port
     if (!AhciAllocateResourceForAdapter(adapterExtension, ConfigInfo)){
         StorPortDebugPrint(0, "\tAhciAllocateResourceForAdapter() ==
FALSE\n");
         return SP_RETURN_ERROR;
     }
 
-    for (index = 0; index < 32; index++)
-    {
-        if ((adapterExtension->PortImplemented & (1<<index)) != 0)
+    for (index = 0; index < MAXIMUM_AHCI_PORT_COUNT; index++)
+    {
+        if ((adapterExtension->PortImplemented & (0x1<<index)) != 0)
             AhciPortInitialize(&adapterExtension->PortExtension[index]);
     }
 
@@ -443,7 +530,7 @@
     HW_INITIALIZATION_DATA hwInitializationData;
     ULONG i, status;
 
-    StorPortDebugPrint(0, "Storahci Loaded 10023\n");
+    StorPortDebugPrint(0, "Storahci Loaded\n");
 
     // initialize the hardware data structure
     AhciZeroMemory((PCHAR)&hwInitializationData, sizeof(HW_INITIALIZATION_DATA));
@@ -471,13 +558,14 @@
     // set required extension sizes
     hwInitializationData.SrbExtensionSize = sizeof(AHCI_SRB_EXTENSION);
     hwInitializationData.DeviceExtensionSize = sizeof(AHCI_ADAPTER_EXTENSION);
-    
+
     // register our hw init data
     status = StorPortInitialize(
                     DriverObject,
                     RegistryPath,
                     &hwInitializationData,
                     NULL);
+
     StorPortDebugPrint(0, "\tstatus:%x\n", status);
     return status;
 }// -- DriverEntry();
@@ -494,7 +582,7 @@
  * software sets GHC.HR to ‘1’ and may poll until this bit is read to be ‘0’, at
which point software knows that
  * the HBA reset has completed.
  * If the HBA has not cleared GHC.HR to ‘0’ within 1 second of software setting
GHC.HR to ‘1’, the HBA is in
- * a hung or locked state. 
+ * a hung or locked state.
  *
  * @param adapterExtension
  *
@@ -538,6 +626,7 @@
  *
  * @param buffer
  */
+__inline
 VOID AhciZeroMemory(
   __in      PCHAR                               buffer,
   __in      ULONG                               bufferSize
@@ -547,3 +636,26 @@
     for (i = 0; i < bufferSize; i++)
         buffer[i] = 0;
 }// -- AhciZeroMemory();
+
+/**
+ * @name IsPortValid
+ * @implemented
+ *
+ * Tells wheather given port is implemented or not
+ *
+ * @param adapterExtension
+ * @param PathId
+ *
+ * @return
+ * return TRUE if bus was successfully reset
+ */
+__inline
+BOOLEAN IsPortValid(
+  __in      PAHCI_ADAPTER_EXTENSION             adapterExtension,
+  __in      UCHAR                               pathId
+)
+{
+    if (pathId >= MAXIMUM_AHCI_PORT_COUNT)
+        return FALSE;
+    return adapterExtension->PortExtension[pathId].IsActive;
+}// -- IsPortValid()

Modified: branches/GSoC_2016/AHCI/drivers/storage/storahci/storahci.h
URL:
http://svn.reactos.org/svn/reactos/branches/GSoC_2016/AHCI/drivers/storage/…
==============================================================================
--- branches/GSoC_2016/AHCI/drivers/storage/storahci/storahci.h	[iso-8859-1] (original)
+++ branches/GSoC_2016/AHCI/drivers/storage/storahci/storahci.h	[iso-8859-1] Tue Jun  7
11:05:32 2016
@@ -4,11 +4,22 @@
  * PURPOSE:        To Implement AHCI Miniport driver targeting storport NT 5.2
  * PROGRAMMERS:    Aman Priyadarshi (aman.eureka(a)gmail.com)
  */
- 
+
 #include "miniport.h"
 #include "storport.h"
 
 #define AHCI_POOL_TAG 'ahci'
+#define MAXIMUM_AHCI_PORT_COUNT 12
+
+// section 3.1.2
+#define AHCI_Global_HBA_CONTROL_HR          (0x1<<0)
+#define AHCI_Global_HBA_CONTROL_IE          (0x1<<1)
+#define AHCI_Global_HBA_CONTROL_MRSM        (0x1<<2)
+#define AHCI_Global_HBA_CONTROL_AE          (0x1<<31)
+
+//////////////////////////////////////////////////////////////
+//              ---- Support Structures ---                 //
+//////////////////////////////////////////////////////////////
 
 typedef struct _AHCI_FIS_DMA_SETUP
 {
@@ -24,7 +35,7 @@
     ULONG Reserved2;        //More reserved
     ULONG DmaBufferOffset;  //Byte offset into buffer. First 2 bits must be 0
     ULONG TranferCount;     //Number of bytes to transfer. Bit 0 must be 0
-    ULONG Reserved3;        //Reserved  
+    ULONG Reserved3;        //Reserved
 } AHCI_FIS_DMA_SETUP;
 
 typedef struct _AHCI_PIO_SETUP_FIS
@@ -54,12 +65,11 @@
 
     USHORT TransferCount;
     UCHAR Reserved5[2];
-
-}  AHCI_PIO_SETUP_FIS;
+} AHCI_PIO_SETUP_FIS;
 
 typedef struct _AHCI_D2H_REGISTER_FIS
 {
-    UCHAR FisType;  // 0x34
+    UCHAR FisType;
     UCHAR Reserved1 :6;
     UCHAR I:1;
     UCHAR Reserved2 :1;
@@ -83,9 +93,9 @@
     UCHAR Reserved4[4];
 } AHCI_D2H_REGISTER_FIS;
 
-typedef struct _AHCI_SET_DEVICE_BITS_FIS {
-
-    UCHAR FisType;   //0xA1
+typedef struct _AHCI_SET_DEVICE_BITS_FIS
+{
+    UCHAR FisType;
 
     UCHAR PMPort: 4;
     UCHAR Reserved1 :2;
@@ -100,9 +110,13 @@
     UCHAR Error;
 
     UCHAR Reserved5[4];
-}  AHCI_SET_DEVICE_BITS_FIS;
-
-// 4.2.2
+} AHCI_SET_DEVICE_BITS_FIS;
+
+//////////////////////////////////////////////////////////////
+//              ---------------------------                 //
+//////////////////////////////////////////////////////////////
+
+// 4.2.2 Command Header
 typedef struct _AHCI_COMMAND_HEADER
 {
     ULONG HEADER_DESCRIPTION;   // DW 0
@@ -115,84 +129,81 @@
 // Received FIS
 typedef struct _AHCI_RECEIVED_FIS
 {
-    AHCI_FIS_DMA_SETUP          DmaSetupFIS;      // 0x00 -- DMA Setup FIS
-    ULONG                       pad0;             // 4 BYTE padding
-    AHCI_PIO_SETUP_FIS          PioSetupFIS;      // 0x20 -- PIO Setup FIS
-    ULONG                       pad1[3];          // 12 BYTE padding
-    AHCI_D2H_REGISTER_FIS       RegisterFIS;      // 0x40 -- Register – Device to Host
FIS
-    ULONG                       pad2;             // 4 BYTE padding
-    AHCI_SET_DEVICE_BITS_FIS    SetDeviceFIS;     // 0x58 -- Set Device Bit FIS
-    ULONG                       UnknowFIS[16];    // 0x60 -- Unknown FIS
-    ULONG                       Reserved[24];     // 0xA0 -- Reserved
+    struct _AHCI_FIS_DMA_SETUP          DmaSetupFIS;      // 0x00 -- DMA Setup FIS
+    ULONG                               pad0;             // 4 BYTE padding
+    struct _AHCI_PIO_SETUP_FIS          PioSetupFIS;      // 0x20 -- PIO Setup FIS
+    ULONG                               pad1[3];          // 12 BYTE padding
+    struct _AHCI_D2H_REGISTER_FIS       RegisterFIS;      // 0x40 -- Register – Device
to Host FIS
+    ULONG                               pad2;             // 4 BYTE padding
+    struct _AHCI_SET_DEVICE_BITS_FIS    SetDeviceFIS;     // 0x58 -- Set Device Bit FIS
+    ULONG                               UnknowFIS[16];    // 0x60 -- Unknown FIS
+    ULONG                               Reserved[24];     // 0xA0 -- Reserved
 } AHCI_RECEIVED_FIS, *PAHCI_RECEIVED_FIS;
 
+// Holds Port Information
 typedef struct _AHCI_PORT
 {
-    ULONG   CLB;        // 0x00, command list base address, 1K-byte aligned
-    ULONG   CLBU;       // 0x04, command list base address upper 32 bits
-    ULONG   FB;         // 0x08, FIS base address, 256-byte aligned
-    ULONG   FBU;        // 0x0C, FIS base address upper 32 bits
-    ULONG   IS;         // 0x10, interrupt status
-    ULONG   IE;         // 0x14, interrupt enable
-    ULONG   CMD;        // 0x18, command and status
-    ULONG   RSV0;       // 0x1C, Reserved
-    ULONG   TFD;        // 0x20, task file data
-    ULONG   SIG;        // 0x24, signature
-    ULONG   SSTS;       // 0x28, SATA status (SCR0:SStatus)
-    ULONG   SCTL;       // 0x2C, SATA control (SCR2:SControl)
-    ULONG   SERR;       // 0x30, SATA error (SCR1:SError)
-    ULONG   SACT;       // 0x34, SATA active (SCR3:SActive)
-    ULONG   CI;         // 0x38, command issue
-    ULONG   SNTF;       // 0x3C, SATA notification (SCR4:SNotification)
-    ULONG   FBS;        // 0x40, FIS-based switch control
-    ULONG   RSV1[11];   // 0x44 ~ 0x6F, Reserved
-    ULONG   Vendor[4];  // 0x70 ~ 0x7F, vendor specific
+    ULONG   CLB;                                // 0x00, command list base address,
1K-byte aligned
+    ULONG   CLBU;                               // 0x04, command list base address upper
32 bits
+    ULONG   FB;                                 // 0x08, FIS base address, 256-byte
aligned
+    ULONG   FBU;                                // 0x0C, FIS base address upper 32 bits
+    ULONG   IS;                                 // 0x10, interrupt status
+    ULONG   IE;                                 // 0x14, interrupt enable
+    ULONG   CMD;                                // 0x18, command and status
+    ULONG   RSV0;                               // 0x1C, Reserved
+    ULONG   TFD;                                // 0x20, task file data
+    ULONG   SIG;                                // 0x24, signature
+    ULONG   SSTS;                               // 0x28, SATA status (SCR0:SStatus)
+    ULONG   SCTL;                               // 0x2C, SATA control (SCR2:SControl)
+    ULONG   SERR;                               // 0x30, SATA error (SCR1:SError)
+    ULONG   SACT;                               // 0x34, SATA active (SCR3:SActive)
+    ULONG   CI;                                 // 0x38, command issue
+    ULONG   SNTF;                               // 0x3C, SATA notification
(SCR4:SNotification)
+    ULONG   FBS;                                // 0x40, FIS-based switch control
+    ULONG   RSV1[11];                           // 0x44 ~ 0x6F, Reserved
+    ULONG   Vendor[4];                          // 0x70 ~ 0x7F, vendor specific
 } AHCI_PORT, *PAHCI_PORT;
 
 typedef struct _AHCI_MEMORY_REGISTERS
 {
     // 0x00 - 0x2B, Generic Host Control
-    ULONG CAP;                      // 0x00, Host capability
-    ULONG GHC;                      // 0x04, Global host control
-    ULONG IS;                       // 0x08, Interrupt status
-    ULONG PI;                       // 0x0C, Port implemented
-    ULONG VS;                       // 0x10, Version
-    ULONG CCC_CTL;                  // 0x14, Command completion coalescing control
-    ULONG CCC_PTS;                  // 0x18, Command completion coalescing ports
-    ULONG EM_LOC;                   // 0x1C, Enclosure management location
-    ULONG EM_CTL;                   // 0x20, Enclosure management control
-    ULONG CAP2;                     // 0x24, Host capabilities extended
-    ULONG BOHC;                     // 0x28, BIOS/OS handoff control and status
-
-    // 0x2C - 0x9F, Reserved
-    ULONG Reserved[0xA0-0x2C];
-
-    // 0xA0 - 0xFF, Vendor specific registers
-    ULONG VendorSpecific[0x100-0xA0];
-
-    AHCI_PORT PortList[32];//1~32
+    ULONG CAP;                                  // 0x00, Host capability
+    ULONG GHC;                                  // 0x04, Global host control
+    ULONG IS;                                   // 0x08, Interrupt status
+    ULONG PI;                                   // 0x0C, Port implemented
+    ULONG VS;                                   // 0x10, Version
+    ULONG CCC_CTL;                              // 0x14, Command completion coalescing
control
+    ULONG CCC_PTS;                              // 0x18, Command completion coalescing
ports
+    ULONG EM_LOC;                               // 0x1C, Enclosure management location
+    ULONG EM_CTL;                               // 0x20, Enclosure management control
+    ULONG CAP2;                                 // 0x24, Host capabilities extended
+    ULONG BOHC;                                 // 0x28, BIOS/OS handoff control and
status
+    ULONG Reserved[0xA0-0x2C];                  // 0x2C - 0x9F, Reserved
+    ULONG VendorSpecific[0x100-0xA0];           // 0xA0 - 0xFF, Vendor specific
registers
+    AHCI_PORT PortList[MAXIMUM_AHCI_PORT_COUNT];
 
 } AHCI_MEMORY_REGISTERS, *PAHCI_MEMORY_REGISTERS;
 
-struct _AHCI_ADAPTER_EXTENSION;
-
+// Holds information for each attached attached port to a given adapter.
 typedef struct _AHCI_PORT_EXTENSION
 {
     ULONG PortNumber;
-    struct _AHCI_ADAPTER_EXTENSION* AdapterExtension;
+    BOOLEAN IsActive;
+    PAHCI_PORT Port;                                    // AHCI Port Infomation
+    PAHCI_RECEIVED_FIS ReceivedFIS;
     PAHCI_COMMAND_HEADER CommandList;
-    PAHCI_RECEIVED_FIS ReceivedFIS;
-    PAHCI_PORT Port;
+    STOR_DEVICE_POWER_STATE DevicePowerState;           // Device Power State
+    struct _AHCI_ADAPTER_EXTENSION* AdapterExtension;   // Port's Adapter
Information
 } AHCI_PORT_EXTENSION, *PAHCI_PORT_EXTENSION;
 
+// Holds Adapter Information
 typedef struct _AHCI_ADAPTER_EXTENSION
 {
-    ULONG   AdapterNumber;
     ULONG   SystemIoBusNumber;
     ULONG   SlotNumber;
     ULONG   AhciBaseAddress;
-    ULONG   IS;                 // Interrupt status
-    ULONG   PortImplemented;
+    PULONG  IS;// Interrupt Status, In case of MSIM == `1`
+    ULONG   PortImplemented;// bit-mapping of ports which are implemented
 
     USHORT  VendorID;
     USHORT  DeviceID;
@@ -202,10 +213,18 @@
     ULONG   CAP;
     ULONG   CAP2;
 
-    PVOID NonCachedExtension;
+    PVOID NonCachedExtension;// holds virtual address to noncached buffer allocated for
Port Extension
+
+    struct
+    {
+        // Message per port or shared port?
+        ULONG MessagePerPort : 1;
+        ULONG Removed : 1;
+        ULONG Reserved : 30; // not in use -- maintain 4 byte alignment
+    } StateFlags;
 
     PAHCI_MEMORY_REGISTERS ABAR_Address;
-    AHCI_PORT_EXTENSION PortExtension[32];
+    AHCI_PORT_EXTENSION PortExtension[MAXIMUM_AHCI_PORT_COUNT];
 } AHCI_ADAPTER_EXTENSION, *PAHCI_ADAPTER_EXTENSION;
 
 typedef struct _AHCI_SRB_EXTENSION