[edk2-platforms][PATCH V1 17/37] CoffeelakeSiliconPkg/Pch: Add Base library instances

["Kubacki, Michael A" <michael.a.kubacki@intel.com>]

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2082

Adds PCH Base library class instances.

* BaseResetSystemLib
* BaseSmbusLib

Cc: Sai Chaganty <rangasai.v.chaganty@intel.com>
Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Ankit Sinha <ankit.sinha@intel.com>
Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
---
 Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseResetSystemLib/BaseResetSystemLib.inf |  38 +
 Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseSmbusLib/BaseSmbusLib.inf             |  39 +
 Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseResetSystemLib/BaseResetSystemLib.c   | 153 +++
 Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseSmbusLib/BaseSmbusLib.c               | 993 ++++++++++++++++++++
 4 files changed, 1223 insertions(+)

diff --git a/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseResetSystemLib/BaseResetSystemLib.inf b/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseResetSystemLib/BaseResetSystemLib.inf
new file mode 100644
index 0000000000..8d68f2dd83
--- /dev/null
+++ b/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseResetSystemLib/BaseResetSystemLib.inf
@@ -0,0 +1,38 @@
+## @file
+# Component description file for Intel Ich7 Reset System Library.
+#
+# Copyright (c) 2019 Intel Corporation. All rights reserved. <BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+INF_VERSION = 0x00010017
+BASE_NAME = BaseResetSystemLib
+FILE_GUID = D4FF05AA-3C7D-4B8A-A1EE-AA5EFA0B1732
+VERSION_STRING = 1.0
+MODULE_TYPE = BASE
+UEFI_SPECIFICATION_VERSION = 2.00
+LIBRARY_CLASS = ResetSystemLib
+CONSTRUCTOR = BaseResetSystemLibConstructor
+#
+# The following information is for reference only and not required by the build tools.
+#
+# VALID_ARCHITECTURES = IA32 X64 IPF
+#
+
+[LibraryClasses]
+IoLib
+DebugLib
+PmcLib
+
+
+[Packages]
+MdePkg/MdePkg.dec
+CoffeelakeSiliconPkg/SiPkg.dec
+
+
+[Sources]
+BaseResetSystemLib.c
+
diff --git a/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseSmbusLib/BaseSmbusLib.inf b/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseSmbusLib/BaseSmbusLib.inf
new file mode 100644
index 0000000000..f3388a2624
--- /dev/null
+++ b/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseSmbusLib/BaseSmbusLib.inf
@@ -0,0 +1,39 @@
+## @file
+# Component description file for PCH Smbus Library.
+#
+# SMBUS Library that layers on top of the I/O Library to directly
+# access a standard SMBUS host controller.
+#
+# Copyright (c) 2019 Intel Corporation. All rights reserved. <BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+INF_VERSION = 0x00010017
+BASE_NAME = BaseSmbusLib
+FILE_GUID = 5C4D0430-F81B-42D3-BB88-4A6CD2796FF8
+VERSION_STRING = 1.0
+MODULE_TYPE = BASE
+LIBRARY_CLASS = SmbusLib
+CONSTRUCTOR = BaseSmbusLibConstructor
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+# VALID_ARCHITECTURES = IA32 X64 IPF EBC
+#
+
+[LibraryClasses]
+BaseLib
+DebugLib
+IoLib
+PciSegmentLib
+
+[Packages]
+MdePkg/MdePkg.dec
+CoffeelakeSiliconPkg/SiPkg.dec
+
+[Sources]
+BaseSmbusLib.c
diff --git a/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseResetSystemLib/BaseResetSystemLib.c b/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseResetSystemLib/BaseResetSystemLib.c
new file mode 100644
index 0000000000..a603f5e794
--- /dev/null
+++ b/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseResetSystemLib/BaseResetSystemLib.c
@@ -0,0 +1,153 @@
+/** @file
+  System reset library services.
+
+  Copyright (c) 2019 Intel Corporation. All rights reserved. <BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Uefi.h>
+#include <Library/IoLib.h>
+#include <Library/DebugLib.h>
+#include <Library/ResetSystemLib.h>
+#include <Library/PmcLib.h>
+#include <Register/PchRegsLpc.h>
+#include <Register/PchRegsPmc.h>
+
+GLOBAL_REMOVE_IF_UNREFERENCED UINT16           mBaseResetSystemABase;
+
+/**
+  Calling this function causes a system-wide reset. This sets
+  all circuitry within the system to its initial state. This type of reset
+  is asynchronous to system operation and operates without regard to
+  cycle boundaries.
+
+  System reset should not return, if it returns, it means the system does
+  not support cold reset.
+**/
+VOID
+EFIAPI
+ResetCold (
+  VOID
+  )
+{
+  IoWrite8 (R_PCH_IO_RST_CNT, V_PCH_IO_RST_CNT_FULLRESET);
+}
+
+/**
+  Calling this function causes a system-wide initialization. The processors
+  are set to their initial state, and pending cycles are not corrupted.
+
+  System reset should not return, if it returns, it means the system does
+  not support warm reset.
+**/
+VOID
+EFIAPI
+ResetWarm (
+  VOID
+  )
+{
+  IoWrite8 (R_PCH_IO_RST_CNT, V_PCH_IO_RST_CNT_HARDRESET);
+}
+
+/**
+  Calling this function causes the system to enter a power state equivalent
+  to the ACPI G2/S5 or G3 states.
+
+  System shutdown should not return, if it returns, it means the system does
+  not support shut down reset.
+**/
+VOID
+EFIAPI
+ResetShutdown (
+  VOID
+  )
+{
+  UINT16         ABase;
+  UINT32         Data32;
+
+  ABase = mBaseResetSystemABase;
+  if (ABase == 0) {
+    ABase = PmcGetAcpiBase ();
+  }
+  ///
+  /// Firstly, GPE0_EN should be disabled to avoid any GPI waking up the system from S5
+  ///
+  IoWrite32 (ABase + R_ACPI_IO_GPE0_EN_127_96, 0);
+
+  ///
+  /// Secondly, PwrSts register must be cleared
+  ///
+  /// Write a "1" to bit[8] of power button status register at
+  /// (PM_BASE + PM1_STS_OFFSET) to clear this bit
+  ///
+  IoWrite16 (ABase + R_ACPI_IO_PM1_STS, B_ACPI_IO_PM1_STS_PWRBTN);
+
+  ///
+  /// Finally, transform system into S5 sleep state
+  ///
+  Data32 = IoRead32 (ABase + R_ACPI_IO_PM1_CNT);
+
+  Data32 = (UINT32) ((Data32 &~(B_ACPI_IO_PM1_CNT_SLP_TYP + B_ACPI_IO_PM1_CNT_SLP_EN)) | V_ACPI_IO_PM1_CNT_S5);
+
+  IoWrite32 (ABase + R_ACPI_IO_PM1_CNT, Data32);
+
+  Data32 = Data32 | B_ACPI_IO_PM1_CNT_SLP_EN;
+
+  IoWrite32 (ABase + R_ACPI_IO_PM1_CNT, Data32);
+
+  return;
+}
+
+/**
+  Calling this function causes the system to enter a power state for platform specific.
+
+  @param[in] DataSize             The size of ResetData in bytes.
+  @param[in] ResetData            Optional element used to introduce a platform specific reset.
+                                  The exact type of the reset is defined by the EFI_GUID that follows
+                                  the Null-terminated Unicode string.
+
+**/
+VOID
+EFIAPI
+ResetPlatformSpecific (
+  IN UINTN            DataSize,
+  IN VOID             *ResetData OPTIONAL
+  )
+{
+  IoWrite8 (R_PCH_IO_RST_CNT, V_PCH_IO_RST_CNT_FULLRESET);
+}
+
+/**
+  Calling this function causes the system to enter a power state for capsule update.
+
+  Reset update should not return, if it returns, it means the system does
+  not support capsule update.
+
+**/
+VOID
+EFIAPI
+EnterS3WithImmediateWake (
+  VOID
+  )
+{
+  ASSERT (FALSE);
+}
+
+/**
+  The library constructuor.
+
+  The function does the necessary initialization work for this library instance.
+
+  @retval     EFI_SUCCESS       The function always return EFI_SUCCESS for now.
+**/
+EFI_STATUS
+EFIAPI
+BaseResetSystemLibConstructor (
+  VOID
+  )
+{
+  mBaseResetSystemABase = PmcGetAcpiBase ();
+
+  return EFI_SUCCESS;
+}
diff --git a/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseSmbusLib/BaseSmbusLib.c b/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseSmbusLib/BaseSmbusLib.c
new file mode 100644
index 0000000000..3d6386d433
--- /dev/null
+++ b/Silicon/Intel/CoffeelakeSiliconPkg/Pch/Library/BaseSmbusLib/BaseSmbusLib.c
@@ -0,0 +1,993 @@
+/** @file
+  PCH SMBUS library implementation built upon I/O library.
+
+  Copyright (c) 2019 Intel Corporation. All rights reserved. <BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Base.h>
+#include <Library/SmbusLib.h>
+#include <Library/BaseLib.h>
+#include <Library/IoLib.h>
+#include <Library/PciLib.h>
+#include <Library/DebugLib.h>
+#include <Library/PciSegmentLib.h>
+#include <Register/PchRegs.h>
+#include <Register/PchRegsSmbus.h>
+
+GLOBAL_REMOVE_IF_UNREFERENCED UINT16           mSmbusIoBase = 0;
+
+/**
+  Gets Io port base address of Smbus Host Controller.
+
+  @retval The Io port base address of Smbus host controller.
+
+**/
+UINT16
+InternalGetSmbusIoPortBaseAddress (
+  VOID
+  )
+{
+  UINT64    SmbusPciBase;
+  UINT16    IoPortBaseAddress;
+
+  if (mSmbusIoBase != 0) {
+    return mSmbusIoBase;
+  }
+
+  SmbusPciBase = PCI_SEGMENT_LIB_ADDRESS (
+                   DEFAULT_PCI_SEGMENT_NUMBER_PCH,
+                   DEFAULT_PCI_BUS_NUMBER_PCH,
+                   PCI_DEVICE_NUMBER_PCH_SMBUS,
+                   PCI_FUNCTION_NUMBER_PCH_SMBUS,
+                   0
+                   );
+  IoPortBaseAddress = (UINT16) PciSegmentRead32 (SmbusPciBase + R_SMBUS_CFG_BASE);
+
+  //
+  // Make sure that the IO port base address has been properly set.
+  //
+  if ((IoPortBaseAddress == 0) || (IoPortBaseAddress == 0xFFFF)) {
+    ASSERT (FALSE);
+    return 0;
+  }
+
+  IoPortBaseAddress &= B_SMBUS_CFG_BASE_BAR;
+  mSmbusIoBase = IoPortBaseAddress;
+
+  return IoPortBaseAddress;
+}
+
+
+/**
+  Acquires the ownership of SMBUS.
+
+  This internal function reads the host state register.
+  If the SMBUS is not available, RETURN_TIMEOUT is returned;
+  Otherwise, it performs some basic initializations and returns
+  RETURN_SUCCESS.
+
+  @param[in]  IoPortBaseAddress The Io port base address of Smbus Host controller.
+
+  @retval     RETURN_SUCCESS    The SMBUS command was executed successfully.
+  @retval     RETURN_TIMEOUT    A timeout occurred while executing the SMBUS command.
+
+**/
+RETURN_STATUS
+InternalSmBusAcquire (
+  IN UINT16                   IoPortBaseAddress
+  )
+{
+  UINT8   HostStatus;
+
+  HostStatus = IoRead8 (IoPortBaseAddress + R_SMBUS_IO_HSTS);
+  if ((HostStatus & B_SMBUS_IO_IUS) != 0) {
+    return RETURN_TIMEOUT;
+  } else if ((HostStatus & B_SMBUS_IO_HBSY) != 0) {
+    //
+    // Clear host status register and exit.
+    //
+    IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HSTS, B_SMBUS_IO_HSTS_ALL);
+    return RETURN_TIMEOUT;
+  }
+  //
+  // Clear out any odd status information (Will Not Clear In Use).
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HSTS, HostStatus);
+
+  return RETURN_SUCCESS;
+}
+
+/**
+  Starts the SMBUS transaction and waits until the end.
+
+  This internal function start the SMBUS transaction and waits until the transaction
+  of SMBUS is over by polling the INTR bit of Host status register.
+  If the SMBUS is not available, RETURN_TIMEOUT is returned;
+  Otherwise, it performs some basic initializations and returns
+  RETURN_SUCCESS.
+
+  @param[in]  IoPortBaseAddress   The Io port base address of Smbus Host controller.
+  @param[in]  HostControl         The Host control command to start SMBUS transaction.
+
+  @retval     RETURN_SUCCESS      The SMBUS command was executed successfully.
+  @retval     RETURN_CRC_ERROR    The checksum is not correct (PEC is incorrect).
+  @retval     RETURN_DEVICE_ERROR The request was not completed because a failure reflected
+                                  in the Host Status Register bit.  Device errors are
+                                  a result of a transaction collision, illegal command field,
+                                  unclaimed cycle (host initiated), or bus errors (collisions).
+
+**/
+RETURN_STATUS
+InternalSmBusStart (
+  IN  UINT16                  IoPortBaseAddress,
+  IN  UINT8                   HostControl
+  )
+{
+  UINT8   HostStatus;
+  UINT8   AuxiliaryStatus;
+
+  //
+  // Set Host Control Register (Initiate Operation, Interrupt disabled).
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HCTL, (UINT8)(HostControl + B_SMBUS_IO_START));
+
+  do {
+    //
+    // Poll INTR bit of Host Status Register.
+    //
+    HostStatus = IoRead8 (IoPortBaseAddress + R_SMBUS_IO_HSTS);
+  } while ((HostStatus & (B_SMBUS_IO_INTR | B_SMBUS_IO_ERROR | B_SMBUS_IO_BYTE_DONE_STS)) == 0);
+
+  if ((HostStatus & B_SMBUS_IO_ERROR) == 0) {
+    return RETURN_SUCCESS;
+  }
+  //
+  // Clear error bits of Host Status Register.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HSTS, B_SMBUS_IO_ERROR);
+  //
+  // Read Auxiliary Status Register to judge CRC error.
+  //
+  AuxiliaryStatus = IoRead8 (IoPortBaseAddress + R_SMBUS_IO_AUXS);
+  if ((AuxiliaryStatus & B_SMBUS_IO_CRCE) != 0) {
+    return RETURN_CRC_ERROR;
+  }
+
+  return RETURN_DEVICE_ERROR;
+}
+
+/**
+  Executes an SMBUS quick, byte or word command.
+
+  This internal function executes an SMBUS quick, byte or word commond.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+
+  @param[in]  HostControl     The value of Host Control Register to set.
+  @param[in]  SmBusAddress    Address that encodes the SMBUS Slave Address,
+                              SMBUS Command, SMBUS Data Length, and PEC.
+  @param[in]  Value           The byte/word write to the SMBUS.
+  @param[out] Status          Return status for the executed command.
+                              This is an optional parameter and may be NULL.
+
+  @retval The byte/word read from the SMBUS.
+
+**/
+UINT16
+InternalSmBusNonBlock (
+  IN  UINT8                     HostControl,
+  IN  UINTN                     SmBusAddress,
+  IN  UINT16                    Value,
+  OUT RETURN_STATUS             *Status
+  )
+{
+  RETURN_STATUS                 ReturnStatus;
+  UINT16                        IoPortBaseAddress;
+  UINT8                         AuxiliaryControl;
+
+  IoPortBaseAddress = InternalGetSmbusIoPortBaseAddress ();
+
+  //
+  // Try to acquire the ownership of SMBUS.
+  //
+  ReturnStatus = InternalSmBusAcquire (IoPortBaseAddress);
+  if (RETURN_ERROR (ReturnStatus)) {
+    goto Done;
+  }
+  //
+  // Set the appropriate Host Control Register and auxiliary Control Register.
+  //
+  AuxiliaryControl = 0;
+  if (SMBUS_LIB_PEC (SmBusAddress)) {
+    AuxiliaryControl |= B_SMBUS_IO_AAC;
+  }
+  //
+  // Set Host Commond Register.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HCMD, (UINT8) SMBUS_LIB_COMMAND (SmBusAddress));
+  //
+  // Write value to Host Data 0 and Host Data 1 Registers.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HD0, (UINT8) Value);
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HD1, (UINT8) (Value >> 8));
+  //
+  // Set Auxiliary Control Regiester.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_AUXC, AuxiliaryControl);
+  //
+  // Set SMBUS slave address for the device to send/receive from.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_TSA, (UINT8) SmBusAddress);
+  //
+  // Start the SMBUS transaction and wait for the end.
+  //
+  ReturnStatus = InternalSmBusStart (IoPortBaseAddress, HostControl);
+  //
+  // Read value from Host Data 0 and Host Data 1 Registers.
+  //
+  Value = (UINT16)(IoRead8 (IoPortBaseAddress + R_SMBUS_IO_HD1) << 8);
+  Value = (UINT16)(Value | IoRead8 (IoPortBaseAddress + R_SMBUS_IO_HD0));
+  //
+  // Clear Host Status Register and Auxiliary Status Register.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HSTS, B_SMBUS_IO_HSTS_ALL);
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_AUXS, B_SMBUS_IO_CRCE);
+
+Done:
+  if (Status != NULL) {
+    *Status = ReturnStatus;
+  }
+
+  return Value;
+}
+
+/**
+  Executes an SMBUS quick read command.
+
+  Executes an SMBUS quick read command on the SMBUS device specified by SmBusAddress.
+  Only the SMBUS slave address field of SmBusAddress is required.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If PEC is set in SmBusAddress, then ASSERT().
+  If Command in SmBusAddress is not zero, then ASSERT().
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+**/
+VOID
+EFIAPI
+SmBusQuickRead (
+  IN  UINTN                     SmBusAddress,
+  OUT RETURN_STATUS             *Status       OPTIONAL
+  )
+{
+  ASSERT (!SMBUS_LIB_PEC (SmBusAddress));
+  ASSERT (SMBUS_LIB_COMMAND (SmBusAddress)  == 0);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if (SMBUS_LIB_PEC (SmBusAddress)           ||
+    (SMBUS_LIB_COMMAND (SmBusAddress)  != 0) ||
+    (SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+    (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return;
+  }
+
+  InternalSmBusNonBlock (
+    V_SMBUS_IO_SMB_CMD_QUICK,
+    SmBusAddress | B_SMBUS_IO_READ,
+    0,
+    Status
+    );
+}
+
+/**
+  Executes an SMBUS quick write command.
+
+  Executes an SMBUS quick write command on the SMBUS device specified by SmBusAddress.
+  Only the SMBUS slave address field of SmBusAddress is required.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If PEC is set in SmBusAddress, then ASSERT().
+  If Command in SmBusAddress is not zero, then ASSERT().
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+**/
+VOID
+EFIAPI
+SmBusQuickWrite (
+  IN  UINTN                     SmBusAddress,
+  OUT RETURN_STATUS             *Status       OPTIONAL
+  )
+{
+  ASSERT (!SMBUS_LIB_PEC (SmBusAddress));
+  ASSERT (SMBUS_LIB_COMMAND (SmBusAddress)  == 0);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if (SMBUS_LIB_PEC (SmBusAddress)           ||
+    (SMBUS_LIB_COMMAND (SmBusAddress)  != 0) ||
+    (SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+    (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return;
+  }
+
+  InternalSmBusNonBlock (
+    V_SMBUS_IO_SMB_CMD_QUICK,
+    SmBusAddress | B_SMBUS_IO_WRITE,
+    0,
+    Status
+    );
+}
+
+/**
+  Executes an SMBUS receive byte command.
+
+  Executes an SMBUS receive byte command on the SMBUS device specified by SmBusAddress.
+  Only the SMBUS slave address field of SmBusAddress is required.
+  The byte received from the SMBUS is returned.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If Command in SmBusAddress is not zero, then ASSERT().
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The byte received from the SMBUS.
+
+**/
+UINT8
+EFIAPI
+SmBusReceiveByte (
+  IN  UINTN          SmBusAddress,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (SMBUS_LIB_COMMAND (SmBusAddress)  == 0);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((SMBUS_LIB_COMMAND (SmBusAddress)  != 0) ||
+      (SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return (UINT8) InternalSmBusNonBlock (
+                   V_SMBUS_IO_SMB_CMD_BYTE,
+                   SmBusAddress | B_SMBUS_IO_READ,
+                   0,
+                   Status
+                   );
+}
+
+/**
+  Executes an SMBUS send byte command.
+
+  Executes an SMBUS send byte command on the SMBUS device specified by SmBusAddress.
+  The byte specified by Value is sent.
+  Only the SMBUS slave address field of SmBusAddress is required.  Value is returned.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If Command in SmBusAddress is not zero, then ASSERT().
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[in]  Value         The 8-bit value to send.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The parameter of Value.
+
+**/
+UINT8
+EFIAPI
+SmBusSendByte (
+  IN  UINTN          SmBusAddress,
+  IN  UINT8          Value,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (SMBUS_LIB_COMMAND (SmBusAddress)  == 0);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((SMBUS_LIB_COMMAND (SmBusAddress)  != 0) ||
+      (SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return (UINT8) InternalSmBusNonBlock (
+                   V_SMBUS_IO_SMB_CMD_BYTE,
+                   SmBusAddress | B_SMBUS_IO_WRITE,
+                   Value,
+                   Status
+                   );
+}
+
+/**
+  Executes an SMBUS read data byte command.
+
+  Executes an SMBUS read data byte command on the SMBUS device specified by SmBusAddress.
+  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
+  The 8-bit value read from the SMBUS is returned.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress    Address that encodes the SMBUS Slave Address,
+                              SMBUS Command, SMBUS Data Length, and PEC.
+  @param[out] Status          Return status for the executed command.
+                              This is an optional parameter and may be NULL.
+
+  @retval The byte read from the SMBUS.
+
+**/
+UINT8
+EFIAPI
+SmBusReadDataByte (
+  IN  UINTN          SmBusAddress,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return (UINT8) InternalSmBusNonBlock (
+                   V_SMBUS_IO_SMB_CMD_BYTE_DATA,
+                   SmBusAddress | B_SMBUS_IO_READ,
+                   0,
+                   Status
+                   );
+}
+
+/**
+  Executes an SMBUS write data byte command.
+
+  Executes an SMBUS write data byte command on the SMBUS device specified by SmBusAddress.
+  The 8-bit value specified by Value is written.
+  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
+  Value is returned.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[in]  Value         The 8-bit value to write.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The parameter of Value.
+
+**/
+UINT8
+EFIAPI
+SmBusWriteDataByte (
+  IN  UINTN          SmBusAddress,
+  IN  UINT8          Value,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return (UINT8) InternalSmBusNonBlock (
+                   V_SMBUS_IO_SMB_CMD_BYTE_DATA,
+                   SmBusAddress | B_SMBUS_IO_WRITE,
+                   Value,
+                   Status
+                   );
+}
+
+/**
+  Executes an SMBUS read data word command.
+
+  Executes an SMBUS read data word command on the SMBUS device specified by SmBusAddress.
+  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
+  The 16-bit value read from the SMBUS is returned.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The byte read from the SMBUS.
+
+**/
+UINT16
+EFIAPI
+SmBusReadDataWord (
+  IN  UINTN          SmBusAddress,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return InternalSmBusNonBlock (
+           V_SMBUS_IO_SMB_CMD_WORD_DATA,
+           SmBusAddress | B_SMBUS_IO_READ,
+           0,
+           Status
+           );
+}
+
+/**
+  Executes an SMBUS write data word command.
+
+  Executes an SMBUS write data word command on the SMBUS device specified by SmBusAddress.
+  The 16-bit value specified by Value is written.
+  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
+  Value is returned.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[in]  Value         The 16-bit value to write.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The parameter of Value.
+
+**/
+UINT16
+EFIAPI
+SmBusWriteDataWord (
+  IN  UINTN          SmBusAddress,
+  IN  UINT16         Value,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return InternalSmBusNonBlock (
+           V_SMBUS_IO_SMB_CMD_WORD_DATA,
+           SmBusAddress | B_SMBUS_IO_WRITE,
+           Value,
+           Status
+           );
+}
+
+/**
+  Executes an SMBUS process call command.
+
+  Executes an SMBUS process call command on the SMBUS device specified by SmBusAddress.
+  The 16-bit value specified by Value is written.
+  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
+  The 16-bit value returned by the process call command is returned.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[in]  Value         The 16-bit value to write.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The 16-bit value returned by the process call command.
+
+**/
+UINT16
+EFIAPI
+SmBusProcessCall (
+  IN  UINTN          SmBusAddress,
+  IN  UINT16         Value,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return InternalSmBusNonBlock (
+           V_SMBUS_IO_SMB_CMD_PROCESS_CALL,
+           SmBusAddress | B_SMBUS_IO_WRITE,
+           Value,
+           Status
+           );
+}
+
+/**
+  Executes an SMBUS block command.
+
+  Executes an SMBUS block read, block write and block write-block read command
+  on the SMBUS device specified by SmBusAddress.
+  Bytes are read from the SMBUS and stored in Buffer.
+  The number of bytes read is returned, and will never return a value larger than 32-bytes.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  It is the caller's responsibility to make sure Buffer is large enough for the total number of bytes read.
+  SMBUS supports a maximum transfer size of 32 bytes, so Buffer does not need to be any larger than 32 bytes.
+
+  @param[in]  HostControl     The value of Host Control Register to set.
+  @param[in]  SmBusAddress    Address that encodes the SMBUS Slave Address,
+                              SMBUS Command, SMBUS Data Length, and PEC.
+  @param[in]  WriteBuffer     Pointer to the buffer of bytes to write to the SMBUS.
+  @param[out] ReadBuffer      Pointer to the buffer of bytes to read from the SMBUS.
+  @param[out] Status          Return status for the executed command.
+                              This is an optional parameter and may be NULL.
+
+  @retval The number of bytes read from the SMBUS.
+
+**/
+UINTN
+InternalSmBusBlock (
+  IN  UINT8                     HostControl,
+  IN  UINTN                     SmBusAddress,
+  IN  UINT8                     *WriteBuffer,
+  OUT UINT8                     *ReadBuffer,
+  OUT RETURN_STATUS             *Status
+  )
+{
+  RETURN_STATUS                 ReturnStatus;
+  UINTN                         Index;
+  UINTN                         BytesCount;
+  UINT16                        IoPortBaseAddress;
+  UINT8                         AuxiliaryControl;
+
+  IoPortBaseAddress = InternalGetSmbusIoPortBaseAddress ();
+
+  BytesCount = SMBUS_LIB_LENGTH (SmBusAddress);
+
+  //
+  // Try to acquire the ownership of SMBUS.
+  //
+  ReturnStatus = InternalSmBusAcquire (IoPortBaseAddress);
+  if (RETURN_ERROR (ReturnStatus)) {
+    goto Done;
+  }
+  //
+  // Set the appropriate Host Control Register and auxiliary Control Register.
+  //
+  AuxiliaryControl = B_SMBUS_IO_E32B;
+  if (SMBUS_LIB_PEC (SmBusAddress)) {
+    AuxiliaryControl |= B_SMBUS_IO_AAC;
+  }
+  //
+  // Set Host Command Register.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HCMD, (UINT8) SMBUS_LIB_COMMAND (SmBusAddress));
+  //
+  // Set Auxiliary Control Regiester.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_AUXC, AuxiliaryControl);
+  //
+  // Clear byte pointer of 32-byte buffer.
+  //
+  IoRead8 (IoPortBaseAddress + R_SMBUS_IO_HCTL);
+
+  if (WriteBuffer != NULL) {
+    //
+    // Write the number of block to Host Block Data Byte Register.
+    //
+    IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HD0, (UINT8) BytesCount);
+    //
+    // Write data block to Host Block Data Register.
+    //
+    for (Index = 0; Index < BytesCount; Index++) {
+      IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HBD, WriteBuffer[Index]);
+    }
+  }
+  //
+  // Set SMBUS slave address for the device to send/receive from.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_TSA, (UINT8) SmBusAddress);
+  //
+  // Start the SMBUS transaction and wait for the end.
+  //
+  ReturnStatus = InternalSmBusStart (IoPortBaseAddress, HostControl);
+  if (RETURN_ERROR (ReturnStatus)) {
+    goto Done;
+  }
+
+  if (ReadBuffer != NULL) {
+    //
+    // Read the number of block from host block data byte register.
+    //
+    BytesCount = IoRead8 (IoPortBaseAddress + R_SMBUS_IO_HD0);
+    //
+    // Write data block from Host Block Data Register.
+    //
+    for (Index = 0; Index < BytesCount; Index++) {
+      ReadBuffer[Index] = IoRead8 (IoPortBaseAddress + R_SMBUS_IO_HBD);
+    }
+  }
+
+Done:
+  //
+  // Clear Host Status Register and Auxiliary Status Register.
+  //
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_HSTS, B_SMBUS_IO_HSTS_ALL);
+  IoWrite8 (IoPortBaseAddress + R_SMBUS_IO_AUXS, B_SMBUS_IO_CRCE);
+
+  if (Status != NULL) {
+    *Status = ReturnStatus;
+  }
+
+  return BytesCount;
+}
+
+/**
+  Executes an SMBUS read block command.
+
+  Executes an SMBUS read block command on the SMBUS device specified by SmBusAddress.
+  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
+  Bytes are read from the SMBUS and stored in Buffer.
+  The number of bytes read is returned, and will never return a value larger than 32-bytes.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  It is the caller's responsibility to make sure Buffer is large enough for the total number of bytes read.
+  SMBUS supports a maximum transfer size of 32 bytes, so Buffer does not need to be any larger than 32 bytes.
+  If Length in SmBusAddress is not zero, then ASSERT().
+  If Buffer is NULL, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[out] Buffer        Pointer to the buffer to store the bytes read from the SMBUS.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The number of bytes read.
+
+**/
+UINTN
+EFIAPI
+SmBusReadBlock (
+  IN  UINTN          SmBusAddress,
+  OUT VOID           *Buffer,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (Buffer != NULL);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   == 0);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((Buffer == NULL)                         ||
+      (SMBUS_LIB_LENGTH (SmBusAddress)   != 0) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return InternalSmBusBlock (
+           V_SMBUS_IO_SMB_CMD_BLOCK,
+           SmBusAddress | B_SMBUS_IO_READ,
+           NULL,
+           Buffer,
+           Status
+           );
+}
+
+/**
+  Executes an SMBUS write block command.
+
+  Executes an SMBUS write block command on the SMBUS device specified by SmBusAddress.
+  The SMBUS slave address, SMBUS command, and SMBUS length fields of SmBusAddress are required.
+  Bytes are written to the SMBUS from Buffer.
+  The number of bytes written is returned, and will never return a value larger than 32-bytes.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  If Length in SmBusAddress is zero or greater than 32, then ASSERT().
+  If Buffer is NULL, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[out] Buffer        Pointer to the buffer to store the bytes read from the SMBUS.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The number of bytes written.
+
+**/
+UINTN
+EFIAPI
+SmBusWriteBlock (
+  IN  UINTN          SmBusAddress,
+  OUT VOID           *Buffer,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (Buffer != NULL);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   >= 1);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   <= 32);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((Buffer == NULL)                         ||
+      (SMBUS_LIB_LENGTH (SmBusAddress)   == 0) ||
+      (SMBUS_LIB_LENGTH (SmBusAddress)   > 32) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return InternalSmBusBlock (
+           V_SMBUS_IO_SMB_CMD_BLOCK,
+           SmBusAddress | B_SMBUS_IO_WRITE,
+           Buffer,
+           NULL,
+           Status
+           );
+}
+
+/**
+  Executes an SMBUS block process call command.
+
+  Executes an SMBUS block process call command on the SMBUS device specified by SmBusAddress.
+  The SMBUS slave address, SMBUS command, and SMBUS length fields of SmBusAddress are required.
+  Bytes are written to the SMBUS from WriteBuffer.  Bytes are then read from the SMBUS into ReadBuffer.
+  If Status is not NULL, then the status of the executed command is returned in Status.
+  It is the caller's responsibility to make sure ReadBuffer is large enough for the total number of bytes read.
+  SMBUS supports a maximum transfer size of 32 bytes, so Buffer does not need to be any larger than 32 bytes.
+  If Length in SmBusAddress is zero or greater than 32, then ASSERT().
+  If WriteBuffer is NULL, then ASSERT().
+  If ReadBuffer is NULL, then ASSERT().
+  If any reserved bits of SmBusAddress are set, then ASSERT().
+
+  @param[in]  SmBusAddress  Address that encodes the SMBUS Slave Address,
+                            SMBUS Command, SMBUS Data Length, and PEC.
+  @param[in]  WriteBuffer   Pointer to the buffer of bytes to write to the SMBUS.
+  @param[out] ReadBuffer    Pointer to the buffer of bytes to read from the SMBUS.
+  @param[out] Status        Return status for the executed command.
+                            This is an optional parameter and may be NULL.
+
+  @retval The number of bytes written.
+
+**/
+UINTN
+EFIAPI
+SmBusBlockProcessCall (
+  IN  UINTN          SmBusAddress,
+  IN  VOID           *WriteBuffer,
+  OUT VOID           *ReadBuffer,
+  OUT RETURN_STATUS  *Status        OPTIONAL
+  )
+{
+  ASSERT (WriteBuffer != NULL);
+  ASSERT (ReadBuffer  != NULL);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   >= 1);
+  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)   <= 32);
+  ASSERT (SMBUS_LIB_RESERVED (SmBusAddress) == 0);
+
+  if ((WriteBuffer == NULL)                    ||
+      (ReadBuffer  == NULL)                    ||
+      (SMBUS_LIB_LENGTH (SmBusAddress)   == 0) ||
+      (SMBUS_LIB_LENGTH (SmBusAddress)   > 32) ||
+      (SMBUS_LIB_RESERVED (SmBusAddress) != 0))
+  {
+    if (Status != NULL) {
+      *Status = RETURN_INVALID_PARAMETER;
+    }
+    return 0;
+  }
+
+  return InternalSmBusBlock (
+           V_SMBUS_IO_SMB_CMD_BLOCK_PROCESS,
+           SmBusAddress | B_SMBUS_IO_WRITE,
+           WriteBuffer,
+           ReadBuffer,
+           Status
+           );
+}
+
+/**
+  The library constructuor.
+
+  The function does the necessary initialization work for this library instance.
+
+  @retval     EFI_SUCCESS       The function always return EFI_SUCCESS for now.
+**/
+RETURN_STATUS
+EFIAPI
+BaseSmbusLibConstructor (
+  VOID
+  )
+{
+  UINT64    SmbusPciBase;
+  UINT16    IoPortBaseAddress;
+
+  //
+  // Init mSmbusIoBase variable.
+  //
+  SmbusPciBase = PCI_SEGMENT_LIB_ADDRESS (
+                   DEFAULT_PCI_SEGMENT_NUMBER_PCH,
+                   DEFAULT_PCI_BUS_NUMBER_PCH,
+                   PCI_DEVICE_NUMBER_PCH_SMBUS,
+                   PCI_FUNCTION_NUMBER_PCH_SMBUS,
+                   0
+                   );
+  IoPortBaseAddress = (UINT16) PciSegmentRead32 (SmbusPciBase + R_SMBUS_CFG_BASE);
+
+  if ((IoPortBaseAddress != 0) && (IoPortBaseAddress != 0xFFFF)) {
+    mSmbusIoBase = IoPortBaseAddress & B_SMBUS_CFG_BASE_BAR;
+  }
+
+  return RETURN_SUCCESS;
+}
-- 
2.16.2.windows.1