[edk2-platforms][PATCH 2/4] Silicon/Bcm27xx: Add segment library to handle nonstandard ECAM

["Pete Batard" <pete@akeo.ie>]

From: Jeremy Linton <lintonrjeremy@gmail.com>

Signed-off-by: Pete Batard <pete@akeo.ie>
---
 Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c   | 1432 ++++++++++++++++++++
 Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.inf |   34 +
 2 files changed, 1466 insertions(+)

diff --git a/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c b/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c
new file mode 100644
index 000000000000..78232d233c5a
--- /dev/null
+++ b/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c
@@ -0,0 +1,1432 @@
+/** @file
+ *
+ * PCI Segment Library for Bcm2711 (RPi4) SoC
+ *
+ * Copyright (c) 2019, Jeremy Linton
+ * Copyright (c) 2017, Linaro, Ltd. All rights reserved.<BR>
+ * Copyright (c) 2007 - 2012, Intel Corporation. All rights reserved.<BR>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause-Patent
+ *
+ **/
+
+#include <Base.h>
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/IoLib.h>
+#include <Library/PcdLib.h>
+#include <Library/PciSegmentLib.h>
+#include <IndustryStandard/Bcm2711.h>
+
+typedef enum {
+  PciCfgWidthUint8 = 0,
+  PciCfgWidthUint16,
+  PciCfgWidthUint32,
+  PciCfgWidthMax
+} PCI_CFG_WIDTH;
+
+/*
+ * This PCIe config space is unusual...
+ * The root port is the first bytes of the register space (offset 0)
+ * The individual devices are then selected by computing their BDF index
+ * and writing that into the CFG_INDEX register (offset 0x9000)
+ * the "ECAM" data is then read/writeable at CFG_DATA (offset 0x8000)
+ */
+
+#define EFI_PCI_ADDR_BUS(bus) ((bus>>20) & 0xFF)    /* Note PCI_SEGMENT_LIB_ADDRESS */
+#define EFI_PCI_ADDR_DEV(dev) ((dev>>15) & 0x1F)
+#define EFI_PCI_ADDR_FUN(fun) ((fun>>12) & 0x07)
+
+/**
+  Assert the validity of a PCI Segment address.
+  A valid PCI Segment address should not contain 1's in bits 28..31 and 48..63
+
+  @param  A The address to validate.
+  @param  M Additional bits to assert to be zero.
+
+**/
+#define ASSERT_INVALID_PCI_SEGMENT_ADDRESS(A,M) \
+  ASSERT (((A) & (0xffff0000f0000000ULL | (M))) == 0)
+
+/**
+  Internal worker function to obtain config space base address.
+
+  @param  Address The address that encodes the PCI Bus, Device, Function and
+                  Register.
+
+  @return The value read from the PCI configuration register.
+
+**/
+
+STATIC
+UINT64
+PciSegmentLibGetConfigBase (
+  IN  UINT64                      Address
+  )
+{
+  STATIC UINT64 LastAccess = 0;     /* Avoid repeat CFG_INDEX updates */
+  UINT64        Base;
+  UINT64        Offset;
+
+  Base = PCIE_REG_BASE;
+  Offset = Address & 0xFFF;         /* Pick off the 4k register offset */
+  Address &= 0xFFFFF000;            /* Clear the offset leave only the BDF */
+
+  /* The root port is at the base of the PCIe register space */
+  if (Address != 0) {
+    /* The current device is at CFG_DATA */
+    Base += PCIE_EXT_CFG_DATA;
+    if (LastAccess != Address) {
+      UINT32 dev = EFI_PCI_ADDR_DEV (Address);
+      /*
+       * Scan things out directly rather than translating the "bus" to a device, etc..
+       * only we need to limit each bus to a single device.
+       */
+      if (dev < 1) {
+          MmioWrite32 (PCIE_REG_BASE + PCIE_EXT_CFG_INDEX, Address);
+          LastAccess = Address;
+      } else {
+          LastAccess = 0;
+          return 0xFFFFFFFF;
+      }
+    }
+  }
+  return Base + Offset;
+}
+
+/**
+  Internal worker function to read a PCI configuration register.
+
+  @param  Address The address that encodes the PCI Bus, Device, Function and
+                  Register.
+  @param  Width   The width of data to read
+
+  @return The value read from the PCI configuration register.
+
+**/
+STATIC
+UINT32
+PciSegmentLibReadWorker (
+  IN  UINT64                      Address,
+  IN  PCI_CFG_WIDTH               Width
+  )
+{
+  UINT64    Base;
+  UINT64    Ret = 0;
+
+  Base = PciSegmentLibGetConfigBase (Address);
+
+  if (Base==0xFFFFFFFF)
+    return Base;
+
+  switch (Width) {
+  case PciCfgWidthUint8:
+    Ret = MmioRead8 (Base);
+    break;
+  case PciCfgWidthUint16:
+    Ret = MmioRead16 (Base);
+    break;
+  case PciCfgWidthUint32:
+    Ret = MmioRead32 (Base);
+    break;
+  default:
+    ASSERT (FALSE);
+  }
+  return Ret;
+}
+
+/**
+  Internal worker function to writes a PCI configuration register.
+
+  @param  Address The address that encodes the PCI Bus, Device, Function and
+                  Register.
+  @param  Width   The width of data to write
+  @param  Data    The value to write.
+
+  @return The value written to the PCI configuration register.
+
+**/
+STATIC
+UINT32
+PciSegmentLibWriteWorker (
+  IN  UINT64                      Address,
+  IN  PCI_CFG_WIDTH               Width,
+  IN  UINT32                      Data
+  )
+{
+  UINT64    Base;
+
+  Base = PciSegmentLibGetConfigBase (Address);
+
+  switch (Width) {
+  case PciCfgWidthUint8:
+    MmioWrite8 (Base, Data);
+    break;
+  case PciCfgWidthUint16:
+    MmioWrite16 (Base, Data);
+    break;
+  case PciCfgWidthUint32:
+    MmioWrite32 (Base, Data);
+    break;
+  default:
+    ASSERT (FALSE);
+  }
+  return Data;
+}
+
+/**
+  Register a PCI device so PCI configuration registers may be accessed after
+  SetVirtualAddressMap().
+
+  If any reserved bits in Address are set, then ASSERT().
+
+  @param  Address The address that encodes the PCI Bus, Device, Function and
+                  Register.
+
+  @retval RETURN_SUCCESS           The PCI device was registered for runtime access.
+  @retval RETURN_UNSUPPORTED       An attempt was made to call this function
+                                   after ExitBootServices().
+  @retval RETURN_UNSUPPORTED       The resources required to access the PCI device
+                                   at runtime could not be mapped.
+  @retval RETURN_OUT_OF_RESOURCES  There are not enough resources available to
+                                   complete the registration.
+
+**/
+RETURN_STATUS
+EFIAPI
+PciSegmentRegisterForRuntimeAccess (
+  IN UINTN  Address
+  )
+{
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (Address, 0);
+  return RETURN_UNSUPPORTED;
+}
+
+/**
+  Reads an 8-bit PCI configuration register.
+
+  Reads and returns the 8-bit PCI configuration register specified by Address.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function,
+                    and Register.
+
+  @return The 8-bit PCI configuration register specified by Address.
+
+**/
+UINT8
+EFIAPI
+PciSegmentRead8 (
+  IN UINT64                    Address
+  )
+{
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (Address, 0);
+
+  return (UINT8) PciSegmentLibReadWorker (Address, PciCfgWidthUint8);
+}
+
+/**
+  Writes an 8-bit PCI configuration register.
+
+  Writes the 8-bit PCI configuration register specified by Address with the value specified by Value.
+  Value is returned.  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+
+  @param  Address     The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  Value       The value to write.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentWrite8 (
+  IN UINT64                    Address,
+  IN UINT8                     Value
+  )
+{
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (Address, 0);
+
+  return (UINT8) PciSegmentLibWriteWorker (Address, PciCfgWidthUint8, Value);
+}
+
+/**
+  Performs a bitwise OR of an 8-bit PCI configuration register with an 8-bit value.
+
+  Reads the 8-bit PCI configuration register specified by Address,
+  performs a bitwise OR between the read result and the value specified by OrData,
+  and writes the result to the 8-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  OrData    The value to OR with the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentOr8 (
+  IN UINT64                    Address,
+  IN UINT8                     OrData
+  )
+{
+  return PciSegmentWrite8 (Address, (UINT8) (PciSegmentRead8 (Address) | OrData));
+}
+
+/**
+  Performs a bitwise AND of an 8-bit PCI configuration register with an 8-bit value.
+
+  Reads the 8-bit PCI configuration register specified by Address,
+  performs a bitwise AND between the read result and the value specified by AndData,
+  and writes the result to the 8-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+  If any reserved bits in Address are set, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  AndData   The value to AND with the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentAnd8 (
+  IN UINT64                    Address,
+  IN UINT8                     AndData
+  )
+{
+  return PciSegmentWrite8 (Address, (UINT8) (PciSegmentRead8 (Address) & AndData));
+}
+
+/**
+  Performs a bitwise AND of an 8-bit PCI configuration register with an 8-bit value,
+  followed a  bitwise OR with another 8-bit value.
+
+  Reads the 8-bit PCI configuration register specified by Address,
+  performs a bitwise AND between the read result and the value specified by AndData,
+  performs a bitwise OR between the result of the AND operation and the value specified by OrData,
+  and writes the result to the 8-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  AndData    The value to AND with the PCI configuration register.
+  @param  OrData    The value to OR with the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentAndThenOr8 (
+  IN UINT64                    Address,
+  IN UINT8                     AndData,
+  IN UINT8                     OrData
+  )
+{
+  return PciSegmentWrite8 (Address, (UINT8) ((PciSegmentRead8 (Address) & AndData) | OrData));
+}
+
+/**
+  Reads a bit field of a PCI configuration register.
+
+  Reads the bit field in an 8-bit PCI configuration register. The bit field is
+  specified by the StartBit and the EndBit. The value of the bit field is
+  returned.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If StartBit is greater than 7, then ASSERT().
+  If EndBit is greater than 7, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to read.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..7.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..7.
+
+  @return The value of the bit field read from the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentBitFieldRead8 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit
+  )
+{
+  return BitFieldRead8 (PciSegmentRead8 (Address), StartBit, EndBit);
+}
+
+/**
+  Writes a bit field to a PCI configuration register.
+
+  Writes Value to the bit field of the PCI configuration register. The bit
+  field is specified by the StartBit and the EndBit. All other bits in the
+  destination PCI configuration register are preserved. The new value of the
+  8-bit register is returned.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If StartBit is greater than 7, then ASSERT().
+  If EndBit is greater than 7, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If Value is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..7.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..7.
+  @param  Value     The new value of the bit field.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentBitFieldWrite8 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT8                     Value
+  )
+{
+  return PciSegmentWrite8 (
+           Address,
+           BitFieldWrite8 (PciSegmentRead8 (Address), StartBit, EndBit, Value)
+           );
+}
+
+/**
+  Reads a bit field in an 8-bit PCI configuration, performs a bitwise OR, and
+  writes the result back to the bit field in the 8-bit port.
+
+  Reads the 8-bit PCI configuration register specified by Address, performs a
+  bitwise OR between the read result and the value specified by
+  OrData, and writes the result to the 8-bit PCI configuration register
+  specified by Address. The value written to the PCI configuration register is
+  returned. This function must guarantee that all PCI read and write operations
+  are serialized. Extra left bits in OrData are stripped.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If StartBit is greater than 7, then ASSERT().
+  If EndBit is greater than 7, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If OrData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..7.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..7.
+  @param  OrData    The value to OR with the PCI configuration register.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentBitFieldOr8 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT8                     OrData
+  )
+{
+  return PciSegmentWrite8 (
+           Address,
+           BitFieldOr8 (PciSegmentRead8 (Address), StartBit, EndBit, OrData)
+           );
+}
+
+/**
+  Reads a bit field in an 8-bit PCI configuration register, performs a bitwise
+  AND, and writes the result back to the bit field in the 8-bit register.
+
+  Reads the 8-bit PCI configuration register specified by Address, performs a
+  bitwise AND between the read result and the value specified by AndData, and
+  writes the result to the 8-bit PCI configuration register specified by
+  Address. The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are
+  serialized. Extra left bits in AndData are stripped.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If StartBit is greater than 7, then ASSERT().
+  If EndBit is greater than 7, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If AndData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..7.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..7.
+  @param  AndData   The value to AND with the PCI configuration register.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentBitFieldAnd8 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT8                     AndData
+  )
+{
+  return PciSegmentWrite8 (
+           Address,
+           BitFieldAnd8 (PciSegmentRead8 (Address), StartBit, EndBit, AndData)
+           );
+}
+
+/**
+  Reads a bit field in an 8-bit port, performs a bitwise AND followed by a
+  bitwise OR, and writes the result back to the bit field in the
+  8-bit port.
+
+  Reads the 8-bit PCI configuration register specified by Address, performs a
+  bitwise AND followed by a bitwise OR between the read result and
+  the value specified by AndData, and writes the result to the 8-bit PCI
+  configuration register specified by Address. The value written to the PCI
+  configuration register is returned. This function must guarantee that all PCI
+  read and write operations are serialized. Extra left bits in both AndData and
+  OrData are stripped.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If StartBit is greater than 7, then ASSERT().
+  If EndBit is greater than 7, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If AndData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+  If OrData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..7.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..7.
+  @param  AndData   The value to AND with the PCI configuration register.
+  @param  OrData    The value to OR with the result of the AND operation.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT8
+EFIAPI
+PciSegmentBitFieldAndThenOr8 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT8                     AndData,
+  IN UINT8                     OrData
+  )
+{
+  return PciSegmentWrite8 (
+           Address,
+           BitFieldAndThenOr8 (PciSegmentRead8 (Address), StartBit, EndBit, AndData, OrData)
+           );
+}
+
+/**
+  Reads a 16-bit PCI configuration register.
+
+  Reads and returns the 16-bit PCI configuration register specified by Address.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+
+  @return The 16-bit PCI configuration register specified by Address.
+
+**/
+UINT16
+EFIAPI
+PciSegmentRead16 (
+  IN UINT64                    Address
+  )
+{
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (Address, 1);
+
+  return (UINT16) PciSegmentLibReadWorker (Address, PciCfgWidthUint16);
+}
+
+/**
+  Writes a 16-bit PCI configuration register.
+
+  Writes the 16-bit PCI configuration register specified by Address with the value specified by Value.
+  Value is returned.  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+
+  @param  Address     The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  Value       The value to write.
+
+  @return The parameter of Value.
+
+**/
+UINT16
+EFIAPI
+PciSegmentWrite16 (
+  IN UINT64                    Address,
+  IN UINT16                    Value
+  )
+{
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (Address, 1);
+
+  return (UINT16) PciSegmentLibWriteWorker (Address, PciCfgWidthUint16, Value);
+}
+
+/**
+  Performs a bitwise OR of a 16-bit PCI configuration register with
+  a 16-bit value.
+
+  Reads the 16-bit PCI configuration register specified by Address, performs a
+  bitwise OR between the read result and the value specified by
+  OrData, and writes the result to the 16-bit PCI configuration register
+  specified by Address. The value written to the PCI configuration register is
+  returned. This function must guarantee that all PCI read and write operations
+  are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+
+  @param  Address The address that encodes the PCI Segment, Bus, Device, Function and
+                  Register.
+  @param  OrData  The value to OR with the PCI configuration register.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT16
+EFIAPI
+PciSegmentOr16 (
+  IN UINT64                    Address,
+  IN UINT16                    OrData
+  )
+{
+  return PciSegmentWrite16 (Address, (UINT16) (PciSegmentRead16 (Address) | OrData));
+}
+
+/**
+  Performs a bitwise AND of a 16-bit PCI configuration register with a 16-bit value.
+
+  Reads the 16-bit PCI configuration register specified by Address,
+  performs a bitwise AND between the read result and the value specified by AndData,
+  and writes the result to the 16-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  AndData   The value to AND with the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT16
+EFIAPI
+PciSegmentAnd16 (
+  IN UINT64                    Address,
+  IN UINT16                    AndData
+  )
+{
+  return PciSegmentWrite16 (Address, (UINT16) (PciSegmentRead16 (Address) & AndData));
+}
+
+/**
+  Performs a bitwise AND of a 16-bit PCI configuration register with a 16-bit value,
+  followed a  bitwise OR with another 16-bit value.
+
+  Reads the 16-bit PCI configuration register specified by Address,
+  performs a bitwise AND between the read result and the value specified by AndData,
+  performs a bitwise OR between the result of the AND operation and the value specified by OrData,
+  and writes the result to the 16-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  AndData   The value to AND with the PCI configuration register.
+  @param  OrData    The value to OR with the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT16
+EFIAPI
+PciSegmentAndThenOr16 (
+  IN UINT64                    Address,
+  IN UINT16                    AndData,
+  IN UINT16                    OrData
+  )
+{
+  return PciSegmentWrite16 (Address, (UINT16) ((PciSegmentRead16 (Address) & AndData) | OrData));
+}
+
+/**
+  Reads a bit field of a PCI configuration register.
+
+  Reads the bit field in a 16-bit PCI configuration register. The bit field is
+  specified by the StartBit and the EndBit. The value of the bit field is
+  returned.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+  If StartBit is greater than 15, then ASSERT().
+  If EndBit is greater than 15, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to read.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..15.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..15.
+
+  @return The value of the bit field read from the PCI configuration register.
+
+**/
+UINT16
+EFIAPI
+PciSegmentBitFieldRead16 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit
+  )
+{
+  return BitFieldRead16 (PciSegmentRead16 (Address), StartBit, EndBit);
+}
+
+/**
+  Writes a bit field to a PCI configuration register.
+
+  Writes Value to the bit field of the PCI configuration register. The bit
+  field is specified by the StartBit and the EndBit. All other bits in the
+  destination PCI configuration register are preserved. The new value of the
+  16-bit register is returned.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+  If StartBit is greater than 15, then ASSERT().
+  If EndBit is greater than 15, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If Value is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..15.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..15.
+  @param  Value     The new value of the bit field.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT16
+EFIAPI
+PciSegmentBitFieldWrite16 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT16                    Value
+  )
+{
+  return PciSegmentWrite16 (
+           Address,
+           BitFieldWrite16 (PciSegmentRead16 (Address), StartBit, EndBit, Value)
+           );
+}
+
+/**
+  Reads the 16-bit PCI configuration register specified by Address,
+  performs a bitwise OR between the read result and the value specified by OrData,
+  and writes the result to the 16-bit PCI configuration register specified by Address.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+  If StartBit is greater than 15, then ASSERT().
+  If EndBit is greater than 15, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If OrData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..15.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..15.
+  @param  OrData    The value to OR with the PCI configuration register.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT16
+EFIAPI
+PciSegmentBitFieldOr16 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT16                    OrData
+  )
+{
+  return PciSegmentWrite16 (
+           Address,
+           BitFieldOr16 (PciSegmentRead16 (Address), StartBit, EndBit, OrData)
+           );
+}
+
+/**
+  Reads a bit field in a 16-bit PCI configuration, performs a bitwise OR,
+  and writes the result back to the bit field in the 16-bit port.
+
+  Reads the 16-bit PCI configuration register specified by Address,
+  performs a bitwise OR between the read result and the value specified by OrData,
+  and writes the result to the 16-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+  Extra left bits in OrData are stripped.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 16-bit boundary, then ASSERT().
+  If StartBit is greater than 7, then ASSERT().
+  If EndBit is greater than 7, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If AndData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    The ordinal of the least significant bit in a byte is bit 0.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    The ordinal of the most significant bit in a byte is bit 7.
+  @param  AndData   The value to AND with the read value from the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT16
+EFIAPI
+PciSegmentBitFieldAnd16 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT16                    AndData
+  )
+{
+  return PciSegmentWrite16 (
+           Address,
+           BitFieldAnd16 (PciSegmentRead16 (Address), StartBit, EndBit, AndData)
+           );
+}
+
+/**
+  Reads a bit field in a 16-bit port, performs a bitwise AND followed by a
+  bitwise OR, and writes the result back to the bit field in the
+  16-bit port.
+
+  Reads the 16-bit PCI configuration register specified by Address, performs a
+  bitwise AND followed by a bitwise OR between the read result and
+  the value specified by AndData, and writes the result to the 16-bit PCI
+  configuration register specified by Address. The value written to the PCI
+  configuration register is returned. This function must guarantee that all PCI
+  read and write operations are serialized. Extra left bits in both AndData and
+  OrData are stripped.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If StartBit is greater than 15, then ASSERT().
+  If EndBit is greater than 15, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If AndData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+  If OrData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..15.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..15.
+  @param  AndData   The value to AND with the PCI configuration register.
+  @param  OrData    The value to OR with the result of the AND operation.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT16
+EFIAPI
+PciSegmentBitFieldAndThenOr16 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT16                    AndData,
+  IN UINT16                    OrData
+  )
+{
+  return PciSegmentWrite16 (
+           Address,
+           BitFieldAndThenOr16 (PciSegmentRead16 (Address), StartBit, EndBit, AndData, OrData)
+           );
+}
+
+/**
+  Reads a 32-bit PCI configuration register.
+
+  Reads and returns the 32-bit PCI configuration register specified by Address.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 32-bit boundary, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function,
+                    and Register.
+
+  @return The 32-bit PCI configuration register specified by Address.
+
+**/
+UINT32
+EFIAPI
+PciSegmentRead32 (
+  IN UINT64                    Address
+  )
+{
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (Address, 3);
+
+  return PciSegmentLibReadWorker (Address, PciCfgWidthUint32);
+}
+
+/**
+  Writes a 32-bit PCI configuration register.
+
+  Writes the 32-bit PCI configuration register specified by Address with the value specified by Value.
+  Value is returned.  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 32-bit boundary, then ASSERT().
+
+  @param  Address     The address that encodes the PCI Segment, Bus, Device,
+                      Function, and Register.
+  @param  Value       The value to write.
+
+  @return The parameter of Value.
+
+**/
+UINT32
+EFIAPI
+PciSegmentWrite32 (
+  IN UINT64                    Address,
+  IN UINT32                    Value
+  )
+{
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (Address, 3);
+
+  return PciSegmentLibWriteWorker (Address, PciCfgWidthUint32, Value);
+}
+
+/**
+  Performs a bitwise OR of a 32-bit PCI configuration register with a 32-bit value.
+
+  Reads the 32-bit PCI configuration register specified by Address,
+  performs a bitwise OR between the read result and the value specified by OrData,
+  and writes the result to the 32-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 32-bit boundary, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function, and Register.
+  @param  OrData    The value to OR with the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT32
+EFIAPI
+PciSegmentOr32 (
+  IN UINT64                    Address,
+  IN UINT32                    OrData
+  )
+{
+  return PciSegmentWrite32 (Address, PciSegmentRead32 (Address) | OrData);
+}
+
+/**
+  Performs a bitwise AND of a 32-bit PCI configuration register with a 32-bit value.
+
+  Reads the 32-bit PCI configuration register specified by Address,
+  performs a bitwise AND between the read result and the value specified by AndData,
+  and writes the result to the 32-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 32-bit boundary, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function,
+                    and Register.
+  @param  AndData   The value to AND with the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT32
+EFIAPI
+PciSegmentAnd32 (
+  IN UINT64                    Address,
+  IN UINT32                    AndData
+  )
+{
+  return PciSegmentWrite32 (Address, PciSegmentRead32 (Address) & AndData);
+}
+
+/**
+  Performs a bitwise AND of a 32-bit PCI configuration register with a 32-bit value,
+  followed a  bitwise OR with another 32-bit value.
+
+  Reads the 32-bit PCI configuration register specified by Address,
+  performs a bitwise AND between the read result and the value specified by AndData,
+  performs a bitwise OR between the result of the AND operation and the value specified by OrData,
+  and writes the result to the 32-bit PCI configuration register specified by Address.
+  The value written to the PCI configuration register is returned.
+  This function must guarantee that all PCI read and write operations are serialized.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 32-bit boundary, then ASSERT().
+
+  @param  Address   The address that encodes the PCI Segment, Bus, Device, Function,
+                    and Register.
+  @param  AndData   The value to AND with the PCI configuration register.
+  @param  OrData    The value to OR with the PCI configuration register.
+
+  @return The value written to the PCI configuration register.
+
+**/
+UINT32
+EFIAPI
+PciSegmentAndThenOr32 (
+  IN UINT64                    Address,
+  IN UINT32                    AndData,
+  IN UINT32                    OrData
+  )
+{
+  return PciSegmentWrite32 (Address, (PciSegmentRead32 (Address) & AndData) | OrData);
+}
+
+/**
+  Reads a bit field of a PCI configuration register.
+
+  Reads the bit field in a 32-bit PCI configuration register. The bit field is
+  specified by the StartBit and the EndBit. The value of the bit field is
+  returned.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 32-bit boundary, then ASSERT().
+  If StartBit is greater than 31, then ASSERT().
+  If EndBit is greater than 31, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to read.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..31.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..31.
+
+  @return The value of the bit field read from the PCI configuration register.
+
+**/
+UINT32
+EFIAPI
+PciSegmentBitFieldRead32 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit
+  )
+{
+  return BitFieldRead32 (PciSegmentRead32 (Address), StartBit, EndBit);
+}
+
+/**
+  Writes a bit field to a PCI configuration register.
+
+  Writes Value to the bit field of the PCI configuration register. The bit
+  field is specified by the StartBit and the EndBit. All other bits in the
+  destination PCI configuration register are preserved. The new value of the
+  32-bit register is returned.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 32-bit boundary, then ASSERT().
+  If StartBit is greater than 31, then ASSERT().
+  If EndBit is greater than 31, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If Value is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..31.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..31.
+  @param  Value     The new value of the bit field.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT32
+EFIAPI
+PciSegmentBitFieldWrite32 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT32                    Value
+  )
+{
+  return PciSegmentWrite32 (
+           Address,
+           BitFieldWrite32 (PciSegmentRead32 (Address), StartBit, EndBit, Value)
+           );
+}
+
+/**
+  Reads a bit field in a 32-bit PCI configuration, performs a bitwise OR, and
+  writes the result back to the bit field in the 32-bit port.
+
+  Reads the 32-bit PCI configuration register specified by Address, performs a
+  bitwise OR between the read result and the value specified by
+  OrData, and writes the result to the 32-bit PCI configuration register
+  specified by Address. The value written to the PCI configuration register is
+  returned. This function must guarantee that all PCI read and write operations
+  are serialized. Extra left bits in OrData are stripped.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If StartBit is greater than 31, then ASSERT().
+  If EndBit is greater than 31, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If OrData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..31.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..31.
+  @param  OrData    The value to OR with the PCI configuration register.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT32
+EFIAPI
+PciSegmentBitFieldOr32 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT32                    OrData
+  )
+{
+  return PciSegmentWrite32 (
+           Address,
+           BitFieldOr32 (PciSegmentRead32 (Address), StartBit, EndBit, OrData)
+           );
+}
+
+/**
+  Reads a bit field in a 32-bit PCI configuration register, performs a bitwise
+  AND, and writes the result back to the bit field in the 32-bit register.
+
+
+  Reads the 32-bit PCI configuration register specified by Address, performs a bitwise
+  AND between the read result and the value specified by AndData, and writes the result
+  to the 32-bit PCI configuration register specified by Address. The value written to
+  the PCI configuration register is returned.  This function must guarantee that all PCI
+  read and write operations are serialized.  Extra left bits in AndData are stripped.
+  If any reserved bits in Address are set, then ASSERT().
+  If Address is not aligned on a 32-bit boundary, then ASSERT().
+  If StartBit is greater than 31, then ASSERT().
+  If EndBit is greater than 31, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If AndData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..31.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..31.
+  @param  AndData   The value to AND with the PCI configuration register.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT32
+EFIAPI
+PciSegmentBitFieldAnd32 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT32                    AndData
+  )
+{
+  return PciSegmentWrite32 (
+           Address,
+           BitFieldAnd32 (PciSegmentRead32 (Address), StartBit, EndBit, AndData)
+           );
+}
+
+/**
+  Reads a bit field in a 32-bit port, performs a bitwise AND followed by a
+  bitwise OR, and writes the result back to the bit field in the
+  32-bit port.
+
+  Reads the 32-bit PCI configuration register specified by Address, performs a
+  bitwise AND followed by a bitwise OR between the read result and
+  the value specified by AndData, and writes the result to the 32-bit PCI
+  configuration register specified by Address. The value written to the PCI
+  configuration register is returned. This function must guarantee that all PCI
+  read and write operations are serialized. Extra left bits in both AndData and
+  OrData are stripped.
+
+  If any reserved bits in Address are set, then ASSERT().
+  If StartBit is greater than 31, then ASSERT().
+  If EndBit is greater than 31, then ASSERT().
+  If EndBit is less than StartBit, then ASSERT().
+  If AndData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+  If OrData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().
+
+  @param  Address   The PCI configuration register to write.
+  @param  StartBit  The ordinal of the least significant bit in the bit field.
+                    Range 0..31.
+  @param  EndBit    The ordinal of the most significant bit in the bit field.
+                    Range 0..31.
+  @param  AndData   The value to AND with the PCI configuration register.
+  @param  OrData    The value to OR with the result of the AND operation.
+
+  @return The value written back to the PCI configuration register.
+
+**/
+UINT32
+EFIAPI
+PciSegmentBitFieldAndThenOr32 (
+  IN UINT64                    Address,
+  IN UINTN                     StartBit,
+  IN UINTN                     EndBit,
+  IN UINT32                    AndData,
+  IN UINT32                    OrData
+  )
+{
+  return PciSegmentWrite32 (
+           Address,
+           BitFieldAndThenOr32 (PciSegmentRead32 (Address), StartBit, EndBit, AndData, OrData)
+           );
+}
+
+/**
+  Reads a range of PCI configuration registers into a caller supplied buffer.
+
+  Reads the range of PCI configuration registers specified by StartAddress and
+  Size into the buffer specified by Buffer. This function only allows the PCI
+  configuration registers from a single PCI function to be read. Size is
+  returned. When possible 32-bit PCI configuration read cycles are used to read
+  from StartAdress to StartAddress + Size. Due to alignment restrictions, 8-bit
+  and 16-bit PCI configuration read cycles may be used at the beginning and the
+  end of the range.
+
+  If any reserved bits in StartAddress are set, then ASSERT().
+  If ((StartAddress & 0xFFF) + Size) > 0x1000, then ASSERT().
+  If Size > 0 and Buffer is NULL, then ASSERT().
+
+  @param  StartAddress  The starting address that encodes the PCI Segment, Bus,
+                        Device, Function and Register.
+  @param  Size          The size in bytes of the transfer.
+  @param  Buffer        The pointer to a buffer receiving the data read.
+
+  @return Size
+
+**/
+UINTN
+EFIAPI
+PciSegmentReadBuffer (
+  IN  UINT64                   StartAddress,
+  IN  UINTN                    Size,
+  OUT VOID                     *Buffer
+  )
+{
+  UINTN                             ReturnValue;
+
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (StartAddress, 0);
+  ASSERT (((StartAddress & 0xFFF) + Size) <= 0x1000);
+
+  if (Size == 0) {
+    return Size;
+  }
+
+  ASSERT (Buffer != NULL);
+
+  //
+  // Save Size for return
+  //
+  ReturnValue = Size;
+
+  if ((StartAddress & BIT0) != 0) {
+    //
+    // Read a byte if StartAddress is byte aligned
+    //
+    *(volatile UINT8 *)Buffer = PciSegmentRead8 (StartAddress);
+    StartAddress += sizeof (UINT8);
+    Size -= sizeof (UINT8);
+    Buffer = (UINT8*)Buffer + 1;
+  }
+
+  if (Size >= sizeof (UINT16) && (StartAddress & BIT1) != 0) {
+    //
+    // Read a word if StartAddress is word aligned
+    //
+    WriteUnaligned16 (Buffer, PciSegmentRead16 (StartAddress));
+    StartAddress += sizeof (UINT16);
+    Size -= sizeof (UINT16);
+    Buffer = (UINT16*)Buffer + 1;
+  }
+
+  while (Size >= sizeof (UINT32)) {
+    //
+    // Read as many double words as possible
+    //
+    WriteUnaligned32 (Buffer, PciSegmentRead32 (StartAddress));
+    StartAddress += sizeof (UINT32);
+    Size -= sizeof (UINT32);
+    Buffer = (UINT32*)Buffer + 1;
+  }
+
+  if (Size >= sizeof (UINT16)) {
+    //
+    // Read the last remaining word if exist
+    //
+    WriteUnaligned16 (Buffer, PciSegmentRead16 (StartAddress));
+    StartAddress += sizeof (UINT16);
+    Size -= sizeof (UINT16);
+    Buffer = (UINT16*)Buffer + 1;
+  }
+
+  if (Size >= sizeof (UINT8)) {
+    //
+    // Read the last remaining byte if exist
+    //
+    *(volatile UINT8 *)Buffer = PciSegmentRead8 (StartAddress);
+  }
+
+  return ReturnValue;
+}
+
+
+/**
+  Copies the data in a caller supplied buffer to a specified range of PCI
+  configuration space.
+
+  Writes the range of PCI configuration registers specified by StartAddress and
+  Size from the buffer specified by Buffer. This function only allows the PCI
+  configuration registers from a single PCI function to be written. Size is
+  returned. When possible 32-bit PCI configuration write cycles are used to
+  write from StartAdress to StartAddress + Size. Due to alignment restrictions,
+  8-bit and 16-bit PCI configuration write cycles may be used at the beginning
+  and the end of the range.
+
+  If any reserved bits in StartAddress are set, then ASSERT().
+  If ((StartAddress & 0xFFF) + Size) > 0x1000, then ASSERT().
+  If Size > 0 and Buffer is NULL, then ASSERT().
+
+  @param  StartAddress  The starting address that encodes the PCI Segment, Bus,
+                        Device, Function and Register.
+  @param  Size          The size in bytes of the transfer.
+  @param  Buffer        The pointer to a buffer containing the data to write.
+
+  @return The parameter of Size.
+
+**/
+UINTN
+EFIAPI
+PciSegmentWriteBuffer (
+  IN UINT64                    StartAddress,
+  IN UINTN                     Size,
+  IN VOID                      *Buffer
+  )
+{
+  UINTN                             ReturnValue;
+
+  ASSERT_INVALID_PCI_SEGMENT_ADDRESS (StartAddress, 0);
+  ASSERT (((StartAddress & 0xFFF) + Size) <= 0x1000);
+
+  if (Size == 0) {
+    return 0;
+  }
+
+  ASSERT (Buffer != NULL);
+
+  // The Bcm/Rpi has a single cfg which can be mapped
+  // to any given device on the bus, which means we need to remap
+  // it basically everytime a new config access is done
+
+  //
+  // Save Size for return
+  //
+  ReturnValue = Size;
+
+  if ((StartAddress & BIT0) != 0) {
+    //
+    // Write a byte if StartAddress is byte aligned
+    //
+    PciSegmentWrite8 (StartAddress, *(UINT8*)Buffer);
+    StartAddress += sizeof (UINT8);
+    Size -= sizeof (UINT8);
+    Buffer = (UINT8*)Buffer + 1;
+  }
+
+  if (Size >= sizeof (UINT16) && (StartAddress & BIT1) != 0) {
+    //
+    // Write a word if StartAddress is word aligned
+    //
+    PciSegmentWrite16 (StartAddress, ReadUnaligned16 (Buffer));
+    StartAddress += sizeof (UINT16);
+    Size -= sizeof (UINT16);
+    Buffer = (UINT16*)Buffer + 1;
+  }
+
+  while (Size >= sizeof (UINT32)) {
+    //
+    // Write as many double words as possible
+    //
+    PciSegmentWrite32 (StartAddress, ReadUnaligned32 (Buffer));
+    StartAddress += sizeof (UINT32);
+    Size -= sizeof (UINT32);
+    Buffer = (UINT32*)Buffer + 1;
+  }
+
+  if (Size >= sizeof (UINT16)) {
+    //
+    // Write the last remaining word if exist
+    //
+    PciSegmentWrite16 (StartAddress, ReadUnaligned16 (Buffer));
+    StartAddress += sizeof (UINT16);
+    Size -= sizeof (UINT16);
+    Buffer = (UINT16*)Buffer + 1;
+  }
+
+  if (Size >= sizeof (UINT8)) {
+    //
+    // Write the last remaining byte if exist
+    //
+    PciSegmentWrite8 (StartAddress, *(UINT8*)Buffer);
+  }
+
+  return ReturnValue;
+}
diff --git a/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.inf b/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.inf
new file mode 100644
index 000000000000..2ee38c06368a
--- /dev/null
+++ b/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.inf
@@ -0,0 +1,34 @@
+## @file
+# PCI Segment Library for Bcm2711 (RPi4) SoC
+#
+# Copyright (c) 2019, Jeremy Linton
+# Copyright (c) 2017, Linaro Ltd. All rights reserved.<BR>
+# Copyright (c) 2007 - 2014, Intel Corporation. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001B
+  BASE_NAME                      = PciSegmentLib
+  FILE_GUID                      = 74fe3f9e-0040-11ea-a7bf-5254005675a0
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = PciSegmentLib
+
+[Sources]
+  PciSegmentLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  Silicon/Broadcom/Bcm27xx/Bcm27xx.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  IoLib
+  PcdLib
+
+[FixedPcd]
+  gBcm27xxTokenSpaceGuid.PcdBcm27xxPciRegBase
-- 
2.21.0.windows.1