[PATCH 3/7] MdePkg: introduce PciCapPciIoLib

[Laszlo Ersek <lersek@redhat.com>]

Add a library class, and a UEFI_DRIVER lib instance, that are layered on
top of PciCapLib, and allow clients to plug an EFI_PCI_IO_PROTOCOL backend
into PciCapLib, for config space access.

(Side note:

Although the UEFI spec says that EFI_PCI_IO_PROTOCOL_CONFIG() returns
EFI_UNSUPPORTED if "[t]he address range specified by Offset, Width, and
Count is not valid for the PCI configuration header of the PCI
controller", this patch doesn't directly document the EFI_UNSUPPORTED
error code, for ProtoDevTransferConfig() and its callers
ProtoDevReadConfig() and ProtoDevWriteConfig(). Instead, the patch refers
to "unspecified error codes". The reason is that in edk2, the
PciIoConfigRead() and PciIoConfigWrite() functions [1] can also return
EFI_INVALID_PARAMETER for the above situation.

Namely, PciIoConfigRead() and PciIoConfigWrite() first call
PciIoVerifyConfigAccess(), which indeed produces the standard
EFI_UNSUPPORTED error code, if the device's config space is exceeded.
However, if PciIoVerifyConfigAccess() passes, and we reach
RootBridgeIoPciRead() and RootBridgeIoPciWrite() [2], then
RootBridgeIoCheckParameter() can still fail, e.g. if the root bridge
doesn't support extended config space (see commit 014b472053ae3).

For all kinds of Limit violations in IO, MMIO, and config space,
RootBridgeIoCheckParameter() returns EFI_INVALID_PARAMETER, not
EFI_UNSUPPORTED. That error code is then propagated up to, and out of,
PciIoConfigRead() and PciIoConfigWrite().

[1] MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c
[2] MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
)

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 MdePkg/MdePkg.dec                                        |   5 +
 MdePkg/MdePkg.dsc                                        |   1 +
 MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.inf |  35 +++
 MdePkg/Include/Library/PciCapPciIoLib.h                  |  58 +++++
 MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.h   |  44 ++++
 MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.c   | 243 ++++++++++++++++++++
 6 files changed, 386 insertions(+)

diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index acda885146ab..0d41b3bb3449 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -160,6 +160,11 @@ [LibraryClasses]
   ##                 access.
   PciCapPciSegmentLib|Include/Library/PciCapPciSegmentLib.h
 
+  ##  @libraryclass  Layered on top of PciCapLib, allows clients to plug an
+  ##                 EFI_PCI_IO_PROTOCOL backend into PciCapLib, for config
+  ##                 space access.
+  PciCapPciIoLib|Include/Library/PciCapPciIoLib.h
+
   ##  @libraryclass  Provides library services to get and set Platform Configuration Database entries.
   PcdLib|Include/Library/PcdLib.h
 
diff --git a/MdePkg/MdePkg.dsc b/MdePkg/MdePkg.dsc
index f655ec827080..c18477d11f49 100644
--- a/MdePkg/MdePkg.dsc
+++ b/MdePkg/MdePkg.dsc
@@ -136,6 +136,7 @@ [Components]
   MdePkg/Library/UefiUsbLib/UefiUsbLib.inf
   MdePkg/Library/UefiPciLibPciRootBridgeIo/UefiPciLibPciRootBridgeIo.inf
   MdePkg/Library/UefiPciSegmentLibPciRootBridgeIo/UefiPciSegmentLibPciRootBridgeIo.inf
+  MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.inf
   MdePkg/Library/SmmLibNull/SmmLibNull.inf
   MdePkg/Library/BaseExtractGuidedSectionLib/BaseExtractGuidedSectionLib.inf
 
diff --git a/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.inf b/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.inf
new file mode 100644
index 000000000000..239a3f4aa8c7
--- /dev/null
+++ b/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.inf
@@ -0,0 +1,35 @@
+## @file
+# Plug an EFI_PCI_IO_PROTOCOL backend into PciCapLib, for config space access.
+#
+# Copyright (C) 2018, Red Hat, Inc.
+#
+# This program and the accompanying materials are licensed and made available
+# under the terms and conditions of the BSD License which accompanies this
+# distribution.  The full text of the license may be found at
+# http://opensource.org/licenses/bsd-license.php
+#
+# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+# WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+##
+
+[Defines]
+  INF_VERSION    = 1.27
+  BASE_NAME      = UefiPciCapPciIoLib
+  FILE_GUID      = 4102F4FE-DA10-4F0F-AC18-4982ED506154
+  MODULE_TYPE    = UEFI_DRIVER
+  VERSION_STRING = 1.0
+  LIBRARY_CLASS  = PciCapPciIoLib
+
+[Sources]
+  UefiPciCapPciIoLib.h
+  UefiPciCapPciIoLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  DebugLib
+  MemoryAllocationLib
+
+[Protocols]
+  gEfiPciIoProtocolGuid ## CONSUMES
diff --git a/MdePkg/Include/Library/PciCapPciIoLib.h b/MdePkg/Include/Library/PciCapPciIoLib.h
new file mode 100644
index 000000000000..553715fd5080
--- /dev/null
+++ b/MdePkg/Include/Library/PciCapPciIoLib.h
@@ -0,0 +1,58 @@
+/** @file
+  Library class layered on top of PciCapLib that allows clients to plug an
+  EFI_PCI_IO_PROTOCOL backend into PciCapLib, for config space access.
+
+  Copyright (C) 2018, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#ifndef __PCI_CAP_PCI_IO_LIB_H__
+#define __PCI_CAP_PCI_IO_LIB_H__
+
+#include <Protocol/PciIo.h>
+
+#include <Library/PciCapLib.h>
+
+
+/**
+  Create a PCI_CAP_DEV object from an EFI_PCI_IO_PROTOCOL instance. The config
+  space accessors are based upon EFI_PCI_IO_PROTOCOL.Pci.Read() and
+  EFI_PCI_IO_PROTOCOL.Pci.Write().
+
+  @param[in] PciIo       EFI_PCI_IO_PROTOCOL representation of the PCI device.
+
+  @param[out] PciDevice  The PCI_CAP_DEV object constructed as described above.
+                         PciDevice can be passed to the PciCapLib APIs.
+
+  @retval EFI_SUCCESS           PciDevice has been constructed and output.
+
+  @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
+**/
+EFI_STATUS
+EFIAPI
+PciCapPciIoDeviceInit (
+  IN  EFI_PCI_IO_PROTOCOL *PciIo,
+  OUT PCI_CAP_DEV         **PciDevice
+  );
+
+
+/**
+  Free the resources used by PciDevice.
+
+  @param[in] PciDevice  The PCI_CAP_DEV object to free, originally produced by
+                        PciCapPciIoDeviceInit().
+**/
+VOID
+EFIAPI
+PciCapPciIoDeviceUninit (
+  IN PCI_CAP_DEV *PciDevice
+  );
+
+#endif // __PCI_CAP_PCI_IO_LIB_H__
diff --git a/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.h b/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.h
new file mode 100644
index 000000000000..a94f65e5a4e3
--- /dev/null
+++ b/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.h
@@ -0,0 +1,44 @@
+/** @file
+  Plug an EFI_PCI_IO_PROTOCOL backend into PciCapLib, for config space access
+  -- internal macro and type definitions.
+
+  Copyright (C) 2018, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#ifndef __UEFI_PCI_CAP_PCI_IO_LIB_H__
+#define __UEFI_PCI_CAP_PCI_IO_LIB_H__
+
+#include <Library/DebugLib.h>
+
+#include <Library/PciCapPciIoLib.h>
+
+#define PROTO_DEV_SIG SIGNATURE_64 ('P', 'C', 'P', 'I', 'O', 'P', 'R', 'T')
+
+typedef struct {
+  //
+  // Signature identifying the derived class.
+  //
+  UINT64 Signature;
+  //
+  // Members added by the derived class, specific to the use of
+  // EFI_PCI_IO_PROTOCOL.
+  //
+  EFI_PCI_IO_PROTOCOL *PciIo;
+  //
+  // Base class.
+  //
+  PCI_CAP_DEV BaseDevice;
+} PROTO_DEV;
+
+#define PROTO_DEV_FROM_PCI_CAP_DEV(PciDevice) \
+  CR (PciDevice, PROTO_DEV, BaseDevice, PROTO_DEV_SIG)
+
+#endif // __UEFI_PCI_CAP_PCI_IO_LIB_H__
diff --git a/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.c b/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.c
new file mode 100644
index 000000000000..84369e4dc3a8
--- /dev/null
+++ b/MdePkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.c
@@ -0,0 +1,243 @@
+/** @file
+  Plug an EFI_PCI_IO_PROTOCOL backend into PciCapLib, for config space access.
+
+  Copyright (C) 2018, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include <Library/MemoryAllocationLib.h>
+
+#include "UefiPciCapPciIoLib.h"
+
+
+/**
+  Transfer bytes between the config space of a given PCI device and a memory
+  buffer.
+
+  ProtoDevTransferConfig() performs as few config space accesses as possible
+  (without attempting 64-bit wide accesses).
+
+  @param[in] PciIo             The EFI_PCI_IO_PROTOCOL representation of the
+                               PCI device.
+
+  @param[in] TransferFunction  The EFI_PCI_IO_PROTOCOL_CONFIG function that
+                               implements the transfer. The direction of the
+                               transfer is inherent to TransferFunction.
+                               TransferFunction() is required to return an
+                               unspecified error if any sub-transfer within
+                               Size bytes from ConfigOffset exceeds the config
+                               space limit of the PCI device.
+
+  @param[in] ConfigOffset      The offset in the config space of the PCI device
+                               at which the transfer should commence.
+
+  @param[in,out] Buffer        The memory buffer where the transfer should
+                               occur.
+
+  @param[in] Size              The number of bytes to transfer.
+
+  @retval EFI_SUCCESS  Size bytes have been transferred between config space
+                       and Buffer.
+
+  @return              Error codes propagated from TransferFunction(). Fewer
+                       than Size bytes may have been transferred.
+**/
+STATIC
+EFI_STATUS
+ProtoDevTransferConfig (
+  IN     EFI_PCI_IO_PROTOCOL        *PciIo,
+  IN     EFI_PCI_IO_PROTOCOL_CONFIG TransferFunction,
+  IN     UINT16                     ConfigOffset,
+  IN OUT UINT8                      *Buffer,
+  IN     UINT16                     Size
+  )
+{
+  while (Size > 0) {
+    EFI_PCI_IO_PROTOCOL_WIDTH Width;
+    UINT16                    Count;
+    EFI_STATUS                Status;
+    UINT16                    Progress;
+
+    //
+    // Pick the largest access size that is allowed by the remaining transfer
+    // Size and by the alignment of ConfigOffset.
+    //
+    // When the largest access size is available, transfer as many bytes as
+    // possible in one iteration of the loop. Otherwise, transfer only one
+    // unit, to improve the alignment.
+    //
+    if (Size >= BIT2 && (ConfigOffset & (BIT2 - 1)) == 0) {
+      Width = EfiPciIoWidthUint32;
+      Count = Size >> Width;
+    } else if (Size >= BIT1 && (ConfigOffset & (BIT1 - 1)) == 0) {
+      Width = EfiPciIoWidthUint16;
+      Count = 1;
+    } else {
+      Width = EfiPciIoWidthUint8;
+      Count = 1;
+    }
+    Status = TransferFunction (PciIo, Width, ConfigOffset, Count, Buffer);
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+    Progress      = Count << Width;
+    ConfigOffset += Progress;
+    Buffer       += Progress;
+    Size         -= Progress;
+  }
+  return EFI_SUCCESS;
+}
+
+
+/**
+  Read the config space of a given PCI device (both normal and extended).
+
+  ProtoDevReadConfig() performs as few config space accesses as possible
+  (without attempting 64-bit wide accesses).
+
+  ProtoDevReadConfig() returns an unspecified error if accessing Size bytes
+  from SourceOffset exceeds the config space limit of the PCI device. Fewer
+  than Size bytes may have been read in this case.
+
+  @param[in] PciDevice           Implementation-specific unique representation
+                                 of the PCI device in the PCI hierarchy.
+
+  @param[in] SourceOffset        Source offset in the config space of the PCI
+                                 device to start reading from.
+
+  @param[out] DestinationBuffer  Buffer to store the read data to.
+
+  @param[in] Size                The number of bytes to transfer.
+
+  @retval RETURN_SUCCESS  Size bytes have been transferred from config space to
+                          DestinationBuffer.
+
+  @return                 Error codes propagated from
+                          EFI_PCI_IO_PROTOCOL.Pci.Read(). Fewer than Size bytes
+                          may have been read.
+**/
+STATIC
+RETURN_STATUS
+EFIAPI
+ProtoDevReadConfig (
+  IN  PCI_CAP_DEV *PciDevice,
+  IN  UINT16      SourceOffset,
+  OUT VOID        *DestinationBuffer,
+  IN  UINT16      Size
+  )
+{
+  PROTO_DEV *ProtoDev;
+
+  ProtoDev = PROTO_DEV_FROM_PCI_CAP_DEV (PciDevice);
+  return ProtoDevTransferConfig (ProtoDev->PciIo, ProtoDev->PciIo->Pci.Read,
+           SourceOffset, DestinationBuffer, Size);
+}
+
+
+/**
+  Write the config space of a given PCI device (both normal and extended).
+
+  ProtoDevWriteConfig() performs as few config space accesses as possible
+  (without attempting 64-bit wide accesses).
+
+  ProtoDevWriteConfig() returns an unspecified error if accessing Size bytes at
+  DestinationOffset exceeds the config space limit of the PCI device. Fewer
+  than Size bytes may have been written in this case.
+
+  @param[in] PciDevice          Implementation-specific unique representation
+                                of the PCI device in the PCI hierarchy.
+
+  @param[in] DestinationOffset  Destination offset in the config space of the
+                                PCI device to start writing at.
+
+  @param[in] SourceBuffer       Buffer to read the data to be stored from.
+
+  @param[in] Size               The number of bytes to transfer.
+
+  @retval RETURN_SUCCESS  Size bytes have been transferred from SourceBuffer to
+                          config space.
+
+  @return                 Error codes propagated from
+                          EFI_PCI_IO_PROTOCOL.Pci.Write(). Fewer than Size
+                          bytes may have been written.
+**/
+STATIC
+RETURN_STATUS
+EFIAPI
+ProtoDevWriteConfig (
+  IN PCI_CAP_DEV *PciDevice,
+  IN UINT16      DestinationOffset,
+  IN VOID        *SourceBuffer,
+  IN UINT16      Size
+  )
+{
+  PROTO_DEV *ProtoDev;
+
+  ProtoDev = PROTO_DEV_FROM_PCI_CAP_DEV (PciDevice);
+  return ProtoDevTransferConfig (ProtoDev->PciIo, ProtoDev->PciIo->Pci.Write,
+           DestinationOffset, SourceBuffer, Size);
+}
+
+
+/**
+  Create a PCI_CAP_DEV object from an EFI_PCI_IO_PROTOCOL instance. The config
+  space accessors are based upon EFI_PCI_IO_PROTOCOL.Pci.Read() and
+  EFI_PCI_IO_PROTOCOL.Pci.Write().
+
+  @param[in] PciIo       EFI_PCI_IO_PROTOCOL representation of the PCI device.
+
+  @param[out] PciDevice  The PCI_CAP_DEV object constructed as described above.
+                         PciDevice can be passed to the PciCapLib APIs.
+
+  @retval EFI_SUCCESS           PciDevice has been constructed and output.
+
+  @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
+**/
+EFI_STATUS
+EFIAPI
+PciCapPciIoDeviceInit (
+  IN  EFI_PCI_IO_PROTOCOL *PciIo,
+  OUT PCI_CAP_DEV         **PciDevice
+  )
+{
+  PROTO_DEV *ProtoDev;
+
+  ProtoDev = AllocatePool (sizeof *ProtoDev);
+  if (ProtoDev == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  ProtoDev->Signature              = PROTO_DEV_SIG;
+  ProtoDev->PciIo                  = PciIo;
+  ProtoDev->BaseDevice.ReadConfig  = ProtoDevReadConfig;
+  ProtoDev->BaseDevice.WriteConfig = ProtoDevWriteConfig;
+
+  *PciDevice = &ProtoDev->BaseDevice;
+  return EFI_SUCCESS;
+}
+
+
+/**
+  Free the resources used by PciDevice.
+
+  @param[in] PciDevice  The PCI_CAP_DEV object to free, originally produced by
+                        PciCapPciIoDeviceInit().
+**/
+VOID
+EFIAPI
+PciCapPciIoDeviceUninit (
+  IN PCI_CAP_DEV *PciDevice
+  )
+{
+  PROTO_DEV *ProtoDev;
+
+  ProtoDev = PROTO_DEV_FROM_PCI_CAP_DEV (PciDevice);
+  FreePool (ProtoDev);
+}
-- 
2.14.1.3.gb7cf6e02401b