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audk/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.h

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OvmfPkg: introduce PciCapPciSegmentLib Add a library class, and a BASE lib instance, that are layered on top of PciCapLib, and allow clients to plug a PciSegmentLib backend into PciCapLib, for config space access. (Side note: The "MaxDomain" parameter is provided because, in practice, platforms exist where a PCI Express device may show up on a root bridge such that the root bridge doesn't support access to extended config space. Earlier the same issue was handled for MdeModulePkg/PciHostBridgeDxe in commit 014b472053ae3. However, that solution does not apply to the PciSegmentLib class, because: (1) The config space accessor functions of the PciSegmentLib class, such as PciSegmentReadBuffer(), have no way of informing the caller whether access to extended config space actually succeeds. (For example, in the UefiPciSegmentLibPciRootBridgeIo instace, which could in theory benefit from commit 014b472053ae3, the EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Pci.Read() status code is explicitly ignored, because there's no way for the lib instance to propagate it to the PciSegmentLib caller. If the EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Pci.Read() call fails, then DxePciSegmentLibPciRootBridgeIoReadWorker() returns Data with indeterminate value.) (2) There is no *general* way for any firmware platform to provide, or use, a PciSegmentLib instance in which access to extended config space always succeeds. In brief, on a platform where config space may be limited to 256 bytes, access to extended config space through PciSegmentLib may invoke undefined behavior; therefore PciCapPciSegmentLib must give platforms a way to prevent such access.) Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Jordan Justen <jordan.l.justen@intel.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
2018-04-28 23:22:59 +02:00
/** @file
Plug a PciSegmentLib backend into PciCapLib, for config space access --
internal macro and type definitions.
Copyright (C) 2018, Red Hat, Inc.
OvmfPkg: Replace BSD License with BSD+Patent License https://bugzilla.tianocore.org/show_bug.cgi?id=1373 Replace BSD 2-Clause License with BSD+Patent License. This change is based on the following emails: https://lists.01.org/pipermail/edk2-devel/2019-February/036260.html https://lists.01.org/pipermail/edk2-devel/2018-October/030385.html RFCs with detailed process for the license change: V3: https://lists.01.org/pipermail/edk2-devel/2019-March/038116.html V2: https://lists.01.org/pipermail/edk2-devel/2019-March/037669.html V1: https://lists.01.org/pipermail/edk2-devel/2019-March/037500.html Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
2019-04-04 01:06:33 +02:00
SPDX-License-Identifier: BSD-2-Clause-Patent
OvmfPkg: introduce PciCapPciSegmentLib Add a library class, and a BASE lib instance, that are layered on top of PciCapLib, and allow clients to plug a PciSegmentLib backend into PciCapLib, for config space access. (Side note: The "MaxDomain" parameter is provided because, in practice, platforms exist where a PCI Express device may show up on a root bridge such that the root bridge doesn't support access to extended config space. Earlier the same issue was handled for MdeModulePkg/PciHostBridgeDxe in commit 014b472053ae3. However, that solution does not apply to the PciSegmentLib class, because: (1) The config space accessor functions of the PciSegmentLib class, such as PciSegmentReadBuffer(), have no way of informing the caller whether access to extended config space actually succeeds. (For example, in the UefiPciSegmentLibPciRootBridgeIo instace, which could in theory benefit from commit 014b472053ae3, the EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Pci.Read() status code is explicitly ignored, because there's no way for the lib instance to propagate it to the PciSegmentLib caller. If the EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Pci.Read() call fails, then DxePciSegmentLibPciRootBridgeIoReadWorker() returns Data with indeterminate value.) (2) There is no *general* way for any firmware platform to provide, or use, a PciSegmentLib instance in which access to extended config space always succeeds. In brief, on a platform where config space may be limited to 256 bytes, access to extended config space through PciSegmentLib may invoke undefined behavior; therefore PciCapPciSegmentLib must give platforms a way to prevent such access.) Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Jordan Justen <jordan.l.justen@intel.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
2018-04-28 23:22:59 +02:00
**/
#ifndef __BASE_PCI_CAP_PCI_SEGMENT_LIB_H__
#define __BASE_PCI_CAP_PCI_SEGMENT_LIB_H__
#include <Library/DebugLib.h>
#include <Library/PciCapPciSegmentLib.h>
#define SEGMENT_DEV_SIG SIGNATURE_64 ('P', 'C', 'P', 'S', 'G', 'M', 'N', 'T')
typedef struct {
//
// Signature identifying the derived class.
//
UINT64 Signature;
//
// Members added by the derived class, specific to the use of PciSegmentLib.
//
PCI_CAP_DOMAIN MaxDomain;
UINT16 SegmentNr;
UINT8 BusNr;
UINT8 DeviceNr;
UINT8 FunctionNr;
//
// Base class.
//
PCI_CAP_DEV BaseDevice;
} SEGMENT_DEV;
#define SEGMENT_DEV_FROM_PCI_CAP_DEV(PciDevice) \
CR (PciDevice, SEGMENT_DEV, BaseDevice, SEGMENT_DEV_SIG)
#endif // __BASE_PCI_CAP_PCI_SEGMENT_LIB_H__