audk/OvmfPkg/Include/Library/PciCapPciIoLib.h

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OvmfPkg: introduce PciCapPciIoLib 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> 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 23:23:10 +02:00
/** @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.
SPDX-License-Identifier: BSD-2-Clause-Patent
OvmfPkg: introduce PciCapPciIoLib 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> 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 23:23:10 +02:00
**/
#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__