system76-edk2/MdeModulePkg/Bus/Pci/PciBusDxe/PciCommand.c

/** @file
  PCI command register operations supporting functions implementation for PCI Bus module.

Copyright (c) 2006 - 2009, Intel Corporation
All rights reserved. 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 "PciBus.h"

/**
  Operate the PCI register via PciIo function interface.

  @param PciIoDevice    Pointer to instance of PCI_IO_DEVICE.
  @param Command        Operator command.
  @param Offset         The address within the PCI configuration space for the PCI controller.
  @param Operation      Type of Operation.
  @param PtrCommand     Return buffer holding old PCI command, if operation is not EFI_SET_REGISTER.

  @return Status of PciIo operation.

**/
EFI_STATUS
PciOperateRegister (
  IN  PCI_IO_DEVICE *PciIoDevice,
  IN  UINT16        Command,
  IN  UINT8         Offset,
  IN  UINT8         Operation,
  OUT UINT16        *PtrCommand
  )
{
  UINT16              OldCommand;
  EFI_STATUS          Status;
  EFI_PCI_IO_PROTOCOL *PciIo;

  OldCommand  = 0;
  PciIo       = &PciIoDevice->PciIo;

  if (Operation != EFI_SET_REGISTER) {
    Status = PciIo->Pci.Read (
                          PciIo,
                          EfiPciIoWidthUint16,
                          Offset,
                          1,
                          &OldCommand
                          );

    if (Operation == EFI_GET_REGISTER) {
      *PtrCommand = OldCommand;
      return Status;
    }
  }

  if (Operation == EFI_ENABLE_REGISTER) {
    OldCommand = (UINT16) (OldCommand | Command);
  } else if (Operation == EFI_DISABLE_REGISTER) {
    OldCommand = (UINT16) (OldCommand & ~(Command));
  } else {
    OldCommand = Command;
  }

  return PciIo->Pci.Write (
                      PciIo,
                      EfiPciIoWidthUint16,
                      Offset,
                      1,
                      &OldCommand
                      );
}

/**
  Check the cpability supporting by given device.

  @param PciIoDevice   Pointer to instance of PCI_IO_DEVICE.

  @retval TRUE         Cpability supportted.
  @retval FALSE        Cpability not supportted.

**/
BOOLEAN
PciCapabilitySupport (
  IN PCI_IO_DEVICE  *PciIoDevice
  )
{
  if ((PciIoDevice->Pci.Hdr.Status & EFI_PCI_STATUS_CAPABILITY) != 0) {
    return TRUE;
  }

  return FALSE;
}

/**
  Locate capability register block per capability ID.

  @param PciIoDevice       A pointer to the PCI_IO_DEVICE.
  @param CapId             The capability ID.
  @param Offset            A pointer to the offset returned.
  @param NextRegBlock      A pointer to the next block returned.

  @retval EFI_SUCCESS      Successfuly located capability register block.
  @retval EFI_UNSUPPORTED  Pci device does not support capability.
  @retval EFI_NOT_FOUND    Pci device support but can not find register block.

**/
EFI_STATUS
LocateCapabilityRegBlock (
  IN PCI_IO_DEVICE  *PciIoDevice,
  IN UINT8          CapId,
  IN OUT UINT8      *Offset,
  OUT UINT8         *NextRegBlock OPTIONAL
  )
{
  UINT8   CapabilityPtr;
  UINT16  CapabilityEntry;
  UINT8   CapabilityID;

  //
  // To check the cpability of this device supports
  //
  if (!PciCapabilitySupport (PciIoDevice)) {
    return EFI_UNSUPPORTED;
  }

  if (*Offset != 0) {
    CapabilityPtr = *Offset;
  } else {

    CapabilityPtr = 0;
    if (IS_CARDBUS_BRIDGE (&PciIoDevice->Pci)) {

      PciIoDevice->PciIo.Pci.Read (
                               &PciIoDevice->PciIo,
                               EfiPciIoWidthUint8,
                               EFI_PCI_CARDBUS_BRIDGE_CAPABILITY_PTR,
                               1,
                               &CapabilityPtr
                               );
    } else {

      PciIoDevice->PciIo.Pci.Read (
                               &PciIoDevice->PciIo,
                               EfiPciIoWidthUint8,
                               PCI_CAPBILITY_POINTER_OFFSET,
                               1,
                               &CapabilityPtr
                               );
    }
  }

  while ((CapabilityPtr >= 0x40) && ((CapabilityPtr & 0x03) == 0x00)) {
    PciIoDevice->PciIo.Pci.Read (
                             &PciIoDevice->PciIo,
                             EfiPciIoWidthUint16,
                             CapabilityPtr,
                             1,
                             &CapabilityEntry
                             );

    CapabilityID = (UINT8) CapabilityEntry;

    if (CapabilityID == CapId) {
      *Offset = CapabilityPtr;
      if (NextRegBlock != NULL) {
        *NextRegBlock = (UINT8) (CapabilityEntry >> 8);
      }

      return EFI_SUCCESS;
    }

    CapabilityPtr = (UINT8) (CapabilityEntry >> 8);
  }

  return EFI_NOT_FOUND;
}

/**
  Locate PciExpress capability register block per capability ID.

  @param PciIoDevice       A pointer to the PCI_IO_DEVICE.
  @param CapId             The capability ID.
  @param Offset            A pointer to the offset returned.
  @param NextRegBlock      A pointer to the next block returned.

  @retval EFI_SUCCESS      Successfuly located capability register block.
  @retval EFI_UNSUPPORTED  Pci device does not support capability.
  @retval EFI_NOT_FOUND    Pci device support but can not find register block.

**/
EFI_STATUS
LocatePciExpressCapabilityRegBlock (
  IN     PCI_IO_DEVICE *PciIoDevice,
  IN     UINT16        CapId,
  IN OUT UINT32        *Offset,
     OUT UINT32        *NextRegBlock OPTIONAL
  )
{
  UINT32  CapabilityPtr;
  UINT32  CapabilityEntry;
  UINT16  CapabilityID;

  //
  // To check the capability of this device supports
  //
  if (!PciIoDevice->IsPciExp) {
    return EFI_UNSUPPORTED;
  }

  if (*Offset != 0) {
    CapabilityPtr = *Offset;
  } else {
    CapabilityPtr = EFI_PCIE_CAPABILITY_BASE_OFFSET;
  }

  while (CapabilityPtr != 0) {
    //
    // Mask it to DWORD alignment per PCI spec
    //
    CapabilityPtr &= 0xFFC;
    PciIoDevice->PciIo.Pci.Read (
                             &PciIoDevice->PciIo,
                             EfiPciIoWidthUint32,
                             CapabilityPtr,
                             1,
                             &CapabilityEntry
                             );

    CapabilityID = (UINT16) CapabilityEntry;

    if (CapabilityID == CapId) {
      *Offset = CapabilityPtr;
      if (NextRegBlock != NULL) {
        *NextRegBlock = (CapabilityEntry >> 20) & 0xFFF;
      }

      return EFI_SUCCESS;
    }

    CapabilityPtr = (CapabilityEntry >> 20) & 0xFFF;
  }

  return EFI_NOT_FOUND;
}