OvmfPkg: Add QemuFwCfgLib library class and implementation

QEMU's Firmware Configuration interface gives the firmware
access to various types of information.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13383 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Include/Library/QemuFwCfgLib.h

@@ -0,0 +1,157 @@
+/** @file
+  QEMU/KVM Firmware Configuration access
+
+  Copyright (c) 2011 - 2012, Intel Corporation. All rights reserved.<BR>
+  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 __FW_CFG_LIB__
+#define __FW_CFG_LIB__
+
+typedef enum {
+  QemuFwCfgItemSignature            = 0x0000,
+  QemuFwCfgItemInterfaceVersion     = 0x0001,
+  QemuFwCfgItemSystemUuid           = 0x0002,
+  QemuFwCfgItemRamSize              = 0x0003,
+  QemuFwCfgItemGraphicsEnabled      = 0x0004,
+  QemuFwCfgItemSmpCpuCount          = 0x0005,
+  QemuFwCfgItemMachineId            = 0x0006,
+  QemuFwCfgItemKernelAddress        = 0x0007,
+  QemuFwCfgItemKernelSize           = 0x0008,
+  QemuFwCfgItemKernelCommandLine    = 0x0009,
+  QemuFwCfgItemInitrdAddress        = 0x000a,
+  QemuFwCfgItemInitrdSize           = 0x000b,
+  QemuFwCfgItemBootDevice           = 0x000c,
+  QemuFwCfgItemNumaData             = 0x000d,
+  QemuFwCfgItemBootMenu             = 0x000e,
+  QemuFwCfgItemMaximumCpuCount      = 0x000f,
+  QemuFwCfgItemKernelEntry          = 0x0010,
+  QemuFwCfgItemKernelData           = 0x0011,
+  QemuFwCfgItemInitrdData           = 0x0012,
+  QemuFwCfgItemCommandLineAddress   = 0x0013,
+  QemuFwCfgItemCommandLineSize      = 0x0014,
+  QemuFwCfgItemCommandLineData      = 0x0015,
+  QemuFwCfgItemKernelSetupAddress   = 0x0016,
+  QemuFwCfgItemKernelSetupSize      = 0x0017,
+  QemuFwCfgItemKernelSetupData      = 0x0018,
+
+  QemuFwCfgItemX86AcpiTables        = 0x8000,
+  QemuFwCfgItemX86SmbiosTables      = 0x8001,
+  QemuFwCfgItemX86Irq0Override      = 0x8002,
+  QemuFwCfgItemX86E820Table         = 0x8003,
+  QemuFwCfgItemX86HpetData          = 0x8004,
+
+} FIRMWARE_CONFIG_ITEM;
+
+
+/**
+  Returns a boolean indicating if the firmware configuration interface
+  is available or not.
+
+  @retval    TRUE   The interface is available
+  @retval    FALSE  The interface is not available
+
+**/
+BOOLEAN
+EFIAPI
+QemuFwCfgIsAvailable (
+  VOID
+  );
+
+
+/**
+  Selects a firmware configuration item for reading.
+
+  Following this call, any data read from this item will start from
+  the beginning of the configuration item's data.
+
+  @param[in] QemuFwCfgItem - Firmware Configuration item to read
+
+**/
+VOID
+EFIAPI
+QemuFwCfgSelectItem (
+  IN FIRMWARE_CONFIG_ITEM   QemuFwCfgItem
+  );
+
+
+/**
+  Reads firmware configuration bytes into a buffer
+
+  If called multiple times, then the data read will
+  continue at the offset of the firmware configuration
+  item where the previous read ended.
+
+  @param[in] Size - Size in bytes to read
+  @param[in] Buffer - Buffer to store data into
+
+**/
+VOID
+EFIAPI
+QemuFwCfgReadBytes (
+  IN UINTN                  Size,
+  IN VOID                   *Buffer  OPTIONAL
+  );
+
+
+/**
+  Reads a UINT8 firmware configuration value
+
+  @return    Value of Firmware Configuration item read
+
+**/
+UINT8
+EFIAPI
+QemuFwCfgRead8 (
+  VOID
+  );
+
+
+/**
+  Reads a UINT16 firmware configuration value
+
+  @return    Value of Firmware Configuration item read
+
+**/
+UINT16
+EFIAPI
+QemuFwCfgRead16 (
+  VOID
+  );
+
+
+/**
+  Reads a UINT32 firmware configuration value
+
+  @return    Value of Firmware Configuration item read
+
+**/
+UINT32
+EFIAPI
+QemuFwCfgRead32 (
+  VOID
+  );
+
+
+/**
+  Reads a UINT64 firmware configuration value
+
+  @return    Value of Firmware Configuration item read
+
+**/
+UINT64
+EFIAPI
+QemuFwCfgRead64 (
+  VOID
+  );
+
+
+#endif
+