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/** @file
Stateful and implicitly initialized fw_cfg library implementation.
Copyright (C) 2013, Red Hat, Inc.
Copyright (c) 2011 - 2013, 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.
**/
#include <Library/DebugLib.h>
#include <Library/QemuFwCfgLib.h>
#include "QemuFwCfgLibInternal.h"
STATIC BOOLEAN mQemuFwCfgSupported = FALSE;
STATIC BOOLEAN mQemuFwCfgDmaSupported;
/**
Returns a boolean indicating if the firmware configuration interface
is available or not.
This function may change fw_cfg state.
@retval TRUE The interface is available
@retval FALSE The interface is not available
**/
BOOLEAN
EFIAPI
QemuFwCfgIsAvailable (
VOID
)
{
return InternalQemuFwCfgIsAvailable ();
}
RETURN_STATUS
EFIAPI
QemuFwCfgInitialize (
VOID
)
{
UINT32 Signature;
UINT32 Revision;
//
// Enable the access routines while probing to see if it is supported.
// For probing we always use the IO Port (IoReadFifo8()) access method.
//
mQemuFwCfgSupported = TRUE;
mQemuFwCfgDmaSupported = FALSE;
QemuFwCfgSelectItem (QemuFwCfgItemSignature);
Signature = QemuFwCfgRead32 ();
DEBUG ((EFI_D_INFO, "FW CFG Signature: 0x%x\n", Signature));
QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);
Revision = QemuFwCfgRead32 ();
DEBUG ((EFI_D_INFO, "FW CFG Revision: 0x%x\n", Revision));
if ((Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) ||
(Revision < 1)
) {
DEBUG ((EFI_D_INFO, "QemuFwCfg interface not supported.\n"));
mQemuFwCfgSupported = FALSE;
return RETURN_SUCCESS;
}
if ((Revision & FW_CFG_F_DMA) == 0) {
DEBUG ((DEBUG_INFO, "QemuFwCfg interface (IO Port) is supported.\n"));
} else {
mQemuFwCfgDmaSupported = TRUE;
DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n"));
}
return RETURN_SUCCESS;
}
/**
Returns a boolean indicating if the firmware configuration interface is
available for library-internal purposes.
This function never changes fw_cfg state.
@retval TRUE The interface is available internally.
@retval FALSE The interface is not available internally.
**/
BOOLEAN
InternalQemuFwCfgIsAvailable (
VOID
)
{
return mQemuFwCfgSupported;
}
/**
Returns a boolean indicating whether QEMU provides the DMA-like access method
for fw_cfg.
@retval TRUE The DMA-like access method is available.
@retval FALSE The DMA-like access method is unavailable.
**/
BOOLEAN
InternalQemuFwCfgDmaIsAvailable (
VOID
)
{
return mQemuFwCfgDmaSupported;
}
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