mirror of https://github.com/acidanthera/audk.git
122 lines
3.1 KiB
C
122 lines
3.1 KiB
C
/** @file
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Stateless fw_cfg library implementation.
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Clients must call QemuFwCfgIsAvailable() first.
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Copyright (C) 2013, Red Hat, Inc.
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Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
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Copyright (c) 2017, Advanced Micro Devices. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Library/BaseLib.h>
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#include <Library/DebugLib.h>
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#include <Library/QemuFwCfgLib.h>
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#include "QemuFwCfgLibInternal.h"
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/**
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Returns a boolean indicating if the firmware configuration interface
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is available or not.
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This function may change fw_cfg state.
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@retval TRUE The interface is available
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@retval FALSE The interface is not available
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**/
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BOOLEAN
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EFIAPI
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QemuFwCfgIsAvailable (
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VOID
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)
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{
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UINT32 Signature;
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UINT32 Revision;
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QemuFwCfgSelectItem (QemuFwCfgItemSignature);
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Signature = QemuFwCfgRead32 ();
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DEBUG ((DEBUG_INFO, "FW CFG Signature: 0x%x\n", Signature));
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QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);
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Revision = QemuFwCfgRead32 ();
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DEBUG ((DEBUG_INFO, "FW CFG Revision: 0x%x\n", Revision));
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if ((Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) ||
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(Revision < 1)
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) {
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DEBUG ((DEBUG_INFO, "QemuFwCfg interface not supported.\n"));
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return FALSE;
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}
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DEBUG ((DEBUG_INFO, "QemuFwCfg interface is supported.\n"));
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return TRUE;
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}
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/**
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Returns a boolean indicating if the firmware configuration interface is
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available for library-internal purposes.
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This function never changes fw_cfg state.
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@retval TRUE The interface is available internally.
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@retval FALSE The interface is not available internally.
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**/
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BOOLEAN
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InternalQemuFwCfgIsAvailable (
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VOID
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)
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{
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//
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// We always return TRUE, because the consumer of this library ought to have
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// called QemuFwCfgIsAvailable before making other calls which would hit this
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// path.
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//
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return TRUE;
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}
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/**
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Returns a boolean indicating whether QEMU provides the DMA-like access method
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for fw_cfg.
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@retval TRUE The DMA-like access method is available.
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@retval FALSE The DMA-like access method is unavailable.
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**/
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BOOLEAN
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InternalQemuFwCfgDmaIsAvailable (
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VOID
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)
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{
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return FALSE;
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}
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/**
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Transfer an array of bytes, or skip a number of bytes, using the DMA
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interface.
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@param[in] Size Size in bytes to transfer or skip.
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@param[in,out] Buffer Buffer to read data into or write data from. Ignored,
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and may be NULL, if Size is zero, or Control is
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FW_CFG_DMA_CTL_SKIP.
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@param[in] Control One of the following:
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FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
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FW_CFG_DMA_CTL_READ - read from fw_cfg into Buffer.
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FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg.
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**/
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VOID
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InternalQemuFwCfgDmaBytes (
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IN UINT32 Size,
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IN OUT VOID *Buffer OPTIONAL,
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IN UINT32 Control
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)
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{
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//
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// We should never reach here
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//
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ASSERT (FALSE);
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CpuDeadLoop ();
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}
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