audk/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c

287 lines
6.4 KiB
C

/** @file
Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
Copyright (C) 2013, Red Hat, Inc.
Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "Uefi.h"
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/IoLib.h>
#include <Library/QemuFwCfgLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include "QemuFwCfgLibInternal.h"
/**
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
)
{
DEBUG ((DEBUG_INFO, "Select Item: 0x%x\n", (UINT16)(UINTN)QemuFwCfgItem));
IoWrite16 (FW_CFG_IO_SELECTOR, (UINT16)(UINTN)QemuFwCfgItem);
}
/**
Reads firmware configuration bytes into a buffer
@param[in] Size - Size in bytes to read
@param[in] Buffer - Buffer to store data into (OPTIONAL if Size is 0)
**/
VOID
EFIAPI
InternalQemuFwCfgReadBytes (
IN UINTN Size,
IN VOID *Buffer OPTIONAL
)
{
if (InternalQemuFwCfgDmaIsAvailable () && (Size <= MAX_UINT32)) {
InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_READ);
return;
}
IoReadFifo8 (FW_CFG_IO_DATA, Size, Buffer);
}
/**
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
)
{
if (InternalQemuFwCfgIsAvailable ()) {
InternalQemuFwCfgReadBytes (Size, Buffer);
} else {
ZeroMem (Buffer, Size);
}
}
/**
Write firmware configuration bytes from a buffer
If called multiple times, then the data written will
continue at the offset of the firmware configuration
item where the previous write ended.
@param[in] Size - Size in bytes to write
@param[in] Buffer - Buffer to read data from
**/
VOID
EFIAPI
QemuFwCfgWriteBytes (
IN UINTN Size,
IN VOID *Buffer
)
{
if (InternalQemuFwCfgIsAvailable ()) {
if (InternalQemuFwCfgDmaIsAvailable () && (Size <= MAX_UINT32)) {
InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_WRITE);
return;
}
IoWriteFifo8 (FW_CFG_IO_DATA, Size, Buffer);
}
}
/**
Skip bytes in the firmware configuration item.
Increase the offset of the firmware configuration item without transferring
bytes between the item and a caller-provided buffer. Subsequent read, write
or skip operations will commence at the increased offset.
@param[in] Size Number of bytes to skip.
**/
VOID
EFIAPI
QemuFwCfgSkipBytes (
IN UINTN Size
)
{
UINTN ChunkSize;
UINT8 SkipBuffer[256];
if (!InternalQemuFwCfgIsAvailable ()) {
return;
}
if (InternalQemuFwCfgDmaIsAvailable () && (Size <= MAX_UINT32)) {
InternalQemuFwCfgDmaBytes ((UINT32)Size, NULL, FW_CFG_DMA_CTL_SKIP);
return;
}
//
// Emulate the skip by reading data in chunks, and throwing it away. The
// implementation below is suitable even for phases where RAM or dynamic
// allocation is not available or appropriate. It also doesn't affect the
// static data footprint for client modules. Large skips are not expected,
// therefore this fallback is not performance critical. The size of
// SkipBuffer is thought not to exert a large pressure on the stack in any
// phase.
//
while (Size > 0) {
ChunkSize = MIN (Size, sizeof SkipBuffer);
IoReadFifo8 (FW_CFG_IO_DATA, ChunkSize, SkipBuffer);
Size -= ChunkSize;
}
}
/**
Reads a UINT8 firmware configuration value
@return Value of Firmware Configuration item read
**/
UINT8
EFIAPI
QemuFwCfgRead8 (
VOID
)
{
UINT8 Result;
QemuFwCfgReadBytes (sizeof (Result), &Result);
return Result;
}
/**
Reads a UINT16 firmware configuration value
@return Value of Firmware Configuration item read
**/
UINT16
EFIAPI
QemuFwCfgRead16 (
VOID
)
{
UINT16 Result;
QemuFwCfgReadBytes (sizeof (Result), &Result);
return Result;
}
/**
Reads a UINT32 firmware configuration value
@return Value of Firmware Configuration item read
**/
UINT32
EFIAPI
QemuFwCfgRead32 (
VOID
)
{
UINT32 Result;
QemuFwCfgReadBytes (sizeof (Result), &Result);
return Result;
}
/**
Reads a UINT64 firmware configuration value
@return Value of Firmware Configuration item read
**/
UINT64
EFIAPI
QemuFwCfgRead64 (
VOID
)
{
UINT64 Result;
QemuFwCfgReadBytes (sizeof (Result), &Result);
return Result;
}
/**
Find the configuration item corresponding to the firmware configuration file.
@param[in] Name - Name of file to look up.
@param[out] Item - Configuration item corresponding to the file, to be passed
to QemuFwCfgSelectItem ().
@param[out] Size - Number of bytes in the file.
@return RETURN_SUCCESS If file is found.
RETURN_NOT_FOUND If file is not found.
RETURN_UNSUPPORTED If firmware configuration is unavailable.
**/
RETURN_STATUS
EFIAPI
QemuFwCfgFindFile (
IN CONST CHAR8 *Name,
OUT FIRMWARE_CONFIG_ITEM *Item,
OUT UINTN *Size
)
{
UINT32 Count;
UINT32 Idx;
if (!InternalQemuFwCfgIsAvailable ()) {
return RETURN_UNSUPPORTED;
}
QemuFwCfgSelectItem (QemuFwCfgItemFileDir);
Count = SwapBytes32 (QemuFwCfgRead32 ());
for (Idx = 0; Idx < Count; ++Idx) {
UINT32 FileSize;
UINT16 FileSelect;
UINT16 FileReserved;
CHAR8 FName[QEMU_FW_CFG_FNAME_SIZE];
FileSize = QemuFwCfgRead32 ();
FileSelect = QemuFwCfgRead16 ();
FileReserved = QemuFwCfgRead16 ();
(VOID)FileReserved; /* Force a do-nothing reference. */
InternalQemuFwCfgReadBytes (sizeof (FName), FName);
if (AsciiStrCmp (Name, FName) == 0) {
*Item = SwapBytes16 (FileSelect);
*Size = SwapBytes32 (FileSize);
return RETURN_SUCCESS;
}
}
return RETURN_NOT_FOUND;
}