audk/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c

371 lines
8.9 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>
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 "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 ((EFI_D_INFO, "Select Item: 0x%x\n", (UINT16)(UINTN) QemuFwCfgItem));
IoWrite16 (FW_CFG_IO_SELECTOR, (UINT16)(UINTN) QemuFwCfgItem);
}
/**
Transfer an array of bytes, or skip a number of bytes, using the DMA
interface.
@param[in] Size Size in bytes to transfer or skip.
@param[in,out] Buffer Buffer to read data into or write data from. Ignored,
and may be NULL, if Size is zero, or Control is
FW_CFG_DMA_CTL_SKIP.
@param[in] Control One of the following:
FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
FW_CFG_DMA_CTL_READ - read from fw_cfg into Buffer.
FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg.
**/
VOID
InternalQemuFwCfgDmaBytes (
IN UINT32 Size,
IN OUT VOID *Buffer OPTIONAL,
IN UINT32 Control
)
{
volatile FW_CFG_DMA_ACCESS Access;
UINT32 AccessHigh, AccessLow;
UINT32 Status;
ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ ||
Control == FW_CFG_DMA_CTL_SKIP);
if (Size == 0) {
return;
}
Access.Control = SwapBytes32 (Control);
Access.Length = SwapBytes32 (Size);
Access.Address = SwapBytes64 ((UINTN)Buffer);
//
// Delimit the transfer from (a) modifications to Access, (b) in case of a
// write, from writes to Buffer by the caller.
//
MemoryFence ();
//
// Start the transfer.
//
AccessHigh = (UINT32)RShiftU64 ((UINTN)&Access, 32);
AccessLow = (UINT32)(UINTN)&Access;
IoWrite32 (FW_CFG_IO_DMA_ADDRESS, SwapBytes32 (AccessHigh));
IoWrite32 (FW_CFG_IO_DMA_ADDRESS + 4, SwapBytes32 (AccessLow));
//
// Don't look at Access.Control before starting the transfer.
//
MemoryFence ();
//
// Wait for the transfer to complete.
//
do {
Status = SwapBytes32 (Access.Control);
ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);
} while (Status != 0);
//
// After a read, the caller will want to use Buffer.
//
MemoryFence ();
}
/**
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;
}