audk/ArmVirtPkg/Library/Fdt16550SerialPortHookLib/Fdt16550SerialPortHookLib.c

57 lines
1.3 KiB
C

/** @file
Platform Hook Library instance for 16550 Uart.
Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Base.h>
#include <Uefi.h>
#include <Pi/PiBootMode.h>
#include <Pi/PiHob.h>
#include <Guid/Early16550UartBaseAddress.h>
#include <Guid/Fdt.h>
#include <Guid/FdtHob.h>
#include <Library/BaseLib.h>
#include <Library/HobLib.h>
#include <Library/PcdLib.h>
#include <Library/PlatformHookLib.h>
/** Platform hook to retrieve the 16550 UART base address from the GUID Hob
that caches the UART base address from early boot stage and store it in
PcdSerialRegisterBase.
@retval RETURN_SUCCESS Success.
@retval RETURN_NOT_FOUND Serial Port information not found.
**/
RETURN_STATUS
EFIAPI
PlatformHookSerialPortInitialize (
VOID
)
{
VOID *Hob;
UINT64 *UartBase;
if (PcdGet64 (PcdSerialRegisterBase) != 0) {
return RETURN_SUCCESS;
}
Hob = GetFirstGuidHob (&gEarly16550UartBaseAddressGuid);
if ((Hob == NULL) || (GET_GUID_HOB_DATA_SIZE (Hob) != sizeof (*UartBase))) {
return RETURN_NOT_FOUND;
}
UartBase = GET_GUID_HOB_DATA (Hob);
if ((UINTN)*UartBase == 0) {
return RETURN_NOT_FOUND;
}
return (RETURN_STATUS)PcdSet64S (PcdSerialRegisterBase, (UINTN)*UartBase);
}