audk/ArmVirtPkg/Library/Fdt16550SerialPortHookLib/EarlyFdt16550SerialPortHook...

138 lines
3.8 KiB
C

/** @file
Early 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 <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/HobLib.h>
#include <Library/PcdLib.h>
#include <Library/PlatformHookLib.h>
#include <libfdt.h>
/** Get the UART base address of the console serial-port from the DT.
This function fetches the node referenced in the "stdout-path"
property of the "chosen" node and returns the base address of
the console UART.
@param [in] Fdt Pointer to a Flattened Device Tree (Fdt).
@param [out] SerialConsoleAddress If success, contains the base address
of the console serial-port.
@retval EFI_SUCCESS The function completed successfully.
@retval EFI_NOT_FOUND Console serial-port info not found in DT.
@retval EFI_INVALID_PARAMETER Invalid parameter.
**/
STATIC
EFI_STATUS
EFIAPI
GetSerialConsolePortAddress (
IN CONST VOID *Fdt,
OUT UINT64 *SerialConsoleAddress
)
{
CONST CHAR8 *Prop;
INT32 PropSize;
CONST CHAR8 *Path;
INT32 PathLen;
INT32 ChosenNode;
INT32 SerialConsoleNode;
INT32 Len;
CONST CHAR8 *NodeStatus;
CONST UINT64 *RegProperty;
if ((Fdt == NULL) || (fdt_check_header (Fdt) != 0)) {
return EFI_INVALID_PARAMETER;
}
// The "chosen" node resides at the the root of the DT. Fetch it.
ChosenNode = fdt_path_offset (Fdt, "/chosen");
if (ChosenNode < 0) {
return EFI_NOT_FOUND;
}
Prop = fdt_getprop (Fdt, ChosenNode, "stdout-path", &PropSize);
if (PropSize < 0) {
return EFI_NOT_FOUND;
}
// Determine the actual path length, as a colon terminates the path.
Path = ScanMem8 (Prop, ':', PropSize);
if (Path == NULL) {
PathLen = AsciiStrLen (Prop);
} else {
PathLen = Path - Prop;
}
// Aliases cannot start with a '/', so it must be the actual path.
if (Prop[0] == '/') {
SerialConsoleNode = fdt_path_offset_namelen (Fdt, Prop, PathLen);
} else {
// Lookup the alias, as this contains the actual path.
Path = fdt_get_alias_namelen (Fdt, Prop, PathLen);
if (Path == NULL) {
return EFI_NOT_FOUND;
}
SerialConsoleNode = fdt_path_offset (Fdt, Path);
}
NodeStatus = fdt_getprop (Fdt, SerialConsoleNode, "status", &Len);
if ((NodeStatus != NULL) && (AsciiStrCmp (NodeStatus, "okay") != 0)) {
return EFI_NOT_FOUND;
}
RegProperty = fdt_getprop (Fdt, SerialConsoleNode, "reg", &Len);
if (Len != 16) {
return EFI_INVALID_PARAMETER;
}
*SerialConsoleAddress = fdt64_to_cpu (ReadUnaligned64 (RegProperty));
return EFI_SUCCESS;
}
/** Platform hook to retrieve the 16550 UART base address from the platform
Device tree and store it in PcdSerialRegisterBase.
@retval RETURN_SUCCESS Success.
@retval RETURN_INVALID_PARAMETER A parameter was invalid.
@retval RETURN_NOT_FOUND Serial port information not found.
**/
RETURN_STATUS
EFIAPI
PlatformHookSerialPortInitialize (
VOID
)
{
RETURN_STATUS Status;
VOID *DeviceTreeBase;
UINT64 SerialConsoleAddress;
if (PcdGet64 (PcdSerialRegisterBase) != 0) {
return RETURN_SUCCESS;
}
DeviceTreeBase = (VOID *)(UINTN)PcdGet64 (PcdDeviceTreeInitialBaseAddress);
if (DeviceTreeBase == NULL) {
return RETURN_NOT_FOUND;
}
Status = GetSerialConsolePortAddress (DeviceTreeBase, &SerialConsoleAddress);
if (RETURN_ERROR (Status)) {
return Status;
}
return (EFI_STATUS)PcdSet64S (PcdSerialRegisterBase, SerialConsoleAddress);
}