MeUma

Function Table

Address	Name	Description
	ModuleEntryPoint
	ReadUnaligned64
	WriteUnaligned64
	IoRead16
	IoWrite16
	IoRead32
	ReadPciCfg16
	PcdGet32
	PcdGetSize
	CompareGuid
	ValidateUmaLocation
	GetOnBoardMeType
	GetMeFs1FromHob
	GetPeiPerformance
	FindPerformanceLogIndex
	IsHeciSkipped
	SendHeciMessage
	MicroDelay
Globals	// ---------------------------------------------------------------------------
The	PPI descriptor (GUID + EFI_PEI_PPI_DESCRIPTOR) for the ME UMA PPI.
Located	in the .data section at 0xffda3390.
extern	EFI_GUID gMeUmaPpiGuid;
The	actual ME_UMA_PPI structure
Flags	/ state byte at 0xffda339c
Function	prototypes
Internal	*functions (previously sub_)**
The	actual read goes through the memory-mapped ECAM or I/O CFG mechanism.
We	construct the address and decode it via the PCI Express library.
UINTN	**Address = (PciCfg.Reg	0) & 0xFFF; // simplified: see PciExpressLib**
Internal	Helpers
points	to Hob + 24
UMA	Parameter Validation
Check	if the ME is in a debug or error mode that skips UMA checking.
if	(!(UINT8)ModuleEntryPoint (NULL, NULL)) {
Calculate	UMA size:
MeUmaSize	= (MeNcMemLowLimit & 0xFFF80000) + 0x80000 - MeNcMemLowBaseAddr
MeUmaSize	+= MeNcMemHighLimit
MeUmaSize	= (MeNcMemLowLimit & 0xFFF80000) + 0x80000 - MeNcMemLowBaseAddr;
Read	the UMA parameters from Silicon registers (via PCI config access).
UmaBase	*= (UINT32* )((UINTN)PciCfgRead (0) + 240); // offset 0xF0**
offset	0xF4
If	base addresses are zero, skip validation.
if	**(MeNcMemLowBaseAddr == 0		MeNcMemLowLimit == 0) {**
Validate	the UMA base addresses match Silicon registers.
if	**(MeNcMemLowBaseAddr != UmaBase		MeNcMemHighBaseAddr != UmaBaseExt) {**
Validate	UMA size: must not exceed 64 MB, must be even (2 MB aligned).
if	(MeUmaSizeCalc >> 20 > 64) {
ME	Type Detection
Check	Debug Mode via PCH PMC (DWR flow).
if	(IsPchDwrFlow ()) {
15	}
Read	the ME Firmware Status (MEFS) register from PCI config.
MeFirmwareStatus	*= (UINT32* )((UINTN)PciCfgRead (0) + 64); // offset 0x40**
Fall	back to HOB if MEFS is invalid.
MeFirmwareStatus	= GetMeFs1FromHob ();
Evaluate	the ME type from the status.
if	((MeFirmwareStatus & 0xF) == 0xF) {
Unknown	type
2	case 2:
1	default:
Could	not read HOB, use fallback path.
DEBUG	((EFI_D_ERROR, "HECI: GetMeFs1FromHob() Can't read correctly MeFwHob info\n"));
Performance	Logging (PEI Performance)
Use	existing HOB data.
Build	fresh HOBs for the performance log and ID array.
HECI	Message / PPI Installation
Entry	Point
if	((IoRead32 (1024068) & 0x80) == 0) {
Check	if the system has valid ME firmware (skip on debug/error).
byte_FFDA339C	= (IsHeciSkipped () < 0) ? 0 : byte_FFDA339C;
Install	the ME UMA PPI.
PeiServices	= GetPeiServices ();

Generated by HR650X BIOS Decompilation Project