UpdatePcdPei

Overview

UpdatePcdPei is a UBA (Universal Board Architecture) PCD update PEIM that locates the UBA PCD Update PPI and invokes board-specific PCD update callbacks during the PEI phase. It reads a PCD_UPDATE_TABLE structure from the UBA protocol data, validates the signature ('PPCD') and version, and calls the board-specific function pointer to apply platform PCD adjustments.

This module enables board-specific PCD customization without modifying the core firmware, allowing a single firmware image to support multiple hardware platforms by dispatching to the correct PCD update routine at boot time.

Key Functions

• ModuleEntryPoint -- Entry point called by the PEI core; delegates to UbaPcdUpdateEntry.
• UbaPcdUpdateEntry -- Locates the gUbaPcdUpdatePpiGuid PPI, retrieves the PCD update table, performs validation, and calls the board-specific callback.

Dependencies

• PeiServicesLocatePpi
• gUbaPcdUpdatePpiGuid protocol
• UBA configuration database PPI
• PCD_UPDATE_TABLE structure (12 bytes, signature 'PPCD', version 1)

Platform

Intel Purley platform, 32-bit PEI environment.