3.1 What is an EDK II module?

An EDK II module consists of source files or binary files and a module definition file (INF file). An INF file describes a module's basic information and interfaces such as consumed/produced library class/PCD/Protocol/Ppi/Guid. (Please refer to the EDK II Extended INF Specification

A typical EDK II module is a firmware component that is built, put in an FFS file and then put into a FV image. The component may be:

 A driver or application which is built to *.efi binary file and put into FFS file as EFI_PE_SECTION:

Figure 2 Firmware Volume

• Raw data binary. For example, $(WORKSPACE)\MdeModulePkg\Logo\Logo.inf is a raw binary module which contains logo bitmap image.

• An option ROM driver that is put into a device's option ROM.

• A standalone UEFI driver

• A standalone UEFI application.

• A library instance that is built to a library object file (.lib) and statically linked to another module.

Note: A module can be released in source code or in EFI binary format.

3.1.1 Module Type

EDK II defines many module types. The module type is used to:

• Indicate the lifecycle for different types of modules. For example, PEIM is dispatched in PEI phase and DXE_DRIVER orUEFI_DRIVER is dispatched at DXE phase;

• Indicate the binary image generation for different types of modules. For example, a PEIM/DXE_DRIVER type module can have "depex" section in .efi binary image; a UEFI_DRIVER can have .ui or .ver section in .efi binary image;

• Indicate EntryPoint() or Constructor() API for different types of modules.

• Indicate the suitable library instance for different types of modules. A library instance will point out what module types are supported in INF file.

Table 1 EDK II Module Types