SetupDesignGuide.pdf - Firmware Encoding Index

Setup Design Guide
DRAFT
Human Interface Infrastructure
Database
Consists of IFR/String/Font
Which has been submitted by varying EFI drivers
Runtime
Buffer
EFI Configuration Driver
Provides User Interface Support
Callable by a Protocol Interface
Runtime Configuration
Application
Can act as a server to
an HTML browser
2.6 How to get hardware information in setup
For the most part, the only hardware interaction that the Configuration Driver has is when it accesses
NVRAM or saves information to an RTC. However, there are times when a developer needs to get
hardware information presented to the user.
In this infrastructure there are two classifications of hardware interaction, single and multiple iteration.
Each of these interactions have varying procedures one must follow as well as varying ramifications.
2.6.1 Single Iteration Hardware Interaction
An EFI driver that uses the EFI setup infrastructure will typically carry both IFR and string data. In
some cases, not all the information that is needed is included at build time. For example, a user might
have a text string which shows what the CPU’s frequency is. In this case, the information is obviously
not available at build time, so the information has to be retrieved.
There are several ways one might go about this. One way might be that the driver that is about to
export the setup data to the HII database calls the appropriate hardware services to determine what the
CPU frequency is, fills in the appropriate string data, and then exports the data to the HII database.
Another way might be that the driver that has exported data to the HII database needs to add
information to the database could use the HII protocol calls for NewString or UpdateForm. Both
of these functions are intended for post-export modification of database information.
Another method, which is used for more complex situations, would be to label the op-code which
required additional data with a DYNAMIC flag. When the data is exported to the HII database, it calls
back to the driver to get the additional data. The driver will do the hardware interaction and return a
packet of data to the database to fill in the appropriate string data.
Once this single level of hardware interaction is complete, the presentation data stored in the database is
static and the DYNAMIC flag is turned off. Due to the static nature of this data, it is able to be used
pre-boot and be exported to an O/S runtime application and be used during that phase of operation.
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