SetupDesignGuide.pdf - Firmware Encoding Index

Setup Design Guide
DRAFT
7.3.3 EFI_FORM_CALLBACK_PROTOCOL.CallBack()
Summary
This is the function that is called to provide results data to the driver. This data consists of a unique key
which is used to identify what data is either being passed back or being asked for.
Prototype
EFI_STATUS
(EFIAPI *EFI_FORM_CALLBACK) (
IN EFI_FORM_CALLBACK_PROTOCOL *This,
IN UINT16
KeyValue,
IN VOID
*Data
);
Parameters
This
KeyValue
Data
A pointer to the EFI_NV_ACCESS_PROTOCOL instance.
A unique value which is sent to the original exporting driver so that
it can identify the type of data to expect. The format of the data
tends to vary based on the op-code that generated the callback.
A pointer to the data being sent to the original exporting driver.
Related Definitions
The Data format will be based on the op-code type that the KeyValue
references.
If OneOf op-code the following is being passed in the Data pointer:
UINT16
Value
If Text op-code there is no user initiated data to be sent other
than the KeyValue. There should be a reasonable expectation that a
response to this callback will be that a message gets posted with a
particular key value and string. This would be done in the
EFI_FORM_CONFIGURATION_PROTOCOL.
NULL
If String op-code the following is being passed in the Data pointer:
CHAR16
*String
If Numeric op-code the following is being passed in the Data
pointer:
UINT16
Value
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