Writing Device Drivers


This function takes the data type model of the user application as an argument and returns the following values:

DDI_MODEL_NONE is returned if no data conversion is necessary. This is the case when application and driver have the same data model (both are ILP32 or LP64). DDI_MODEL_ILP32 is returned if the driver is compiled to the LP64 data model and is communicating with a 32-bit application. Typically, the code that returns the application data model is conditionally compiled depending on the _MULTI_DATAMODEL macro. This macro is defined by the system when the driver supports multiple data models.

If the driver supports multiple data models, it will switch on the return value of ddi_model_convert_from(9F). The DDI_MODEL_ILP32 case should define a 32-bit version of the structure being passed in. Use ddi_copyin(9F) to copy the structure from user space to the 32-bit version of the structure, and then assign each field in the 32-bit structure to the 64-bit version. Otherwise, the code should be unchanged.

The sections that follow show code examples of the use of ddi_model_convert_from(9F).