RapidIO: The Next Generation Communication Fabric For Embedded Application

10.2. SYSTEM APPLICATION PROGRAMMING INTERFACES

In order to provide a standardized programming interface to RapidIO hardware, the RapidIO Technical Working Group has defined sets of standard applications programming interfaces (API), that should be used by configuration and operating system software to interact with the RapidIO hardware. By working through an API rather than directly interacting with the RapidIO hardware and registers, insulation against low level changes is provided. The most basic level of API provided are the hardware abstraction layer (HAL) functions. The higher-level functions should rely on the support functions provided by the HAL functions to ensure portability between different platforms.

Device-specific (vendor-specific) functions are functions defined by a device manufacturer that use hardware resources outside of the scope of the RapidIO specifications. The main purpose of these functions is to provide HAL support to the standard RapidIO functions. An important goal of this software API specification is to minimize or eliminate the use of device-specific functions required for enumeration so that the portability of the API across hardware platforms is maximized.

Virtually all of the APIs, when referencing the RapidIO system, will contain at least three parameters. These parameters are: localport, destid and hopcount. Localport refers to the local RapidIO port that the transaction is either targeted at our should be sent out of. Devices can have more ...