Chapter 8: Structure of a Kernel-Level Driver

This chapter discusses when the driver entry points are called, what parameters they receive, and what actions they are expected to take. For a conceptual overview of the kernel and drivers, see "Kernel-Level Device Control". For details on how a driver is compiled, linked, and added to IRIX, see Chapter 10, "Building and Installing a Driver."

Note: This chapter discusses device drivers. The entry point conventions for STREAMS drivers are covered in Chapter 19, "STREAMS Drivers." The primary topics covered in this chapter are:

• "Summary of Driver Structure" summarizes the entry points and how they are made known to the kernel.

• "Driver Flag Constant" documents a public constant the driver must supply.

• "Initialization Entry Points" documents the entry points that are called at boot time and when a loadable driver is loaded.

• "Open and Close Entry Points" documents the entry points called by the open() and close() kernel functions.

• "Control Entry Point" documents the entry point called by the ioctl() kernel function.

• "Data Transfer Entry Points" documents the entry points called by the read() and write() kernel functions.

• "Poll Entry Point" documents the entry point called by the poll() kernel function.

• "Memory Map Entry Points" documents the entry points called by the mmap() kernel function.

• "Interrupt Entry Point" documents the entry point called to handle a device interrupt.

• "Support Entry Points" documents the entry points that support kernel operations and system administration.

• "Planning for Multiprocessor Use" points out methods for writing a multiprocessor-aware driver.

Summary of Driver Structure

Driver Flag Constant

Initialization Entry Points

Open and Close Entry Points

Control Entry Point

Data Transfer Entry Points

Poll Entry Point

Memory Map Entry Points

Interrupt Entry Point

Support Entry Points

Handling 32-Bit and 64-Bit Execution Models

Planning for Multiprocessor Use