About This Book

This book discusses topics associated with writing device drivers that operate on the Extended Industry Standard Architecture (EISA) bus and the Industry Standard Architecture (ISA) bus.

Audience

This book is intended for systems engineers who:

• Use standard library interfaces to develop programs in the C language

• Know the Bourne or some other shell based on the UNIX® operating system

• Understand basic UNIX concepts such as kernel, shell, process, configuration, and autoconfiguration

• Understand how to use the Digital UNIX programming tools, compilers, and debuggers

• Develop programs in an environment that involves dynamic memory allocation, linked list data structures, and multitasking

• Understand the hardware device for which the driver is being written

• Understand the basics of the CPU hardware architecture, including interrupts, direct memory access (DMA) operations, and I/O

This book assumes that you have a strong background in operating systems based on the UNIX operating system. It also assumes that you have a strong background in systems and C programming, and that you are familiar with topics presented in Writing Device Drivers: Tutorial. In addition, the book assumes that you have no source code licenses.

New and Changed Features

In this version of Digital UNIX, there are several new features that change the way you implement device drivers. The following list summarizes the issues you need to consider when deciding whether to update device drivers written on previous versions of Digital UNIX to the current version of the Digital UNIX operating system. Although existing device drivers are binary compatible with the current version of Digital UNIX, you might want to make these changes to take advantage of the single binary module technology:

• Method for registering interrupt handlers

• Method for registering block and character device driver interfaces

• Use of bus-specific option structure and structure snippet

• Driver object files

• Elimination of the stanza.static file fragment

• Elimination of the stanza.loadable file fragment

• Changes to the files file fragment

• Elimination of the config.file file fragment

• Method for configuring and unconfiguring controllers

• Method for identifying bus, controller, and device information

• Use of name_data.c files

• Method for specifying device special file information

• Use of device driver header file

For more information on these and other changes to device drivers, see Writing Device Drivers: Tutorial.

Chapter 8 of this book has been revised to describe the use of the sysconfigtab file for defining EISA and ISA bus options. This method for defining bus options replaces the use of the eisa_option_data.c and isa_option_data.c files.

Chapter 9 has been added to this manual. It describes how to write a configuration file for configuring an EISA or ISA bus with the EISA Configuration Utility (ECU).

A new Appendix B has been added to this manual. It describes the configuration file format recognized by the ECU.

Scope of the Book

The book is for users of the Digital UNIX operating system on computer systems developed by Digital Equipment Corporation. The book builds on the concepts and topics presented in Writing Device Drivers: Tutorial, the core book for developing device drivers on Digital UNIX. This book introduces driver writers to topics specific to EISA/ISA buses and that are beyond the scope of the core tutorial. The book presents an example driver that operates on the EISA bus.

The book does not emphasize a specific type of device driver. However, mastering the concepts and examples presented in this book can prepare you for writing a variety of device drivers that operate on the EISA bus.

Organization

The book contains the following chapters and appendixes.

Chapter 1	Review of Device Driver Concepts
	Reviews general device driver concepts, which are discussed in detail in Writing Device Drivers: Tutorial.
Chapter 2	EISA/ISA Bus Architectures
	Discusses aspects of the EISA/ISA bus hardware and software architectures with which you must be familiar.
Chapter 3	Structure of EISA/ISA Bus Device Drivers
	Describes the sections that make up EISA/ISA bus device drivers.
Chapter 4	Data Structures for EISA/ISA Bus Device Drivers
	Discusses the data structures developed for use with EISA/ISA bus device drivers.
Chapter 5	The get_config Kernal Interface
	Discusses the kernel interfaces that EISA/ISA bus device drivers use.
Chapter 6	Device Autoconfiguration on EISA/ISA Buses
	Discusses the sequence of events that occurs during the autoconfiguration of devices that operate on EISA/ISA buses.
Chapter 7	EISA Bus Device Driver Example
	Describes the /dev/envram device driver, which operates on the EISA bus.
Chapter 8	EISA/ISA Bus Device Driver Configuration
	Describes the sysconfigtab entries that the driver needs to create so that it can be statically or dynamically configured.
Chapter 9	Writing an EISA Configuration File
	Describes how to write a configuration file, including examples of EISA and ISA configuration files.
Appendix A	EISA/ISA Bus-Specific Reference Information
	Describes, in reference-page style, the header file, data structures, kernel support interfaces, and device driver interfaces that are specific to EISA/ISA buses.
Appendix B	Configuration File Format
	Describes the format of a configuration file to define a hardware configuration for the EISA Configuration Utility (ECU).
Appendix C	EISA Bus Device Driver Source Listing
	Contains the source code listing for the /dev/envram example driver.
Appendix D	Summary Tables
	Presents tables that summarize the header files, kernel interfaces, data structures, and other interfaces that device drivers use.
Glossary	Defines terms related to EISA/ISA buses.

Related Documentation

The printed version of the Digital UNIX documentation set is color coded to help specific audiences quickly find the books that meet their needs. (You can order the printed documentation from Digital.) This color coding is reinforced with the use of an icon on the spines of books. The following list describes this convention:

Audience	Icon	Color Code
General users	G	Blue
System and network administrators	S	Red
Programmers	P	Purple
Device driver writers	D	Orange
Reference page users	R	Green

Some books in the documentation set help meet the needs of several audiences. For example, the information in some system books is also used by programmers. Keep this in mind when searching for information on specific topics.

The Documentation Overview, Glossary, and Master Index provides information on all of the books in the Digital UNIX documentation set.

Writing device drivers is a complex task; driver writers require knowledge in a variety of areas. One way to acquire this knowledge is to have at least the following categories of documentation available:

• Hardware documentation

• Bus-specific device driver documentation

• Operating system overview documentation

• Programming tools documentation

• System management documentation

• Porting documentation

• Reference pages

The following sections list the documentation associated with each of these categories. EISA bus device driver writers should also be familiar with the Extended Industry Standard Architecture Revision 3.10 specification. ISA bus device driver writers might also find this specification useful. This specification defines a high-performance, open-architecture bus available to personal computer (PC) manufacturers, expansion board vendors, software developers, and semiconductor suppliers.

Hardware Documentation

You should have available the hardware manual associated with the device for which you are writing the device driver. Also, you should have access to the manual that describes the architecture associated with the CPU that the driver operates on, for example, the Alpha Architecture Reference Manual.

Device Driver Documentation

The following documents contain information that pertains to writing any device driver:

• Writing Device Drivers: Tutorial

  This manual provides information for systems engineers who write device drivers for hardware that runs the Digital UNIX operating system. Systems engineers can find information on driver concepts, device driver interfaces, kernel interfaces used by device drivers, kernel data structures, configuration of device drivers, and header files related to device drivers.

• Writing Device Drivers: Reference

  This manual contains descriptions of the header files, kernel support interfaces, ioctl commands, global variables, data structures, device driver interfaces, and bus configuration interfaces associated with device drivers. The descriptions are formatted similarly to the Digital UNIX reference pages.

• Writing Device Drivers: Advanced Topics

  This manual provides information on topics that are beyond the scope of the core tutorial. Systems engineers can find information on such advanced topics as kernel threads and writing device drivers in a symmetric multiprocessing (SMP) environment. The manual also contains information about writing disk drivers.

The following books provide information about writing device drivers for a specific bus:

• Writing PCI Bus Device Drivers

  This manual provides information for systems engineers who write device drivers for the PCI bus. The manual describes PCI bus-specific topics, including PCI bus architecture and data structures that PCI bus device drivers use.

• Writing Device Drivers for the SCSI/CAM Architecture Interfaces

  This manual provides information for systems engineers who write device drivers for the SCSI/CAM Architecture interfaces.

  The manual provides an overview of the Digital UNIX SCSI/CAM Architecture and describes User Agent routines, data structures, common and generic routines and macros, error handling and debugging routines.

  The manual includes information on configuration and installation. Examples show how programmers can define SCSI/CAM device drivers and write to the SCSI/CAM special I/O interface supplied by Digital to process special SCSI I/O commands.

• Writing TURBOchannel Device Drivers

  This manual contains information systems engineers need to write device drivers that operate on the TURBOchannel bus. The manual describes TURBOchannel-specific topics, including TURBOchannel kernel interfaces that TURBOchannel device drivers use.

• Writing VMEbus Device Drivers

  This manual contains information systems engineers need to write device drivers that operate on the VMEbus. The manual describes VMEbus-specific topics, including VMEbus architecture and kernel interfaces that VMEbus device drivers use. A VMEbus device driver example illustrates the use of these kernel interfaces.

Operating System Overview Documentation

Refer to the Technical Overview for a technical introduction to the Digital UNIX operating system. This manual provides a technical overview of the Digital UNIX system, focusing on the networking subsystem, the file system, virtual memory, and the development environment. In addition, the manual lists all system limits.

This manual does not supersede the Software Product Description (SPD), which is the definitive description of the Digital UNIX system.

Programming Tools Documentation

To create your device drivers, you use a number of programming development tools and should have on hand the manuals that describe how to use these tools. The following manuals provide information related to programming tools used in the Digital UNIX operating system environment:

• Kernel Debugging

  This manual provides information about debugging kernels. The manual describes using the dbx, kdbx, and kdebug debuggers to find problems in kernel code. It also describes how to write a kdbx utility extension and how to create and analyze a crash dump file.

  This manual is for system administrators responsible for modifying, rebuilding, and debugging the kernel configuration. It is also for system programmers who need to debug their kernel space programs.

• Programming Support Tools

  This manual describes several commands and utilities in the Digital UNIX system, including facilities for text manipulation, macro and program generation, and source file management.

  The commands and utilities described in this manual are primarily for programmers, but some of them (such as grep, awk, sed, and the Source Code Control System (SCCS)) are useful for other users. This manual assumes that you are a moderately experienced user of UNIX systems.

• Programmer's Guide

  This manual describes the programming environment of the Digital UNIX operating system, with an emphasis on the C programming language.

  This manual is for all programmers who use the Digital UNIX operating system to create or maintain programs in any supported language.

System Management Documentation

Refer to the System Administration manual for information about building a kernel and for general information on system administration. This manual describes how to configure, use, and maintain the Digital UNIX operating system. It includes information on general day-to-day activities and tasks, changing your system configuration, and locating and eliminating sources of trouble.

This manual is for the system administrators responsible for managing the operating system. It assumes a knowledge of operating system concepts, commands, and configurations.

Porting Documentation

Refer to the Digital UNIX Migration Guide for information on migrating to Digital UNIX. This manual compares the Digital UNIX operating system to the ULTRIX operating system by describing the differences between the two systems.

This manual has three audiences, as follows:

• General users can read this manual to determine the differences between using an ULTRIX system and using the Digital UNIX system.

• System and network administrators can read this manual to determine the differences between ULTRIX and Digital UNIX system administration.

• Programmers can read this manual to determine the differences between the ULTRIX programming environment and the Digital UNIX programming environment.

This manual assumes you are familiar with the ULTRIX operating system.

Reference Pages

The following reference pages are of interest to device driver writers:

• Reference Pages Section 2

  This section defines system calls (entries into the Digital UNIX kernel) that programmers use. The introduction to Section 2, intro(2), lists error numbers with brief descriptions of their meanings. The introduction also defines many of the terms used in this section. This section is for programmers.

• Reference Pages Section 3

  This section describes the routines available in Digital UNIX programming libraries, including the C library, Motif library, and X library. This section is for programmers. In printed format, this section is divided into six volumes.

• Reference Pages Section 5

  Section 5 contains miscellaneous information, including ASCII character codes, mail-addressing formats, text-formatting macros, and a description of the root file system. This section is for programmers and system administrators.

• Reference Pages Section 7

  Section 7 describes special files, related device driver functions, databases, and network support. This section is for programmers and system administrators.

• Reference Pages Section 8 and 1m

  This section describes commands for system operation and maintenance. It is for system administrators. In printed format, this section is divided into two volumes.

Reader's Comments

Digital welcomes any comments and suggestions you have on this and other Digital UNIX manuals.

You can send your comments in the following ways:

• Fax: 603-881-0120 Attn: UEG Publications, ZK03-3/Y32

• Internet electronic mail: readers_comment@zk3.dec.com

  A Reader's Comment form is located on your system in the following location:

  /usr/doc/readers_comment.txt
  

• Mail:

  Digital Equipment Corporation
  UEG Publications Manager
  ZK03-3/Y32
  110 Spit Brook Road
  Nashua, NH 03062-9987

  A Reader's Comment form is located in the back of each printed manual. The form is postage paid if you mail it in the United States.

Please include the following information along with your comments:

• The full title of the book and the order number. (The order number is printed on the title page of this book and on its back cover.)

• The section numbers and page numbers of the information on which you are commenting.

• The version of Digital UNIX that you are using.

• If known, the type of processor that is running the Digital UNIX software.

The Digital UNIX Publications group cannot respond to system problems or technical support inquiries. Please address technical questions to your local system vendor or to the appropriate Digital technical support office. Information provided with the software media explains how to send problem reports to Digital.

Conventions

This book uses the following conventions:

. . .	A vertical ellipsis indicates that a portion of an example that would normally be present is not shown.
filename	In examples and function definitions, this typeface indicates variable values.
get_config	In examples and function definitions, this typeface indicates names that you must type exactly as shown.
BOARD	In syntax definitions, this typeface indicates keywords that you must type exactly as shown.
identifier	In syntax definitions, this typeface indicates variables.
[ ]	In formal parameter declarations, brackets indicate arrays. Brackets can also specify ranges, as for device minor numbers and device special files in file fragments. In syntax definitions, brackets indicate items that are optional.
. . .	In syntax definitions, a horizontal ellipsis indicates that the preceding item can be repeated one or more times.
{ | }	In syntax definitions, vertical bars separating items that appear between braces indicate that you choose one item from among those listed.

This book uses the word kernel ``interface'' instead of kernel ``routine'' or kernel ``macro'' because, from the driver writer's point of view, it does not matter whether the interface is a routine or a macro.