About This Book

This book discusses topics associated with writing drivers for devices that operate on the Peripheral Component Interconnect (PCI) Local Bus in the Digital UNIX® operating system.

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 Digital 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
Are familiar with the contents of PCI Local Bus Specification Revision 2.1, especially Chapter 6 ("Configuration Space")

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

Although existing device drivers are binary compatible with the current version of Digital UNIX, you may want to take advantage of the single binary module technology. 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.

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.

Scope of the Book

The book is directed towards 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 the Digital UNIX operating system. This book introduces driver writers to topics specific to the PCI bus and that are beyond the scope of the core tutorial. The book presents an example driver that operates on the PCI bus.

The book does not emphasize any specific types of device drivers. However, mastering the concepts and examples presented in this book would be useful preparation for writing a variety of device drivers that operate on the PCI bus.

Organization

This book contains the following chapters and appendixes:

Chapter 1 Review of Device Driver Concepts

Reviews general device driver concepts that are discussed in detail in Writing Device Drivers: Tutorial.

Chapter 2 PCI Bus Architectures

Discusses aspects of the PCI bus hardware and software architectures that may influence the way in which you design a PCI bus device driver.

Chapter 3 Structure of a PCI Bus Device Driver

Describes the sections that make up a PCI bus device driver.

Chapter 4 Data Structures That PCI Bus Device Drivers Use

Discusses the data structures developed for use with PCI bus device drivers.

Chapter 5 Device Configuration on the PCI Bus

Discusses the sequence of events that occurs during the configuration of devices that operate on the PCI bus.

Chapter 6 PCI Bus Device Driver Example

Describes how to code a character device driver for a real device that operates on the PCI bus.

Appendix A PCI Bus-Specific Reference Information

Presents, in reference page style, descriptions of the header file, data structures, kernel support interfaces, and device driver interfaces that are specific to the PCI bus.

Appendix B PCI Bus Device Driver Source Listing

Contains the source code listing for the example driver presented in this book.

Appendix C Summary Tables

Presents tables that summarize the header files, kernel interfaces, data structures, and other interfaces that device drivers use.

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
Programming tools documentation
System management documentation
Porting documentation
Reference pages

The following sections list the documentation associated with each of these categories. PCI bus device driver writers should also be familiar with PCI Local Bus Specification Revision 2.1. An acquaintance with PCI to PCI Bridge Architecture Specification may also be helpful. To obtain copies of these documents, contact the PCI Special Interest Group at the following address:

PCI Special Interest Group
P.O. Box 14070
Portland, OR 97214 USA

(800) 433-5177 (U.S)
(503) 797-4297 (International)
(503) 234-6762 (FAX)

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.

Bus-Specific Device Driver Documentation

Writing Device Drivers: Tutorial is the core manual for developing device drivers on the Digital UNIX operating system. It contains information needed for developing drivers on any bus that operates on Digital platforms. Writing Device Drivers: Advanced Topics and Writing Device Drivers: Reference are companion volumes to the tutorial.

Writing Device Drivers: Advanced Topics describes 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.

Writing Device Drivers: Reference describes, in reference page style, the header files, kernel interfaces, data structures, and other interfaces that device drivers use.

The following books provide information about writing device drivers for a specific bus that is beyond the scope of the core tutorial, advanced topics, and reference:

Writing EISA and ISA Bus Device Drivers
This manual provides information for systems engineers who write device drivers for the EISA/ISA bus. The manual describes EISA/ISA bus-specific topics, including EISA/ISA bus architecture and data structures that EISA/ISA 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.

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 a discussion of the differences between the Digital UNIX and ULTRIX operating systems.

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 the reader is 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 4
This section describes the format of system files and how the files are used. The files described include assembler and link editor output, system accounting, and file system formats. This section is for programmers and system administrators. In printed format, this section is divided into two volumes.
Reference Pages Section 5
This section 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
This section 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.

. . . In syntax definitions, a horizontal ellipsis indicates that the preceding item can be repeated one or more times.

filename In examples, syntax descriptions, and function definitions, this typeface indicates variable values.

buf In function definitions and syntax definitions used in driver configuration, this typeface is used to indicate names that you must type exactly as shown.

[ ] In formal parameter declarations in function definitions and in structure declarations, brackets indicate arrays. Brackets are also used to specify ranges for device minor numbers and device special files in file fragments. However, for the syntax definitions used in driver configuration, these brackets indicate items that are optional.

| Vertical bars separating items that appear in the syntax definitions used in driver configuration 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.

Chapter 1	Review of Device Driver Concepts
	Reviews general device driver concepts that are discussed in detail in Writing Device Drivers: Tutorial.
Chapter 2	PCI Bus Architectures
	Discusses aspects of the PCI bus hardware and software architectures that may influence the way in which you design a PCI bus device driver.
Chapter 3	Structure of a PCI Bus Device Driver
	Describes the sections that make up a PCI bus device driver.
Chapter 4	Data Structures That PCI Bus Device Drivers Use
	Discusses the data structures developed for use with PCI bus device drivers.
Chapter 5	Device Configuration on the PCI Bus
	Discusses the sequence of events that occurs during the configuration of devices that operate on the PCI bus.
Chapter 6	PCI Bus Device Driver Example
	Describes how to code a character device driver for a real device that operates on the PCI bus.
Appendix A	PCI Bus-Specific Reference Information
	Presents, in reference page style, descriptions of the header file, data structures, kernel support interfaces, and device driver interfaces that are specific to the PCI bus.
Appendix B	PCI Bus Device Driver Source Listing
	Contains the source code listing for the example driver presented in this book.
Appendix C	Summary Tables
	Presents tables that summarize the header files, kernel interfaces, data structures, and other interfaces that device drivers use.

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

. . .	A vertical ellipsis indicates that a portion of an example that would normally be present is not shown.
. . .	In syntax definitions, a horizontal ellipsis indicates that the preceding item can be repeated one or more times.
`filename`	In examples, syntax descriptions, and function definitions, this typeface indicates variable values.
buf	In function definitions and syntax definitions used in driver configuration, this typeface is used to indicate names that you must type exactly as shown.
[ ]	In formal parameter declarations in function definitions and in structure declarations, brackets indicate arrays. Brackets are also used to specify ranges for device minor numbers and device special files in file fragments. However, for the syntax definitions used in driver configuration, these brackets indicate items that are optional.
\|	Vertical bars separating items that appear in the syntax definitions used in driver configuration indicate that you choose one item from among those listed.