Essential Linux Device Drivers (Hardcover)

Description

 

“Probably the most wide ranging and complete Linux device driver book I’ve read.”

--Alan Cox, Linux Guru and Key Kernel Developer

 

“Very comprehensive and detailed, covering almost every single Linux device driver type.”

--Theodore Ts’o, First Linux Kernel Developer in North America and Chief Platform Strategist of the Linux Foundation

 

The Most Practical Guide to Writing Linux Device Drivers

Linux now offers an exceptionally robust environment for driver development: with today’s kernels, what once required years of development time can be accomplished in days. In this practical, example-driven book, one of the world’s most experienced Linux driver developers systematically demonstrates how to develop reliable Linux drivers for virtually any device. Essential Linux Device Drivers is for any programmer with a working knowledge of operating systems and C, including programmers who have never written drivers before. Sreekrishnan Venkateswaran focuses on the essentials, bringing together all the concepts and techniques you need, while avoiding topics that only matter in highly specialized situations. Venkateswaran begins by reviewing the Linux 2.6 kernel capabilities that are most relevant to driver developers. He introduces simple device classes; then turns to serial buses such as I2C and SPI; external buses such as PCMCIA, PCI, and USB; video, audio, block, network, and wireless device drivers; user-space drivers; and drivers for embedded Linux–one of today’s fastest growing areas of Linux development. For each, Venkateswaran explains the technology, inspects relevant kernel source files, and walks through developing a complete example.

 

• Addresses drivers discussed in no other book, including drivers for I2C, video, sound, PCMCIA, and different types of flash memory

• Demystifies essential kernel services and facilities, including kernel threads and helper interfaces

• Teaches polling, asynchronous notification, and I/O control

• Introduces the Inter-Integrated Circuit Protocol for embedded Linux drivers

• Covers multimedia device drivers using the Linux-Video subsystem and Linux-Audio framework

• Shows how Linux implements support for wireless technologies such as Bluetooth, Infrared, WiFi, and cellular networking

• Describes the entire driver development lifecycle, through debugging and maintenance

• Includes reference appendixes covering Linux assembly, BIOS calls, and Seq files

Table of Contents

Foreword xxi

Preface xxiii

Acknowledgments  xxix

About the Author  xxx

Chapter 1 Introduction 1

Evolution  2

The GNU Copyleft  3

Kernelorg  4

Mailing Lists and Forums  4

Linux Distributions  5

Looking at the Sources  6

Building the Kernel  10

Loadable Modules  12

Before Starting  14

Chapter 2 A Peek Inside the Kernel 17

Booting Up  18

Kernel Mode and User Mode  30

Process Context and Interrupt Context  30

Kernel Timers  31

HZ and Jiffies  31

Long Delays  33

Short Delays  36

Pentium Time Stamp Counter  36

Real Time Clock  37

Concurrency in the Kernel  39

Spinlocks and Mutexes  39

Atomic Operators  45

Reader-Writer Locks  46

Debugging  48

Process Filesystem  49

Allocating Memory  49

Looking at the Sources  52

Chapter 3 Kernel Facilities 55

Kernel Threads  56

Creating a Kernel Thread  56

Process States and Wait Queues  61

User Mode Helpers  63

Helper Interfaces  65

Linked Lists  65

Hash Lists  72

Work Queues  72

Notifier Chains  74

Completion Interface  78

Kthread Helpers  81

Error-Handling Aids  83

Looking at the Sources  85

Chapter 4 Laying the Groundwork 89

Introducing Devices and Drivers  90

Interrupt Handling  92

Interrupt Context  92

Assigning IRQs  94

Device Example: Roller Wheel  94

Softirqs and Tasklets  99

The Linux Device Model  103

Udev  103

Sysfs, Kobjects, and Device Classes  106

Hotplug and Coldplug  110

Microcode Download  111

Module Autoload  112

Memory Barriers  114

Power Management  114

Looking at the Sources  115

Chapter 5 Character Drivers 119

Char Driver Basics  120

Device Example: System CMOS  121

Driver Initialization  122

Open and Release  127

Exchanging Data  129

Seek  136

Control  137

Sensing Data Availability  139

Poll  139

Fasync  142

Talking to the Parallel Port  145

Device Example: Parallel Port LED Board  146

RTC Subsystem  156

Pseudo Char Drivers  157

Misc Drivers  160

Device Example: Watchdog Timer  160

Character Caveats  166

Looking at the Sources  167

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Chapter 6 Serial Drivers 171

Layered Architecture  173

UART Drivers  176

Device Example: Cell Phone  178

RS-485  191

TTY Drivers  192

Line Disciplines  194

Device Example: Touch Controller  195

Looking at the Sources  205

Chapter 7 Input Drivers 207

Input Event Drivers  210

The Evdev Interface  210

Input Device Drivers  216

Serio  217

Keyboards  217

Mice  220

Touch Controllers  227

Accelerometers  228

Output Events  228

Debugging  230

Looking at the Sources  231

Chapter 8 The Inter-Integrated Circuit Protocol 233

What’s I2C/SMBus?  234

I2C Core  235

Bus Transactions  237

Device Example: EEPROM  238

Initializing  238

Probing the Device  241

Checking Adapter Capabilities  244

Accessing the Device  244

More Methods  246

Device Example: Real Time Clock  247

I2C-dev  251

Hardware Monitoring Using LM-Sensors  251

The Serial Peripheral Interface Bus  251

The 1-Wire Bus  254

Debugging  254

Looking at the Sources  255

Chapter 9 PCMCIA and Compact Flash 257

What’s PCMCIA/CF?  258

Linux-PCMCIA Subsystem  260

Host Controller Drivers  262

PCMCIA Core  263

Driver Services  263

Client Drivers  264

Data Structures  264

Device Example: PCMCIA Card  267

Tying the Pieces Together  271

PCMCIA Storage  272

Serial PCMCIA  272

Debugging  273

Looking at the Sources  275

Chapter 10 Peripheral Component Interconnect 277

The PCI Family  278

Addressing and Identification  281

Accessing PCI Regions  285

Configuration Space  285

I/O and Memory  286

Direct Memory Access  288

Device Example: Ethernet-Modem Card  292

Initializing and Probing  293

Data Transfer  301

Debugging  308

Looking at the Sources  308

Chapter 11 Universal Serial Bus 311

USB Architecture  312

Bus Speeds  314

Host Controllers  315

Transfer Types  315

Addressing  316

Linux-USB Subsystem  317

Driver Data Structures  317

The usb_device Structure  318

USB Request Blocks  319

Pipes  321

Descriptor Structures  322

Enumeration  324

Device Example: Telemetry Card  324

Initializing and Probing  325

Accessing Registers  332

Data Transfer  335

Class Drivers  338

Mass Storage  339

USB-Serial  345

Human Interface Devices  348

Bluetooth  348

Gadget Drivers  348

Debugging  349

Looking at the Sources  351

Chapter 12 Video Drivers 355

Display Architecture  356

Linux-Video Subsystem  359

Display Parameters  361

The Frame Buffer API  362

Frame Buffer Drivers  365

Device Example: Navigation System  365

Console Drivers  380

Device Example: Cell Phone Revisited  382

Boot Logo  387

Debugging  387

Looking at the Sources  388

Chapter 13 Audio Drivers 391

Audio Architecture  392

Linux-Sound Subsystem  394

Device Example: MP3 Player  396

Driver Methods and Structures  399

ALSA Programming  409

Debugging  412

Looking at the Sources  412

Chapter 14 Block Drivers 415

Storage Technologies  416

Linux Block I/O Layer  421

I/O Schedulers  422

Block Driver Data Structures and Methods  423

Device Example: Simple Storage Controller  426

Initialization  427

Block Device Operations  430

Disk Access  432

Advanced Topics  434

Debugging  436

Looking at the Sources  437

Chapter 15 Network Interface Cards 439

Driver Data Structures  440

Socket Buffers  441

The Net Device Interface  443

Activation  444

Data Transfer  444

Watchdog  445

Statistics  445

Configuration  446

Bus Specific  448

Talking with Protocol Layers  448

Receive Path  448

Transmit Path  449

Flow Control  449

Buffer Management and Concurrency Control  450

Device Example: Ethernet NIC  451

ISA Network Drivers  457

Asynchronous Transfer Mode  458

Network Throughput  459

Driver Performance  459

Protocol Performance  461

Looking at the Sources  461

Chapter 16 Linux Without Wires 465

Bluetooth  467

BlueZ  469

Device Example: CF Card  471

Device Example: USB Adapter  471

RFCOMM  473

Networking  475

Human Interface Devices  477

Audio  477

Debugging  478

Looking at the Sources  478

Infrared  478

Linux-IrDA  480

Device Example: Super I/O Chip  482

Device Example: IR Dongle  483

IrComm  486

Networking  486

IrDA Sockets  487

Linux Infrared Remote Control  488

Looking at the Sources  489

WiFi  489

Configuration  490

Device Drivers  494

Looking at the Sources  496

Cellular Networking  496

GPRS  496

CDMA  498

Current Trends  500

Chapter 17 Memory Technology Devices 503

What’s Flash Memory?  504

Linux-MTD Subsystem  505

Map Drivers  506

Device Example: Handheld  506

NOR Chip Drivers  511

NAND Chip Drivers  513

User Modules  516

Block Device Emulation  516

Char Device Emulation  517

JFFS2  517

YAFFS2  518

MTD-Utils  518

Configuring MTD  519

eXecute In Place  520

The Firmware Hub  520

Debugging  524

Looking at the Sources  524

Chapter 18 Embedding Linux 527

Challenges  528

Component Selection  530

Tool Chains  531

Embedded Bootloaders  531

Memory Layout  535

Kernel Porting  537

Embedded Drivers  538

Flash Memory  538

UART  539

Buttons and Wheels  539

PCMCIA/CF  540

SD/MMC  540

USB  540

RTC  541

Audio  541

Touch Screen  541

Video  541

CPLD/FPGA  542

Connectivity  542

Domain-Specific Electronics  542

More Drivers  543

The Root Filesystem  544

NFS-Mounted Root  544

Compact Middleware  546

Test Infrastructure  548

Debugging  548

Board Rework  549

Debuggers  550

Chapter 19 Drivers in User Space 551

Process Scheduling and Response Times  553

The Original Scheduler  553

The O(1) Scheduler  553

The CFS Scheduler  555

Response Times  555

Accessing I/O Regions  558

Accessing Memory Regions  562

User Mode SCSI  565

User Mode USB  567

User Mode I2C  571

UIO  573

Looking at the Sources  574

Chapter 20 More Devices and Drivers 577

ECC Reporting  578

Device Example: ECC-Aware Memory Controller  579

Frequency Scaling  583

Embedded Controllers  584

ACPI  585

ISA and MCA  587

FireWire  588

Intelligent Input/Output  589

Amateur Radio  590

Voice over IP  590

High-Speed Interconnects  591

InfiniBand  592

RapidIO  592

Fibre Channel  592

iSCSI  593

Chapter 21 Debugging Device Drivers 595

Kernel Debuggers  596

Entering a Debugger  597

Kernel Debugger (kdb)  598

Kernel GNU Debugger (kgdb)  600

GNU Debugger (gdb)  604

JTAG Debuggers  605

Downloads  609

Kernel Probes  609

Kprobes  609

Jprobes  614

Return Probes  617

Limitations  619

Looking at the Sources  620

Kexec and Kdump  620

Kexec  620

Kexec with Kdump  621

Kdump  622

Looking at the Sources  629

Profiling  629

Kernel Profiling with OProfile  629

Application Profiling with Gprof  633

Tracing  634

Linux Trace Toolkit  634

Linux Test Project  638

User Mode Linux  638

Diagnostic Tools  638

Kernel Hacking Config Options  639

Test Equipment  640

Chapter 22 Maintenance and Delivery 641

Coding Style  642

Change Markers  642

Version Control  643

Consistent Checksums  643

Build Scripts  645

Portable Code  647

Chapter 23 Shutting Down 649

Checklist  650

What Next?  651

Appendix A Linux Assembly 653

Debugging  659

Appendix B Linux and the BIOS 661

Real Mode Calls  662

Protected Mode Calls  665

BIOS and Legacy Drivers  666

Appendix C Seq Files 669

The Seq File Advantage  670

Updating the NVRAM Driver  677

Looking at the Sources  679

Index  681