Chapter 1��Introduction 1 Evolution 2 The GNU Copyleft 3 Kernel.org 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 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