FreeBSD Device Drivers by Kong, Joseph -- Read -- Imperial Library of Trantor

Index

FreeBSD Device Drivers About the Technical Reviewer Foreword Acknowledgments Introduction

Who Is This Book For? Prerequisites Contents at a Glance Welcome Aboard!

1. Building and Running Modules

Types of Device Drivers Loadable Kernel Modules

Module Event Handler DECLARE_MODULE Macro

name data sub order

Hello, world! Compiling and Loading Character Drivers

d_foo Functions Character Device Switch Table make_dev and destroy_dev Functions

Mostly Harmless

echo_write Function echo_read Function echo_modevent Function DEV_MODULE Macro Don’t Panic

Block Drivers Are Gone Conclusion

2. Allocating Memory

Memory Management Routines malloc_type Structures

MALLOC_DEFINE Macro MALLOC_DECLARE Macro

Tying Everything Together Contiguous Physical Memory Management Routines A Straightforward Example Conclusion

3. Device Communication and Control

ioctl Defining ioctl Commands Implementing ioctl

echo_write Function echo_set_buffer_size Function echo_ioctl Function echo_modevent Function Don’t Panic

Invoking ioctl sysctl Implementing sysctls, Part 1 sysctl Context Management Routines Creating Dynamic sysctls

SYSCTL_STATIC_CHILDREN Macro SYSCTL_CHILDREN Macro

Implementing sysctls, Part 2

sysctl_set_buffer_size Function Don’t Panic

Conclusion

4. Thread Synchronization

A Simple Synchronization Problem A More Complex Synchronization Problem

race_new Function race_find Function race_destroy Function race_ioctl Function race_modevent Function The Root of the Problem

Preventing Race Conditions Mutexes

Spin Mutexes Sleep Mutexes

Mutex Management Routines Implementing Mutexes

race_modevent Function Don’t Panic

Shared/Exclusive Locks Shared/Exclusive Lock Management Routines Implementing Shared/Exclusive Locks Reader/Writer Locks Reader/Writer Lock Management Routines Condition Variables Condition Variable Management Routines General Guidelines

Avoid Recursing on Exclusive Locks Avoid Holding Exclusive Locks for Long Periods of Time

Conclusion

5. Delaying Execution

Voluntary Context Switching, or Sleeping Implementing Sleeps and Condition Variables

sleep_modevent Function load Function sleep_thread Function sysctl_debug_sleep_test Function unload Function Don’t Panic

Kernel Event Handlers Callouts Callouts and Race Conditions Taskqueues

Global Taskqueues Taskqueue Management Routines

Conclusion

6. Case Study: Virtual Null Modem

Prerequisites Code Analysis

nmdm_modevent Function nmdm_clone Function nmdm_alloc Function nmdm_outwakeup Function nmdm_task_tty Function nmdm_inwakeup Function nmdm_modem Function nmdm_param Function nmdm_timeout Function bits_per_char Function Don’t Panic

Conclusion

7. Newbus and Resource Allocation

Autoconfiguration and Newbus Drivers

device_foo Functions Device Method Table DRIVER_MODULE Macro

name busname driver devclass evh arg

Tying Everything Together

foo_pci_probe Function foo_pci_attach Function d_foo Functions foo_pci_detach Function Don’t Panic

Hardware Resource Management Conclusion

8. Interrupt Handling

Registering an Interrupt Handler Interrupt Handlers in FreeBSD Implementing an Interrupt Handler

pint_identify Function pint_probe Function pint_attach Function pint_detach Function pint_open Function pint_close Function pint_write Function pint_read Function pint_intr Function Don’t Panic

Generating Interrupts on the Parallel Port Conclusion

9. Case Study: Parallel Port Printer Driver

Code Analysis

lpt_identify Function lpt_probe Function lpt_detect Function lpt_port_test Function lpt_attach Function lpt_detach Function lpt_open Function lpt_read Function lpt_write Function lpt_intr Function lpt_timeout Function lpt_push_bytes Function lpt_close Function lpt_ioctl Function lpt_request_ppbus Function lpt_release_ppbus Function

Conclusion

10. Managing and Using Resources

I/O Ports and I/O Memory

Reading from I/O Ports and I/O Memory Writing to I/O Ports and I/O Memory Stream Operations

Memory Barriers Tying Everything Together

led_identify Function led_probe Function led_attach Function led_detach Function led_open Function led_close Function led_read Function led_write Function

Conclusion

11. Case Study: Intelligent Platform Management Interface Driver

Code Analysis

ipmi_pci_probe Function ipmi_pci_match Function ipmi_pci_attach Function ipmi2_pci_probe Function ipmi2_pci_attach Function

Conclusion

12. Direct Memory Access

Implementing DMA

Initiating a DMA Data Transfer Dismantling DMA

Creating DMA Tags Tearing Down DMA Tags DMA Map Management Routines, Part 1 Loading (DMA) Buffers into DMA Maps

bus_dma_segment Structures bus_dmamap_load Function bus_dmamap_load_mbuf Function bus_dmamap_load_mbuf_sg Function bus_dmamap_load_uio Function bus_dmamap_unload Function

DMA Map Management Routines, Part 2 A Straightforward Example Synchronizing DMA Buffers Conclusion

13. Storage Drivers

disk Structures

Descriptive Fields Storage Device Methods Mandatory Media Properties Optional Media Properties Driver Private Data

disk Structure Management Routines Block I/O Structures Block I/O Queues Tying Everything Together

at45d_attach Function at45d_delayed_attach Function at45d_get_info Function at45d_wait_for_device_ready Function at45d_get_status Function at45d_strategy Function at45d_task Function

Block I/O Completion Routines Conclusion

14. Common Access Method

How CAM Works A (Somewhat) Simple Example

mfip_attach Function mfip_detach Function mfip_action Function mfip_poll Function mfip_start Function mfip_done Function

SIM Registration Routines

cam_simq_alloc Function cam_sim_alloc Function xpt_bus_register Function

Action Routines

XPT_PATH_INQ XPT_RESET_BUS XPT_GET_TRAN_SETTINGS XPT_SET_TRAN_SETTINGS XPT_SCSI_IO XPT_RESET_DEV

Conclusion

15. USB Drivers

About USB Devices More About USB Devices USB Configuration Structures

Mandatory Fields Optional Fields USB Transfer Flags

USB Transfers (in FreeBSD) USB Configuration Structure Management Routines USB Methods Structure Tying Everything Together

ulpt_probe Function ulpt_attach Function ulpt_detach Function ulpt_open Function ulpt_reset Function unlpt_open Function ulpt_close Function ulpt_ioctl Function ulpt_watchdog Function ulpt_start_read Function ulpt_stop_read Function ulpt_start_write Function ulpt_stop_write Function ulpt_write_callback Function ulpt_read_callback Function ulpt_status_callback Function

Conclusion

16. Network Drivers, Part 1: Data Structures

Network Interface Structures Network Interface Structure Management Routines

ether_ifattach Function ether_ifdetach Function

Network Interface Media Structures Network Interface Media Structure Management Routines Hello, world! mbuf Structures Message Signaled Interrupts Implementing MSI MSI Management Routines Conclusion

17. Network Drivers, Part 2: Packet Reception and Transmission

Packet Reception

em_rxeof Function em_handle_rx Function

Packet Transmission

em_start_locked Function em_txeof Function

Post Packet Transmission Conclusion

References Index About the Author Colophon A. UPDATES

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