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Writing Device Drivers     Oracle Solaris 11.1 Information Library
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Document Information

Preface

Part I Designing Device Drivers for the Oracle Solaris Platform

1.  Overview of Oracle Solaris Device Drivers

2.  Oracle Solaris Kernel and Device Tree

3.  Multithreading

4.  Properties

5.  Managing Events and Queueing Tasks

6.  Driver Autoconfiguration

7.  Device Access: Programmed I/O

8.  Interrupt Handlers

9.  Direct Memory Access (DMA)

10.  Mapping Device and Kernel Memory

11.  Device Context Management

12.  Power Management

13.  Hardening Oracle Solaris Drivers

14.  Layered Driver Interface (LDI)

Part II Designing Specific Kinds of Device Drivers

15.  Drivers for Character Devices

16.  Drivers for Block Devices

17.  SCSI Target Drivers

18.  SCSI Host Bus Adapter Drivers

19.  Drivers for Network Devices

20.  USB Drivers

21.  SR-IOV Drivers

Part III Building a Device Driver

22.  Compiling, Loading, Packaging, and Testing Drivers

23.  Debugging, Testing, and Tuning Device Drivers

24.  Recommended Coding Practices

Part IV Appendixes

A.  Hardware Overview

SPARC Processor Issues

SPARC Data Alignment

Member Alignment in SPARC Structures

SPARC Byte Ordering

SPARC Register Windows

SPARC Multiply and Divide Instructions

x86 Processor Issues

x86 Byte Ordering

x86 Architecture Manuals

Endianness

Store Buffers

System Memory Model

Total Store Ordering (TSO)

Partial Store Ordering (PSO)

Bus Architectures

Device Identification

Supported Interrupt Types

Bus Specifics

PCI Local Bus

PCI Address Domain

PCI Configuration Address Space

PCI Configuration Base Address Registers

PCI Memory Address Space

PCI I/O Address Space

PCI Hardware Configuration Files

PCI Express

SBus

SBus Physical Address Space

Physical SBus Addresses

SBus Hardware Configuration Files

Device Issues

Timing-Critical Sections

Delays

Internal Sequencing Logic

Interrupt Issues

PROM on SPARC Machines

Open Boot PROM 3

Forth Commands

Walking the PROMs Device Tree

Mapping the Device

Reading and Writing

B.  Summary of Oracle Solaris DDI/DKI Services

C.  Making a Device Driver 64-Bit Ready

D.  Console Frame Buffer Drivers

E.  pci.conf File

Index

Endianness

To achieve the goal of multiple-platform, multiple-instruction-set architecture portability, host bus dependencies were removed from the drivers. The first dependency issue to be addressed was the endianness, that is, byte ordering, of the processor. For example, the x86 processor family is little-endian while the SPARC architecture is big-endian.

Bus architectures display the same endianness types as processors. The PCI local bus, for example, is little-endian, the SBus is big-endian, the ISA bus is little-endian, and so on.

To maintain portability between processors and buses, DDI-compliant drivers must be endian neutral. Although drivers can manage their endianness by runtime checks or by preprocessor directives like #ifdef _LITTLE_ENDIAN in the source code, long-term maintenance can be troublesome. In some cases, the DDI framework performs the byte swapping using a software approach. In other cases, byte swapping can be done by hardware page-level swapping as in memory management unit (MMU) or by special machine instructions. The DDI framework can take advantage of the hardware features to improve performance.

Figure A-1 Byte Ordering Required for Host Bus Dependency

image:Diagram shows byte swapping to reverse endianness.

Along with being endian-neutral, portable drivers must also be independent from data ordering of the processor. Under most circumstances, data must be transferred in the sequence instructed by the driver. However, sometimes data can be merged, batched, or reordered to streamline the data transfer, as illustrated in the following figure. For example, data merging can be applied to accelerate graphics display on frame buffers. Drivers have the option to advise the DDI framework to use other optimal data transfer mechanisms during the transfer.

Figure A-2 Data Ordering Host Bus Dependency

image:Diagram shows reordering of bytes by CPU.