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Writing Device Drivers
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Part I Designing Device Drivers for the Solaris Platform

1.  Overview of Solaris Device Drivers

2.  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 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

Part III Building a Device Driver

21.  Compiling, Loading, Packaging, and Testing Drivers

22.  Debugging, Testing, and Tuning Device Drivers

23.  Recommended Coding Practices

Part IV Appendixes

A.  Hardware Overview

B.  Summary of Solaris DDI/DKI Services

C.  Making a Device Driver 64-Bit Ready

D.  Console Frame Buffer Drivers

Solaris Consoles and the Kernel Terminal Emulator

x86 Platform Console Communication

SPARC Platform Console Communication

Console Visual I/O Interfaces

I/O Control Interfaces

Polled I/O Interfaces

Video Mode Change Callback Interface

Implementing the Visual I/O Interfaces in Console Frame Buffer Drivers








Implementing Polled I/O in Console Frame Buffer Drivers

Frame Buffer Specific Configuration Module

The X Window System Frame Buffer Specific DDX Module

Developing, Testing, and Debugging Console Frame Buffer Drivers

Testing the I/O Control Interfaces

Testing the Polled I/O Interfaces

Testing the Video Mode Change Callback Function

Additional Suggestions for Testing Console Frame Buffer Drivers


Solaris Consoles and the Kernel Terminal Emulator

The role of the kernel terminal emulator is to render text onto the console frame buffer in the proper position and representation determined by the frame buffer's screen height, width, and pixel depth mode. The terminal emulator also drives scrolling, controls a software cursor, and interprets ANSI terminal escape sequences. The terminal emulator accesses the console frame buffer in either VGA text mode or pixel mode, depending upon the graphics card. To be used as a Solaris console frame buffer driver, your frame buffer driver must be compatible with the Solaris kernel terminal emulator. The target platform is the most significant factor that determines whether you need to modify your frame buffer driver to make your driver compatible with the Solaris kernel terminal emulator.

x86 Platform Console Communication

On x86 platforms, the Solaris kernel terminal emulator module (tem) uses VGA text mode exclusively to interact with the vgatext module. The vgatext module uses industry standard VGA text mode to interact with x86 compatible frame buffer devices. Because the vgatext module already supports the console frame buffer interfaces, x86 frame buffer drivers are compatible with the kernel tem module. You do not need to add special interfaces to x86 frame buffer drivers.

The remainder of this appendix applies to SPARC platforms only.

SPARC Platform Console Communication

SPARC frame buffer drivers typically do not operate in VGA text mode. SPARC frame buffer drivers typically are required to send pixel patterns that depict the text and images displayed. The kernel tem requires SPARC drivers to support specific interfaces to facilitate rendering data to the screen, perform scrolling, and display a text cursor. How the driver actually renders data sent from the tem onto the screen depends on the device. The driver typically draws the data into video memory according to the hardware and video mode.

The Solaris OS provides interfaces that enable the kernel terminal emulator to drive compatible console frame buffers directly. The advantages of converting a driver to be compatible with the kernel terminal emulator are:

SPARC console frame buffer drivers are not required to be compatible with the kernel terminal emulator. If the console frame buffer driver is not compatible with the kernel terminal emulator, the system uses the FCode terminal emulator in the OpenBoot PROM.

The console frame buffer is identified through the EEPROM screen environment variable. The system determines whether the console frame buffer is compatible with the kernel terminal emulator module by checking whether the frame buffer driver exports the tem-support DDI property. If the tem-support property is exported, then the system issues the VIS_DEVINIT I/O control (ioctl) command to the frame buffer driver during system boot, while configuring the console. If the tem-support DDI property is exported and the VIS_DEVINIT ioctl command succeeds and returns a compatible version number to the tem, the system configures the system console to utilize that frame buffer driver through the kernel terminal emulator. See the ioctl(9E) man page for information about the I/O control driver entry point.

SPARC drivers that support the kernel terminal emulator should export the tem-support DDI property. This property indicates that the driver supports the kernel terminal emulator. If a frame buffer driver exports the tem-support DDI property, then that driver will be handled early in the boot process, while the console is being configured. If a frame buffer driver does not export the tem-support property, then that driver might not be handled early enough in the boot process.


When set to 1, this DDI property indicates that this driver is compatible with the console kernel frame buffer interface.

The kernel terminal emulator module interacts with the console frame buffer driver through two major interfaces:

The following section provides detailed information.