5.2. Writing the Device Driver Without DriverWizard

There may be times when you choose to write your driver directly, without using DriverWizard. In such cases, either follow the steps outlined in this section to create a new driver project, or select a WinDriver sample that most closely resembles your target driver and modify it to suit your specific requirements.

5.2.1. Include the Required WinDriver Files

  1. Include the relevant WinDriver header files in your driver project.
    All header files are found under the WinDriver/include directory.

    All WinDriver projects require the windrvr.h header file.
    When using the WDC_xxx API [B.2], include the wdc_lib.h and wdc_defs. header files (these files already include windrvr.h).

    Include any other header file that provides APIs that you wish to use from your code (e.g., files from the WinDriver/samples/shared directory, which provide convenient diagnostics functions.)

  2. Include the relevant header files from your source code: For example, to use API from the windrvr.h header file, add the following line to the code:
    #include "windrvr.h"
  3. Link your code with the WDAPI library (Windows) / shared object (Linux):
    • For Windows: WinDriver\lib\<CPU>\wdapi1411.lib, where the <CPU> directory is either x86 (32-bit binaries for x86 platforms), amd64 (64-bit binaries for x64 platforms), or amd64\x86 (32-bit binaries for x64 platforms [A.2]
    • For Linux: From the WinDriver/lib directory — libwdapi1411.so or libwdapi1411_32.so (for 32-bit applications targeted at 64-bit platforms)
      Note: When using libwdapi1411_32.so, first create a copy of this file in a different directory and rename it to libwdapi1411.so, then link your code with the renamed file [A.2].

    You can also include the library's source files in your project instead of linking the project with the library. The C source files are located under the WinDriver/src/wdapi directory.

    When linking your project with the WDAPI library/framework/shared object, you will need to distribute this binary with your driver.
    For Windows, get wdapi1411.dll / wdapi1411_32.dll (for 32-bit applications targeted at 64-bit platforms) from the WinDriver\redist directory.
    For Linux, get libwdapi1411.so / libwdapi1411_32.so (for 32-bit applications targeted at 64-bit platforms) from the WinDriver/lib directory.

    Note: On Windows and Linux, when using the DLL/shared object file for 32-bit applications on 64-bit platforms (wdapi1411_32.dll / libwdapi1411_32.so), rename the copy of the file in the distribution package, by removing the _32 portion [A.2].
    For detailed distribution instructions, refer to Chapter 14.

  4. Add any other WinDriver source files that implement API that you which to use in your code (e.g., files from the WinDriver/samples/shared directory.)

5.2.2. Write Your Code

This section outlines the calling sequence when using the WDC_xxx API [B.2].

  1. Call WDC_DriverOpen() [B.3.2] to open a handle to WinDriver and the WDC library, compare the version of the loaded driver with that of your driver source files, and register your WinDriver license (for registered users).
  2. For PCI/PCI Express devices, call WDC_PciScanDevices() [B.3.4] to scan the PCI bus and locate your device.
  3. For PCI/PCI Express devices, call WDC_PciGetDeviceInfo() [B.3.16] to retrieve the resources information for your selected device.
    For ISA devices, define the resources yourself within a WD_CARD structure.
  4. Call WDC_PciDeviceOpen() [B.3.17] / WDC_IsaDeviceOpen() [B.3.18] (depending on your device), and pass to the function the device's resources information. These functions return a handle to the device, which you can later use to communicate with the device using the WDC_xxx API.
  5. Communicate with the device using the WDC_xxx API (see the description in Appendix B).
    To enable interrupts, call WDC_IntEnable() [B.3.48].
    To register to receive notifications for Plug-and-Play and power management events, call WDC_EventRegister() [B.3.52].
  6. When you are done, call WDC_IntDisable() [B.3.49] to disable interrupt handling (if previously enabled), call WDC_EventRegister() [B.3.52] to unregister Plug-and-Play and power management event handling (if previously registered), and then call WDC_PciDeviceClose() [B.3.19] / WDC_IsaDeviceClose() [B.3.20] (depending on your device) in order to close the handle to the device.
  7. Call WDC_DriverClose() [B.3.3] to close the handles to WinDriver and the WDC library.

5.2.3. Configure and Build Your Code

After including the required files and writing your code, make sure that the required build flags and environment variables are set, then build your code.

When developing a driver for a 64-bit platform [A], your project or makefile must include the KERNEL_64BIT preprocessor definition. In the makefiles, the definition is added using the -D flag: -DKERNEL_64BIT. (The sample and wizard-generated Linux and Windows GCC makefiles and the Windows MS Visual Studio projects, in the 64-bit WinDriver toolkit, already include this definition.)
Before building your code, verify that the WD_BASEDIR environment variable is set to the location of the of the WinDriver installation directory.
On Windows and Linux you can define the WD_BASEDIR environment variable globally — as explained in Chapter 3: For Windows — refer to the Windows WD_BASEDIR note in Section 3.2.1; for Linux: refer to Section, Step 8.