VxWorks 7 SDK for RISC-V (SiFive HiFive Unmatched)

Introduction

The VxWorks 7 SDK is a development environment dedicated to VxWorks application developers which includes the following features:

• standard cross-compilation tools based on clang/LLVM which can be used to build both downloadable kernel modules (DKM) and RTP (Real Time Process) applications
• simplified build management: makefile, cmake, roll-your own
• target / architecture specific: includes a generic VxWorks kernel which is bootable on the target platform
• header files and libraries for application development
• Wind River Debugger (wrdbg)
• documentation

This guide helps you get up and running with developing applications for platforms running VxWorks. You can use it for creating new applications, or just exploration of VxWorks capabilities.

Setting up the development environment

You should start by downloading a VxWorks SDK for your platform of choice from https://labs.windriver.com and unpacking it. Refer to the documentation in docs in the unpacked SDK for additional information on creating and debugging applications.

OS requirements

The SDKs are meant to run on Linux hosts. Some of the examples in this document are specific to Debian derivatives.

Prerequisite(s)

Host dependencies

On Debian derivatives, the following packages need to be installed:

$ sudo apt install build-essential libc6-i386 uml-utilities nfs-kernel-server

Having an FTP server installed on your development host will make application deployment easier and allow you to access the host file system from a VxWorks target.

To accommodate for the varying runtime configurations of the VxWorks kernel images included in the SDKs, you may be interested in using an FTP server option based on pyftpdlib.

Install pyftpdlib:

$ sudo apt install python3-pip
$ sudo pip3 install pyftpdlib

Booting VxWorks using TFTP

Prebuilt VxWorks binaries can be located in vxsdk/bsps/sifive_generic_1_0_1_1.

Set the target board network parameters from the U-Boot shell:

=> setenv ipaddr 192.168.0.3
=> setenv netmask 255.255.255.0
=> setenv serverip 192.168.0.2
=> setenv bootargs 'gem(0,0)host:vxWorks h=192.168.0.2 e=192.168.0.3:ffffff00 u=target pw=vxTarget f=0x01'

Boot and Run VxWorks

Load the VxWorks image file from the workstation using the U-Boot shell:

=> tftpboot 84000000 uVxWorks

Load the DTB file from the workstation using the U-Boot shell:

=> tftpboot 88000000 hifive-unmatched-a00.dtb

Run the VxWorks image using the U-Boot shell:

=> bootm 84000000 - 88000000

Application development

Start by opening a Linux terminal window and going to the location of your unpacked VxWorks SDK.

Source the SDK development environment before using the SDK.

$ source sdkenv.sh

Customizing the values for the user (u) and password (pw) parameters to the ones matching a valid FTP user on your development host will allow you to access the host file system from the VxWorks instance running in QEMU. The VxWorks instance will have access to the root folder of your FTP server.

Developing applications from the command line

The VxWorks compiler driver (wr-cc/wr-c++) utility lets you invoke VxWorks toolchains to compile your real time process (RTP) application from command line. The SDK development environment includes a set of environment variables (CC, CXX, CPP, etc) which match the various compiler driver utilities.

Procedure:

1. Create a C source file foo.c:

#include <stdio.h>

int main(void)
    {
    printf("hello, world!\n");
    return 0;
    }

1. Compile the source file foo.c to create a Real Time Process application.

$ wr-cc -rtp foo.c -static -o foo.vxe

or

$ $CC -rtp foo.c -static -o foo.vxe

Alternatively, you can also create a Makefile and then call make to compile the source file.

all:
    $CC -rtp foo.c -static -o foo.vxe

$ make

Developing applications using CMake

By default, a generated VxWorks SDK includes CMake. When the application developer sources the SDK environment, they will automatically have access to CMake. There is no need to download, install and configure CMake separately. With VxWorks CMake, you can build existing CMake examples that are included in the generated SDK, or you can create your own projects.

CMake examples can be found in the directories /examples/rtp/hello_cmake_rtp and /examples/dkm/hello_cmake_dkm

Procedure:

1. Create a project directory, called my_project.

$ mkdir my_project

1. Create the CMakeLists.txt file in the project folder.

2. To build your project, run the following command:

$ cmake -D CMAKE_TOOLCHAIN_FILE=${WIND_SDK_HOME}/vxsdk/sysroot/mk/rtp.toolchain.cmake .

Note: RTP is used in the example. If you would like to build a DKM project instead, change the toolchain name to dkm.toolchain.cmake.

Running applications

After you have started VxWorks on your target, start an FTP server on port 21 with user "target" and password "vxTarget" and FTP root in the current user's home.

$ sudo python3 -m pyftpdlib -p 21 -u target -P vxTarget -d $HOME &

Switching to the "cmd" shell will allow you to navigate to the location of your application with greater ease.

-> cmd
[vxWorks *]# 

Assuming the application is located in $HOME/:

[vxWorks *]# cd /host.host
[vxWorks *]# ls foo.vxe
./foo.vxe
[vxWorks *]# more foo.c
#include <stdio.h>

int main(int argc, char **argv) {
    printf("Hello World\n");
    return 0;
}
[vxWorks *]# foo.vxe
Launching process 'foo' ...
Process 'foo' (process Id = 0xffff8000004bb6e0) launched.
Hello World