Toolchain Overlay File
Introduction
The Overlay is a tar file that includes modified versions of processor configuration dependent files that are required by various toolchain tools, such as binutils, gcc, and gdb. The overlay described here has a specific layout and is intended for toolchain generators, such as buildroot, OpenADK or crosstool-NG.
Creating the overlay
The overlay file shipped by Tensilica uses a flat directory structure, which is not suitable for buildroot or crosstool-NG at the moment. The file is part of the generated processor package, and can be found in the XtDevTools directory:
XtDevTools/install/build/$VERSION/$XTENSA_CORE/src/xtensa-config-overlay.tar.gz
The following script converts this file and writes the modified version to xtensa-overlay.tar. Simply provide the path and name of the overlay provided by Tensilica when running the script:
./make-overlay.sh $XTENSA_CORE path/to/xtensa-config-overlay.tar.gz .
The file xtensa_$XTENSA_CORE.tar.gz created by the script can now be used to build buildroot or crosstool-NG. For more information how to configure those generators, please see Buildroot or crosstool-NG.
(Note that there is also a similar overlay file in the generated processor package provided by Tensilica, but it has a different directory layout and is not suitable for the script provided below. It can be found under .../$XTENSA_CORE/xtensa-elf/src/linux/misc/linux-overlay.tar.gz)
Conversion Script
https://github.com/foss-xtensa/xtensa-config/blob/master/make-overlay.sh
Example Files
The following files are the original and generated overlay file for the DC_D_233L processor.
- http://www.linux-xtensa.org/pub/xtensa-config-overlay.tar.gz - Original overlay file provided by Tensilica
- http://www.linux-xtensa.org/pub/xtensa-overlay.tgz - : Generated overlay file, applicable to buildroot and crosstool-NG
Ready to go overlay archives (can be used with buildroot and OpenADK)
https://github.com/jcmvbkbc/xtensa-toolchain-build/tree/master/overlays