There are numerous ways to build a cross toolchain for your architecture. For ARM, there are so many possible combinations of hardware and software configurations that it will be difficult to find the exact one that matches your CPU and board. Do you have an existing Linux system running on it? If so, you'll want to know what version of many things are, particularly the standard C library.
I absolutely do not recommend trying to roll your own toolchain. There are systems available, many for free, that you can use to do the build. Crosstool-NG
is one I've used successfully. LinuxLink
is another. OpenEmbedded
will build a toolcahin and a whole lot more. There are other systems if you look around.