Actually I'm confused. All I want is to install Linux preferably Debian-based, on a custom board.
I know about device tree which is a text file and I have to create as device drivers.
The things that I don't know are FEX? SPL? u-boot-spl? kernel? filesystem? mainline?
I've check e-linux and linux-sunxi.
As you know I'm a newbie, and I don't know much, and this is why I'm asking out for help from those kind people who are willing to give me their precious time to help me.
Thanks again.
So here are some Allwinner and embedded Linux glossary:
* FEL (not FEX) is the first-stage bootloader of Allwinner chips, located in internal mask ROM. When the chip is powered on the processor core start fetching code from this location. It searches the peripherals for some code that it can load and execute, and falls back to a low level recovery mode if the search for bootable media failed. It is similar to the UEFI BIOS in your PC.
* SPL is the second-stage bootloader, and u-boot-spl is the version of SPL provided by U-Boot. When the microprocessor is just booted up the main dynamic memory is not initialized. Thus the FEL only have a few kB of built-in SRAM (often called core tightly-coupled RAM) to work with, hence the amount of code that can be loaded by the FEL is very limited. SPL initializes the main memory and loads the actual bootloader to the main memory.
* Concepts of
kernels and
filesystems are better explained on Wikipedia.
* The mainline of some software means the software directly from the original author. In the case of Linux kernel and U-Boot it means the Linux kernel code directly from Linus Torvalds. In the case of U-Boot it means the U-Boot code directly from Denx Software Engineering GmbH.
Speaking of, since you are having questions about the software side of things, you may also want to raise the questions on Stack Overflow. There are way more software engineers there than here.