buildroot for arm kernel defconfig

Question

I am trying to build a buildroot with kernel image, and after doing make menuconfig and make, I am getting:

No kernel defconfig name specified, check your BR2_LINUX_KERNEL_DEFCONFIG setting

I can set a string to the defconfig, but I don't know what to put there.

My target system is an AT91SAM9RL board.

edit: I found out there are some pre-made config files to some devices, actually not exactly matching to my target.

Bickford

Here I describe a sample minimal runnable setup for QEMU: #47557762 – Supporter

Answer 1

You can issue the default configuration process by running make xxx_defconfig and that make target is a file in the folder arch/arm/configs/. These default configurations are not designed to exactly fit your target, but are rather meant to be a superset so you only have to modify them a bit.

The make xxx_defconfig creates your initial .config, which you can now edit through make menuconfig and make your changes. After that, you can run make which will then compile the kernel using your settings.

Transplant

Ok i got it, seems like its working. Pretty long buildtime in a VM tough. – Bickford

I would just add that defconfig files are now in buildroot root directory configs subfolder (buildroot-2012.02). – Furan

Not exactly. configs subfolder contains buildroot defconfig which points to a linux defconfig located in board subfolder. e.g. BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/freescale/mpc8315erdb/linux-3.12.config" – Podium

Why must the configuration file's name end with 'defconfig'? – Affra

When you clone git repository of buildroot you can find some default configuration files in the config directory. all this files are called <something>_defconfig (like raspberrypi_defconfig) – Raddle