A repo for boards based on AM335X, including u-boot、kernel、rootfs、others, all of them are located at the branches, just as as follows.
U-BOOT
branch: u-boot
git from: git://git.ti.com/ti-u-boot/ti-u-boot.git
refer to: http://processors.wiki.ti.com/index.php/Linux_Core_U-Boot_User%27s_Guide
KERNEL
branch: kernel
git from: git://git.ti.com/processor-sdk/processor-sdk-linux.git
refer to: http://processors.wiki.ti.com/index.php/Linux_Kernel_Users_Guide
BUILDROOT
branch: buildroot
git from: git://git.busybox.net/buildroot
refer to: https://buildroot.org/docs.html
OTHERS
TOOLCHAIN
site: https://releases.linaro.org/components/toolchain/binaries/6.2-2016.11/arm-linux-gnueabihf/
package: gcc-linaro-6.2.1-2016.11-x86_64_arm-linux-gnueabihf.tar.xz