Yocto project
When you want to use embedded Linux in your products, Rose-ES recommends using Yocto.
"The Yocto Project is a Linux Foundation workgroup whose goal is to produce tools and processes that will enable the creation of Linux distributions for embedded software that are independent of the underlying architecture of the embedded software itself" —Wikipedia—.
For this purpose, the Yocto workgroup selected existing projects and created a complete set of templates, tools and methods which spans all areas you need: Build framework, SDK deployment, emulation, test automation and package management.
Even more, the main strength of Yocto is that it's tested on several reference target architectures (including support for ARM, MIPS, PowerPC and x86) and is released twice a year.
Also many semiconductor manufacturers support and participate in this project, like Intel, Atmel, Texas instruments and so on.