In the early days of embedded Linux development (circa Y2K), a significant part of the embedded computer was to port the open source code to run on the hardware platform being targeted. Unless engineers were running code on an Intel x86 board, it was not a trivial effort to develop the embedded computer and cross-compile the open source middleware to run on the hardware. In the years since, an increasing number of hardware companies have discovered that providing free Linux BSPs is necessary to ensuring the wide adoption of their hardware into embedded applications. Whereas in the early days it might have taken weeks or months to get to a Linux shell prompt over a console port, these days it should only take a few hours.
refer to: http://embedded-computing.com/articles/the-not-code-quality/