Merrifield is Intel's mobile phone chip they plan to unveil in 2014 that they began publicly talking about over the summer and then more details were revealed in September at the San Francisco IDF conference. Merrifield should debut next calendar year as a SoC for mobile phones. Merrifield is important in that it's the first System-on-a-Chip coming out of Intel to support LTE wireless communication.
The Merrifield SoC is based upon Intel's 22nm Silvermont architecture and hopes to compete with ARM for the high-end smartphone market. Details are still fairly scarce on Intel's Merrifield specs, but we should get a better idea in the months ahead. Intel has said that Merrifield will offer 50%+ better performance over current chips while providing much better battery life.
The Intel Merrifield patches to be published so far include gpio-langwell support, pci_id, sdhci-pci, USB DWC3, and other basic areas. The patches haven't been incredibly exciting, but there's more patches Intel has queued up but are pending review on these initial patches first from upstream kernel developers.
For what kernel patches don't get back-ported, the Intel Merrifield support will hopefully start landing into the Linux 3.13 kernel and then the support and its features/performance begin to be ironed out over the next few Linux kernel release cycles.