Linaro: https://www.linaro.org/
OpenWRT: https://www.openwrt.org/
Going on a bit of a tangent:
Most of the time these companies just don't care.
If you don't mind getting your hands dirty, then have a look at some vendor kernel trees. For example, a $300AUD router released last year is running 2.6.34brcm - http://www.tp-link.com.au/download/Archer-D9.html#GPL-Code
The 802.11AC card in that router will likely never have open source drivers. I'm pretty sure the routing engine is closed source too, although with 2x Cortex A9 chips I would have thought you could get away with doing it in software.
Linaro: https://www.linaro.org/
OpenWRT: https://www.openwrt.org/
Going on a bit of a tangent:
Most of the time these companies just don't care.
If you don't mind getting your hands dirty, then have a look at some vendor kernel trees. For example, a $300AUD router released last year is running 2.6.34brcm - http://www.tp-link.com.au/download/Archer-D9.html#GPL-Code
The 802.11AC card in that router will likely never have open source drivers. I'm pretty sure the routing engine is closed source too, although with 2x Cortex A9 chips I would have thought you could get away with doing it in software.