[Cerowrt-devel] Why we are discussing ARM [was: Cross-compiling to armhf]

[Juliusz Chroboczek]

We've got pretty much off-topic for both of these lists, so I guess
I should explain to folks who are not in the know why we are discussing
ARM.

Historically, much of the Babel/mesh routing/bufferbloat work has happened
on MIPS boxes.  Our elderly Asus 500GP are still rock solid, if a little
slow, and our main workhorse is still the lovely WNDR3700v2, with its two
independent Gigabit Ethernets, its two independent 802.11n 2x2 radios with
support for simultaneous AP and mesh.

MIPS remains my favourite architecture (look, Ma, no condition codes!),
but it has been slowly dying over the last years.  While Imagination
Technologies have been producing new releases of the arch and apparently
new cores, I haven't seen an exciting MIPS chip for ages.  Dave has been
bullying me into looking at ARM boards -- and while the instruction set is
not a pretty sight, the ecosystem is healthy, with chips spanning the
whole range from ridiculously cheap microcontrollers to things that are
marketed as server CPUs (the Intel folks laughing in the background spoils
the effect somewhat, though).  Add to this that the 64-bit ISA is an
almost exact clone of MIPS (except that it still has condition codes, grr,
have those people never written a compiler?).

So here, at Babel Towers, we're seriously considering switching to ARM
when we next have funding for new hardware, and dropping OpenWRT in favour
of stock Debian.  Things that we've been considering:

  CHIP board: https://getchip.com/
  Turris Omnia: https://omnia.turris.cz/en/
  Snickerdoodle board: http://krtkl.com/

Nothing we have found is as nice as the old WNDR3700/3800.  The CHIP is
marvelously cheap (cheap enough to give out to students!) and has flexible
power requirements, but it doesn't have wired Ethernet, and its wifi is
connected over SDIO, with everything that entails.  The Turris Omnia is
badly overspecced, with a price to match.  The Snickerdoodle is promising,
but it's currently vapourware, its WiFi sucks, and when combined with the
dual-Ethernet daughterboard it becomes fairly expensive.

Things that we haven't been considering, Dave's enthusiasm notwithstanding:

  Raspberry Pi: doesn't run armhf userspace, no wifi, eth connected by USB;
  Raspberry Pi v2/v3: requires binary blobs, wifi and eth connected over USB;
  Beagleboard variants: look nice, but no wifi;
  MeshSR: they did almost everything wrong.

So, folks, if anyone has good experiences with cheap ARM boards that have
wifi and Ethernet and work well with a stock Debian userspace, I'm interested.

-- Juliusz