I'm using OpenBSD/loongson on a Lemote Yeeloong laptop.
since PMON can only read from an ext2fs, we have a bootloader there, which loads your kernel from the FFS root partition (similar to ofwboot on ppc). See below for commands to have it actually load.
 - Loongson 2F processor at 800MHz (64bit MIPS CPU)
 - sillicon motion sm712 videocard driving a 1024x600 screen
 - 1GB Ram (normal laptop size)
 - 160GB Disk (normal sata connectors, 2.5")
 - 300k uvideo
 - realtek ethernet 8139 (100Mbit) and wifi RTL8187B (a/b/g)
 - US keyboard layout (with minor changes)

dmesg is at dmesg.loongson
Stuff that works:
 - X (default config, in framebuffer mode)
 - wifi (wep is just fine, wpa should also work)
 - battery status (charging, % full, etc)
 - audio (both built-in speakers, and headphones.  recording should also work.)
 - webcam (yes, really!)
You can install OpenBSD-current on it with no problems, even when you wipe the drive.
You *must* make sure that you follow the PMON instructions in INSTALL.loongson, especially
PMON> set moresz 30
PMON> set ShowBootMenu no
PMON> set al /dev/fs/ext2@wd0/boot/boot
PMON> set bsd /bsd
That is, if you want to actually /boot/ the damn thing.

Pictures of it from my Flickr photostream: http://www.flickr.com/photos/25924358@N06/sets/72157615580541658/.

Interesting links:
  • http://www.openbsd.org/loongson.html
  • http://wiki.gnewsense.org/Projects/Lemote
  • http://www.lemote.com/english/yeeloong.html
  • http://en.wikipedia.org/wiki/Loongson
  • http://wiki.gnewsense.org/Projects/GNewSenseToMIPS
  • http://dev.gentoo.org/~redhatter/mips/loongson/
  • http://www.debian.org/ports/mipsel/