xf86-video-dove is an X.org graphics driver ("DDX") for the graphics hardware included in Marvell MMP2/MMP3 (OLPC XO-1.75 and XO-4). This driver originated from Marvell/Cubox but doesn't currently seem to have a public/central development repository, so we've forked our own version for now, and made a number of our own changes/fixes. See the README for a bit more info.
For acceleration, the driver relies on galcore in the kernel, which is accessed through the (closed source) libgfx-marvell library.
Questions and contributions should be sent to the devel mailing list.
It is thought that this driver is based on a very old code drop from Vivante. There might be newer code now available: OLPC has received (under NDA) a GPL-licensed X/EXA driver (VIVANTE_GAL_Unified_Src_drv_EXA-addon_4.6.9.p8.org.tgz), and a closed-source DRI counterpart (VIVANTE_GAL_Unified_Src_drv_DRI-addon_4.6.9.p8.noGPL.org.tgz). This would seem to be related to a graphics driver for the Freescale platform e.g. this one.
There is also etna_viv, an open-source experimental driver for this type of hardware, that could become a very interesting option in future.