Supporting ATI Radeon chipset RS780(RV710) video boards in framebuffer of linux kernel

Kernel supports RV710 in drivers/gpu/drm/radeon(r600),but I want gpu
acceleration in framebuffer for RV710 to use in directfb, I try to migrate
code from drivers/gpu/drm/radeon to drivers/video/aty/ to support
directfb, but it's very difficulty, because I have not the datasheet for
RV710, I don't konw how to set registers to draw a line, or a rectangle,
if someone has the datasheet for rv710, please sent me, thanks very
much!!!