try fix periodic mode support
experiment with ns8250
update
Revert "update"

This reverts commit ed38912882a4e06ec28a48cc2fea6124f39f6e45.
experiment uart
experiment uart
experiment with uart
update timer code
Merge branch 'master' of https://github.com/tsgan/allwinner_a10
update timer code
update timer code (style)
update timer code (style)
update timer code to enable timer in start
update timer code
experiment timer code
experiment timer code
experiment timer code
update timer to support periodic and oneshot mode
update timer code
sync timer code