mmc: tmio: use PIO for short transfers
authorGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Mon, 7 Mar 2011 10:33:11 +0000 (11:33 +0100)
committerChris Ball <cjb@laptop.org>
Fri, 25 Mar 2011 14:39:05 +0000 (10:39 -0400)
commit5f52c3552946eafa13f89c949449d16ce2b58b24
tree193ab366bf12a261235a2f8c0ae4c5ae182b941d
parent51fc7b2ce74d31b7d9a6bd3c57bf6c1cc77e837d
mmc: tmio: use PIO for short transfers

This patch allows transferring of some requests in PIO and some in DMA
mode and defaults to using DMA only for transfers longer than 8 bytes.
This is especially useful with SDIO, which can have lots of 2- and 4-byte
transfers, creating unnecessary high overhead, when executed in DMA.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
drivers/mmc/host/tmio_mmc.c