c278150e0d
DMA on this hardware is limited to dealing with a single page at a time. Previously, the driver was set up accordingly to request single-page DMA buffers, however that had the effect of generating a large number of small MMC requests for data I/O. Improve the driver to accept scatter-gather DMA buffers of larger sizes. Iterate through those buffers a page at a time. Testing with dd, this increases write performance from 2mb/sec to 10mb/sec, and increases read performance from 4mb/sec to 14mb/sec. Signed-off-by: Daniel Drake <drake@endlessm.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>