tree a6913470397af37729670966b9683aec48edb525
parent e2dbf5ebcc983b0349ab507bf7dd5562cf88dd24
author Guennadi Liakhovetski <g.liakhovetski@gmx.de> 1295625402 +0100
committer Grant Likely <grant.likely@secretlab.ca> 1295629355 -0700

spi/spi_sh_msiof: consolidate data in 8-bit mode into 32-bit words

Instead of sending data 8 bits at a time in 8-bit SPI mode, swap bytes
and send and receive them 32 bits at a time. Tested with an SD-card,
with which this patch reduced the number of interrupts by 50%, when
reading 5MiB of data (there are also small service packets, the number
of interrupts, produced by 512-byte sectors should, of course, drop by
75%), and improved throughput by more than 40%.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>