mmc: tmio_mmc: implement a bounce buffer for unaligned DMA

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For example, with SDIO WLAN cards, some transfers happen with buffers at
odd addresses, whereas the SH-Mobile DMA engine requires even addresses
for SDHI. This patch extends the tmio driver with a bounce buffer, that
is used for single entry scatter-gather lists both for sending and
receiving. If we ever encounter unaligned transfers with multi-element
sg lists, this patch will have to be extended. For now it just falls
back to PIO in this and other unsupported cases.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

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Guennadi Liakhovetski 2010-12-22 12:02:15 +01:00 • committed by Chris Ball

parent e0bc6ff8b8

commit 93173054f2

2 changed files with 84 additions and 6 deletions

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89

drivers/mmc/host/tmio_mmc.c

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1

include/linux/mfd/tmio.h

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