mmc: tmio_mmc: implement a bounce buffer for unaligned DMA

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>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/mfd/tmio.h b/include/linux/mfd/tmio.h
index 085f041197dc..dbfc053b1f95 100644
--- a/include/linux/mfd/tmio.h
+++ b/include/linux/mfd/tmio.h
@@ -66,6 +66,7 @@ void tmio_core_mmc_clk_div(void __iomem *cnf, int shift, int state);
 struct tmio_mmc_dma {
         void *chan_priv_tx;
         void *chan_priv_rx;
+        int alignment_shift;
 };
 
 /*