tree 14493161aee3ee512b98effd23fdc982d3f98891
parent 63c0ae2b09e6d050b04f2a61bb46441df552d0ba
author Masahiro Yamada <yamada.masahiro@socionext.com> 1581666026 +0900
committer Peng Fan <peng.fan@nxp.com> 1582182597 +0800

mmc: sdhci: use dma_map_single() instead of flush_cache() before DMA

Currently, sdhci_prepare_dma() calls flush_cache() regardless of the
DMA direction.

Actually, cache invalidation is enough when reading data from the device.

This is correctly handled by dma_map_single(), which mimics the DMA-API
in Linux kernel. Drivers can be agnostic which cache operation occurs
behind the scene.

This commit also sanitizes the difference between the virtual address
and the dma address.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>