This driver currently performs cache operation before the DMA start, but does nothing after the DMA completion.
When reading data by DMA, the cache invalidation is needed also after finishing the DMA transfer. Otherwise, the CPU might read data from the cache instead of from the main memory when speculative memory read or memory prefetch occurs.
Instead of calling the cache operation directly, this commit adds dma_unmap_single(), which performs cache invalidation internally, but drivers do not need which operation is being run.
Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com ---
Changes in v2: None
drivers/mmc/sdhci.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c index 77a88bc043e4..9b7c5f8f684f 100644 --- a/drivers/mmc/sdhci.c +++ b/drivers/mmc/sdhci.c @@ -215,6 +215,10 @@ static int sdhci_transfer_data(struct sdhci_host *host, struct mmc_data *data) return -ETIMEDOUT; } } while (!(stat & SDHCI_INT_DATA_END)); + + dma_unmap_single(host->start_addr, data->blocks * data->blocksize, + mmc_get_dma_dir(data)); + return 0; }