mmc: dw_mmc: exynos: increase DMA threshold value for exynos7870

Exynos 7870 compatible controllers, such as SDIO ones are not able to
perform DMA transfers for small sizes of data (~16 to ~512 bytes),
resulting in cache issues in subsequent transfers. Increase the DMA
transfer threshold to 512 to allow the shorter transfers to take place,
bypassing DMA.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
index 261344d3a8cfe69cf76db2abc968bf8f1fd80c5f..4b76b997ddc15da15c181bb429bff7c2366063a9 100644 (file)
--- a/drivers/mmc/host/dw_mmc-exynos.c
+++ b/drivers/mmc/host/dw_mmc-exynos.c
@@ -141,6 +141,7 @@ static int dw_mci_exynos_priv_init(struct dw_mci *host)
                priv->ctrl_type == DW_MCI_TYPE_EXYNOS7870_SMU) {
                /* Quirk needed for certain Exynos SoCs */
                host->quirks |= DW_MMC_QUIRK_FIFO64_32;
+               host->dma_threshold = 512;
        }
 
        if (priv->ctrl_type == DW_MCI_TYPE_ARTPEC8) {