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authorSonny Rao <sonnyrao@chromium.org>2014-10-16 09:58:05 -0700
committerUlf Hansson <ulf.hansson@linaro.org>2014-11-10 12:40:35 +0100
commit536f6b91d21b81bec6c8a675b3a00052ee05f986 (patch)
treec9e998819fd46fc6a64bd0b12bcfcf7cef86a511
parent390e316c606de2f839389698f4531004cfe1bafd (diff)
mmc: dw_mmc: Reset DMA before enabling IDMAC
We've already got a reset of DMA after it's done. Add one before we start DMA too. This fixes a data corruption on Rockchip SoCs which will get bad data when doing a DMA transfer after doing a PIO transfer. We tested this on an Exynos 5800 with HS200 and didn't notice any difference in sequential read throughput. Signed-off-by: Sonny Rao <sonnyrao@chromium.org> Signed-off-by: Doug Anderson <dianders@chromium.org> Tested-by: Doug Anderson <dianders@chromium.org> Acked-by: Jaehoon Chung <jh80.chung@samsung.com> Tested-by: Jaehoon Chung <jh80.chung@samsung.com> Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
-rw-r--r--drivers/mmc/host/dw_mmc.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 69f0cc68d5b..ca67f6923bf 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -83,6 +83,7 @@ struct idmac_desc {
#endif /* CONFIG_MMC_DW_IDMAC */
static bool dw_mci_reset(struct dw_mci *host);
+static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset);
#if defined(CONFIG_DEBUG_FS)
static int dw_mci_req_show(struct seq_file *s, void *v)
@@ -448,6 +449,10 @@ static void dw_mci_idmac_start_dma(struct dw_mci *host, unsigned int sg_len)
dw_mci_translate_sglist(host, host->data, sg_len);
+ /* Make sure to reset DMA in case we did PIO before this */
+ dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET);
+ dw_mci_idmac_reset(host);
+
/* Select IDMAC interface */
temp = mci_readl(host, CTRL);
temp |= SDMMC_CTRL_USE_IDMAC;