Hi, Sonny.
On 10/17/2014 01:58 AM, Sonny Rao wrote:
> 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.
Didn't affect the write throughput?
I tested this on exynos3/4 with DDR50 and HS200.
Acked-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
Tested-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
>
> Signed-off-by: Sonny Rao <sonnyrao@xxxxxxxxxxxx>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> Tested-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> ---
> drivers/mmc/host/dw_mmc.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 69f0cc6..ca67f69 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;
>
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