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mmc: dw_mmc: Reset DMA before enabling IDMAC

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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>
This commit is contained in:
Sonny Rao 2014-10-16 09:58:05 -07:00 committed by Ulf Hansson
parent 390e316c60
commit 536f6b91d2
1 changed files with 5 additions and 0 deletions
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5
drivers/mmc/host/dw_mmc.c
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@ -83,6 +83,7 @@ struct idmac_desc {
#endif /* CONFIG_MMC_DW_IDMAC */ #endif /* CONFIG_MMC_DW_IDMAC */
static bool dw_mci_reset(struct dw_mci *host); 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) #if defined(CONFIG_DEBUG_FS)
static int dw_mci_req_show(struct seq_file *s, void *v) 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); 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 */ /* Select IDMAC interface */
temp = mci_readl(host, CTRL); temp = mci_readl(host, CTRL);
temp |= SDMMC_CTRL_USE_IDMAC; temp |= SDMMC_CTRL_USE_IDMAC;