Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752292AbaJPQ6N (ORCPT ); Thu, 16 Oct 2014 12:58:13 -0400 Received: from mail-oi0-f73.google.com ([209.85.218.73]:43642 "EHLO mail-oi0-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751872AbaJPQ6L (ORCPT ); Thu, 16 Oct 2014 12:58:11 -0400 From: Sonny Rao To: Alim Akhtar , linux-mmc@vger.kernel.org Cc: Heiko Stuebner , Seungwon Jeon , Jaehoon Chung , Ulf Hansson , dianders@chromium.org, eddie.cai@rock-chips.com, addy.ke@rock-chips.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sonny Rao Subject: [PATCH v2] mmc: dw_mmc: Reset DMA before enabling IDMAC Date: Thu, 16 Oct 2014 09:58:05 -0700 Message-Id: <1413478686-6857-1-git-send-email-sonnyrao@chromium.org> X-Mailer: git-send-email 2.1.0.rc2.206.gedb03e5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Signed-off-by: Doug Anderson Tested-by: Doug Anderson --- 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; -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/