Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751848AbaJQM3H (ORCPT ); Fri, 17 Oct 2014 08:29:07 -0400 Received: from mail-yk0-f172.google.com ([209.85.160.172]:45223 "EHLO mail-yk0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751215AbaJQM3E (ORCPT ); Fri, 17 Oct 2014 08:29:04 -0400 MIME-Version: 1.0 In-Reply-To: <1413478686-6857-1-git-send-email-sonnyrao@chromium.org> References: <1413478686-6857-1-git-send-email-sonnyrao@chromium.org> From: Alim Akhtar Date: Fri, 17 Oct 2014 17:58:22 +0530 Message-ID: Subject: Re: [PATCH v2] mmc: dw_mmc: Reset DMA before enabling IDMAC To: Sonny Rao Cc: "linux-mmc@vger.kernel.org" , Heiko Stuebner , Seungwon Jeon , Jaehoon Chung , Ulf Hansson , Douglas Anderson , Eddie Cai , Addy Ke , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sonny, On Thu, Oct 16, 2014 at 10:28 PM, 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. > > Signed-off-by: Sonny Rao > Signed-off-by: Doug Anderson > Tested-by: Doug Anderson This looks fine. Reviewed-by: Alim Akhtar > --- > 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 > -- Regards, Alim -- 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/