Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755490AbaJNQvb (ORCPT ); Tue, 14 Oct 2014 12:51:31 -0400 Received: from mail-vc0-f175.google.com ([209.85.220.175]:38999 "EHLO mail-vc0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755473AbaJNQv1 (ORCPT ); Tue, 14 Oct 2014 12:51:27 -0400 MIME-Version: 1.0 In-Reply-To: References: <1412618020-22278-1-git-send-email-sonnyrao@chromium.org> Date: Tue, 14 Oct 2014 09:51:26 -0700 X-Google-Sender-Auth: ZsbAcs56yyOuBKqEuWkppdwF_iM Message-ID: Subject: Re: [PATCH] mmc: dw_mmc: Reset DMA before enabling IDMAC From: Doug Anderson To: Alim Akhtar Cc: =?UTF-8?B?RWRkaWUgQ2FpKOiUoeaeqyk=?= , Ulf Hansson , "linux-mmc@vger.kernel.org" , Heiko Stuebner , Sonny Rao , Seungwon Jeon , "linux-kernel@vger.kernel.org" , Addy Ke , Jaehoon Chung , "linux-arm-kernel@lists.infradead.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, On Thu, Oct 9, 2014 at 5:36 PM, Doug Anderson wrote: > Alim, > > On Thu, Oct 9, 2014 at 3:19 PM, Alim Akhtar wrote: >> Thats fine, I think every vendor (most of them) has a custom >> implementation of dw_mmc, but they do have VERID register to check the >> dw_mmc version. >> The reason why I asked is, I have seen inconsistency in card >> enumeration on few controller version, and this patch alone does not >> help, and adding a call to dw_mci_idmac_reset() after DMA reset is >> needed. And this is what is recommended in the synopsys's data book >> also. >> Do you see any issue/side effect after adding dw_mci_idmac_reset()? > > A quick test shows no problem with adding this to Sonny's patch: > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 66dc8fe..588b5b8 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -481,6 +481,7 @@ static void dw_mci_idmac_start_dma(struct dw_mci > *host, unsigned int 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); > > I'll start reboot tests now to see how it behaves... I think Sonny is > out of the office for a few days so we might need to wait for a spin, > but I'll run with that change in the meantime and see how it behaves > for me. > > Thanks! Just FYI that I've been running with Alim's proposed change for several days and it seems solid. I think Sonny may be able to spin his patch this week. :) -Doug -- 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/