From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755588AbaJNT6o (ORCPT ); Tue, 14 Oct 2014 15:58:44 -0400 Received: from mail-yk0-f175.google.com ([209.85.160.175]:47987 "EHLO mail-yk0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755499AbaJNT6m (ORCPT ); Tue, 14 Oct 2014 15:58:42 -0400 MIME-Version: 1.0 In-Reply-To: References: <1412618020-22278-1-git-send-email-sonnyrao@chromium.org> From: Alim Akhtar Date: Wed, 15 Oct 2014 01:28:01 +0530 Message-ID: Subject: Re: [PATCH] mmc: dw_mmc: Reset DMA before enabling IDMAC To: Doug Anderson 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 Doug, On Tue, Oct 14, 2014 at 10:21 PM, Doug Anderson wrote: > 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. :) > Sounds great. Thanks for testing. > -Doug -- Regards, Alim