From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCCDBC433F5 for ; Mon, 27 Aug 2018 11:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 844E6208B9 for ; Mon, 27 Aug 2018 11:03:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 844E6208B9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727382AbeH0Otu (ORCPT ); Mon, 27 Aug 2018 10:49:50 -0400 Received: from mga18.intel.com ([134.134.136.126]:33931 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726902AbeH0Otu (ORCPT ); Mon, 27 Aug 2018 10:49:50 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Aug 2018 04:03:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,295,1531810800"; d="scan'208";a="66281277" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.137]) ([10.237.72.137]) by fmsmga008.fm.intel.com with ESMTP; 27 Aug 2018 04:03:35 -0700 Subject: Re: [PATCH v2 11/40] mmc: sdhci: Add a quirk to skip clearing the transfer mode register on tuning To: Aapo Vienamo , Rob Herring , Mark Rutland , Thierry Reding , Jonathan Hunter , Ulf Hansson , Mikko Perttunen , Stefan Agner Cc: devicetree@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org References: <1533924522-1037-1-git-send-email-avienamo@nvidia.com> <1533924522-1037-12-git-send-email-avienamo@nvidia.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: Date: Mon, 27 Aug 2018 14:01:52 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1533924522-1037-12-git-send-email-avienamo@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/08/18 21:08, Aapo Vienamo wrote: > Add SDHCI_QUIRK2_TUNE_SKIP_XFERRMODE_REG_PROG to skip programming the > SDHCI_TRANSFER_MODE in sdhci_set_transfer_mode() if tuning command is > being sent. > > On Tegra210 and Tegra186 the tuning sequence hangs if the SDHCI > transfer mode register is touched. > > Signed-off-by: Aapo Vienamo > --- > drivers/mmc/host/sdhci.c | 6 ++++++ > drivers/mmc/host/sdhci.h | 2 ++ > 2 files changed, 8 insertions(+) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index a7b5602..04dc443 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -1028,6 +1028,12 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host, > > if (data == NULL) { > if (host->quirks2 & > + SDHCI_QUIRK2_TUNE_SKIP_XFERMODE_REG_PROG && > + (cmd->opcode == MMC_SEND_TUNING_BLOCK || > + cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200)) { > + return; > + } Rather than introduce a quirk, can't we just dodge the unnecessary write e.g. diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 1b3fbd9bd5c5..68af6a67e397 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1033,10 +1033,19 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host, if (cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200) sdhci_writew(host, 0x0, SDHCI_TRANSFER_MODE); } else { - /* clear Auto CMD settings for no data CMDs */ + u16 orig; + + /* clear Auto CMD settings for no data CMDs */ mode = sdhci_readw(host, SDHCI_TRANSFER_MODE); - sdhci_writew(host, mode & ~(SDHCI_TRNS_AUTO_CMD12 | - SDHCI_TRNS_AUTO_CMD23), SDHCI_TRANSFER_MODE); + orig = mode; + mode &= ~(SDHCI_TRNS_AUTO_CMD12 | SDHCI_TRNS_AUTO_CMD23); + /* + * Do not write transfer mode unnecessarily because it + * can upset some host controllers (e.g. sdhci-tregra) + * during tuning. + */ + if (mode != orig) + sdhci_writew(host, new_mode, SDHCI_TRANSFER_MODE); } return; } Alternatively > + if (host->quirks2 & > SDHCI_QUIRK2_CLEAR_TRANSFERMODE_REG_BEFORE_CMD) { > sdhci_writew(host, 0x0, SDHCI_TRANSFER_MODE); > } else { > diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h > index 23966f8..0a99008 100644 > --- a/drivers/mmc/host/sdhci.h > +++ b/drivers/mmc/host/sdhci.h > @@ -450,6 +450,8 @@ struct sdhci_host { > * obtainable timeout. > */ > #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT (1<<17) > +/* Don't clear the SDHCI_TRANSFER_MODE register on tuning commands */ > +#define SDHCI_QUIRK2_TUNE_SKIP_XFERMODE_REG_PROG (1<<18) > > int irq; /* Device IRQ */ > void __iomem *ioaddr; /* Mapped address */ >