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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 A0CCBC76186 for ; Wed, 24 Jul 2019 02:22:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 610C820651 for ; Wed, 24 Jul 2019 02:22:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="z4hxi5G1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727806AbfGXCWJ (ORCPT ); Tue, 23 Jul 2019 22:22:09 -0400 Received: from mail-ot1-f65.google.com ([209.85.210.65]:39988 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726108AbfGXCWJ (ORCPT ); Tue, 23 Jul 2019 22:22:09 -0400 Received: by mail-ot1-f65.google.com with SMTP id s7so131957oth.7 for ; Tue, 23 Jul 2019 19:22:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=DLF4pm4RL0wA5hcVMMrw5NHFRQ2ig5s8he/98rvlGyk=; b=z4hxi5G1bGRKaxWUmoOapIH+np2Z8tsVglNR9ERPddstRiq1j+A8iaNPQj935G+M7h 3yqJUpOVU86A4Z0eoouJecKlZXZ7G7dRajE79VKd3RQe8MfNzzist2Eu+WvktxfNhtjN W6SOLeN4cPTx8t1SngtztORzM+JDxOlvVfEAgnvT0AzT4W0Uv0NhiehmCPaUYtXrbf3Z 2bRBT9XbxdIKTb9bdhXnNbbZtISNzn4jEJdR1gZmtBUGY+A6RBB1AWn24FS/nzODNjmN K24AURwQG2mM+llYT3GsFwP/sAE/u4iMIS+OfBIesHOQkyFA5U092OEe/HPyjsOXHDdI lTDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=DLF4pm4RL0wA5hcVMMrw5NHFRQ2ig5s8he/98rvlGyk=; b=BezeNPYUpuN5RQauy8tKGJkxLiooTBqetXkD3LlzCNRkVMUBb3S3Nv8GdgFg0cLTGK Nyf25VTy5lXhXrldB3D3eyhDSKH1yg89sQ5Qu4igVVM2C9ptcwvjhLVm3NbfH3dNuCWH N5USRYmh3MjK/qfI+o+jz0ZUTkp9txJu0d8TQ/0dmZszhpgkbJJ0UUvD57q86YS6yi2x UCl+9+jeCM2eG9L8mYxEOsyFh8wZNNtyfVWv2bxZWEIcE6qrXduG+bufexGvZmecB1nk jgW+1KOjZxwEGUSV46nMaYNG3551mZ8uX7571WRMH6tBust7RJ1a3ovt0Ye+oH3o3wkM 5Iiw== X-Gm-Message-State: APjAAAUm9eBDLRDLzDx/sRrvkVfmy+mHnmXwQRWpOJnNmFwxXcXzeb29 iX+HGiPOscQGHAPYEMDImH0rCJ8DZZgFDPJDxaURxQ== X-Google-Smtp-Source: APXvYqxnOt402L5HhNkgDDvSy4DpF7ukOVhYefdp2TGaYvy/AB0kwedVYo2x2l8D2jCfGB1qH9kpkALSvsj4T0IXBwM= X-Received: by 2002:a9d:1718:: with SMTP id i24mr20907922ota.269.1563934928175; Tue, 23 Jul 2019 19:22:08 -0700 (PDT) MIME-Version: 1.0 References: <89c3ef495c367d58ca3abe99a1f82c48f8c08705.1563274904.git.baolin.wang@linaro.org> In-Reply-To: From: Baolin Wang Date: Wed, 24 Jul 2019 10:21:56 +0800 Message-ID: Subject: Re: [PATCH v4] mmc: host: sdhci-sprd: Fix the incorrect soft reset operation when runtime resuming To: Ulf Hansson Cc: Adrian Hunter , Chunyan Zhang , Orson Zhai , Vincent Guittot , "linux-mmc@vger.kernel.org" , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 23 Jul 2019 at 20:39, Ulf Hansson wrote: > > On Tue, 23 Jul 2019 at 05:05, Baolin Wang wrote: > > > > Hi Ulf, > > > > On Mon, 22 Jul 2019 at 19:54, Ulf Hansson wrote: > > > > > > On Wed, 17 Jul 2019 at 04:29, Baolin Wang wrote: > > > > > > > > In sdhci_runtime_resume_host() function, we will always do software reset > > > > for all, which will cause Spreadtrum host controller work abnormally after > > > > resuming. > > > > > > What does "software reset for all" means? > > > > The SD host controller specification defines 3 types software reset: > > software reset for data line, software reset for command line and > > software reset for all. > > Software reset for all means this reset affects the entire Host > > controller except for the card detection circuit. > > Thanks for clarifying, please update the changelog accordingly. Sure, sorry for confusing. > > > > > > > > > > > > > > Thus for Spreadtrum platform that will not power down the SD/eMMC card during > > > > runtime suspend, we should not do software reset for all. > > > > > > Normally, sdhci hosts that enters runtime suspend doesn't power off > > > the card (there are some exceptions like PCI variants). > > > > Yes, same as our controller. > > > > > > > > So, what's so special here and how does the reset come into play? I > > > don't see sdhci doing a reset in sdhci_runtime_suspend|resume_host() > > > and nor doesn the callback from the sdhci-sprd.c variant doing it. > > > > In sdhci_runtime_resume_host(), it will issue sdhci_init(host, 0) to > > issue software reset for all. > > Aha, I didn't read the code carefully enough. Apologize for the noise. No worries :) > > > > > > > > > To fix this > > > > issue, adding a specific reset operation that adds one condition to validate > > > > the power mode to decide if we can do software reset for all or just reset > > > > command and data lines. > > > > > > > > Signed-off-by: Baolin Wang > > > > --- > > > > Changess from v3: > > > > - Use ios.power_mode to validate if the card is power down or not. > > > > > > > > Changes from v2: > > > > - Simplify the sdhci_sprd_reset() by issuing sdhci_reset(). > > > > > > > > Changes from v1: > > > > - Add a specific reset operation instead of changing the core to avoid > > > > affecting other hardware. > > > > --- > > > > drivers/mmc/host/sdhci-sprd.c | 19 ++++++++++++++++++- > > > > 1 file changed, 18 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c > > > > index 603a5d9..94f9726 100644 > > > > --- a/drivers/mmc/host/sdhci-sprd.c > > > > +++ b/drivers/mmc/host/sdhci-sprd.c > > > > @@ -373,6 +373,23 @@ static unsigned int sdhci_sprd_get_max_timeout_count(struct sdhci_host *host) > > > > return 1 << 31; > > > > } > > > > > > > > +static void sdhci_sprd_reset(struct sdhci_host *host, u8 mask) > > > > +{ > > > > + struct mmc_host *mmc = host->mmc; > > > > + > > > > + /* > > > > + * When try to reset controller after runtime suspend, we should not > > > > + * reset for all if the SD/eMMC card is not power down, just reset > > > > + * command and data lines instead. Otherwise will meet some strange > > > > + * behaviors for Spreadtrum host controller. > > > > + */ > > > > + if (host->runtime_suspended && (mask & SDHCI_RESET_ALL) && > > > > + mmc->ios.power_mode == MMC_POWER_ON) > > > > + mask = SDHCI_RESET_CMD | SDHCI_RESET_DATA; > > > > > > Can sdhci_sprd_reset() be called when the host is runtime suspended? > > > > When host tries to runtime resume in sdhci_runtime_resume_host(), it > > will call reset operation to do software reset. > > Right, I see that now, thanks for clarifying. > > However, there are still some weird things going on in > sdhci_runtime_resume_host(). Like why is host->ops->enable_dma() > called first, directly from sdhci_runtime_resume_host(), then again in > sdhci_do_reset(), after host->ops->reset() has been called. Looks like > the first call to ->enable_dma() doesn't make sense? I am mot sure, since our host did not supply enable_dma() operation. This logic was used by some other hardware and worked well, I am not sure if it can reveal some issues if we change the logic here. Adrian, could you help to explain why we put enable_dma() in front of software reset? > > > > > > That sounds like a bug to me, no? > > > > Since our controller will meet some strange behaviors if we do > > software reset for all in sdhci_runtime_resume_host(), and try to > > avoid changing the core logic of sdhci_runtime_resume_host() used by > > other hardware controllers, thus I introduced a specific reset ops and > > added some condition to make sure we just do software reset command > > and data lines from runtime suspend state. > > I understand, but perhaps it would become more clear if > sdhci_runtime_resume_host() is re-factored a bit. Maybe the caller can > give it some new parameter to let it decide if a SDHCI_RESET_ALL shall > be done or not. Yes, sounds reasonable, but need change other host drivers which issued the sdhci_runtime_resume_host(). Adrian, if you also agree with Ulf's suggestion, then I will post new patches to add a parameter to decide the reset mode. Thanks. -- Baolin Wang Best Regards