From patchwork Fri Mar 29 20:46:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Halaney X-Patchwork-Id: 13611055 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A344148CCD for ; Fri, 29 Mar 2024 20:50:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711745438; cv=none; b=sJ5O1KpfExKed2/yawE4PD2ej6VuScWDBq1gHWw7czmgyox9fjxJLTkKqj35h8/g0qDAP5T1nQ5WuX1Klfw1pdaFRezB22CmzIEeSFsmA18Aqy5aISPzMwQ9RYUSAm3tB1nQXtRdIh8XVATO3/LLyVBtClTBz12XLfpNHbAFKgU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711745438; c=relaxed/simple; bh=rUiFGJENhkjaL5XQk3rVKmNTCac0phrGlXxO+qQgbyw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=erwNqvVoNms4lPJ12Tz/K0dbwc3cVPfYeiBUTN5w1kqGCb+fFL+8JGsGeXmQme8DAVCX7TWOO5B2wZ6bZkvgTzhXZ+7weXN6QgFSFmi1WIfmVtyK0x5FR7p304EH9U+JHSD38BVw5SFkWHjy1YUmQbGXoBIP9XbLbUO/oYfmMJU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Rwx9wsfm; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Rwx9wsfm" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1711745435; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kfliicv5toOd2B87oyO1cEhsCWrclX7x2KOA+OKHojY=; b=Rwx9wsfmQ81+Sm2pfj+F5OwJsfHI0tgP3fkh2nXRXEo8d636Cc3q3dFLZiFfX1jrHHxnzo 6u6qE8zMVSm4rZ+zBlDfpi3oqT/bvhoWRnKI/DaYK+n5q1Zip9onpdNAljtyMIfz06ZMmQ SWpzBjlSiNnS8TpLd1fNmiaxtDoiY+E= Received: from mail-qv1-f72.google.com (mail-qv1-f72.google.com [209.85.219.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-172-noR1HHE1ORaWqlgxz7XEIw-1; Fri, 29 Mar 2024 16:50:34 -0400 X-MC-Unique: noR1HHE1ORaWqlgxz7XEIw-1 Received: by mail-qv1-f72.google.com with SMTP id 6a1803df08f44-698ec7e66e1so12390356d6.2 for ; Fri, 29 Mar 2024 13:50:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711745433; x=1712350233; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=kfliicv5toOd2B87oyO1cEhsCWrclX7x2KOA+OKHojY=; b=ncz2cMlpeulnLEN5N0GPiluPDP0auTsixBCslY8nmjM+E1jElfFXil6ZgsIdGJTSt3 QHHElrMsvFTcD36Wj3DZkgxhp1Cl15+qmFdRS0hxMTN9Z1R/Vzwi19izP9+2mxzFyqwj NryKNIvv+G8/GJAl5avBpxjOICQARkaprUI2GVnUAH1misqxqP9JeiFRA7Pr1GsYNCRQ FB58tcmyz5FC0pLPZNDV/pATxBMYmfh5Vi4HXxskQZYEIYjs5ouaYKKrPJGo8jLIwR9/ 0kLAWyYFGLjPa3GA9AfyQMFB5xZqhmZ1aSB0b196mvsF4o5rvYxn8oPDYI2YjBiDqoAb 6gHA== X-Forwarded-Encrypted: i=1; AJvYcCXMeL96lysePA18irwApv+DrlYe8ljRsTUxH5XMi4iPYZGDbIOJsfoK0Ec9kEG/cazAaouBMb4M6hNkbE80IouM4lBi/bxEkxow8g== X-Gm-Message-State: AOJu0Yy+yGxLb/21YjASAx9xQt7m0r4VRRs3KOwIaIbZY5RRGHIljbn+ +IoeAvCN4g+BtrXBI7xVNOHynQarrn2B3grS+ygHlKmr/plgPMS+q2IY2jdtdy0FsjCrzhuzdRh D3j+dA+C7V0X18zu48wdLKZmpD53aUK63EsTm31G6oU3S8lEuR6TXzybfdfs= X-Received: by 2002:a05:6214:190a:b0:696:b095:c429 with SMTP id er10-20020a056214190a00b00696b095c429mr3119259qvb.40.1711745433046; Fri, 29 Mar 2024 13:50:33 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGSRd/5i8QlyLSkwg85Jxr+u352RMnwF3m/7r26iSWU00W9M/Q4Hw8RMOt9vf05jAbg6L8gpQ== X-Received: by 2002:a05:6214:190a:b0:696:b095:c429 with SMTP id er10-20020a056214190a00b00696b095c429mr3119243qvb.40.1711745432697; Fri, 29 Mar 2024 13:50:32 -0700 (PDT) Received: from x1gen2nano.redhat.com ([2600:1700:1ff0:d0e0::33]) by smtp.gmail.com with ESMTPSA id jz10-20020a0562140e6a00b00698f27c6460sm794271qvb.110.2024.03.29.13.50.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Mar 2024 13:50:31 -0700 (PDT) From: Andrew Halaney To: Andy Gross , Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , "James E.J. Bottomley" , "Martin K. Petersen" , Hannes Reinecke , Janek Kotas , Alim Akhtar , Avri Altman , Bart Van Assche , Can Guo , Anjana Hari Cc: Andrew Halaney , Will Deacon , linux-arm-msm@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Manivannan Sadhasivam Subject: [PATCH v5 08/11] scsi: ufs: core: Perform read back after disabling interrupts Date: Fri, 29 Mar 2024 15:46:50 -0500 Message-ID: <20240329-ufs-reset-ensure-effect-before-delay-v5-8-181252004586@redhat.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240329-ufs-reset-ensure-effect-before-delay-v5-0-181252004586@redhat.com> References: <20240329-ufs-reset-ensure-effect-before-delay-v5-0-181252004586@redhat.com> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mailer: b4 0.13.0 Currently, interrupts are cleared and disabled prior to registering the interrupt. An mb() is used to complete the clear/disable writes before the interrupt is registered. mb() ensure that the write completes, but completion doesn't mean that it isn't stored in a buffer somewhere. The recommendation for ensuring these bits have taken effect on the device is to perform a read back to force it to make it all the way to the device. This is documented in device-io.rst and a talk by Will Deacon on this can be seen over here: https://youtu.be/i6DayghhA8Q?si=MiyxB5cKJXSaoc01&t=1678 Let's do that to ensure these bits hit the device. Because the mb()'s purpose wasn't to add extra ordering (on top of the ordering guaranteed by writel()/readl()), it can safely be removed. Fixes: 199ef13cac7d ("scsi: ufs: avoid spurious UFS host controller interrupts") Reviewed-by: Manivannan Sadhasivam Reviewed-by: Bart Van Assche Reviewed-by: Can Guo Signed-off-by: Andrew Halaney --- drivers/ufs/core/ufshcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index a89887878d98..268fcfebd7bd 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -10616,7 +10616,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq) * Make sure that UFS interrupts are disabled and any pending interrupt * status is cleared before registering UFS interrupt handler. */ - mb(); + ufshcd_readl(hba, REG_INTERRUPT_ENABLE); /* IRQ registration */ err = devm_request_irq(dev, irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba);