From patchwork Thu Dec 21 18:25:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Halaney X-Patchwork-Id: 757835 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 5CBAF76DAB for ; Thu, 21 Dec 2023 18:25:54 +0000 (UTC) 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="enNpJMA4" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1703183153; 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=4md7/lhuz61o/OLaxynlTwcjr95vaOPE75vAR/46vcY=; b=enNpJMA4fN8JH3VNlV3uLcxRq80vl2Oc+/iVP7UrgiyZnNRsoWhRTigt40jpd0er/UInIB Dk0cw0HmMGSxQvT5DjkjsyRsRpqJL1xa8LeZ5epFQuZBQqpC8IsJBaO9cgbcNMFQzchx1H rSwENWZW1vzdnEkOci3Tlr7kaAq/oOU= Received: from mail-qv1-f70.google.com (mail-qv1-f70.google.com [209.85.219.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-323-lbDaR5FQMuiXv9Tx9_-zKg-1; Thu, 21 Dec 2023 13:25:51 -0500 X-MC-Unique: lbDaR5FQMuiXv9Tx9_-zKg-1 Received: by mail-qv1-f70.google.com with SMTP id 6a1803df08f44-67ec592bc29so15300126d6.0 for ; Thu, 21 Dec 2023 10:25:51 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703183151; x=1703787951; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=4md7/lhuz61o/OLaxynlTwcjr95vaOPE75vAR/46vcY=; b=sBDq3wkDud7Tq3GTEvHwbTxjZv8kSPqpb5w6ytKpg6dE0Rgk7vDQ7HArgBCrtoWJKm 3qIyW7rh6T1MoSYgyBUFy1PHN/pyfpZF3tPfdMphVtwjCDMJEeuUwxW2Q8vWn9h3b7SQ h5X50YmUhehJH3mKPkjlNtqr+KLQWHrax8lewv7B++ZWMNUvJ6V8f6USiCiD7YesdgzM 5IxRKR5n54vhgggZI/BBvxJmwZvsNQmgi+T2Ly4I9lbOnXycmFHOPoW49uqhmzOb79Wg wCSHEFoNneVFugDvQQg4nPbezGA857Zv3Axf0WAem6mPYNlaoNF3Y1AzZev0L8QXcjLI IYUw== X-Gm-Message-State: AOJu0YyPGAXbSR2CFHb4I63CyMDmX4Vuk+baUzDAxcpstuaZpqnBmn+R mOlhK4436NKmR0y/7sLj4Y3vttWte0R/YAwhf4ibyMV6v6awTPPOYnueOtK1xP5KaHit4d6fk47 X0S6LqhIqPZS0pkbQDgVO788UPo17ehGb0w== X-Received: by 2002:a05:6214:f04:b0:67f:106c:aaca with SMTP id gw4-20020a0562140f0400b0067f106caacamr136463qvb.48.1703183151343; Thu, 21 Dec 2023 10:25:51 -0800 (PST) X-Google-Smtp-Source: AGHT+IExmZV+caO5vbXAe3tRFmp3a2qAi57YtrPfWuDvh+LaHqaf0w9mGD/BoRsz8IzVXIh+shJ/JQ== X-Received: by 2002:a05:6214:f04:b0:67f:106c:aaca with SMTP id gw4-20020a0562140f0400b0067f106caacamr136438qvb.48.1703183151057; Thu, 21 Dec 2023 10:25:51 -0800 (PST) Received: from [192.168.1.163] ([2600:1700:1ff0:d0e0::37]) by smtp.gmail.com with ESMTPSA id da7-20020a05621408c700b0067f2c03d4adsm779605qvb.100.2023.12.21.10.25.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Dec 2023 10:25:50 -0800 (PST) From: Andrew Halaney Date: Thu, 21 Dec 2023 12:25:25 -0600 Subject: [PATCH RFC v2 08/11] scsi: ufs: core: Perform read back after disabling interrupts Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20231221-ufs-reset-ensure-effect-before-delay-v2-8-75af2a9bae51@redhat.com> References: <20231221-ufs-reset-ensure-effect-before-delay-v2-0-75af2a9bae51@redhat.com> In-Reply-To: <20231221-ufs-reset-ensure-effect-before-delay-v2-0-75af2a9bae51@redhat.com> To: Andy Gross , Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , "James E.J. Bottomley" , "Martin K. Petersen" , Yaniv Gardi , Dov Levenglick , Hannes Reinecke , Subhash Jadavani , Gilad Broner , Venkat Gopalakrishnan , Janek Kotas , Alim Akhtar , Avri Altman , Bart Van Assche , Anjana Hari , Dolev Raviv , Can Guo Cc: Will Deacon , linux-arm-msm@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Halaney X-Mailer: b4 0.12.3 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") Signed-off-by: Andrew Halaney Reviewed-by: Manivannan Sadhasivam --- 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 7bfb556e5b8e..bb603769b029 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -10568,7 +10568,7 @@ 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);