From patchwork Thu Dec 21 19:09:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Halaney X-Patchwork-Id: 13502579 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 1D71276DD3 for ; Thu, 21 Dec 2023 19:11:06 +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="DsAn/8l5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1703185866; 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=xUUJuT608SRhCl6+0/SpXWAx7Kuk//nvBAACeA7YhJo=; b=DsAn/8l52t3BMaF/dCEVxgi6sP+NAKM7H3vT/b8z9zZMsGumc/Jx2Fh+x+xi4higT7bQ4f E6XiPWFp6Gzo+sPRqKj9WXE7aONpiSipKOTABzpQ0sJqlstY2bOAOrudkbAgDq6gOeD75T 8P2jO/20HBTGYqkDWlkbHsLTZSy1z78= Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-625-QsPhizhbPeWmBBubi49yEA-1; Thu, 21 Dec 2023 14:11:04 -0500 X-MC-Unique: QsPhizhbPeWmBBubi49yEA-1 Received: by mail-qk1-f197.google.com with SMTP id af79cd13be357-781293a471fso24551585a.3 for ; Thu, 21 Dec 2023 11:11:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703185860; x=1703790660; 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=xUUJuT608SRhCl6+0/SpXWAx7Kuk//nvBAACeA7YhJo=; b=gI0QXDp5sLgCY4lsvfM76HxyAAy5ndfT6UiIkVdXdqObvjIY4lJ6ghRYBttEcvOya2 HGq62Qw+grzcKtHtUOWyvNRiAA0kE0KBsq29HjHNrc92DOhtWOZUMbCizu9XZEVvRn5a nSSNtDfyEDdjMiVLsU1I5fzkREJvQCLmAzBAmKssu4HRKU7H/gh6c27M3Ng1mB2dkZyL ti451fW/0EfKJNsFffIxstximJXKDyOOUmQ2ZlQtq9e81aQEjjpSNOuBdBbbVbbW2LEL rwHQFdgdfTSECiDMtrswK9DmUku/3AmJS7g5dzDBp7BVHJRipBdherxgBQgeZI/sPZLQ BiMg== X-Gm-Message-State: AOJu0YydVJNOqkUJlGQPPDfUzxLJVYmQNk+jS/TovLwevfhAUDC2d4yH sgPir4mUUPKXXnJnMgByL4/Voe3/ghx1/ngaa/M+d0aDYlMJsHak8SLG0/EU8jTlQ2mba6nkxTD 9A/CFAdJSHxkbB4Q4uq8i3Q9zNj0eYw== X-Received: by 2002:ae9:e00e:0:b0:781:1a4a:584f with SMTP id m14-20020ae9e00e000000b007811a4a584fmr318118qkk.120.1703185859665; Thu, 21 Dec 2023 11:10:59 -0800 (PST) X-Google-Smtp-Source: AGHT+IHiXPBhS4kKMnaigM0VOu3Xfp4mKtcc2Em3gQUXqUh7Nc2UYXmSf9LOeMTOGyICyCpbM5rz5g== X-Received: by 2002:ae9:e00e:0:b0:781:1a4a:584f with SMTP id m14-20020ae9e00e000000b007811a4a584fmr318097qkk.120.1703185859419; Thu, 21 Dec 2023 11:10:59 -0800 (PST) Received: from fedora.redhat.com ([2600:1700:1ff0:d0e0::37]) by smtp.gmail.com with ESMTPSA id 25-20020a05620a04d900b0077f0a4bd3c6sm846370qks.77.2023.12.21.11.10.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Dec 2023 11:10:56 -0800 (PST) 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 Cc: Andrew Halaney , Will Deacon , linux-arm-msm@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH RFC v3 07/11] scsi: ufs: core: Perform read back after writing UTP_TASK_REQ_LIST_BASE_H Date: Thu, 21 Dec 2023 13:09:53 -0600 Message-ID: <20231221-ufs-reset-ensure-effect-before-delay-v3-7-2195a1b66d2e@redhat.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231221-ufs-reset-ensure-effect-before-delay-v3-0-2195a1b66d2e@redhat.com> References: <20231221-ufs-reset-ensure-effect-before-delay-v3-0-2195a1b66d2e@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 0.12.3 Currently, the UTP_TASK_REQ_LIST_BASE_L/UTP_TASK_REQ_LIST_BASE_H regs are written to and then completed with an mb(). 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 the 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: 88441a8d355d ("scsi: ufs: core: Add hibernation callbacks") Signed-off-by: Andrew Halaney Reviewed-by: Bart Van Assche Reviewed-by: Can Guo --- 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 d1e33328ff3f..7bfb556e5b8e 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -10351,7 +10351,7 @@ int ufshcd_system_restore(struct device *dev) * are updated with the latest queue addresses. Only after * updating these addresses, we can queue the new commands. */ - mb(); + ufshcd_readl(hba, REG_UTP_TASK_REQ_LIST_BASE_H); /* Resuming from hibernate, assume that link was OFF */ ufshcd_set_link_off(hba);