From mboxrd@z Thu Jan 1 00:00:00 1970 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 C60E976DDF for ; Thu, 21 Dec 2023 18:25:56 +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="F7fequ4V" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1703183155; 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=F7fequ4VIRhX6t6qYOHntkIvt8CQokcEKjGn/U0tUQkQVopRnXMKqtVTxDp137WRdBtCBI LfvZAG45B3jGTP6jsnreth9bc/9I0y9AlT1iw02CzPJzFg8XAA6FEPEW9ir9/bInORAbbs mM8ET+MwoNTsi6vRDnPO5J7R/4CVMRk= Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-475-bYbruVEgOsGNvrLHMR86tw-1; Thu, 21 Dec 2023 13:25:54 -0500 X-MC-Unique: bYbruVEgOsGNvrLHMR86tw-1 Received: by mail-qk1-f200.google.com with SMTP id af79cd13be357-7810802421bso131705285a.2 for ; Thu, 21 Dec 2023 10:25:54 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703183150; x=1703787950; 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=xUUJuT608SRhCl6+0/SpXWAx7Kuk//nvBAACeA7YhJo=; b=P2iE1QJV3grzQKxH3Zuw1KhJE0RGKeI0uHXoyiOa4ZmL4zs2SbUNzMtFLciis/pmxG gXWHqy2hzSmANz63TZu0VZIepV67utCfFk771abwaZ77saIsL7GAKz3MjDI7Axw4mEcw VyiWtgUy2bYD7fd2JC1Qg7Yo84JHLdA/y4/cNlKgxx1kk5s6Rz2q5NyTgtM76g8pz2rs nx8f+8m2QbOdSlcXSRGbylJsmbdsJpdoo0Lr7Y8YOYsmR8TKhvhthNr6MpOOYss9iteT 4L/NvwOiKlZFr4HkLPeF1YZ9H8tiHcO+9vMXQN3ChD6CMnN06FaqiTGFqJgNiDw1jkas MZQQ== X-Gm-Message-State: AOJu0Yzk1y+GDVB2b+llHm0tlMQvKCwd0JiH2i+WEeyRzIrfsi5Y5hxB MtaftP5tt9B8WU6jqHPTT2T46gIXCmbuxHPRDNM01kHLAlSGWGM2/Fo+nVPiwWO/9Biqek9C+aJ u0/dHu12OzkUFEsgZhArsGSNsKp3c1g== X-Received: by 2002:a05:6214:23cf:b0:67a:a721:f313 with SMTP id hr15-20020a05621423cf00b0067aa721f313mr119304qvb.83.1703183150067; Thu, 21 Dec 2023 10:25:50 -0800 (PST) X-Google-Smtp-Source: AGHT+IGJ9Kju9IqTA5EEJRzv9VHVG6omJS9ICt+kO57nwljfFPxGim4CiNb9HpK10WnlhSNr539//w== X-Received: by 2002:a05:6214:23cf:b0:67a:a721:f313 with SMTP id hr15-20020a05621423cf00b0067aa721f313mr119290qvb.83.1703183149828; Thu, 21 Dec 2023 10:25:49 -0800 (PST) Received: from [192.168.1.163] ([2600:1700:1ff0:d0e0::37]) by smtp.gmail.com with ESMTPSA id da7-20020a05621408c700b0067f2c03d4adsm779605qvb.100.2023.12.21.10.25.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Dec 2023 10:25:46 -0800 (PST) From: Andrew Halaney Date: Thu, 21 Dec 2023 12:25:24 -0600 Subject: [PATCH RFC v2 07/11] scsi: ufs: core: Perform read back after writing UTP_TASK_REQ_LIST_BASE_H Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20231221-ufs-reset-ensure-effect-before-delay-v2-7-75af2a9bae51@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, 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 --- 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); -- 2.43.0