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=-10.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 34638C433E0 for ; Thu, 23 Jul 2020 05:14:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E01620714 for ; Thu, 23 Jul 2020 05:14:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="t+lpyZ3B" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726115AbgGWFOT (ORCPT ); Thu, 23 Jul 2020 01:14:19 -0400 Received: from mail29.static.mailgun.info ([104.130.122.29]:34588 "EHLO mail29.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725773AbgGWFOT (ORCPT ); Thu, 23 Jul 2020 01:14:19 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1595481258; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=L8urZGZji+YiLr59Yc6bfwfReJYjnRXe3+RKFtKbzFU=; b=t+lpyZ3BUNH7Ro6hRxu8Bf+2J1znv9prJRvxJkayNku09GLydsGRZBQAwPkrw85hTrX2KCaQ cILPMRMi+zOIBI3+38AnClq3mJQVx9XELBGUi7O2vlFVXxySHzdSlq03fesN6bzCqpaGkaTr fmB5xoQEYuHnj8oudUyuqeJu0XQ= X-Mailgun-Sending-Ip: 104.130.122.29 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n15.prod.us-west-2.postgun.com with SMTP id 5f191ca2ed710aec620f7ec6 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 23 Jul 2020 05:14:10 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id C8AB2C43395; Thu, 23 Jul 2020 05:14:10 +0000 (UTC) Received: from [192.168.0.13] (unknown [183.83.138.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: akashast) by smtp.codeaurora.org (Postfix) with ESMTPSA id D823AC433C6; Thu, 23 Jul 2020 05:14:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org D823AC433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=akashast@codeaurora.org Subject: Re: [PATCH] soc: qcom-geni-se: Don't use relaxed writes when writing commands To: Douglas Anderson , Andy Gross , Bjorn Andersson Cc: linux-arm-msm@vger.kernel.org, swboyd@chromium.org, Rajendra Nayak , Sai Prakash Ranjan , Wolfram Sang , msavaliy@codeaurora.org, Greg Kroah-Hartman , Matthias Kaehlcke , linux-kernel@vger.kernel.org References: <20200722150113.1.Ia50ab5cb8a6d3a73d302e6bdc25542d48ffd27f4@changeid> From: Akash Asthana Message-ID: <7a4dcef8-fd2a-e714-8b05-724c77c7a012@codeaurora.org> Date: Thu, 23 Jul 2020 10:43:52 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200722150113.1.Ia50ab5cb8a6d3a73d302e6bdc25542d48ffd27f4@changeid> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/23/2020 3:31 AM, Douglas Anderson wrote: > Writing the command is the final step in kicking off a transfer. > Let's use writel() to ensure that any other memory accesses are done > before the command kicks off. It's expected that this is mostly > relevant if we're in DMA mode but since it doesn't appear to regress > performance in a measurable way [1] even in PIO mode and it's easier > to reason about then let's just always use it. > > NOTE: this patch came about due to code inspection. No actual > problems were observed that this patch fixes. > > [1] Tested by timing "flashrom -p ec" on a Chromebook which stresses > GENI SPI a lot. > > Suggested-by: Stephen Boyd > Signed-off-by: Douglas Anderson > --- Reviewed-by: Akash Asthana -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project