From patchwork Mon Jan 22 17:24:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Halaney X-Patchwork-Id: 13525888 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 675EA6280A for ; Mon, 22 Jan 2024 17:25:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705944331; cv=none; b=m/Gb0dNJlgREDOZ1hhhUZz1bB15U8h4EUH3U5gLF2sAsbXmAFZMocbTx5n8mlyGLa0zntJl/fufNBdjSIl7UqP+vn3029rKhmCm6xi17hX7jftF2cNvQ6npNOwu3JxxGpmJ5V1NhlfEqxot3qkpz2o9FalzlYnvt0t1SlQTZPZU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705944331; c=relaxed/simple; bh=eqU9bnJJL8L6334KQv0i2/sTryAarZX2XDro3a1bVTs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ttWeroKZFlq7eI1gFgogSDAPsYcpDzqWT/+9IjQff5AjdnIupjC2MlqAMhXSjgt/GsMJzJYBkGB9+IaHbfAJufVx3/XflbXggL4Tczss+V8HXNCWYjMjU/ViT/iUx7JH759lENDEzJQrXJSqVUpR0YgNksecSWeOcptVwk8T8EQ= 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=dIOWq8xk; arc=none smtp.client-ip=170.10.129.124 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="dIOWq8xk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1705944325; 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=v9E8LP/sXchUxMDynkpMldI5w3cNLtCQjxmXDj4qu+Y=; b=dIOWq8xkxjsVlzEfUN7tHOFrCD6zts4YUeRRA00Bam7eZlB2tdU5Dgs9TrqmKYLIplgX8c TrorVX8PtfsKCSyT3P7gWfD9ZPakW9hDn8KRWf/xkmclkIC5ykymgkWdUAMMeyF/YobpXh EfaeLkBM5ObzFhJ2TkG5L3wYG52OQfc= Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-387-0tPhQiI0OjmGcEufnsmvMA-1; Mon, 22 Jan 2024 12:25:24 -0500 X-MC-Unique: 0tPhQiI0OjmGcEufnsmvMA-1 Received: by mail-qt1-f198.google.com with SMTP id d75a77b69052e-42a02969f69so55894671cf.3 for ; Mon, 22 Jan 2024 09:25:24 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705944320; x=1706549120; 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=v9E8LP/sXchUxMDynkpMldI5w3cNLtCQjxmXDj4qu+Y=; b=X2jB0YTOKY+tFjKPUzi81aWAZll/A9fkcAzLHWEDD5LCnfNGa2ERMZBiBR1m1T/WIv ZEGrcTCbtKH2YDmbvk5tefZZlsygsgxPq+R2cMBLdIHVG357SPEe6wB9zrIZIj+2GOFO shauJLE6FVW/XSGCgfld77EYmmTdNu0FvfvrXuwJlQAp0P+/mATSgEgdfu5skGeXgMQV viKW01Y5Cya/OHi8jTFOKuXbrJoSL4xXqDth0uwwwGcRrRNV2BsSSJHbdHTAkWJLuUpt 1ysZK3dgiOWh36ANcsuW02Ib9DwLMuZFW8Rsvzv4J9hqUXm56b6QkW1zJg8RGnitBavw w6zQ== X-Gm-Message-State: AOJu0YyT712CFHPFjuIoHCFCCl5k4NAqwpCJq5iIsJbxcHKQb5cNMAlg XEIM1ye1j+RURUZPbmr8YKmv7aXLlCSQoe21Xo30fevPvsEN0S8zL1AsbHIJ0zOsqfunsSrS53u PN9d4mAazHKHNSC8cPTkwN1hMFToxR+yU65SMjCRyo5lt0kK982rWbHQKXB0= X-Received: by 2002:ac8:5c06:0:b0:42a:2be8:37f8 with SMTP id i6-20020ac85c06000000b0042a2be837f8mr7667928qti.46.1705944319780; Mon, 22 Jan 2024 09:25:19 -0800 (PST) X-Google-Smtp-Source: AGHT+IEw9tYpVM1Vb6nwYLykf7yZWc23Mfc1dOE48wD53sQO6xtnskKBD0ZYOxmi4yAMEBoT5Y13vg== X-Received: by 2002:ac8:5c06:0:b0:42a:2be8:37f8 with SMTP id i6-20020ac85c06000000b0042a2be837f8mr7667911qti.46.1705944319483; Mon, 22 Jan 2024 09:25:19 -0800 (PST) Received: from fedora.redhat.com ([2600:1700:1ff0:d0e0::37]) by smtp.gmail.com with ESMTPSA id c7-20020a05620a200700b00781ae860c31sm2280992qka.70.2024.01.22.09.25.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 09:25:17 -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, Manivannan Sadhasivam Subject: [PATCH RFC v4 09/11] scsi: ufs: core: Perform read back after disabling UIC_COMMAND_COMPL Date: Mon, 22 Jan 2024 11:24:05 -0600 Message-ID: <20240122-ufs-reset-ensure-effect-before-delay-v4-9-90a54c832508@redhat.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122-ufs-reset-ensure-effect-before-delay-v4-0-90a54c832508@redhat.com> References: <20240122-ufs-reset-ensure-effect-before-delay-v4-0-90a54c832508@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 UIC_COMMAND_COMPL interrupt is disabled and a wmb() is used to complete the register write before any following writes. wmb() ensures the writes complete in that order, but completion doesn't mean that it isn't stored in a buffer somewhere. The recommendation for ensuring this bit has 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 bit hits the device. Because the wmb()'s purpose wasn't to add extra ordering (on top of the ordering guaranteed by writel()/readl()), it can safely be removed. Fixes: d75f7fe495cf ("scsi: ufs: reduce the interrupts for power mode change requests") Reviewed-by: Bart Van Assche Reviewed-by: Can Guo Reviewed-by: Manivannan Sadhasivam 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 9b6355555897..9bf490bb8eed 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -4240,7 +4240,7 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd) * Make sure UIC command completion interrupt is disabled before * issuing UIC command. */ - wmb(); + ufshcd_readl(hba, REG_INTERRUPT_ENABLE); reenable_intr = true; } spin_unlock_irqrestore(hba->host->host_lock, flags);