From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <lersek@redhat.com>
Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (No client certificate requested)
 by ml01.01.org (Postfix) with ESMTPS id A26C51A1EC4
 for <edk2-devel@ml01.01.org>; Fri, 14 Oct 2016 05:06:51 -0700 (PDT)
Received: from int-mx14.intmail.prod.int.phx2.redhat.com
 (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (No client certificate requested)
 by mx1.redhat.com (Postfix) with ESMTPS id 20FBE13854;
 Fri, 14 Oct 2016 12:06:51 +0000 (UTC)
Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-51.phx2.redhat.com
 [10.3.116.51])
 by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id
 u9EC6nk4007152; Fri, 14 Oct 2016 08:06:50 -0400
To: Bhupesh Sharma <bhupesh.sharma@nxp.com>
References: <1476437615-29534-1-git-send-email-bhupesh.sharma@nxp.com>
From: Laszlo Ersek <lersek@redhat.com>
Cc: edk2-devel@ml01.01.org
Message-ID: <38e8d690-b981-4b37-1ad2-6c6975ad2a9a@redhat.com>
Date: Fri, 14 Oct 2016 14:06:49 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.4.0
MIME-Version: 1.0
In-Reply-To: <1476437615-29534-1-git-send-email-bhupesh.sharma@nxp.com>
X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16
 (mx1.redhat.com [10.5.110.25]); Fri, 14 Oct 2016 12:06:51 +0000 (UTC)
Subject: Re: [PATCH 1/1] MdePkg/IoLib: Add support for big-endian MMIO
X-BeenThere: edk2-devel@lists.01.org
X-Mailman-Version: 2.1.21
Precedence: list
List-Id: EDK II Development  <edk2-devel.lists.01.org>
List-Unsubscribe: <https://lists.01.org/mailman/options/edk2-devel>,
 <mailto:edk2-devel-request@lists.01.org?subject=unsubscribe>
List-Archive: <http://lists.01.org/pipermail/edk2-devel/>
List-Post: <mailto:edk2-devel@lists.01.org>
List-Help: <mailto:edk2-devel-request@lists.01.org?subject=help>
List-Subscribe: <https://lists.01.org/mailman/listinfo/edk2-devel>,
 <mailto:edk2-devel-request@lists.01.org?subject=subscribe>
X-List-Received-Date: Fri, 14 Oct 2016 12:06:51 -0000
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit

On 10/14/16 11:33, Bhupesh Sharma wrote:
> Various IPs on NXP/FSL SoCs having ARM64 cores have big-endian
> MMIO interfaces.
> 
> This implies that a byte-swap operation is needed to read/write
> such BE MMIO registers from the LE ARM64 cores.
> 
> This patch adds the support for the same.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@nxp.com>
> ---
>  MdePkg/Include/Library/IoLib.h               | 364 ++++++++++++++++++++
>  MdePkg/Library/BaseIoLibIntrinsic/IoLibArm.c | 479 +++++++++++++++++++++++++++
>  2 files changed, 843 insertions(+)

I think this is both overkill and incomplete, at the same time :)

- Incomplete because only one IoLib instance gets the implementation.

- Overkill because you can easily use the SwapBytes16, SwapBytes32,
SwapBytes64 functions -- also from BaseLib --, for transforming
MmioWrite arguments and MmioRead results.

Thanks
Laszlo