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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 77242C3279B for ; Wed, 4 Jul 2018 17:22:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3865323C6A for ; Wed, 4 Jul 2018 17:22:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3865323C6A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deltatee.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752816AbeGDRWB (ORCPT ); Wed, 4 Jul 2018 13:22:01 -0400 Received: from ale.deltatee.com ([207.54.116.67]:42902 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752218AbeGDRV7 (ORCPT ); Wed, 4 Jul 2018 13:21:59 -0400 Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1falTR-00087x-RT; Wed, 04 Jul 2018 11:21:50 -0600 To: Andy Shevchenko Cc: Fabio Estevam , Horia Geanta , Aymen Sghaier , Andrew Morton , linux-kernel , Linux-Arch , "linux-ntb@googlegroups.com" , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , Arnd Bergmann , Greg Kroah-Hartman , Dan Douglass , Herbert Xu , "David S. Miller" References: <20180622194752.11221-1-logang@deltatee.com> <6e5224b9-343f-990c-19bd-fe37c6fbdc9b@deltatee.com> <7ddda181-6337-32cc-7a0d-43fc6a7ba78b@deltatee.com> <991b2298-bb3f-dad3-c93b-b43ee5f372de@deltatee.com> <55236e2b-a2a5-493a-5696-19c5926885b3@deltatee.com> From: Logan Gunthorpe Message-ID: <851ae9b3-80c8-1089-060c-f4baa4e57489@deltatee.com> Date: Wed, 4 Jul 2018 11:21:47 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: davem@davemloft.net, herbert@gondor.apana.org.au, dan.douglass@nxp.com, gregkh@linuxfoundation.org, arnd@arndb.de, linux-crypto@vger.kernel.org, linux-ntb@googlegroups.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, aymen.sghaier@nxp.com, horia.geanta@nxp.com, festevam@gmail.com, andy.shevchenko@gmail.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v18 6/7] crypto: caam: cleanup CONFIG_64BIT ifdefs when using io{read|write}64 X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/4/2018 11:16 AM, Andy Shevchenko wrote: > On Wed, Jul 4, 2018 at 8:13 PM, Logan Gunthorpe wrote: >> On 7/4/2018 11:10 AM, Andy Shevchenko wrote: >>> We have an iDMA 32-bit hardware (see drivers/dma/dw/) which has an >>> extension 64-bit registers where only one of them has a specific bit >>> to "commit" the changes written to all of them. And by some very >>> unknown reason that bit is in lo part which automatically means we >>> must to write it last. >> >> And it supports both BE and LE? And in both cases it's the lo part? > > It's only LE for now. So the main question is if they were to add BE support, would they leave the trigger in the same address or swap it to the other address so that it's always the LO part that triggers? Otherwise it's hard to say what we really want for the BE variants of the non-atomic hi-lo operations. In the end, the driver author is free to use specifically which ever function is necessary in any given situation (lo-hi vs hi-lo) and they can read the definitions and no one is using them yet. So either way is probably just as valid and it's probably not really worth fussing too much about. Logan