Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751947AbdGaSAi (ORCPT ); Mon, 31 Jul 2017 14:00:38 -0400 Received: from ale.deltatee.com ([207.54.116.67]:56751 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751352AbdGaSAf (ORCPT ); Mon, 31 Jul 2017 14:00:35 -0400 To: Andy Shevchenko Cc: "linux-kernel@vger.kernel.org" , Linux-Arch , linux-ntb@googlegroups.com, linux-crypto , Arnd Bergmann , Greg Kroah-Hartman , =?UTF-8?Q?Horia_Geant=c4=83?= , Stephen Bates , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Suresh Warrier , Nicholas Piggin References: <20170726231917.6073-1-logang@deltatee.com> <20170726231917.6073-4-logang@deltatee.com> <5c52d908-3b77-c5c6-99a7-1164d878ac95@deltatee.com> <3a4c9453-20be-8164-85eb-5ad4d596a299@deltatee.com> From: Logan Gunthorpe Message-ID: <65ca8848-3a99-bda8-5165-9453b70316fa@deltatee.com> Date: Mon, 31 Jul 2017 12:00:11 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 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: npiggin@gmail.com, warrier@linux.vnet.ibm.com, mpe@ellerman.id.au, paulus@samba.org, benh@kernel.crashing.org, sbates@raithlin.com, horia.geanta@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, andy.shevchenko@gmail.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v5 3/6] iomap: introduce io{read|write}64_{lo_hi|hi_lo} X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 680 Lines: 20 On 31/07/17 11:58 AM, Andy Shevchenko wrote: > On Mon, Jul 31, 2017 at 7:31 PM, Logan Gunthorpe wrote: >> On 31/07/17 10:10 AM, Andy Shevchenko wrote: >>> Some drivers (hardware) would like to have non-atomic MMIO accesses >>> when readq() defined >> >> Huh? But that's the whole point of the io64-nonatomic header. If a >> driver wants a specific non-atomic access they should just code two 32 >> bit accesses. > You mean to call them directly as lo_hi_XXX() or hi_lo_XXX() ? > Yes it would work. I suppose you could do that too but I really meant just using two io32 calls. That's the most explicit way to indicate you want a non-atomic access. Logan