From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758486Ab0JVTez (ORCPT ); Fri, 22 Oct 2010 15:34:55 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:45518 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756747Ab0JVTey (ORCPT ); Fri, 22 Oct 2010 15:34:54 -0400 Message-ID: <4CC1E717.7070707@ti.com> Date: Fri, 22 Oct 2010 15:33:43 -0400 From: Cyril Chemparathy Reply-To: cyril@ti.com Organization: Texas Instruments User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.14) Gecko/20101006 Lightning/1.0b1 Thunderbird/3.0.9 MIME-Version: 1.0 To: Arnd Bergmann CC: Andrew Morton , "davinci-linux-open-source@linux.davincidsp.com" , "spi-devel-general@lists.sourceforge.net" , "broonie@opensource.wolfsonmicro.com" , "lrg@slimlogic.co.uk" , "dbrownell@users.sourceforge.net" , "grant.likely@secretlab.ca" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "rpurdie@rpsys.net" Subject: Re: [PATCH v3 01/12] misc: add driver for sequencer serial port References: <1287694873-12904-1-git-send-email-cyril@ti.com> <20101021161224.b4c0b623.akpm@linux-foundation.org> <4CC18605.80007@ti.com> <201010221448.17728.arnd@arndb.de> In-Reply-To: <201010221448.17728.arnd@arndb.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/22/2010 08:48 AM, Arnd Bergmann wrote: > On Friday 22 October 2010 14:39:33 Cyril Chemparathy wrote: >>>> +/* Register Access Helpers */ >>>> +static inline u32 ssp_read(struct ti_ssp *ssp, int reg) >>>> +{ >>>> + return __raw_readl(ssp->regs + reg); >>>> +} >>>> + >>>> +static inline void ssp_write(struct ti_ssp *ssp, int reg, u32 val) >>>> +{ >>>> + __raw_writel(val, ssp->regs + reg); >>>> +} >>> >>> Why are the __raw functions used here? >>> >> >> These registers are to be accessed native endian at all times, and >> therefore the le32 conversion done otherwise is inappropriate. > > Won't that break on out-of-order CPUs that need the extra synchronization > done in readl/writel? > AFAICS, ioremap()ed space on ARMv6 should be strongly ordered. > > ... > Thanks Cyril.