From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cyril Chemparathy Subject: Re: [PATCH v3 01/12] misc: add driver for sequencer serial port Date: Fri, 22 Oct 2010 15:33:43 -0400 Message-ID: <4CC1E717.7070707@ti.com> 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> Reply-To: cyril-l0cyMroinI0@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org" , "dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" , "broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "rpurdie-Fm38FmjxZ/leoWH0uzbU5w@public.gmane.org" , "spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" , Andrew Morton , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "lrg-kDsPt+C1G03kYMGBc/C6ZA@public.gmane.org" To: Arnd Bergmann Return-path: In-Reply-To: <201010221448.17728.arnd-r2nGTMty4D4@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.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. ------------------------------------------------------------------------------ Nokia and AT&T present the 2010 Calling All Innovators-North America contest Create new apps & games for the Nokia N8 for consumers in U.S. and Canada $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store http://p.sf.net/sfu/nokia-dev2dev