From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: [PATCH] MTD: OMAP2-NAND: Fix partition reading from board info Date: Mon, 4 Aug 2008 14:37:34 -0700 Message-ID: <200808041437.34822.david-b@pacbell.net> References: <9c9fda240807011627v60428f9eh3c2bb17cdc8ce6ea@mail.gmail.com> <200808041326.38840.david-b@pacbell.net> <20080804205617.GF31974@xi.wantstofly.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp119.sbc.mail.sp1.yahoo.com ([69.147.64.92]:28335 "HELO smtp119.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1765651AbYHDVhh (ORCPT ); Mon, 4 Aug 2008 17:37:37 -0400 In-Reply-To: <20080804205617.GF31974@xi.wantstofly.org> Content-Disposition: inline Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Lennert Buytenhek Cc: Tony Lindgren , "Kamat, Nishant" , "linux-omap@vger.kernel.org" , Kyungmin Park , "linux-mtd@lists.infradead.org" On Monday 04 August 2008, Lennert Buytenhek wrote: > > I've never seen CPU endianity being hardwired in any ARM system ever > -- but maybe OMAP is different. I'll let TI answer that one, since I'm not going to look at docs for all the ARM's I've ever used. My observation stands *REGARDLESS* of whether endianness was fixed in hardware, bootloader, or kernel ... and in any case, with very few exceptions (not including OMAP), Linux uses ARMs in LE mode: ~/kernel/linux-2.6/arch/arm/configs$ grep ENDIAN * | egrep -v '#' |egrep -v OHCI ixp2000_defconfig:CONFIG_ARCH_SUPPORTS_BIG_ENDIAN=y ixp2000_defconfig:CONFIG_CPU_BIG_ENDIAN=y ixp23xx_defconfig:CONFIG_ARCH_SUPPORTS_BIG_ENDIAN=y ixp23xx_defconfig:CONFIG_CPU_BIG_ENDIAN=y ixp4xx_defconfig:CONFIG_ARCH_SUPPORTS_BIG_ENDIAN=y ixp4xx_defconfig:CONFIG_CPU_BIG_ENDIAN=y ~/kernel/linux-2.6/arch/arm/configs$ ls | wc -l 105 ~/kernel/linux-2.6/arch/arm/configs$ To repeat: there's no point in having the words byteswapped when writing, then again when reading, like this driver does. All that does is ensure slow I/O paths. Were you disagreeing with that main point? Or just quibbling about where any unusual big-endianness might come from? - Dave