From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 10717B6EDD for ; Fri, 9 Jul 2010 22:58:27 +1000 (EST) In-Reply-To: <20100708150904.79feffdd@schlenkerla.am.freescale.net> References: <1278614421.1801.0@antares> <20100708150904.79feffdd@schlenkerla.am.freescale.net> Mime-Version: 1.0 (Apple Message framework v753.1) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: From: Segher Boessenkool Subject: Re: [PATCH] arch/powerpc/lib/copy_32.S: Use alternate memcpy for MPC512x and MPC52xx Date: Fri, 9 Jul 2010 14:59:09 +0200 To: Scott Wood Cc: =?ISO-8859-1?Q?Albrecht_Dre=DF?= , Steve Deiters , linuxppc-dev@lists.ozlabs.org, David Woodhouse List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , >>> Actually, this is something which might need closer attention - >>> and maybe some support in the device tree indicating which read or >>> write width a device can accept? >> >> There already is "device-width"; the drivers never should use any >> other access width unless they *know* that will work. > > Wouldn't you want to use "bank-width" instead? We were talking about single devices. But, sure, when you have multiple devices in parallel the driver needs to know about that. > It would be nice to have a device tree property that can specify that > all access widths supported by the CPU will work, though. Oh please no. A device binding should not depend on what CPU there is in the system. There could be multiple CPUs of different architectures, even. To figure out how to access a device, the driver looks at the device's node, and all its parent nodes (or asks generic code to do that, or platform code). Segher