From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Pitre Subject: Re: [PATCH 02/04] smc91x: introduce platform data flags Date: Wed, 20 Feb 2008 22:28:59 -0500 (EST) Message-ID: References: <20080220095740.22645.36783.sendpatchset@clockwork.opensource.se> <20080220095802.22645.44691.sendpatchset@clockwork.opensource.se> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Transfer-Encoding: 7BIT Cc: netdev@vger.kernel.org, lethal@linux-sh.org, akpm@linux-foundation.org To: Magnus Damm Return-path: Received: from relais.videotron.ca ([24.201.245.36]:51718 "EHLO relais.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751387AbYBUD3D (ORCPT ); Wed, 20 Feb 2008 22:29:03 -0500 Received: from xanadu.home ([66.131.194.97]) by VL-MH-MR002.ip.videotron.ca (Sun Java(tm) System Messaging Server 6.3-4.01 (built Aug 3 2007; 32bit)) with ESMTP id <0JWK00BRDKCB11C0@VL-MH-MR002.ip.videotron.ca> for netdev@vger.kernel.org; Wed, 20 Feb 2008 22:28:59 -0500 (EST) In-reply-to: Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 21 Feb 2008, Magnus Damm wrote: > On Thu, Feb 21, 2008 at 12:58 AM, Nicolas Pitre wrote: > > On Wed, 20 Feb 2008, Magnus Damm wrote: > > > > > This patch introduces struct smc91x_platdata and modifies the driver so > > > bus width is checked during run time using SMC_nBIT() instead of > > > SMC_CAN_USE_nBIT. > > > > > > Signed-off-by: Magnus Damm > > > --- > > > > NAK. > > > > The SMC91C111 (for example) is often used on devices which have a CPU > > clock barely higher than the network throughput, hence it is crutial for > > those devices to have the most efficient access possible to the chip or > > performance will suffer. This is the main reason behind the heavily > > macroized register access so things are always optimized for the data > > bus capabilities at compile time. > > I understand that you want to keep the code as fast as possible. So do > I. But I want to remove the need to modify smc91x.h for each board I > want to support. It is much better in my opinion to have a wide range > of boards supported but a little bit lower throughput compared to only > a few boards supported and excellent performance... People can always > modify the header file by themselves if they want to squeeze out that > extra percent of performance. Sure. That's perfectly fine for new boards. But existing setups should not regress due to this change. > > I think you should add a SMC_DYNAMIC_BUS_CONFIG and redefine SMC_nBITS() > > so they dereference cfg.flags only when it is defined. > > Sure, good idea. I'll fix that. Do you mind if I make that the default > behavior? So boards that doesn't have any hard coded configuration in > smc91x.h can use the platform data flags method for configuration > instead. Yes, that's fine. Nicolas