Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756750Ab0DFQci (ORCPT ); Tue, 6 Apr 2010 12:32:38 -0400 Received: from smtp.nokia.com ([192.100.105.134]:64127 "EHLO mgw-mx09.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751669Ab0DFQcc (ORCPT ); Tue, 6 Apr 2010 12:32:32 -0400 Date: Tue, 6 Apr 2010 19:32:11 +0300 From: Felipe Balbi To: ext Madhusudhan Cc: "me@felipebalbi.com" , "'kishore kadiyala'" , "'Vimal Singh'" , "tony@atomide.com" , "svenkatr@ti.com" , "linux-omap@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Lavinen Jarkko (Nokia-D/Helsinki)" Subject: Re: [PATCH v3] OMAP: Fix for bus width which improves SD card's peformance. Message-ID: <20100406163211.GA29117@nokia.com> Reply-To: felipe.balbi@nokia.com References: <003b01cad0f0$6ea78040$544ff780@am.dhcp.ti.com> <003c01cad1b1$da2cdbf0$544ff780@am.dhcp.ti.com> <20100405164839.GB17388@gandalf> <007c01cad4e4$26c5a700$544ff780@am.dhcp.ti.com> <20100406050035.GA32537@gandalf> <003901cad5a4$730264d0$544ff780@am.dhcp.ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <003901cad5a4$730264d0$544ff780@am.dhcp.ti.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-OriginalArrivalTime: 06 Apr 2010 16:32:22.0877 (UTC) FILETIME=[BBFE40D0:01CAD5A6] X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1837 Lines: 55 On Tue, Apr 06, 2010 at 06:16:01PM +0200, ext Madhusudhan wrote: > > >> -----Original Message----- >> From: Felipe Balbi [mailto:me@felipebalbi.com] >> Sent: Tuesday, April 06, 2010 12:01 AM >> To: Madhusudhan >> Cc: me@felipebalbi.com; 'kishore kadiyala'; 'Vimal Singh'; >> tony@atomide.com; svenkatr@ti.com; linux-omap@vger.kernel.org; linux- >> kernel@vger.kernel.org; jarkko.lavinen@nokia.com >> Subject: Re: [PATCH v3] OMAP: Fix for bus width which improves SD card's >> peformance. >> >> Hi, >> >> On Mon, Apr 05, 2010 at 12:19:29PM -0500, Madhusudhan wrote: >> > Since the first if command already checks for the 8-bit the second check >> > like >= 4 is definitely not readable in my opinion. >> >> how come ??? >> >> > Functionally do you see anything wrong with this patch?? >> >> functionally no, but (hypothetical situation) and if on >> omap4/5/6/whatever, omap controller supports a bigger bus width then >> you'll have to add a line like: >> >> + if (mmc_slot(host).wires == 16) >> + mmc->caps |= (MMC_CAP_16_BIT_DATA | MMC_CAP_8_BIT_DATA | >> + MMC_CAP_4_BIT_DATA); >> - if (mmc_slot(host).wires == 8) >> + else if (mmc_slot(host).wires == 8) >> >> do you see the problem ?? In my opinion it doesn't scale well. >> > >The point we should note here is that MMC spec supports a max bus width of >8-bit. So anything beyond 8-bit is not in the picture as of today. in that case, the code could be: WARN_ON(mmc_slot(host).wires > 8); if (mmc_slot(host).wires == 8) mmc->caps |= MMC_CAP_8_BIT_DATA; if (mmc_slot(host).wires >= 4) mmc->caps |= MMC_CAP_4_BIT_DATA; -- balbi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/