From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nishanth Menon Subject: Re: [PATCH v8 2/2] omap hsmmc: adaptation of sdma descriptor autoloading feature Date: Fri, 7 May 2010 14:26:07 -0500 Message-ID: <4BE4694F.3060901@ti.com> References: <004501caed38$03e7b9f0$544ff780@am.dhcp.ti.com> <000601caee06$b2c8a9b0$544ff780@am.dhcp.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from comal.ext.ti.com ([198.47.26.152]:39984 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758024Ab0EGT0T (ORCPT ); Fri, 7 May 2010 15:26:19 -0400 In-Reply-To: <000601caee06$b2c8a9b0$544ff780@am.dhcp.ti.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: "Chikkature Rajashekar, Madhusudhan" Cc: "Shilimkar, Santosh" , 'kishore kadiyala' , "S, Venkatraman" , "linux-omap@vger.kernel.org" , "linux-mmc@vger.kernel.org" , "linux-arm-kernel@lists.arm.linux.org.uk" , 'Adrian Hunter' , "Kadiyala, Kishore" , 'Tony Lindgren' Chikkature Rajashekar, Madhusudhan had written, on 05/07/2010 11:59 AM, the following: > >> >>> -----Original Message----- >>> From: Chikkature Rajashekar, Madhusudhan >>> Sent: Thursday, May 06, 2010 9:50 PM >>> To: Shilimkar, Santosh; 'kishore kadiyala' >>> Cc: S, Venkatraman; linux-omap@vger.kernel.org; linux- >> mmc@vger.kernel.org; linux-arm- >>> kernel@lists.arm.linux.org.uk; 'Adrian Hunter'; Kadiyala, Kishore; 'Tony >> Lindgren' >>> Subject: RE: [PATCH v8 2/2] omap hsmmc: adaptation of sdma descriptor >> autoloading feature >>> >>> >>>> -----Original Message----- >>>> From: Shilimkar, Santosh [mailto:santosh.shilimkar@ti.com] >>>> Sent: Thursday, May 06, 2010 4:39 AM >>>> To: kishore kadiyala >>>> Cc: S, Venkatraman; linux-omap@vger.kernel.org; linux- >> mmc@vger.kernel.org; >>>> linux-arm-kernel@lists.arm.linux.org.uk; Chikkature Rajashekar, >>>> Madhusudhan; Adrian Hunter; Kadiyala, Kishore; Tony Lindgren >>>> Subject: RE: [PATCH v8 2/2] omap hsmmc: adaptation of sdma descriptor >>>> autoloading feature >>>> >>>>> -----Original Message----- >>>>> From: kishore kadiyala [mailto:kishorek.kadiyala@gmail.com] >>>>> Sent: Thursday, May 06, 2010 2:32 PM >>>>> To: Shilimkar, Santosh >>>>> Cc: S, Venkatraman; linux-omap@vger.kernel.org; linux- >>>> mmc@vger.kernel.org; linux-arm- >>>>> kernel@lists.arm.linux.org.uk; Chikkature Rajashekar, Madhusudhan; >>>> Adrian Hunter; Kadiyala, Kishore; >>>>> Tony Lindgren >>>>> Subject: Re: [PATCH v8 2/2] omap hsmmc: adaptation of sdma >> descriptor >>>> autoloading feature >>>>> <> >>>>> >>>>>>> I am not clear about the method. The board files export the >>>>>>> omap_mmc_platform_data. >>>>>>> Does it imply that all board files have to change and export >>>>>>> the capability so that it can be queried ? >>>>>> No. You don't have to modify the board files. This would need >>>>>> change in devices.c which common for all omap boards. >>>>>> >>>>>> I don't have a strong opinion on this point but just put forth an >>>>>> alternate way to avoid such SOC specific check in drivers. >>>>>> You can take call on this >>>>> Agree. How about adding a flag in hsmmc.h & omap_mmc_platform_data, >>>>> that would take care of SDMA & SDMA_DLAOD in the driver instead >> going >>>>> with SOC check . >>>> Good idea Kishore. >>>> Venkat, >>>> Can you do what kishore is suggesting. >>>> >>> omap_mmc_platform_data is MMC specific platform data. Why add a SDMA >>> specific feature capability into it? Even though you add it there, you >> will >>> still need to have a cpu check before that can be set in a common code. >>> >> CPU checks are allowed to be in the platform files. That is where such >> machine/SOC specific differentiation should be done and not in the device >> drivers. >> That way device drivers remains clean and portable. >> >> I want to stop this thread here since neither the patch author nor the >> file >> maintainer thinks that cpu checks in the device drivers is bad idea. >> >> Please decide within yourself and move on. >> > > I am not saying that it is wrong. My point here is that adding this > particular flag into MMC platform data to differentiate a SDMA specific > feature which got introduced post certain SOC may not be needed. But you can > always post your comments on the list which will be looked at by a wider > audience and finally the right patch will go in. Please see [1] for SOC specific feature handling. any reasons we can't handle it by adding a new feature? [1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/arm/plat-omap/include/plat/cpu.h#l439 -- Regards, Nishanth Menon