Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751617AbaGTJqF (ORCPT ); Sun, 20 Jul 2014 05:46:05 -0400 Received: from mail-pa0-f45.google.com ([209.85.220.45]:37469 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751505AbaGTJpx (ORCPT ); Sun, 20 Jul 2014 05:45:53 -0400 Message-ID: <53CB8FC4.4050009@gmail.com> Date: Sun, 20 Jul 2014 17:45:40 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Lennox Wu CC: Richard Weinberger , Arnd Bergmann , Lars-Peter Clausen , Guenter Roeck , Greg Kroah-Hartman , Dmitry Torokhov , linux-iio@vger.kernel.org, Benjamin Herrenschmidt , Tom Gundersen , Thierry Reding , Marek Vasut , Liqin Chen , msalter@redhat.com, linux-pwm@vger.kernel.org, devel@driverdev.osuosl.org, linux-watchdog@vger.kernel.org, linux-input@vger.kernel.org, "linux-kernel@vger.kernel.org" , knaack.h@gmx.de, Martin Schwidefsky , Martin Schwidefsky , jic23@kernel.org, Geert Uytterhoeven , cmetcalf@tilera.com, heiko.carstens@de.ibm.com Subject: Re: [PATCH] drivers: Let several drivers depends on HAS_IOMEM for 'devm_ioremap_resource' References: <201407130545.23004.marex@denx.de> <6823014.2plXDE9VA9@wuerfel> <53C7A819.40403@metafoo.de> <6485666.LVFO2YCEQx@wuerfel> <53C8114D.30601@nod.at> <53C86C10.2000608@gmail.com> <53C8CE59.3060103@nod.at> <53C8FA78.1020501@gmail.com> <53C8FC1E.9090003@nod.at> <53C9612E.3040001@gmail.com> <53CB801D.1030603@gmail.com> In-Reply-To: <53CB801D.1030603@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/20/2014 04:38 PM, Chen Gang wrote: > On 07/19/2014 02:02 AM, Chen Gang wrote: >>> 2014-07-18 18:51 GMT+08:00 Richard Weinberger : >>>> Am 18.07.2014 12:44, schrieb Chen Gang: >>>>> On 07/18/2014 03:35 PM, Richard Weinberger wrote: >>>>>> Am 18.07.2014 02:36, schrieb Chen Gang: >>>>>>> >>>>>>> On 07/18/2014 02:09 AM, Richard Weinberger wrote: >>>>>>>> Am 17.07.2014 12:48, schrieb Arnd Bergmann: >>>>>>>>> AFAICT, NO_IOMEM only has a real purpose on UML these days. Could we take >>>>>>>>> a shortcut here and make COMPILE_TEST depend on !UML? Getting random stuff >>>>>>>>> to build on UML seems pointless to me and we special-case it in a number of >>>>>>>>> places already. >>>>>>>> >>>>>>>> If UML is the only arch without io memory the dependency on !UML seems >>>>>>>> reasonable to me. :-) >>>>>>>> >>>>>>> >>>>>>> For me, if only uml left, I suggest to implement dummy functions within >>>>>>> uml instead of let CONFIG_UML appear in generic include directory. And >>>>>>> then remove all HAS_IOMEM and NO_IOMEM from kernel. >>>>>> >>>>>> Erm, this is something completely different. >>>>>> I thought we're focusing on COMPILE_TEST? >>>>>> >>>>> >>>>> COMPILE_TEST is none-architecture specific, but UML is. So in generic >>>>> include folder, if we're focusing on choosing whether COMPILE_TEST or >>>>> UML, for me, I will choose COMPILE_TEST. >>>>> >>>>> If we're not only focusing on COMPILE_TEST, for me, if something only >>>>> depend on one architecture, I'd like to put them under "arch/*/" folder. >>>>> >>>>> Especially, after that, we can remove all HAS_IOMEM and NO_IOMEM, nobody >>>>> has to think of them again. :-) >>>> >>>> And then we end up with a solution that on UML a lot of completely useless >>>> drivers are build which fail in various interesting manners because you'll >>>> add stubs for all kinds of io memory related functions to arch/um/? >>>> We had this kind of discussion already. You'll need more than ioremap... >>>> >>>> I like Arnd's idea *much* more to make COMPILE_TEST depend on !UML. >>>> >> >> That will let UML itself against COMPILE_TEST (but all the other >> architectures not). >> >> And if let COMPILE_TEST depend on !UML, can we still remove all >> HAS_IOMEM and NO_IOMEM from kernel? (I guess so). >> >> If we can remove them, we can send related patch firstly -- that will >> let current discussion be in UML architecture wide instead of kernel >> wide. >> > > Next, I shall: > > - Remove HAS_IOMEM and NO_IOMEM from kernel, firstly. > > - Try to make dummy IOMEM functions for score architecture. > > - Continue discussing with UML for it. > Oh, sorry, I forgot, after remove IOMEM from kernel, also s390 and tile need implement dummy IOMEM if !PCI. If possible, I shall try to implement the dummy IOMEM in 'asm-generic', and let uml, score, s390 and tile use them when they need. > > By the way: how about HAS_DMA? can we treat it as HAS_IOMEM (remove > it from kernel)? (for me, I guess we can not). > > > At present, I shall finish sending patch for removing IOMEM today, and > continue to welcome any ideas, suggestions or completions for IOMEM or > DMA. > > Thanks. -- Chen Gang Open share and attitude like air water and life which God blessed -- 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/