From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DBC60C4338F for ; Wed, 4 Aug 2021 07:56:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B424F60E96 for ; Wed, 4 Aug 2021 07:56:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236013AbhHDH4W (ORCPT ); Wed, 4 Aug 2021 03:56:22 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3574 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235977AbhHDH4V (ORCPT ); Wed, 4 Aug 2021 03:56:21 -0400 Received: from fraeml706-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4GfkZK1dqrz6GFWC; Wed, 4 Aug 2021 15:55:53 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml706-chm.china.huawei.com (10.206.15.55) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Wed, 4 Aug 2021 09:56:07 +0200 Received: from [10.47.90.65] (10.47.90.65) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 4 Aug 2021 08:56:06 +0100 Subject: Re: [GIT PULL 1/2] asm-generic: rework PCI I/O space access To: Arnd Bergmann CC: Linus Torvalds , linux-arch , linux-pci , "Linux Kernel Mailing List" , Niklas Schnelle References: From: John Garry Message-ID: <5e8dfbd2-a6c0-6d02-53e9-1f29aebcc44e@huawei.com> Date: Wed, 4 Aug 2021 08:55:38 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.90.65] X-ClientProxiedBy: lhreml751-chm.china.huawei.com (10.201.108.201) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On 03/08/2021 13:15, Arnd Bergmann wrote: >> That seems reasonable. And asm-generic io.h should be ifdef'ed by >> HAS_IOPORT. In your patch you had it under CONFIG_IOPORT - was that >> intentional? > No, that was a typo. Thanks for pointing this out. > >> On another point, I noticed SCSI driver AHA152x depends on ISA, but is >> not an isa driver - however it does use port IO. Would such dependencies >> need to be changed to depend on HAS_IOPORT? > I'm not sure what you mean here. As far as I can tell, AHA152x is an ISA > driver in the sense that it is a driver for ISA add-on cards. However, it > is not a 'struct isa_driver' in the sense that AHA1542 is, AHA152x is even > older and uses the linux-2.4 style initialization using a module_init() > function that does the probing. ok, fine. So I just wonder what the ISA kconfig dependency gets us for aha152x. I experimented by removing the kconfig dependency and enabling for the arm64 (which does not have CONFIG_ISA) std defconfig and it built fine. > >> I did notice that arm32 support CONFIG_ISA - not sure why. > This is for some of the earlier machines we support: > mach-footbridge has some on-board ISA components, while > SA1100, PXA25x and S3C2410 each have at least one machine > with a PC/104 connector using ISA signaling for add-on cards. > > There are also a couple of platforms with PCMCIA or CF slots > using the same ISA style I/O signals, but those have separate > drivers. > >>> HARDCODED_IOPORT: (or another name you might think of,) Used by >>> drivers that unconditionally do inb()/outb() without checking the >>> validity of the address using firmware or other methods first. >>> depends on HAS_IOPORT and possibly architecture specific >>> settings. >> Yeah, that sounds the same as what I was thinking. Maybe IOPORT_NATIVE >> could work as a name. I would think that only x86/ia64 would define it. >> A concern though is that someone could argue that is a functional >> dependency, rather than just a build dependency. > You can have those on a number of platforms, such as early > PowerPC CHRP or pSeries systems, a number of MIPS workstations > including recent Loongson machines, and many Alpha platforms. > hmmm... if some machines under an arch support "native" port IO and some don't, then if we use a common multi-platform defconfig which defines HARDCODED_IOPORT, then we still build for platforms without "native" port IO, which is not ideal. > Maybe the name should reflect that these all use PC-style ISA/LPC > port numbers without the ISA connectors. Thanks, john