From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:58210 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935986AbeFRJcI (ORCPT ); Mon, 18 Jun 2018 05:32:08 -0400 Date: Mon, 18 Jun 2018 10:32:01 +0100 From: Lorenzo Pieralisi To: Rob Herring , Jan Kiszka Cc: Scott Branden , Guenter Roeck , Bjorn Helgaas , linux-pci@vger.kernel.org, Ley Foon Tan , Russell King Subject: Re: [v4] PCI: improve host drivers compile test coverage Message-ID: <20180618093201.GA18994@e107981-ln.cambridge.arm.com> References: <20180405193154.27897-1-robh@kernel.org> <20180612170229.GA10141@roeck-us.net> <20180613100935.GA7707@e107981-ln.cambridge.arm.com> <20180613181146.GA28856@roeck-us.net> <20180615125847.GA7735@e107981-ln.cambridge.arm.com> <980b68c0-6034-b495-753f-c75c04e0f5d1@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-pci-owner@vger.kernel.org List-ID: On Fri, Jun 15, 2018 at 12:34:51PM -0600, Rob Herring wrote: > On Fri, Jun 15, 2018 at 11:55 AM, Scott Branden > wrote: > > Hi Lorenzo, > > > > > > > > On 18-06-15 05:58 AM, Lorenzo Pieralisi wrote: > >> > >> On Wed, Jun 13, 2018 at 11:11:46AM -0700, Guenter Roeck wrote: > >>> > >>> On Wed, Jun 13, 2018 at 11:09:35AM +0100, Lorenzo Pieralisi wrote: > >>>> > >>>> [+Jan, Ley Foon, RMK] > >>>> > >>>> On Tue, Jun 12, 2018 at 10:02:29AM -0700, Guenter Roeck wrote: > >>>>> > >>>>> On Thu, Apr 05, 2018 at 02:31:54PM -0500, Rob Herring wrote: > >>>>>> > >>>>>> Add COMPILE_TEST on driver config options with it. Some ARM drivers > >>>>>> still have arch dependencies, so we have to keep those dependent on > >>>>>> ARM. > >>>>>> > >>>>>> Cc: Lorenzo Pieralisi > >>>>>> Cc: Bjorn Helgaas > >>>>>> Cc: linux-pci@vger.kernel.org > >>>>>> Signed-off-by: Rob Herring > >>>>> > >>>>> This patch has the undesirable side effect that it selects PCI_DOMAINS > >>>>> for > >>>>> sparc32:allmodconfig, which in turn results in > >>>>> > >>>>> drivers/ata/pata_ali.c: In function 'ali_init_chipset': > >>>>> drivers/ata/pata_ali.c:469:38: error: > >>>>> implicit declaration of function 'pci_domain_nr'; did you mean > >>>>> 'pci_iomap_wc'? > >>>>> > >>>>> Unfortunately, 37bd62d224c82 ("PCI: Enable PCI_DOMAINS along with > >>>>> generic > >>>>> PCI host controller") has pretty much the same result. No idea how to > >>>>> fix > >>>>> the problem, so I won't even try. > >>>> > >>>> Sorry about that. > >>>> > >>>> One option would consist in removing all PCI_DOMAINS selection from > >>>> drivers/pci/controller/Kconfig and delegate it to arches even though > >>>> this would force PCI_DOMAINS selection on all ARM platforms (it is > >>>> already selected for ARCH_MULTIPLATFORM). > >>>> > >>>> Or we add back arch dependency to the relevant host bridges. > >>>> > >>>> Everything else I have in mind seems overkill to me given that this > >>>> patch was added to improve test coverage (we could add a default > >>>> pci_domain_nr() stub - weak or #define - that returns 0 in case arches > >>>> do not provide an implementation but do we really want to do that ?). > >>>> > >>>> Thoughts appreciated. > >>>> > >>> From the definition of PCI_DOMAINS, I suspect the original idea was that > >>> drivers should depend on it, not select it. Especially auto-selecting > >>> it with PCI_HOST_GENERIC seems like a bad idea to me. However, that is > >>> just me. I'll leave it up to Bjorn to decide what if anything he wants > >>> to do about it. > >> > >> Here is a patch that should reinstate the previous behaviour but > >> it will make PCI_DOMAINS a visible option on ARM 32-bit systems; whether > >> that's acceptable that's the question I need to answer, it should > >> honour old configs and it does not force PCI_DOMAINS selection on > >> non-DT arch/arm PCI host controllers (that do not need PCI_DOMAINS > >> anyway so I suspect that enabling it on all ARM 32-bit platforms > >> should not break anything but I preferred to be cautious). > > > > I think this change will also require a patch enabling CONFIG_PCI_DOMAINS in > > multi_v7_defconfig and iproc_defconfig at the very least? > > Perhaps the sub-arches that want this should select it. It is more a > platform option/decision more than a controller option. Yes, that makes sense, I assume ARCH_VIRT is a sensible choice for virtual machines configuration, Jan ? I will add a PCI_DOMAINS selection to all (ARM) arches that select PCI_DOMAINS in drivers/pci/controller/Kconfig. For Jailhouse configurations I need Jan's input, I assume adding the selection to ARCH_VIRT is the correct way forward, please let me know asap. Lorenzo