From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424799AbcFMP4v (ORCPT ); Mon, 13 Jun 2016 11:56:51 -0400 Received: from foss.arm.com ([217.140.101.70]:53160 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424417AbcFMP4t (ORCPT ); Mon, 13 Jun 2016 11:56:49 -0400 Date: Mon, 13 Jun 2016 16:56:46 +0100 From: Liviu.Dudau@arm.com To: Lorenzo Pieralisi Cc: Bjorn Helgaas , Tomasz Nowicki , arnd@arndb.de, will.deacon@arm.com, catalin.marinas@arm.com, rafael@kernel.org, hanjun.guo@linaro.org, okaya@codeaurora.org, jchandra@broadcom.com, robert.richter@caviumnetworks.com, mw@semihalf.com, ddaney@caviumnetworks.com, wangyijing@huawei.com, Suravee.Suthikulpanit@amd.com, msalter@redhat.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, jcm@redhat.com, andrea.gallo@linaro.org, dhdang@apm.com, jeremy.linton@arm.com, liudongdong3@huawei.com, cov@codeaurora.org Subject: Re: [PATCH V9 09/11] ARM64/PCI: ACPI support for legacy IRQs parsing and consolidation with DT code Message-ID: <20160613155646.GF1165@e106497-lin.cambridge.arm.com> References: <1465588519-11334-1-git-send-email-tn@semihalf.com> <1465588519-11334-10-git-send-email-tn@semihalf.com> <20160610233612.GB7671@localhost> <20160613104005.GA26738@red-moon> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20160613104005.GA26738@red-moon> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 13, 2016 at 11:40:05AM +0100, Lorenzo Pieralisi wrote: > On Fri, Jun 10, 2016 at 06:36:12PM -0500, Bjorn Helgaas wrote: > > On Fri, Jun 10, 2016 at 09:55:17PM +0200, Tomasz Nowicki wrote: > > > To enable PCI legacy IRQs on platforms booting with ACPI, arch code > > > should include ACPI specific callbacks that parse and set-up the > > > device IRQ number, equivalent to the DT boot path. Owing to the current > > > ACPI core scan handlers implementation, ACPI PCI legacy IRQs bindings > > > cannot be parsed at device add time, since that would trigger ACPI scan > > > handlers ordering issues depending on how the ACPI tables are defined. > > > > Uh, OK :) I can't figure out exactly what the problem is here -- I > > don't know where to look if I wanted to fix the scan handler ordering > > issues, and I don't know how I could tell if it would ever be safe to > > move this from driver probe-time back to device add-time. > > Right, the commit log could have been more informative. > > pcibios_add_device() was added in: > > commit d1e6dc91b532 ("arm64: Add architectural support for PCI") > > whose commit log does not specify why legacy IRQ parsing should > be done at pcibios_add_device() either, so honestly we had to > do with the information we have at hand. Because at that time (September 2014) there was no pcibios_alloc_irq() (added June 2015 by commit 890e4847587fcf) and after that nobody bothered to update the arm64 code to make use of the new API. Best regards, Liviu > > > I also notice that x86 and ia64 call acpi_pci_irq_enable() even later, > > when the driver *enables* the device. Is there a reason you didn't do > > it at the same time as x86 and ia64? This is another of those pcibios > > hooks that really don't do anything arch-specific, so I can imagine > > refactoring this somehow, someday. > > Yes, with [1], that was the goal, that stopped because [1] does not > work on x86. > > Only DT platform(s) affected by this change are all platforms relying on > drivers/pci/host/pci-xgene.c (others rely on pci_fixup_irqs() that > should be removed too), if on those platforms probing IRQs at device > enable time works ok I can update this patch (it can be done through [1] > once we figure out what to do with it on x86) and move the IRQ set-up at > pcibios_enable_device() time. > > @Duc: any feedback on this ? > > Thanks, > Lorenzo > > [1] http://www.spinics.net/lists/linux-pci/msg45950.html > > > Did we have this conversation before? It seems vaguely familiar, so I > > apologize if you already explained this once. > > > > > To solve this problem and consolidate FW PCI legacy IRQs parsing in > > > one single pcibios callback (pending final removal), this patch moves > > > DT PCI IRQ parsing to the pcibios_alloc_irq() callback (called by > > > PCI core code at device probe time) and adds ACPI PCI legacy IRQs > > > parsing to the same callback too, so that FW PCI legacy IRQs parsing > > > is confined in one single arch callback that can be easily removed > > > when code parsing PCI legacy IRQs is consolidated and moved to core > > > PCI code. > > > > > > Signed-off-by: Tomasz Nowicki > > > Suggested-by: Lorenzo Pieralisi > > > --- > > > arch/arm64/kernel/pci.c | 11 ++++++++--- > > > 1 file changed, 8 insertions(+), 3 deletions(-) > > > > > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > > > index d5d3d26..b3b8a2c 100644 > > > --- a/arch/arm64/kernel/pci.c > > > +++ b/arch/arm64/kernel/pci.c > > > @@ -51,11 +51,16 @@ int pcibios_enable_device(struct pci_dev *dev, int mask) > > > } > > > > > > /* > > > - * Try to assign the IRQ number from DT when adding a new device > > > + * Try to assign the IRQ number when probing a new device > > > */ > > > -int pcibios_add_device(struct pci_dev *dev) > > > +int pcibios_alloc_irq(struct pci_dev *dev) > > > { > > > - dev->irq = of_irq_parse_and_map_pci(dev, 0, 0); > > > + if (acpi_disabled) > > > + dev->irq = of_irq_parse_and_map_pci(dev, 0, 0); > > > +#ifdef CONFIG_ACPI > > > + else > > > + return acpi_pci_irq_enable(dev); > > > +#endif > > > > > > return 0; > > > } > > > -- > > > 1.9.1 > > > > > > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯