From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH v13 10/12] PCI: Assign unassigned bus resources in
 pci_scan_root_bus()
Date: Tue, 30 Sep 2014 07:02:01 +1000
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To: Yinghai Lu <yinghai@kernel.org>
Cc: Liviu Dudau <Liviu.Dudau@arm.com>, Bjorn Helgaas <bhelgaas@google.com>, Arnd Bergmann <arnd@arndb.de>, Rob Herring <robh+dt@kernel.org>, Jason Gunthorpe <jgunthorpe@obsidianresearch.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <Will.Deacon@arm.com>, Russell King <linux@arm.linux.org.uk>, linux-pci <linux-pci@vger.kernel.org>, Linus Walleij <linus.walleij@linaro.org>, Tanmay Inamdar <tinamdar@apm.com>, Grant Likely <grant.likely@secretlab.ca>, Sinan Kaya <okaya@codeaurora.org>, Jingoo Han <jg1.han@samsung.com>, Kukjin Kim <kgene.kim@samsung.com>, Suravee Suthikulanit <suravee.suthikulpanit@amd.com>, linux-arch <linux-arch@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, Device Tree ML <devicetree@vger.kernel.org>, LAKML <linux-arm-kernel@lists.infradead.org>, Jiang Liu <jiang.liu@linux.intel.com>
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On Mon, 2014-09-29 at 12:06 -0700, Yinghai Lu wrote:
> On Mon, Sep 29, 2014 at 11:25 AM, Yinghai Lu <yinghai@kernel.org> wrote:
> > On Mon, Sep 29, 2014 at 7:29 AM, Liviu Dudau <Liviu.Dudau@arm.com> wrote:
> >> If the firmware has not assigned all the bus resources and we are not just
> >> probing the PCI buses, it makes sense to assign the unassigned resources
> >> in pci_scan_root_bus().
> >>
> >> Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
> >> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> >> CC: Arnd Bergmann <arnd@arndb.de>
> >> CC: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
> >> CC: Rob Herring <robh+dt@kernel.org>
> >> ---
> >>  drivers/pci/probe.c | 3 +++
> >>  1 file changed, 3 insertions(+)
> >>
> >> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> >> index 636d1c9..d2ebd49 100644
> >> --- a/drivers/pci/probe.c
> >> +++ b/drivers/pci/probe.c
> >> @@ -1951,6 +1951,9 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
> >>         if (!found)
> >>                 pci_bus_update_busn_res_end(b, max);
> >>
> >> +       if (!pci_has_flag(PCI_PROBE_ONLY))
> >> +               pci_assign_unassigned_bus_resources(b);
> >> +
> >>         pci_bus_add_devices(b);
> >>         return b;
> >>  }
> >
> > No, you can not do it that early.
> >
> > On x86, we need to call
> > pcibios_resource_survey_bus at first.
> 
> on x86:
> pcibios_init
> pcibios_resource_survey()
> pcibios_assign_resources() via fs_initcall
 
Right and on powerpc and others as well. We need to survey existing
resources. We also have a number of platform things that might need
to happen before we do the final re-assignment pass.

Ben.