From: Liviu Dudau <Liviu.Dudau@arm.com>
To: Yijing Wang <wangyijing@huawei.com>
Cc: Liviu Dudau <liviu@dudau.co.uk>, Tony Luck <tony.luck@intel.com>,
Russell King <linux@arm.linux.org.uk>,
Arnd Bergmann <arnd@arndb.de>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"huxinwei@huawei.com" <huxinwei@huawei.com>,
Thierry Reding <thierry.reding@gmail.com>,
Yijing Wang <wangyijing0307@gmail.com>,
"suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>,
Bjorn Helgaas <bhelgaas@google.com>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>, Wuyun <wuyun.wu@huawei.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH 01/16] PCI: Enhance pci_scan_root_bus() to support default IO/MEM resources
Date: Tue, 18 Nov 2014 14:23:54 +0000 [thread overview]
Message-ID: <20141118142354.GH12037@e106497-lin.cambridge.arm.com> (raw)
In-Reply-To: <546B317E.4090800@huawei.com>
On Tue, Nov 18, 2014 at 11:46:06AM +0000, Yijing Wang wrote:
> On 2014/11/18 17:36, Arnd Bergmann wrote:
> > On Tuesday 18 November 2014 15:44:23 Yijing Wang wrote:
> >> On 2014/11/17 18:08, Arnd Bergmann wrote:
> >>> On Monday 17 November 2014 18:21:35 Yijing Wang wrote:
> >>>> - list_for_each_entry(window, resources, list)
> >>>> - if (window->res->flags & IORESOURCE_BUS) {
> >>>> - found =3D true;
> >>>> - break;
> >>>> - }
> >>>> + if (!resources) {
> >>>> + pci_add_resource(&default_res, &ioport_resource);
> >>>> + pci_add_resource(&default_res, &iomem_resource);
> >>>> + pci_add_resource(&default_res, &busn_resource);
> >>>> + } else {
> >>>>
> >>>
> >>> Isn't it almost always wrong to do this? You are adding all of the
> >>> I/O ports and memory to the host bridge, which will prevent you from
> >>> adding another host bridge, and the iomem_resource normally
> >>> includes a lot of addresses that are not accessible by the PCI host.
> >>
> >> Hi Arnd, pci host bridge windows are the ranges allow child devices to=
setup
> >> from. Add all of IO/MEM here just a limit to child devices, no request=
for these
> >> resources, so it won't hurt another host bridge. Some platforms have n=
o dts or ACPI
> >> report host bridge resources, in this case, we directly assign ioport/=
iomem_resources
> >> as the root resources of PCI devices.
> >=20
> > But it would be wrong to allow hosts to allocate a device BAR that is n=
ot
> > visible through the host bridge. I think we need to keep these separate
> > from the general case: if you call any of the modern interfaces you hav=
e
> > to provide the resources and a device. I notice that there is only one
> > caller of pci_scan_bus_parented(), we should probably change that over =
to
> > pci_scan_root_bus() or your new interface and remove the old one, but
> > keep pci_scan_bus() as the only entry point for all of the legacy users
> > that do not know about the resources.
>=20
> Ok, I will move this out of the generic interface.
My suggestion would actually be to trigger a warning/error if you detect th=
at the resources
are missing. That way we can force the drivers to clean up.
Best regards,
Liviu
>=20
> Thanks!
> Yijing.
>=20
> >=20
> > =09Arnd
> >=20
> > .
> >=20
>=20
>=20
> --=20
> Thanks!
> Yijing
>=20
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>=20
--=20
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
| I would like to |
| fix the world, |
| but they're not |
| giving me the |
\ source code! /
---------------
=C2=AF\_(=E3=83=84)_/=C2=AF
next prev parent reply other threads:[~2014-11-18 14:24 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-17 10:21 [RFC PATCH 00/16] Refine PCI host bridge scan interfaces Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 01/16] PCI: Enhance pci_scan_root_bus() to support default IO/MEM resources Yijing Wang
2014-11-17 10:08 ` Arnd Bergmann
2014-11-18 7:44 ` Yijing Wang
2014-11-18 9:36 ` Arnd Bergmann
2014-11-18 11:46 ` Yijing Wang
2014-11-18 14:23 ` Liviu Dudau [this message]
2014-11-19 1:15 ` Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 02/16] PCI: Use pci_scan_root_bus() instead of pci_scan_bus() Yijing Wang
2014-11-18 14:28 ` Liviu Dudau
2014-11-19 1:19 ` Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 03/16] PCI: Clean up pci_scan_bus() Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 04/16] PCI: Rip out pci_bus_add_devices() from pci_scan_root_bus() Yijing Wang
2014-11-18 14:34 ` Liviu Dudau
2014-11-19 1:21 ` Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 05/16] PCI: Use pci_scan_root_bus() instead of pci_scan_bus_parented() Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 06/16] PCI: Use u32 type to combine PCI domain and bus number Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 07/16] PCI: Separate pci_host_bridge creation out of pci_create_root_bus() Yijing Wang
2014-11-17 10:56 ` Arnd Bergmann
2014-11-18 8:32 ` Yijing Wang
2014-11-18 9:30 ` Arnd Bergmann
2014-11-18 11:44 ` Yijing Wang
2014-11-18 12:25 ` Arnd Bergmann
2014-11-18 12:41 ` Yijing Wang
2014-11-18 14:48 ` Liviu Dudau
2014-11-19 2:24 ` Yijing Wang
2014-11-19 16:29 ` Liviu Dudau
2014-11-20 2:00 ` Yijing Wang
2014-11-18 15:30 ` Liviu Dudau
2014-11-19 1:42 ` Yijing Wang
2014-11-19 16:37 ` Liviu Dudau
2014-11-20 2:47 ` Yijing Wang
2014-11-20 9:47 ` Liviu Dudau
2014-11-21 2:53 ` Yijing Wang
2014-11-21 9:53 ` Liviu Dudau
2014-11-17 10:21 ` [RFC PATCH 08/16] PCI: Introduce pci_scan_host_bridge() and pci_host_info Yijing Wang
2014-11-18 15:42 ` Liviu Dudau
2014-11-19 2:09 ` Yijing Wang
2014-11-19 16:41 ` Liviu Dudau
2014-11-20 2:54 ` Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 09/16] PCI: Associate .get_msi_ctrl() with pci_host_bridge Yijing Wang
2014-11-17 15:03 ` Lorenzo Pieralisi
2014-11-17 10:21 ` [RFC PATCH 10/16] PCI: Add of_scan_bus() to pci_host_info Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 11/16] x86/PCI: Use pci_scan_host_bridge() instead of pci_create_root_bus() Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 12/16] ia64/PCI: Remove the redundant bus variable Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 13/16] ia64/PCI: Use pci_scan_host_bridge() to refactor pci_acpi_scan_root() Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 14/16] arm/PCI: Introduce pci_get_domain_nr() Yijing Wang
2014-11-17 12:08 ` Lorenzo Pieralisi
2014-11-18 0:55 ` Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 15/16] arm/PCI: Use pci_scan_host_bridge() instead of pci_scan_root_bus() Yijing Wang
2014-11-17 10:21 ` [RFC PATCH 16/16] powerpc/PCI: Use pci_scan_host_bridge() to scan PCI bus Yijing Wang
2014-11-17 14:13 ` [RFC PATCH 00/16] Refine PCI host bridge scan interfaces Arnd Bergmann
2014-11-18 11:17 ` Yijing Wang
2014-11-18 11:30 ` Arnd Bergmann
2014-11-18 11:45 ` Lorenzo Pieralisi
2014-11-18 12:14 ` Yijing Wang
2014-11-18 12:17 ` Yijing Wang
2014-11-18 12:27 ` Arnd Bergmann
2014-11-20 12:01 ` Tomasz Nowicki
2014-11-20 13:15 ` Arnd Bergmann
2014-11-20 11:54 ` Tomasz Nowicki
2014-11-20 12:08 ` Liviu Dudau
2014-11-20 12:53 ` Tomasz Nowicki
2014-11-20 16:39 ` Liviu Dudau
2014-11-21 2:58 ` Yijing Wang
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