From: Boqun Feng <boqun.feng@gmail.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: "Bjorn Helgaas" <bhelgaas@google.com>,
"Arnd Bergmann" <arnd@arndb.de>, "Marc Zyngier" <maz@kernel.org>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Will Deacon" <will@kernel.org>,
"K. Y. Srinivasan" <kys@microsoft.com>,
"Haiyang Zhang" <haiyangz@microsoft.com>,
"Stephen Hemminger" <sthemmin@microsoft.com>,
"Wei Liu" <wei.liu@kernel.org>,
"Dexuan Cui" <decui@microsoft.com>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-pci@vger.kernel.org,
"Sunil Muthuswamy" <sunilmut@microsoft.com>,
"Mike Rapoport" <rppt@kernel.org>
Subject: Re: [PATCH v6 8/8] PCI: hv: Turn on the host bridge probing on ARM64
Date: Thu, 19 Aug 2021 20:19:54 +0800 [thread overview]
Message-ID: <YR5MaiCZrFJ71AwY@boqun-archlinux> (raw)
In-Reply-To: <20210809155343.GA31511@lpieralisi>
Hi,
On Mon, Aug 09, 2021 at 04:53:43PM +0100, Lorenzo Pieralisi wrote:
> On Mon, Aug 09, 2021 at 10:38:48PM +0800, Boqun Feng wrote:
> > On Tue, Aug 03, 2021 at 06:14:51PM +0100, Lorenzo Pieralisi wrote:
> > > On Tue, Jul 27, 2021 at 02:06:57AM +0800, Boqun Feng wrote:
> > > > Now we have everything we need, just provide a proper sysdata type for
> > > > the bus to use on ARM64 and everything else works.
> > > >
> > > > Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> > > > ---
> > > > drivers/pci/controller/pci-hyperv.c | 7 +++++++
> > > > 1 file changed, 7 insertions(+)
> > > >
> > > > diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> > > > index e6276aaa4659..62dbe98d1fe1 100644
> > > > --- a/drivers/pci/controller/pci-hyperv.c
> > > > +++ b/drivers/pci/controller/pci-hyperv.c
> > > > @@ -40,6 +40,7 @@
> > > > #include <linux/kernel.h>
> > > > #include <linux/module.h>
> > > > #include <linux/pci.h>
> > > > +#include <linux/pci-ecam.h>
> > > > #include <linux/delay.h>
> > > > #include <linux/semaphore.h>
> > > > #include <linux/irqdomain.h>
> > > > @@ -448,7 +449,11 @@ enum hv_pcibus_state {
> > > > };
> > > >
> > > > struct hv_pcibus_device {
> > > > +#ifdef CONFIG_X86
> > > > struct pci_sysdata sysdata;
> > > > +#elif defined(CONFIG_ARM64)
> > > > + struct pci_config_window sysdata;
> > >
> > > This is ugly. HV does not need pci_config_window at all right
> > > (other than arm64 pcibios_root_bridge_prepare()) ?
> > >
> >
> > Right.
> >
> > > The issue is that in HV you have to have *some* sysdata != NULL, it is
> > > just some data to retrieve the hv_pcibus_device.
> > >
> > > Mmaybe we can rework ARM64 ACPI code to store the acpi_device in struct
> > > pci_host_bridge->private instead of retrieving it from pci_config_window
> > > so that we decouple HV from the ARM64 back-end.
> > >
> > > HV would just set struct pci_host_bridge->private == NULL.
> > >
> >
> > Works for me, but please note that pci_sysdata is an x86-specific
> > structure, so we still need to define a fake pci_sysdata inside
> > pci-hyperv.c, like:
> >
> > #ifndef CONFIG_X86
> > struct pci_sysdata { };
> > #end
> >
> > > I need to think about this a bit, I don't think it should block
> > > this series though but it would be nicer.
> >
> > After a quick look into the code, seems that what we need to do is to
> > add an additional parameter for acpi_pci_root_create() and introduce a
> > slightly different version of pci_create_root_bus(). A question is:
> > should we only do this for ARM64, or should we also do this for
> > other acpi_pci_root_create() users (x86 and ia64)? Another question
> > comes to my mind is, while we are at it, is there anything else that we
> > want to move from sysdata to ->private? These questions are out of scope
> > of this patchset, I think. Maybe it's better that we address them in the
> > future, and I can send out separate RFC patches to start the discussion.
> > Does that sound like a plan to you?
>
> Yes it does and we can start from ARM64 - what I really don't like
> is the arch/arm64 dependency with the HV controller driver as I
> described, being forced to have a struct pci_config_window in the
> driver is not really nice or clean IMO.
>
> Not that I expect any other PCI host bridge driver with ACPI coming
> anytime soon but even if it is not within set (that we can merge) I'd
> like to see the decoupling rework done asap, let me put it this way.
>
Just want to check whether the following is a good starter for the
decoupling rework?
https://lore.kernel.org/lkml/20210811153619.88922-1-boqun.feng@gmail.com/
If so, is there any other concern about taking this patchset? ;-)
Regards,
Boqun
> Thanks,
> Lorenzo
>
> > Regards,
> > Boqun
> >
> > >
> > > Lorenzo
> > >
> > > > +#endif
> > > > struct pci_host_bridge *bridge;
> > > > struct fwnode_handle *fwnode;
> > > > /* Protocol version negotiated with the host */
> > > > @@ -3075,7 +3080,9 @@ static int hv_pci_probe(struct hv_device *hdev,
> > > > dom_req, dom);
> > > >
> > > > hbus->bridge->domain_nr = dom;
> > > > +#ifdef CONFIG_X86
> > > > hbus->sysdata.domain = dom;
> > > > +#endif
> > > >
> > > > hbus->hdev = hdev;
> > > > INIT_LIST_HEAD(&hbus->children);
> > > > --
> > > > 2.32.0
> > > >
next prev parent reply other threads:[~2021-08-19 12:20 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-26 18:06 [PATCH v6 0/8] PCI: hv: Support host bridge probing on ARM64 Boqun Feng
2021-07-26 18:06 ` [PATCH v6 1/8] PCI: Introduce domain_nr in pci_host_bridge Boqun Feng
2021-07-26 18:06 ` [PATCH v6 2/8] PCI: Support populating MSI domains of root buses via bridges Boqun Feng
2021-07-27 16:14 ` Bjorn Helgaas
2021-07-26 18:06 ` [PATCH v6 3/8] arm64: PCI: Restructure pcibios_root_bridge_prepare() Boqun Feng
2021-08-23 9:43 ` Catalin Marinas
2021-07-26 18:06 ` [PATCH v6 4/8] arm64: PCI: Support root bridge preparation for Hyper-V Boqun Feng
2021-08-19 16:13 ` Boqun Feng
2021-08-20 17:49 ` Catalin Marinas
2021-08-23 9:12 ` Lorenzo Pieralisi
2021-08-23 9:43 ` Catalin Marinas
2021-07-26 18:06 ` [PATCH v6 5/8] PCI: hv: Generify PCI probing Boqun Feng
2021-07-26 18:06 ` [PATCH v6 6/8] PCI: hv: Set ->domain_nr of pci_host_bridge at probing time Boqun Feng
2021-07-26 18:06 ` [PATCH v6 7/8] PCI: hv: Set up MSI domain at bridge " Boqun Feng
2021-07-26 18:06 ` [PATCH v6 8/8] PCI: hv: Turn on the host bridge probing on ARM64 Boqun Feng
2021-08-03 17:14 ` Lorenzo Pieralisi
2021-08-09 14:38 ` Boqun Feng
2021-08-09 15:53 ` Lorenzo Pieralisi
2021-08-19 12:19 ` Boqun Feng [this message]
2021-07-27 16:12 ` [PATCH v6 0/8] PCI: hv: Support " Bjorn Helgaas
2021-08-02 8:13 ` Boqun Feng
2021-08-02 8:15 ` Boqun Feng
2021-08-02 23:05 ` Bjorn Helgaas
2021-08-19 14:17 ` Lorenzo Pieralisi
2021-08-19 15:47 ` Boqun Feng
2021-08-23 10:10 ` Lorenzo Pieralisi
2021-08-23 12:49 ` Boqun Feng
2021-08-23 10:02 ` Lorenzo Pieralisi
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