From: Jon Masters <jcm@redhat.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Tomasz Nowicki <tn@semihalf.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
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, Liviu.Dudau@arm.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,
andrea.gallo@linaro.org, dhdang@apm.com, jeremy.linton@arm.com,
liudongdong3@huawei.com, cov@codeaurora.org
Subject: Re: [PATCH V8 5/9] pci, acpi: add acpi hook to assign domain number.
Date: Fri, 10 Jun 2016 14:54:59 -0400 (EDT) [thread overview]
Message-ID: <8620FB5B-4A60-48B6-A6E0-38D2007CD360@redhat.com> (raw)
In-Reply-To: <20160610181836.GA7843@localhost>
Hi Bjorn,
Sorry for top posting while on the road. If this refactoring can happen later, is it possible to merge now (well, -next anyway) and explore other work as next steps?
Jon.
--
Computer Architect | Sent from my 64-bit #ARM Powered phone
> On Jun 10, 2016, at 13:18, Bjorn Helgaas <helgaas@kernel.org> wrote:
>
>> On Fri, Jun 10, 2016 at 06:49:32PM +0200, Tomasz Nowicki wrote:
>>> On 10.06.2016 17:49, Lorenzo Pieralisi wrote:
>>>> On Fri, Jun 10, 2016 at 04:14:58PM +0100, Lorenzo Pieralisi wrote:
>>>> Hi Bjorn, Tomasz,
>>>>
>>>> On Tue, Jun 07, 2016 at 07:15:59PM -0500, Bjorn Helgaas wrote:
>>>>
>>>> [...]
>>>>
>>>>>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>>>>>> index eb431b5..2b52178 100644
>>>>>> --- a/drivers/pci/pci.c
>>>>>> +++ b/drivers/pci/pci.c
>>>>>> @@ -7,6 +7,7 @@
>>>>>> * Copyright 1997 -- 2000 Martin Mares <mj@ucw.cz>
>>>>>> */
>>>>>>
>>>>>> +#include <linux/acpi.h>
>>>>>> #include <linux/kernel.h>
>>>>>> #include <linux/delay.h>
>>>>>> #include <linux/init.h>
>>>>>> @@ -4941,7 +4942,7 @@ int pci_get_new_domain_nr(void)
>>>>>> }
>>>>>>
>>>>>> #ifdef CONFIG_PCI_DOMAINS_GENERIC
>>>>>> -void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
>>>>>> +static int of_pci_bus_domain_nr(struct device *parent)
>>>>>
>>>>> Can we do a little cleanup before this patch?
>>>>>
>>>>> - pci_bus_assign_domain_nr() is only used inside drivers/pci, so
>>>>> maybe we move the prototype to drivers/pci/pci.h?
>>>>>
>>>>> - I don't really like the style of calling a function that
>>>>> internally assigns bus->domain_nr. Could we do something like
>>>>> this instead?
>>>>>
>>>>> int pci_bus_domain_nr(...)
>>>>> {
>>>>> ...
>>>>> return domain;
>>>>> }
>>>>>
>>>>> ... pci_create_root_bus(...)
>>>>> {
>>>>> ...
>>>>> b->domain_nr = pci_bus_domain_nr(...);
>>>>
>>>> We noticed while preparing v9, that this would force us to
>>>> write an empty pci_bus_domain_nr() prototype for
>>>> !PCI_DOMAINS_GENERIC (ie every arch but ARM/ARM64) that should
>>>> return 0 to keep current behaviour unchanged.
>>>>
>>>> That's why pci_bus_assign_domain_nr() was there, so that it
>>>> was compiled out on !PCI_DOMAINS_GENERIC.
>>>>
>>>> I really would like v9 to be final so let's fix it before posting it
>>>> shortly please.
>>>>
>>>> For the above we have three options:
>>>>
>>>> 1) Leave code as-is in v8
>>>>
>>>> 2) in pci_create_root_bus():
>>>> #ifdef CONFIG_PCI_DOMAINS_GENERIC
>>>> b->domain_nr = pci_bus_domain_nr(...);
>>>> #endif
>>>>
>>>> + other changes requested above
>>>>
>>>> 3) in pci_create_root_bus()
>>>>
>>>> b->domain_nr = pci_bus_domain_nr(...);
>>>>
>>>> unguarded and a stub:
>>>>
>>>> #ifndef CONFIG_PCI_DOMAINS_GENERIC
>>>> static inline int pci_bus_domain_nr() { return 0; }
>>>> #endif
>>>>
>>>> + other changes requested above
>>>
>>> Actually, Tomasz made me notice that pci_bus.domain_nr is
>>> only declared for CONFIG_PCI_DOMAINS_GENERIC so (3) is not
>>> even an option and IMO (2) is not much nicer than code in
>>> v8 as-is with an ifdef in the middle of pci_create_root_bus().
>>
>> To me (1) is nicer too. Bjorn what is your take on this? This is
>> last bit before sending v9.
>
> My preference is (2). The ifdef in pci_create_root_bus() is a little
> ugly, but I like it better because it will fit nicely into Arnd's
> idea of having the native drivers allocate and fill in a host bridge
> structure before calling the PCI core. The domain is one thing those
> drivers could fill in. I like that model much better than having the
> PCI core make callbacks to get information that we should have passed
> in to begin with.
>
> The current code suggests that assigning the domain is the PCI core's
> responsibility, and that's not really the case -- for ACPI it's
> totally up to pci_root.c, for other drivers it comes from the DT, and
> for others it might depend on the driver's knowledge of the hardware
> (I'm thinking of parisc, where, I think we currently put all the
> bridges in the same domain, but IIRC they *could* each be in their own
> domain with a full [bus 00-ff] range for each bridge because each
> bridge has its own config space access mechanism).
>
> But it's not that big a deal either way -- we could do this bit of
> restructuring later, too.
>
> Bjorn
next prev parent reply other threads:[~2016-06-10 18:55 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-30 15:14 [PATCH V8 0/9] Support for ARM64 ACPI based PCI host controller Tomasz Nowicki
2016-05-30 15:14 ` [PATCH V8 1/9] PCI: ecam: move ecam.h to linux/include/pci-ecam.h Tomasz Nowicki
2016-06-02 9:48 ` Lorenzo Pieralisi
2016-05-30 15:14 ` [PATCH V8 2/9] PCI: ecam: Add parent device field to pci_config_window Tomasz Nowicki
2016-06-02 10:13 ` Lorenzo Pieralisi
2016-05-30 15:14 ` [PATCH V8 3/9] pci: Add new function to unmap IO resources Tomasz Nowicki
2016-06-02 16:50 ` Lorenzo Pieralisi
2016-05-30 15:14 ` [PATCH V8 4/9] acpi, pci: Support IO resources when parsing PCI host bridge resources Tomasz Nowicki
2016-06-02 17:30 ` Lorenzo Pieralisi
2016-06-07 23:56 ` Bjorn Helgaas
2016-05-30 15:14 ` [PATCH V8 5/9] pci, acpi: add acpi hook to assign domain number Tomasz Nowicki
2016-06-08 0:15 ` Bjorn Helgaas
2016-06-08 10:21 ` Tomasz Nowicki
2016-06-08 13:22 ` Bjorn Helgaas
2016-06-10 15:14 ` Lorenzo Pieralisi
2016-06-10 15:49 ` Lorenzo Pieralisi
2016-06-10 16:49 ` Tomasz Nowicki
2016-06-10 18:18 ` Bjorn Helgaas
2016-06-10 18:54 ` Jon Masters [this message]
2016-05-30 15:14 ` [PATCH V8 6/9] arm64, pci, acpi: ACPI support for legacy IRQs parsing and consolidation with DT code Tomasz Nowicki
2016-05-30 15:14 ` [PATCH V8 7/9] acpi: Add generic MCFG table handling Tomasz Nowicki
2016-06-03 11:38 ` Lorenzo Pieralisi
2016-06-06 12:55 ` Tomasz Nowicki
2016-06-08 1:56 ` Bjorn Helgaas
2016-06-08 12:21 ` Tomasz Nowicki
2016-06-08 13:17 ` Bjorn Helgaas
2016-06-08 13:44 ` Tomasz Nowicki
2016-05-30 15:14 ` [PATCH V8 8/9] arm64, pci, acpi: Provide ACPI-specific prerequisites for PCI bus enumeration Tomasz Nowicki
2016-06-02 9:45 ` Lorenzo Pieralisi
2016-06-02 9:51 ` Tomasz Nowicki
2016-05-30 15:14 ` [PATCH V8 9/9] pci, acpi: ARM64 support for ACPI based generic PCI host controller Tomasz Nowicki
2016-05-30 15:38 ` Arnd Bergmann
2016-05-30 16:13 ` Jayachandran C
2016-06-02 9:35 ` Lorenzo Pieralisi
2016-06-02 9:44 ` Tomasz Nowicki
2016-06-08 2:14 ` Bjorn Helgaas
2016-06-01 7:36 ` [PATCH V8 0/9] Support for ARM64 ACPI based " Gabriele Paoloni
2016-06-02 7:31 ` Jon Masters
2016-06-02 10:06 ` Gabriele Paoloni
2016-06-02 8:52 ` Tomasz Nowicki
2016-06-02 9:58 ` Gabriele Paoloni
2016-06-02 8:48 ` Jon Masters
2016-06-07 23:13 ` Bjorn Helgaas
2016-06-08 9:20 ` Dongdong Liu
2016-06-09 16:45 ` Suravee Suthikulanit
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