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SubjectRe: [PATCH V2 22/23] pci, acpi: Match PCI config space accessors against platfrom specific quirks.
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On 12/22/2015 10:48 PM, Gabriele Paoloni wrote:
> Hi Tomasz
>
>> -----Original Message-----
>> From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
>> owner@vger.kernel.org] On Behalf Of Tomasz Nowicki
>> Sent: 22 December 2015 10:20
>> To: Gabriele Paoloni; bhelgaas@google.com; arnd@arndb.de;
>> will.deacon@arm.com; catalin.marinas@arm.com; rjw@rjwysocki.net;
>> hanjun.guo@linaro.org; Lorenzo.Pieralisi@arm.com; okaya@codeaurora.org;
>> jiang.liu@linux.intel.com; Stefano.Stabellini@eu.citrix.com
>> Cc: robert.richter@caviumnetworks.com; mw@semihalf.com;
>> Liviu.Dudau@arm.com; ddaney@caviumnetworks.com; tglx@linutronix.de;
>> Wangyijing; 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; jchandra@broadcom.com; jcm@redhat.com
>> Subject: Re: [PATCH V2 22/23] pci, acpi: Match PCI config space
>> accessors against platfrom specific quirks.
>>
>> On 21.12.2015 12:47, Gabriele Paoloni wrote:
>>> 2) In the quirk mechanism you proposed, I see that the callback
>> function
>>> allows to do some preparation work for the host bridge. For
>> example in
>>> Hisilicon hip05 case we would need to read some values from the
>> ACPI
>>> table (see acpi_pci_root_hisi_add() function in
>>> https://lkml.org/lkml/2015/12/3/426).
>>> I am quite new to ACPI and I wonder if it is OK to add such
>> "Packages"
>>> to the PCI host bridge ACPI device...or maybe we need to declare
>> a new
>>> one...?
>>
>> I may miss sth so please correct me in that case.
>>
>> https://lkml.org/lkml/2015/12/3/426 shows that you need special
>> handling for root->secondary.start bus number only, right? So how about
>> creating special MCFG region <rc-base:rc-base+rc-size> only for
>> <segment,bus>.
>> Like that:
>>
>> [0008] Base Address : <rc-base>
>> [0002] Segment Group Number : <segment>
>> [0001] Start Bus Number : <root->secondary.start>
>> [0001] End Bus Number : <root->secondary.start>
>> [0004] Reserved : 00000000
>>
>>
>> static const struct dmi_system_id hisi_quirk[] = {
>> {
>> .ident = "HiSi...",
>> .matches = {
>> DMI_MATCH(<whatever you need to match your platform>),
>> },
>> },
>> { }
>> };
>>
>> static struct pci_ops hisi_ecam_pci_ops = {
>> .map_bus = pci_mcfg_dev_base,
>> .read = hisi_pcie_cfg_read,
>> .write = hisi_pcie_cfg_write,
>> };
>>
>> DECLARE_ACPI_MCFG_FIXUP(hisi_quirk, &hisi_ecam_pci_ops,
>> <segment>, <bus>);
>>
>> With above code you can use your custom PCI config accessor only for
>> that region.
>>
>> Let me know if that is not enough for you.
>
> In principle I think it can work...
>
> Liudongdong, Guo Hanjun what is your opinion about?

Let me and Dongdong prepare a patch for Hip05 and then will
back to this discussion to see if we met some problems.

Thanks
Hanjun


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