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Subject: Re: [RFC PATCH 1/3] pci, acpi: Match PCI config space accessors
 against platfrom specific ECAM quirks.
To: Arnd Bergmann <arnd@arndb.de>
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From: Tomasz Nowicki <tn@semihalf.com>
Message-ID: <5750218F.9030406@semihalf.com>
Date: Thu, 2 Jun 2016 14:07:43 +0200
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On 02.06.2016 13:42, Arnd Bergmann wrote:
> On Thursday, June 2, 2016 10:41:01 AM CEST Tomasz Nowicki wrote:
>> +struct pci_ecam_ops *pci_mcfg_get_ops(struct acpi_pci_root *root)
>> +{
>> +       int bus_num = root->secondary.start;
>> +       int domain = root->segment;
>> +       struct pci_cfg_fixup *f;
>> +
>> +       if (!mcfg_table)
>> +               return &pci_generic_ecam_ops;
>> +
>> +       /*
>> +        * Match against platform specific quirks and return corresponding
>> +        * CAM ops.
>> +        *
>> +        * First match against PCI topology <domain:bus> then use OEM ID and
>> +        * OEM revision from MCFG table standard header.
>> +        */
>> +       for (f = __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixups; f++) {
>> +               if ((f->domain == domain || f->domain == PCI_MCFG_DOMAIN_ANY) &&
>> +                   (f->bus_num == bus_num || f->bus_num == PCI_MCFG_BUS_ANY) &&
>> +                   (!strncmp(f->oem_id, mcfg_table->header.oem_id,
>> +                             ACPI_OEM_ID_SIZE)) &&
>> +                   (f->oem_revision == mcfg_table->header.oem_revision))
>> +                       return f->ops;
>> +       }
>> +       /* No quirks, use ECAM */
>> +       return &pci_generic_ecam_ops;
>> +}
>> +
>>   int pci_mcfg_lookup(struct acpi_pci_root *root)
>
> Can you explain the use of pci_ecam_ops instead of pci_ops here?
>

I wanted to get associated bus_shift and use it to setup configuration 
region properly before calling pci_ecam_create. Please see next patch.

Thanks,
Tomasz