Re: [PATCH v3] PCI/ACPI: xgene: Add ECAM quirk for X-Gene PCIe controller

[Duc Dang]

On Mon, Dec 5, 2016 at 1:20 PM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote:
> On Fri, Dec 02, 2016 at 11:06:30PM -0800, Duc Dang wrote:
>> On Fri, Dec 2, 2016 at 3:39 PM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote:
>
>> > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
>> > index 8a177a1..a16fc8e 100644
>> > --- a/arch/arm64/kernel/pci.c
>> > +++ b/arch/arm64/kernel/pci.c
>> > @@ -114,6 +114,19 @@ int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
>> >         return 0;
>> >  }
>> >
>> > +static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
>> > +{
>> > +       struct resource_entry *entry, *tmp;
>> > +       int status;
>> > +
>> > +       status = acpi_pci_probe_root_resources(ci);
>> > +       resource_list_for_each_entry_safe(entry, tmp, &ci->resources) {
>> > +               if (!(entry->res->flags & IORESOURCE_WINDOW))
>> > +                       resource_list_destroy_entry(entry);
>> > +       }
>> > +       return status;
>> > +}
>> > +
>> >  /*
>> >   * Lookup the bus range for the domain in MCFG, and set up config space
>> >   * mapping.
>> > @@ -190,6 +203,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
>> >         }
>> >
>> >         root_ops->release_info = pci_acpi_generic_release_info;
>> > +       root_ops->prepare_resources = pci_acpi_root_prepare_resources;
>> >         root_ops->pci_ops = &ri->cfg->ops->pci_ops;
>> >         bus = acpi_pci_root_create(root, root_ops, &ri->common, ri->cfg);
>> >         if (!bus)
>>
>> I tried your patch above with my X-Gene ECAM v4 patch on Mustang, here
>> is the kernel boot log and output of 'cat /proc/iomem'. The PCIe core
>> does not print the MMIO space as a window (which is expected per your
>> patch above).
>
> Thanks!
>
>> ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff])
>> acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI]
>> acpi PNP0A08:00: _OSC: OS now controls [PCIeHotplug PME AER PCIeCapability]
>> acpi PNP0A08:00: MCFG quirk: ECAM at [mem 0xe0d0000000-0xe0dfffffff] for [bus 00-ff] with xgene_v1_pcie_ecam_ops
>> acpi PNP0A08:00: [Firmware Bug]: ECAM area [mem 0xe0d0000000-0xe0dfffffff] not reserved in ACPI namespace
>> acpi PNP0A08:00: ECAM at [mem 0xe0d0000000-0xe0dfffffff] for [bus 00-ff]
>> Remapped I/O 0x000000e010000000 to [io  0x0000-0xffff window]
>> PCI host bridge to bus 0000:00
>> pci_bus 0000:00: root bus resource [io  0x0000-0xffff window] (bus address [0x10000000-0x1000ffff])
>> pci_bus 0000:00: root bus resource [mem 0xe040000000-0xe07fffffff window] (bus address [0x40000000-0x7fffffff])
>> pci_bus 0000:00: root bus resource [mem 0xf000000000-0xffffffffff window]
>> pci_bus 0000:00: root bus resource [bus 00-ff]
>
> Yup, no bridge register space here; that's good.  I assume the bridge
> registers are at [mem 0x1f2b0000-0x1f2bffff] as shown in /proc/iomem
> below.

Yes,  the bridge registers are at [mem 0x1f2b0000-0x1f2bffff].

>
>> [root@(none) ~]# cat /proc/io mem
>> ...
>> 19000000-19007fff : 808622B7:00
>> 1900c100-190fffff : 808622B7:00
>>   1900c100-190fffff : 808622B7:00
>> 19800000-19807fff : 808622B7:01
>> 1980c100-198fffff : 808622B7:01
>>   1980c100-198fffff : 808622B7:01
>> ...
>> 1f280000-1f28ffff : 808622B7:00
>> 1f290000-1f29ffff : 808622B7:01
>
> I'm curious what these "808622B7" devices are.  Per ACPI 6.0, sec
> 6.1.5, that looks like a PCI vendor ID, which I guess is a valid ACPI
> ID.  But these resources don't seem to have any connection with PCI
> (they're not in any of the host bridge apertures).

These are DesignWare USB 3.0 controllers (DWC3). The ACPI ID is
defined in drivers/usb/dwc3/core.c.
>
>> 1f2b0000-1f2bffff : PNP0A08:00
>
> Looks like the bridge register space; good.

Yes, it is.

>
>> e040000000-e07fffffff : PCI Bus 0000:00
>>   e040000000-e0401fffff : PCI Bus 0000:01
>>     e040000000-e0400fffff : 0000:01:00.0
>>       e040000000-e0400fffff : mlx4_core
>>     e040100000-e0401fffff : 0000:01:00.0
>
>> e0d0000000-e0dfffffff : PCI ECAM
>
> This region should be described in either a PNP0C02 device or (if we
> decide we can allow "consumer" descriptors) the PNP0A08 device.  I
> assume you'll fix that in a future firmware release.

Yes, future firmware will have PNP0C02 node that describes this ECAM
space (or a new resource in PNP0A08 if we use 'consumer' descriptor).

>
> But I think this reservation from pci_ecam_create() is good enough for
> now.
>
>> f000000000-ffffffffff : PCI Bus 0000:00
>>   f000000000-f001ffffff : PCI Bus 0000:01
>>     f000000000-f001ffffff : 0000:01:00.0
>>       f000000000-f001ffffff : mlx4_core
Regards,
Duc Dang.