Re: [PATCH 3/6] pci, thunder: Add PCIe host controller devicetree bindings

From: Robert Richter
Date: Tue Oct 07 2014 - 10:43:56 EST


On 24.09.14 18:06:04, Arnd Bergmann wrote:
> > + compatible = "cavium,thunder-pcie";
> > + device_type = "pci";
> > + msi-parent = <&its>;
> > + bus-range = <0 255>;
> > + #size-cells = <2>;
> > + #address-cells = <3>;
> > + reg = <0x8480 0x00000000 0 0x10000000>; /* Configuration space */
> > + ranges = <0x03000000 0x8010 0x00000000 0x8010 0x00000000 0x70 0x00000000>, /* mem ranges */
> > + <0x03000000 0x8300 0x00000000 0x8300 0x00000000 0x80 0x00000000>,
> > + <0x03000000 0x87e0 0x00000000 0x87e0 0x00000000 0x01 0x00000000>;
> > + };
>
> If you claim the entire 0-255 bus range, I think you should also
> specify a domain, otherwise it's not predictable which domain you
> get.

Liviu's code assigns a unique id to the domain if missing, see
of_pci_get_domain_nr(). So I don't think we need to add a "pci-domain"
property here.

Liviu's DT implementation that assigns a unique number differs a bit
from ACPI which states: "If _SEG [aka domain number] does not exist,
OSPM assumes that all PCI bus segments are in PCI Segment Group 0."

Maybe of_pci_get_domain_nr() should be similar to ACPI. If there are
multiple root bridges, the "pci-domain" property could be forced
instead.

-Robert
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