On 07.10.14 16:01:49, Liviu Dudau wrote: > On Tue, Oct 07, 2014 at 03:27:44PM +0100, Robert Richter wrote: > > 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. > > Not anymore! That function is gone in v12 onwards. What is in -next has > a new function called of_get_pci_domain_nr() (slight name change) but > that only gets the value set in the "linux,pci-domain" property of the > device node. It is the choice of the host bridge driver to use that > function or to use pci_get_new_domain_nr() which *does* generate an > unique id every time it gets called. I am quite confused a bit on which is the latest code base now. I was looking into Bjorn's pci/host-generic and there is a different implemetation: ---- /** * This function will try to obtain the host bridge domain number by * using of_alias_get_id() call with "pci-domain" as a stem. If that * fails, a local allocator will be used. The local allocator can * be requested to return a new domain_nr if the information is missing * from the device tree. * * @node: device tree node with the domain information * @allocate_if_missing: if DT lacks information about the domain nr, * allocate a new number. * * Returns the associated domain number from DT, or a new domain number * if DT information is missing and @allocate_if_missing is true. If * @allocate_if_missing is false then the last allocated domain number * will be returned. */ int of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing) { int domain; domain = atomic_read(&of_domain_nr); if (domain == -1) { /* first run, get max defined domain nr in device tree */ domain = of_get_max_pci_domain_nr(); /* then set the start value for allocator to be max + 1 */ atomic_set(&of_domain_nr, domain + 1); } domain = of_alias_get_id(node, "pci-domain"); if (domain == -ENODEV) { domain = atomic_read(&of_domain_nr); if (allocate_if_missing) atomic_inc(&of_domain_nr); } return domain; } EXPORT_SYMBOL_GPL(of_pci_get_domain_nr); ---- This differs also from v13. Please check. It would be good to have a stable code base to work with, so I would prefer incremental patches on top of Bjorn's pci/host-generic. > > 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. > > Indeed. But the enforcing is left as an exercise to the host bridge > implementor for the moment. Right, can be added later. Thanks, -Robert -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html