[PATCH v7 4/6] pci: Introduce a domain number for pci_host_bridge.

Bjorn Helgaas
2014-04-08T16:28:39Z

On Tue, Apr 8, 2014 at 4:20 AM, Liviu Dudau <Liviu.Dudau@arm.com> wrote:
> On Mon, Apr 07, 2014 at 11:44:51PM +0100, Bjorn Helgaas wrote:

>> Let me try to explain my concern about the
>> pci_create_root_bus_in_domain() interface. We currently have these
>> interfaces:
>>
>> pci_scan_root_bus()
>> pci_scan_bus()
>> pci_scan_bus_parented()
>> pci_create_root_bus()
>> ...

>> One alternative is to add an _in_domain() variant of each of these
>> interfaces, but that doesn't seem very convenient either. My idea of
>> passing in a structure would also require adding variants, so there's
>> not really an advantage there, but I am thinking of the next
>> unification effort, e.g., for NUMA node info. I don't really want to
>> have to change all the _in_domain() interfaces to also take yet
>> another parameter for the node number.
>
> OK, what about this: all the functions that you have mentioned take a
> void *sysdata parameter. Should we convert this opaque pointer into a
> specific structure that holds the domain_nr and (in future) the NUMA
> node info?

I doubt if we can make sysdata itself generic because I suspect we
need a way to have *some* arch-specific data. But maybe the arch
could supply a structure containing a struct device *, domain, struct
pci_ops *, list of resources, aperture info, etc. I wonder if struct
pci_host_bridge would be a reasonable place to put this stuff, e.g.,
something like this:

struct pci_host_bridge {
int domain;
int node;
struct device *dev;
struct pci_ops *ops;
struct list_head resources;
void *sysdata;
struct pci_bus *bus; /* filled in by core, not by arch */
... /* other existing contents managed by core */
};

struct pci_bus *pci_scan_host_bridge(struct pci_host_bridge *bridge);