Re: Associating nodes with phandles for pci devices

On 23/01/15 11:38, Chris Packham wrote:

Hi Arnd,

Thanks for the quick response (and sorry for the horribly formatted
message, travelling with only a webmail interface at the moment).

On Fri, 23 Jan 2015, Arnd Bergmann wrote:

quoted

On Friday 23 January 2015 19:02:33 Chris Packham wrote:

quoted

Hi,

I'm working on a new board that has a marvell,dsa switch. Similar to
the kirkwood-mv88f6281gtw-ge board. However the major difference is
that instead of being connected to an integrated Ethernet port it is
connected via a PCI-e Ethernet port (basically a NIC hardwired onto
the board).

Generally you don't need to define PCI devices in the .dts because
the bus is scanned at run time and the method for identifying devices
is well defined. But to satisfy the marvell,dsa binding[1] I need to
tell it the Ethernet port it is connected to. The answer might be in
the PCI bindings but the urls in the documentation[2] don't appear to
be valid anymore.

Is it possible to enumerate PCI devices in the .dts? Or is there a
way of satisfying the dsa requirements without knowing the Ethernet
device?

In general, it is possible, and we do that on PowerPC, but it may be that
there are parts missing on ARM and you have to try it out.

In particular, you need to know the address of the PCI device and then
create a device node that will be associated with the
pci_dev->dev.of_node
pointer.

Encouraging to know. I think I can figure out the relevant addresses for
my device based on the run-time scan.

BTW, one thing that is high in my TODO list regarding DSA is to stop
using this platform device/driver architecture and use the actual device
driver model. Your switch driver entry point would be a pci_drive
probe's function where you end-up registering a switch the DSA. This
should solve portions of your problem although this is a long shot as we
need to convert existing drivers as well.

Can you think of a good example. I found a few ppc boards that have an
PCI-ISA bridge that get's enumerated in the .dts. I think I can make sense
of them but because they are bridges there's a lot of extra stuff for
the down stream devices.

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