Re: Associating nodes with phandles for pci devices

Hi All,

Back onto this from a brief hiatus

On 01/24/2015 11:40 AM, Florian Fainelli wrote:

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

quoted

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.

With Arnd's help I've figured out the appropriate reg property for my 
PCI based Ethernet nodes.

	pcie-controller {
		pcie@1,0 {
			ethernet0: tg3@01,0 {
				reg = <0x00000000 0 0 0 0>;
			};
			ethernet1: tg3@01,1 {
				reg = <0x00000100 0 0 0 0>;
			};
		};
	};

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.

My current problem is that of_find_device_by_node() (called by 
dsa_of_probe) can't find the device. After a bit of debugging I can see 
that the populated platform bus only goes as far as 
/soc/pcie-controller, anything beyond that seems to be missing. I can't 
see anything obvious in of_platform_bus_create() that would actually 
stop it from continuing down the pcie-controller branch provided the dts 
actually enumerates the children.

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