On 13 July 2016 at 15:50, Felipe Balbi [off-list ref] wrote:

Rafał Miłecki [off-list ref] writes:

quoted

On 13 July 2016 at 15:20, Felipe Balbi [off-list ref] wrote:

quoted

Rafał Miłecki [off-list ref] writes:

quoted

Hi again,

This is my second try of getting HCD providers into usb subsystem.

During discussion of V1 I realized there are about 26 drivers adding a
single HCD and all of them would need to be modified. So instead I
decided to put relevant code in usb_add_hcd. It checks if the HCD we
register is a primary one and if so, it registers a proper provider.

Please note that of_hcd_xlate_simple was also extended to allow getting
shared HCD (which is used e.g. in case of XHCI).

So now you can have something like:

ohci: ohci@21000 {
      #usb-cells = <0>;
      compatible = "generic-ohci";
      reg = <0x00001000 0x1000>;
      interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>;
};

ehci: ehci@22000 {
      #usb-cells = <0>;
      compatible = "generic-ehci";
      reg = <0x00002000 0x1000>;
      interrupts = <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>;
};

xhci: xhci@23000 {
      #usb-cells = <1>;
      compatible = "generic-xhci";
      reg = <0x00003000 0x1000>;
      interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
};

The last (second) patch is not supposed to be applied, it's used only as
a proof and example of how providers can be used.

nowhere here (or in previous patch) you clarify why exactly you need
this. What is your LED trigger supposed to do? Why can't it handle ports
changing number in different boots? Why do we need this at all? Why is
your code DT-specific?

There are still too many 'unknowns' here.

Are you sure you saw my reply to Peter's question?
[off-list ref]
http://www.spinics.net/lists/linux-usb/msg143708.html
http://marc.info/?l=linux-usb&m=146838735627093&w=2

I think it should answer (some of?) your questions. Can you read it
and see if it gets a bit clearer?

well, all that says is that you're writing a LED trigger to toggle LED
when a USB device gets added to a specified port. I don't think you need
the actual port number for that. You should have a phandle to the actual
port, whatever its number is, or a phandle to the (root-)Hub and a port
number from that hub.

The problem, really, is that DT descriptor of USB Hosts is very, very
minimal. Perhaps there's something more extensively defined from the
original Open Firmware USB Addendum.

Thanks for your effort and looking at this closely. You're right, I'm
interested in referencing USB ports, but I'm using controller phandle
(and then I specify ports manually).

Having each port described by DT would be helpful, it's just something
I didn't find implemented, so I started looking for different ways. It
seems I should have picked a different solution.

So should I work on describing USB ports in DT instead? This looks
like a complex thing to describe, so I'd like to ask for some guidance
first. What do you think about following schema/example?

ohci@1000 {
        compatible = "generic-ohci";
        reg = <0x00001000 0x1000>;
        interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>;

        primary-hcd {
                ohci_port0: port@0 {
                        reg = <0>;
                };

                ohci_port1: port@1 {
                        reg = <1>;
                };
        }
};

ehci@2000 {
        compatible = "generic-ehci";
        reg = <0x00002000 0x1000>;
        interrupts = <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>;

        primary-hcd {
                ehci_port0: port@0 {
                        reg = <0>;
                };

                ehci_port1: port@1 {
                        reg = <1>;
                };
        }
};

xhci@3000 {
        compatible = "generic-xhci";
        reg = <0x00003000 0x1000>;
        interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;

        primary-hcd {
        };

        shared-hcd {
                xhci_port0: port@0 {
                        reg = <0>;
                };
        }
};

With such a DT struct, how could I query port for a Linux-assigned number?

For example with OHCI, EHCI and XHCI drivers compiled, Linux assigns
number 4 to my XHCI's shared HCD's root hub:
xhci-hcd 18023000.xhci: xHCI Host Controller
xhci-hcd 18023000.xhci: new USB bus registered, assigned bus number 4
hub 4-0:1.0: USB hub found
hub 4-0:1.0: 1 port detected

If I disable OHCI and EHCI I get:
xhci-hcd xhci-hcd.0: xHCI Host Controller
xhci-hcd xhci-hcd.0: new USB bus registered, assigned bus number 2
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 1 port detected

So I need my "usbport" trigger driver to be able to get "4-1" in the
first case and "2-1" in the second case. I guess I should use
&xhci_port0 but what then? How could I translate it into
Linux-assigned numbering?

There's also no documentation for your new bindings nor are there any
user demonstrating how DT should be written to use these new bindings.

IMO, if you're describing it in DT and you need a specific port name,
your bindings are wrong.

OK, point taken. I'll make sure to document it once we agree how to
proceed with implementation.

-- 
Rafał
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