Re: imx21-hcd bugs, device descriptor read/64, error -110

On Thursday 16 August 2007, Midhun Agnihotram wrote:
> Hi All,
> 
> > I'd expect are turned off in that code.  So the real OHCI driver, or
> > maybe the isp116x code (OHCI-ish but likewise not real OHCI) would
> > probably offer more useful guidance.
> >
> > - Dave
> 
>   I am now developing a USB driver for IMX21 based on the OHCI S3C2410
> USB driver (since both are ARM based). I have made the changes in
> ohci.h for the register's physical addresses (I could not map every
> field - I did as many as I could map).

Don't modify any part of the OHCI driver ... the imx21 controller
is *NOT OHCI* and you'd end up breaking code that a lot of folk
rely on ...


>    My USB hub has been detected by the kernel. And there are three
> ports on the system - 1 USB host port and 2 USB device ports. The Hub
> says that 0 ports have been detected.
> 
> hub 1-0:1.0: USB hub found
> hub 1-0:1.0: 0 ports detected
> 
>     I could trace out that USB ports information is got from
> get_hub_descriptor method in hub.c. This sends a control message to
> get the descriptor. Here is where it is finding zero ports.
> 
>   What is this command? Isnt this command from the USB specification
> and hence should be a standard? In that case I will not need to worry
> about the command.

Thing is, you don't have an actual hub device ... you're implementing
a "root hub" that response to the same API requests we make to real
hubs, but the messages never go out on the wire.  So *YOU* are the one
who will implement the guts of get_hub_descriptor() for your hardware
root hub, according to the relevant bits of chapter 11 of the USB 2.0
specification.


>   What does this do? Is this returning 0 ports due to mismatched
> physical addresses? Where else could have this gone wrong?

Your code returned the an invalid root hub descriptor.

- Dave

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