Re: Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug,

From: Segher Boessenkool
Date: Wed Oct 27 2010 - 18:05:43 EST


>> > |1. How do I locate all usb nodes in the device tree?
>> > |
>> > |2. How do I know if a particular usb node is OHCI?

You look for compatible "usb-ohci".

But this doesn't help you. You do not know yet if the
problem happens for all usb-ohci; for example, it could be
that you have the console output device on usb; or as another
example, it could be that this firmware leaves all pci devices
in some active state.

So as I see it you have only two options:

1) Figure out what exactly is going on;
or 2) make the kernel shut down all pci devices early (either
in actual kernel code, or in an OF boot script).

> The big question that I'm still stumbling over is how to access the device
> registers. The "reg" property looks like this:

You should look at "assigned-addresses", not "reg". Well,
you first need to look at "reg" to figure out what entry
in "assigned-addresses" to use.


Segher

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