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Re: USB hangs on AU1100

To: Thiemo Seufer <ths@networkno.de>
Subject: Re: USB hangs on AU1100
From: "Maciej W. Rozycki" <macro@linux-mips.org>
Date: Thu, 5 May 2005 18:51:38 +0100 (BST)
Cc: "'linux-mips@linux-mips.org'" <linux-mips@linux-mips.org>
In-reply-to: <20050505172017.GC1628@hattusa.textio>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20050505155435.GA28227@enneenne.com> <1115311361.1614.6.camel@localhost.localdomain> <20050505172017.GC1628@hattusa.textio>
Sender: linux-mips-bounce@linux-mips.org
On Thu, 5 May 2005, Thiemo Seufer wrote:

> > > I'm just using USB host support on a AU1100 developing board (DB1100
> > > configuration) and i notice that CPU locks in function
> > > au1xxx_start_hc():
> > > 
> > >         /* wait for reset complete (read register twice; see au1500 
> > > errata) */
> > >         while (au_readl(USB_HOST_CONFIG),
> > >                 !(au_readl(USB_HOST_CONFIG) & USBH_ENABLE_RD))
> > >                 udelay(1000);
> > > 
> > > while waiting for USB controller to reset. I checked it out and I
> > > discovered that register USB_HOST_CONFIG is fixed at value 0xe! So the
> > > controller never reset...
> > > 
> > > Linux is 2.6.12-rc3 from CVS.
> > > 
> > > Someone knows whats wrong?
> > 
> > It sounds like this is a custom Au1100 based board? What boot code are
> > you running?  I'm guessing the SOC isn't setup correctly or you have a
> > HW problem.
> 
> I wonder if the code works reliable. At least, a comma operator isn't a
> sequence point, which means the compiler is free to change the execution
> order.

 Good point -- even though the code is valid C, it's complete rubbish.  
I'd suggest rewriting it to get something readable first.

  Maciej

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