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Re: PowerPC FEC problems
- From: Andrew Lunn <andrew at lunn dot ch>
- To: ken king <kknhuntsville at yahoo dot com>
- Cc: ecos-discuss at ecos dot sourceware dot org
- Date: Fri, 6 May 2005 13:49:17 +0200
- Subject: Re: [ECOS] PowerPC FEC problems
- References: <20050506114449.21990.qmail@web60219.mail.yahoo.com>
> > Check the addresses you are using from receive and
> > transmit buffers.
> > Do you remember to map the virtual addresses into
> > bus addresses before
> > programming them into the ethernet device? Does
> > memory realy exist at
> > the address?
> >
> > Andrew
> >
> > --
> > Before posting, please read the FAQ:
> > http://ecos.sourceware.org/fom/ecos
> > and search the list archive:
> > http://ecos.sourceware.org/ml/ecos-discuss
> >
> Yes, I can dump memory around the BDs (Buffer
> descriptors) and they look correct. The memory
> pointed to by the BD can also be dumped and it
> has the same contents as displayed on the
> console if eth debugging is on, i.e looks like the
> bootp frames. I can put a scope on the PHYs
> tx_clock and tx_en -- the clock is running, but
> tx_en is never asserted.
You can look at the memory from the processor, so you know you have
the correct virtual address. However, the DMA might not be using the
virtual address. It will be using some bus address. Bus addresses can
be different from virtual addresses. Read the datasheet and see what
it says about the addresses to be used for programming the DMA engine.
Andrew
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