[PATCH]: [MPC5200] Add ATA DMA support

Grant Likely grant.likely at secretlab.ca
Sat Dec 20 18:15:27 EST 2008


On Tue, Nov 25, 2008 at 8:19 AM, Matt Sealey <matt at genesi-usa.com> wrote:
>
>
> On Tue, Nov 25, 2008 at 8:45 AM, Lehmann, Hans (Ritter Elektronik)
> <hans.lehmann at ritter-elektronik.de> wrote:
>>
>> Tim, Grant,
>>
>> just an info.
>>
>> Very often the Bestcomm-FEC crashed without any error logs if I initiate a
>> transaction over FEC and save the file to disk (I rememeber I have read
>> something like that). A restart of FEC don't work.
>> But no I figured out, if I connect to the other ethernet port of our board
>> (natsemi) the FEC will awake to life again, if I initiate a new transaction
>> over natsemi. This seems a little oddly to me.
>
> Hi guys,
>
> We tried to get the SUSE guys to push the patch into openSUSE 11.1 release
> and the tests came back negative here too with regards to FEC support; for
> some odd reason, it does this;
>
> https://bugzilla.novell.com/show_bug.cgi?id=445856#c10
>
> There is some weird interaction here, but I can't imagine what it might be.
> Tim, did you ever see any ethernet problems like this?

It looks like something getting messed up during allocation of buffers
and not DMA operation related at all.  I don't see the problem here...

Digging deeper I think the problem is due to this:

>   ------- Comment #6 From Olaf Hering 2008-11-18 01:32:52 MST  -------
>
> Also, the patches do not seem to apply and compile with our kernel-source.
> bcom_task->bd changed to void*, this breaks sound/ppc/mpc52xx_ac97.c. It looks
> like an unneeded cosmetic change.
> The Kconfig changes are appearently also not required for an existing .config.
>
> I removed the bcom_task->bd  change.

The patch does depend on bcom_task->bd being (void *).  Without it the
calculation of BD offsets is entirely wrong in bcom_get_bd().

That being said, the next version of the patch will leave the pointer
as (bcom_bd *) and handle the offset calculation in a different way.

g.

-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.



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