Re: PCI support under 2.6.11.4 on MPC8272ADS ???

From: Andrei Konovalov <akonovalov@ru•mvista.com>
To: "Walter L. Wimer III" <walt.wimer@timesys•com>
Cc: linuxppc-embedded@ozlabs•org
Subject: Re: PCI support under 2.6.11.4 on MPC8272ADS ???
Date: Tue, 29 Mar 2005 20:41:32 +0400	[thread overview]
Message-ID: <4249853C.3060302@ru.mvista.com> (raw)
In-Reply-To: <1112112084.26645.27.camel@excalibur.timesys.com>

Walter L. Wimer III wrote:
> Thanks to all who offered suggestions regarding PCI on the MPC8272ADS.
> I too suspected that the PCI bus frequency may have been the problem,
> and even spent some time looking at the clock configuration in the
> Freescale documentation before I posted my message.  The documentation
> seemed very confusing, so I decided to pursue a few different avenues in
> parallel, including posting to the list.
> 
> Since Andrei and Vitaly further implicated the bus frequency, I went
> back and took a closer look at it.  After much staring at the
> documentation, dumping registers, trying a 66MHz-capable card, etc. I
> can report that this was indeed the problem.  A 66MHz-capable Promise
> IDE controller card does seem to work.
> 
> I'd like to change the bus speed to <= 33MHz, but this still looks non-
> trivial.  If I understand things properly, it looks like my best bet is
> to modify the Hard Reset Configuration Word in flash to set the
> PCI_MODCK bit to "low range" (25 to 50 MHz, instead of 50 to 66 MHz).
> 
> Can anyone confirm my understanding?

Yes, we've used HRCW of 0x0c72361a.

BTW, I guess it sould be rather simple to modify the CPLD
to set the PCI_MODCK to "low range" if at least one of the PCI
cards inserted is not 66MHz capable.
Something like
   CfgByte3 = [0,0,0,!BCSR4.M66EN,ModckH0,ModckH1,ModckH2,ModckH3];
(this is not the correct code for the CPLD, but illustrates the idea).

Thanks,
Andrei

> Thanks again!
> 
> Walt
> 
> 
> 
> On Fri, 2005-03-25 at 17:07 +0300, Vitaly Bordug wrote:
> 
>>Hi Walt,
>>
>>Well, the incorrect VendorID almost clearly points to the incompatible
>>PCI bus frequency - try to set it to 33Mhz. 
>>AFAIR, I saw my network card as video adapter in the lspci output. 
>>
>>The 2.4 stuff was tested rather thoroughly. The current 2.6.11 support
>>is examined with HPT370 and PDC20268 PCI IDE.
>>
>>You may also try my latest patch to the stock linux 2.5. 
>>
>>Wimer, Walt wrote: 
>>
>>>Using Vitaly's 2.4-based patch below as a starting point, I've been
>>>adding PCI support to 2.6.11.4 for the MPC8272ADS board.
>>>
>>>The good news is that I think I have PCI interrupts pretty well sorted
>>>out, and I see *something* half-way reasonable from "lspci".
>>>
>>>The bad news is that neither of the ethernet cards that I'm trying will
>>>actually work, and I see some very weird behavior with PCI configuration
>>>space:
>>>
>>>  Card 1:  Some Realtek RTL8139D-based card
>>>  Card 2:  NETGEAR FA311 (National Semi DP83815 chip)
>>>
>>>With either card installed alone, both U-Boot and my kernel identify the
>>>cards correctly in PCI configuration space.
>>>
>>>With *both* cards installed, both U-Boot and my kernel see the Realtek-
>>>based card correctly, but the NETGEAR card has a corrupted Vendor ID
>>>(e.g. 0x1000 or 0x1003 instead of the correct 0x100b).  This happens
>>>regardless of which PCI slots I use for the cards (I've tried virtually
>>>every combination).  This smells of a power problem or something to me.
>>>
>>>And again, even with either card alone, the drivers have serious
>>>problems talking to the cards.  I get various error messages from
>>>the drivers and I see badly mangled packets on the wire.  It's also
>>>not uncommon for the whole system to freeze...
>>>
>>>Has anyone else seen similar behavior?
>>>
>>>Has anyone had success with PCI on this board (under any kernel
>>>version)?
>>>
>>>
>>>Any ideas / data points are appreciated.
>>>
>>>
>>>Thanks!!!
>>>
>>>Walt Wimer
>>>
>>>
>>>
>>>  
>>>
>>>>This patch adds PCI bridge support for MPC8272 and PQ2FADS to the
>>>>current linuxppc-2.4 tree. Actually it has been tested with 8272, but
>>>>PQ2 _should_ also work, though it will complain that host bridge ID is
>>>>unrecognized.
>>>>
>>>>Signed-off-by: Vitaly Bordug <vbordug at ru.mvista.com>
>>>>
>>>>--
>>>>Sincerely, Vitaly
>>>>
>>>>-------------- next part --------------
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>>>>Url : http://ozlabs.org/pipermail/linuxppc-embedded/attachments/20050218/12060ce8/pq2-pci.bin
>>>>    
>>>
>>>
>>>  
>>
>>-- 
>>Sincerely, 
>>Vitaly
> 
> 
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