From: Gary Thomas <gary@mlbassoc•com>
To: Kumar Gala <galak@kernel•crashing.org>
Cc: linuxppc-dev@ozlabs•org
Subject: Re: PCI changes 2.6.26 => 2.6.28
Date: Tue, 21 Apr 2009 17:00:49 -0600 [thread overview]
Message-ID: <49EE5021.4020703@mlbassoc.com> (raw)
In-Reply-To: <46B035C0-624F-41E4-BFDD-C16479CF8FC8@kernel.crashing.org>
Kumar Gala wrote:
>>>> I'm still looking into how the PCI address register for the video
>>>> card did not get written, even though the system obviously thinks
>>>> it did (hence "virtual")
>>>>
>>>
>>> It most definitely has something to do with 0xC0000000 being
>>> assigned to the video card. I changed my DTS to move everything
>>> up (started the whole space at 0xC4000000) and the video card
>>> came to life! Of course, I'm not interested in this hack,
>>> so the simplest thing would be to figure out why 2.6.26 allocated
>>> that outgoing window and 2.6.28 doesn't
>>
>> So I think the difference is due to the change in PCI code between
>> 2.6.26 and .28 for 83xx. If you notice we exclude the FSL device in
>> .26 you have:
>>
>>>> c0000000-c7ffffff : 0000:00:00.0
>>
>> and in .28 its gone. This accounts for the allocation differences.
>> What I don't get is why the behavior would vary based on address.
>>
>> Can you dump out the PCI inbound/outbound registers. I have a theory
>> as to what's going on and want to confirm it.
I found the difference - in 2.6.28 the inbound/outbound windows
don't seem to be set up at all. In 2.6.26, the function 'fsl_add_bridge'
was common among architectures and ended up calling 'setup_pci_atmu'
which created those mappings. In 2.6.28, the 83xx PCI setup code
has been refactored. It uses 'mpc83xx_add_bridge' instead of
'fsl_add_bridge' and 'setup_pci_atmu' is not called at all :-(
I'm sure this is the problem.
> Also, what's your .dts look like for the PCI node.
For the record:
bus-range = <0 0>;
ranges = <0x02000000 0x0 0xC0000000 0xC0000000 0x0 0x10000000
0x01000000 0x0 0x00000000 0xB8000000 0x0 0x00100000>;
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
next prev parent reply other threads:[~2009-04-21 23:00 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-21 16:24 PCI changes 2.6.26 => 2.6.28 Gary Thomas
2009-04-21 20:30 ` Gary Thomas
2009-04-21 20:32 ` Gary Thomas
2009-04-21 20:33 ` Kumar Gala
2009-04-21 20:45 ` Gary Thomas
2009-04-21 22:22 ` Gary Thomas
2009-04-21 22:38 ` Kumar Gala
2009-04-21 22:50 ` Kumar Gala
2009-04-21 23:00 ` Gary Thomas [this message]
2009-04-21 23:41 ` Kumar Gala
2009-04-21 23:45 ` Gary Thomas
2009-04-22 3:51 ` Kumar Gala
2009-04-23 14:24 ` Gary Thomas
2009-04-23 18:47 ` Kumar Gala
2009-04-23 22:27 ` Gary Thomas
2009-04-27 13:17 ` Benjamin Herrenschmidt
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