From: Gary Thomas <gary@mlbassoc•com>
To: Kumar Gala <galak@kernel•crashing.org>
Cc: Scott Wood <scottwood@freescale•com>,
linuxppc-dev <linuxppc-dev@ozlabs•org>,
avorontsov@ru•mvista.com
Subject: Re: PCI on 834x
Date: Thu, 25 Feb 2010 07:25:47 -0700 [thread overview]
Message-ID: <4B86886B.5000304@mlbassoc.com> (raw)
In-Reply-To: <4B85B182.2030508@mlbassoc.com>
On 02/24/2010 04:08 PM, Gary Thomas wrote:
> On 02/24/2010 03:25 PM, Kumar Gala wrote:
>>
>> On Feb 24, 2010, at 4:14 PM, Gary Thomas wrote:
>>
>>> On 02/24/2010 01:51 PM, Anton Vorontsov wrote:
>>>> On Wed, Feb 24, 2010 at 02:26:20PM -0600, Scott Wood wrote:
>>>>> Gary Thomas wrote:
>>>>>> Yes, I'm using the exact same kernel with these two different PCI
>>>>>> setups (done by the boot loader).
>>>>>>
>>>>>> Restricting the memory via mem=128M has no effect - the PCI layout
>>>>>> is the same.
>>>>>>
>>>>>> I think the outbound window size is required because of how the Linux PCI
>>>>>> remaps the space (note in my dumps that it put the MMIO of the
>>>>>> boards starting
>>>>>> at 0xD0000000 when the inbound window is 0x10000000)
>>>>>
>>>>> I see where the amount of RAM is mattering -- Linux is assigning
>>>>> outbound I/O space to the PCI controller itself (device 00:00.0) and
>>>>> the amount that it asks for seems to differ based on memory size.
>>>>> Linux ought to skip that device when assigning resources. Some
>>>>> platforms do this (search for pci_exclude_device), but it seems to
>>>>> be missing on 83xx.
>>>>
>>>> Actually, 83xx had these exclude_device hooks, but they were removed:
>>>>
>>>> commit d8f1324a5063c833862328ceafabc53ac3cc4f71
>>>> Author: Kumar Gala<galak@kernel•crashing.org>
>>>> Date: Wed Sep 12 22:14:10 2007 -0500
>>>>
>>>> [POWERPC] 83xx: Removed PCI exclude of PHB
>>>>
>>>> Now that the generic code doesn't assign resources for Freescale
>>>> PHBs we dont have to explicitly exclude it.
>>>>
>>>> Signed-off-by: Kumar Gala<galak@kernel•crashing.org>
>>>>
>>>>
>>>> May be the generic code started to assign the resources again?
>>>>
>>>
>>> That cracked it; I re-enabled the exclusion of the bridge and now
>>> it's all working fine.
>>>
>>> Thanks for the help
>>>
>>> Note: I'm working with a fairly old kernel, so these results would
>>> have to be reworked against the latest.
>>
>> Odd that the generic code isn't dealing with that for you.
>
> Remember it's an old kernel (2.6.28), so who knows the status.
> As I said, I'll revisit this when I move to a newer kernel.
>
I may have been too hasty pronouncing this fixed. Indeed, the
SATA interface now works, but my video card (Fujitsu Coral-P)
does not work when it's mapped at the bottom of the PCI space :-(
With the bridge mapped, the video ends up at a non-zero address
(0xC8000000..0xCFFFFFFF). If it gets mapped to 0xC0000000, it
fails to respond to MMIO accesses.
Any ideas how I might get around this? Is there a way to force
the PCI allocator to start somewhere other than [relative] zero?
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
next prev parent reply other threads:[~2010-02-25 14:25 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-24 15:49 PCI on 834x Gary Thomas
2010-02-24 18:48 ` Scott Wood
2010-02-24 19:14 ` Gary Thomas
2010-02-24 19:31 ` Scott Wood
2010-02-24 19:47 ` Gary Thomas
2010-02-24 20:26 ` Scott Wood
2010-02-24 20:51 ` Anton Vorontsov
2010-02-24 22:14 ` Gary Thomas
2010-02-24 22:25 ` Kumar Gala
2010-02-24 23:08 ` Gary Thomas
2010-02-25 14:25 ` Gary Thomas [this message]
2010-02-25 20:49 ` Benjamin Herrenschmidt
2010-02-25 21:03 ` Scott Wood
2010-02-25 21:11 ` Gary Thomas
2010-02-25 21:24 ` Scott Wood
2010-02-25 23:43 ` Gary Thomas
2010-02-25 23:49 ` Scott Wood
2010-02-25 22:36 ` Benjamin Herrenschmidt
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