From: Gary Thomas <gary@mlbassoc•com>
To: Scott Wood <scottwood@freescale•com>
Cc: avorontsov@ru•mvista.com, linuxppc-dev <linuxppc-dev@ozlabs•org>
Subject: Re: PCI on 834x
Date: Thu, 25 Feb 2010 14:11:48 -0700 [thread overview]
Message-ID: <4B86E794.6020403@mlbassoc.com> (raw)
In-Reply-To: <4B86E5A7.9090607@freescale.com>
On 02/25/2010 02:03 PM, Scott Wood wrote:
> Benjamin Herrenschmidt wrote:
>> On Thu, 2010-02-25 at 07:25 -0700, Gary Thomas wrote:
>>> 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?
>>
>> I'm not familiar with the way the FSL bridge works, but it would
>> be possible to invert MMIO and DMA on your PCI bus. IE. Have MMIO go
>> from 0....2G and DMA from 2G..4G for example. Provided the FSL bridge
>> can offset the DMA back down to 0 (memory). Can it ?
>
> It can, but I don't see how that would help, if the problem is that the video card doesn't like the low 30 bits of its MMIO address being zero.
>
> Gary, can you check that the MMIO addresses are going to the PCI bus as-is, and aren't being translated down to zero? I.e. POTARn should equal POBARn, and likewise in the device
> tree's pci node's ranges.
Hmm, that doesn't match with how I've always had this setup. I have:
POTAR0 = 0x00000000
POTBR0 = 0x000C0000 (0xC0000000 >> 12)
My device tree mappings are:
ranges = <0x02000000 0x0 0xC0000000 0xC0000000 0x0 0x10000000
0x01000000 0x0 0x00000000 0xB8000000 0x0 0x00100000>
n.b. I don't run U-Boot on these platforms (being the author
of RedBoot and all... :-)
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
next prev parent reply other threads:[~2010-02-25 21:11 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
2010-02-25 20:49 ` Benjamin Herrenschmidt
2010-02-25 21:03 ` Scott Wood
2010-02-25 21:11 ` Gary Thomas [this message]
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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