From: Segher Boessenkool <segher@kernel•crashing.org>
To: David Gibson <david@gibson•dropbear.id.au>
Cc: linuxppc-dev@ozlabs•org
Subject: Re: [PATCH v3] [POWERPC] 85xx: Add basic Uniprocessor MPC8572 DS port
Date: Wed, 12 Sep 2007 16:00:38 +0200 [thread overview]
Message-ID: <44b4b3a133980aeb6c596aad71612e6c@kernel.crashing.org> (raw)
In-Reply-To: <20070912035351.GF20218@localhost.localdomain>
>>>> + uli1575@0 {
>>>> + reg = <0 0 0 0 0>;
>>>
>>> This looks kind of bogus...
>>
>> Its a PCIe to PCI bridge that is transparent.
>
> Right.... if it has no control registers, I think it should just lack
> 'reg', not define a zero-length register block.
"reg" for PCI config registers has length 0 always, it's defined that
way in the PCI binding.
But if this thing is transparent, it doesn't have PCI config regs.
>>>> + #size-cells = <2>;
>>>> + #address-cells = <3>;
>>>> + ranges = <02000000 0 80000000
>>>> + 02000000 0 80000000
>>>> + 0 20000000
>>>> + 01000000 0 00000000
>>>> + 01000000 0 00000000
>>>> + 0 00100000>;
>
> And if truly transparent, it should perhaps have just ranges;
> indicating that child addresses are identity mapped to parent
> addresses.
If truly transparent, the node should just not be there at all!
>>>> + pci_bridge@0 {
>>>
>>> Ok.. why is pci_bridge nested within uli1575 - with the matching reg
>>> and ranges, it looks like they ought to be one device. Also if this
>>> is a PCI<->PCI bridge, I believe it shold have device_type = "pci".
>>
>> We've been using this as it stands for a while. If there are some
>> changes here that make sense I'm willing to make them.
>
> Right, at present I don't see why you couldn't just ditch the
> pci_bridge node, and drop its contents straight into the uli1575 node.
Yeah. The preferred name for PCI-to-PCI bridge nodes is simply "pci",
btw.
Segher
next prev parent reply other threads:[~2007-09-12 14:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-11 19:37 [PATCH v3] [POWERPC] 85xx: Add basic Uniprocessor MPC8572 DS port Kumar Gala
2007-09-12 3:11 ` David Gibson
2007-09-12 3:33 ` Kumar Gala
2007-09-12 3:53 ` David Gibson
2007-09-12 14:00 ` Segher Boessenkool [this message]
2007-09-12 15:08 ` MDIO & phy device tree bindings (was Re: [PATCH v3] [POWERPC] 85xx: Add basic Uniprocessor MPC8572 DS port) Kumar Gala
2007-09-12 15:13 ` [PATCH v3] [POWERPC] 85xx: Add basic Uniprocessor MPC8572 DS port Kumar Gala
2007-09-12 14:10 ` Segher Boessenkool
2007-09-13 3:27 ` Kumar Gala
2007-09-12 13:36 ` Segher Boessenkool
2007-09-13 3:28 ` Kumar Gala
2007-09-13 4:21 ` David Gibson
2007-09-13 17:06 ` Segher Boessenkool
2007-09-13 18:24 ` Kumar Gala
2007-09-13 22:30 ` Segher Boessenkool
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