From: Segher Boessenkool <segher@kernel•crashing.org>
To: David Gibson <dwg@au1•ibm.com>
Cc: Olof Johansson <olof@lixom•net>,
linuxppc-dev@ozlabs•org,
Loeliger Jon-LOELIGER <jdl@Freescale•com>
Subject: Re: [PATCH v2 6/7] Holly DTS
Date: Mon, 14 May 2007 14:33:13 +0200 [thread overview]
Message-ID: <1777f196ba995c48a00d72b94a4dbbd8@kernel.crashing.org> (raw)
In-Reply-To: <20070514002457.GD6517@localhost.localdomain>
>>> easiest is to
>>> replace it with a configurable poison value. When using asm output,
>>> or with a map file, it might be possible to generate out-of-band
>>> information which we can use to check that the right things are
>>> filled
>>> in.
>>>
>>> It's not a simply a matter of making the kernel parser recognize the
>>> uninitialized info, because there's no way to encode that in the dtb
>>> itself.
>>
>> There can be, with a new DTB version -- perhaps simply
>> define proplen == -1 to mean "undefined" or similar.
>
> That doesn't quite do it, because I'd prefer ? to cover cases where
> the property's length is known, just not its value. In particular
> that could be useful for device trees where *only* non-moving edits
> are required by the bootloader, letting us use the asm output mode as
> intended.
[First things first -- it is generally wrong to
require properties to have a certain length, newer
(versions of) bindings can add extra fields to the
end of a property. It should be okay for this ??
stuff though, if a bootwrapper/firmware fills in
the property it better know its whole semantics,
including the new part.]
Okay, so use negative lengths to represent undefined
properties of a certain length, and use -inf to mean
"completely undefined yet". Or some other encoding,
there are many ways that would work.
My point is that you need a new DTB version to properly
represent ??.
Segher
next prev parent reply other threads:[~2007-05-14 14:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-05 16:13 [PATCH v2 0/7] Add support for 750CL Holly board Josh Boyer
2007-05-05 16:14 ` [PATCH v2 0/1] Add tsi108_pci.h for common PCI functions Josh Boyer
2007-05-05 16:15 ` [PATCH v2 2/7] Generalize tsi108 PHY types Josh Boyer
2007-05-05 16:16 ` [PATCH v2 3/7] Generalize TSI 108 PCI setup Josh Boyer
2007-05-05 16:17 ` [PATCH v2 4/7] Add support for 750CL Holly board Josh Boyer
2007-05-07 4:22 ` Paul Mackerras
2007-05-07 10:32 ` Josh Boyer
2007-05-05 16:19 ` [PATCH v2 5/7] Holly defconfig Josh Boyer
2007-05-05 16:20 ` [PATCH v2 6/7] Holly DTS Josh Boyer
2007-05-05 17:21 ` Segher Boessenkool
2007-05-05 18:12 ` Josh Boyer
2007-05-05 20:44 ` Segher Boessenkool
2007-05-05 21:36 ` Josh Boyer
2007-05-06 0:47 ` Segher Boessenkool
2007-05-05 19:13 ` Olof Johansson
2007-05-05 19:46 ` Josh Boyer
2007-05-05 20:51 ` Segher Boessenkool
2007-05-05 20:49 ` Segher Boessenkool
2007-05-07 17:50 ` Loeliger Jon-LOELIGER
2007-05-09 0:49 ` David Gibson
2007-05-09 7:40 ` Stephen Rothwell
2007-05-09 10:29 ` Josh Boyer
2007-05-09 15:28 ` Segher Boessenkool
2007-05-10 23:54 ` David Gibson
2007-05-12 12:02 ` Segher Boessenkool
2007-05-14 0:24 ` David Gibson
2007-05-14 12:33 ` Segher Boessenkool [this message]
2007-05-14 16:16 ` Scott Wood
2007-05-06 0:40 ` David Gibson
2007-05-07 13:11 ` Josh Boyer
2007-05-08 0:06 ` David Gibson
2007-05-05 16:20 ` [PATCH v2 7/7] Holly bootwrapper Josh Boyer
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