From: Marian Balakowicz <m8@semihalf•com>
To: Grant Likely <grant.likely@secretlab•ca>
Cc: linuxppc-dev@ozlabs•org, Martin Krause <Martin.Krause@tqs•de>,
David Gibson <david@gibson•dropbear.id.au>
Subject: Re: [PATCH 05/11] [POWERPC] TQM5200 DTS
Date: Tue, 30 Oct 2007 16:34:50 +0100 [thread overview]
Message-ID: <47274F1A.8030301@semihalf.com> (raw)
In-Reply-To: <fa686aa40710290840w41e2ffeo38b9497ce76e155@mail.gmail.com>
Grant Likely wrote:
> On 10/29/07, Marian Balakowicz <m8@semihalf•com> wrote:
>> David Gibson wrote:
>>> On Thu, Oct 25, 2007 at 05:46:19PM +0200, Marian Balakowicz wrote:
>>>> Grant Likely wrote:
>>>>> On 10/25/07, Martin Krause <Martin.Krause@tqs•de> wrote:
>>> [snip]
>>>>>> On a board with 16 MiB FLASH for example the "big-fs" _and_ the "misc"
>>>>>> partition could not be used. "big-fs", because the memory is too small
>>>>>> (which is OK) and "misc", because it overlaps 1 MiB over the physikal
>>>>>> flash border. So only the first 9 MiB of the flash could be used in Linux.
>>>>>> The remaining 7 MiB couldn't be accessed.
>>>>> Perhaps it would be better to drop the flash layout from the in-kernel
>>>>> dts files entirely since flash layout can be a fluid thing.
>>>> Well, but that would not be really user friendly, I'd rather stick
>>>> with some default config.
>>> Strictly speaking the device-tree is not the right place for flash
>>> partitioning information. We put it there because it's preferable to
>>> having hardcoded per-board flash layouts in the code itself.
>>>
>>> It only really works well, though, when there are strong conventions
>>> (shared with the firmware) about how to partition the flash.
>>>
>>> Where it's really up to the user to determine how they want to lay out
>>> their flash, putting things in the device tree isn't a really good
>>> idea.
>> In principle, you are right, we should not be putting a user dependent
>> configuration into .dts files. But on the other hand, bindings have
>> been defined for flash-like devices and their partition layouts and
>> physmap_of device driver is expecting to get this information from the
>> blob. So, it is the place for it. But if we are not to put partition
>> layouts into the default kernel .dts files then we should
>> provide/maintain some examples an that may be a even bigger mess.
>>
>>> Incidentally, it's not required that *all* the flash address space be
>>> in partitions, so it is possible only give partitions for those flash
>>> chunks which the firmware needs to know about.
>> That might be nicer solution but different variants of TQM5200 boards
>> do not share the same subset of partitions (default u-boot partitions
>> at least), so it will not help much.
>
> It's probably more appropriate to have the flash partition layout in
> the u-boot environment and have u-boot populate the partition
> information in the device tree.
Yes, it's more appropriate but such feature is not currently available
in U-boot, so it has to be hand crafted until then. It just seemed
more convenient to have some reference example before there is a
support for passing partition layout from firmware.
But all right, will remove flash layouts from in-kernel .dts files.
Cheers,
m.
next prev parent reply other threads:[~2007-10-30 15:35 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-23 23:13 [PATCH 00/11] [POWERPC] Add TQM5200/CM5200/Motion-PRO board support Marian Balakowicz
2007-10-23 23:13 ` [PATCH 01/11] [POWERPC] Add 'machine: ...' line to common show_cpuinfo() Marian Balakowicz
2007-10-23 23:23 ` David Gibson
2007-10-25 14:17 ` Marian Balakowicz
2007-10-23 23:59 ` Olof Johansson
2007-10-24 7:11 ` Stephen Rothwell
2007-10-25 4:33 ` Milton Miller
2007-10-25 14:47 ` Marian Balakowicz
2007-10-23 23:13 ` [PATCH 02/11] [POWERPC] Add 'lpb' bus type for MPC5200 LocalPlus Bus Marian Balakowicz
2007-10-24 0:09 ` Olof Johansson
2007-10-25 14:55 ` Marian Balakowicz
2007-10-23 23:13 ` [PATCH 03/11] [POWERPC] Add common mpc52xx_setup_pci() routine Marian Balakowicz
2007-10-24 7:16 ` Stephen Rothwell
2007-10-23 23:13 ` [PATCH 04/11] [POWERPC] Add generic support for MPC5200 based boards Marian Balakowicz
2007-10-24 14:03 ` Grant Likely
2007-10-23 23:13 ` [PATCH 05/11] [POWERPC] TQM5200 DTS Marian Balakowicz
2007-10-24 1:51 ` David Gibson
2007-10-24 14:09 ` Grant Likely
2007-10-25 15:23 ` Marian Balakowicz
2007-10-25 9:57 ` Martin Krause
2007-10-25 13:53 ` Grant Likely
2007-10-25 15:46 ` Marian Balakowicz
2007-10-26 1:33 ` David Gibson
2007-10-29 14:18 ` Marian Balakowicz
2007-10-29 15:40 ` Grant Likely
2007-10-30 0:58 ` David Gibson
2007-10-30 5:58 ` Grant Likely
2007-10-30 15:34 ` Marian Balakowicz [this message]
2007-10-23 23:13 ` [PATCH 06/11] [POWERPC] TQM5200 defconfig Marian Balakowicz
2007-10-23 23:13 ` [PATCH 07/11] [POWERPC] CM5200 DTS Marian Balakowicz
2007-10-23 23:13 ` [PATCH 08/11] [POWERPC] CM5200 defconfig Marian Balakowicz
2007-10-23 23:13 ` [PATCH 09/11] [POWERPC] Motion-PRO: Add LED support Marian Balakowicz
2007-10-24 14:18 ` Grant Likely
2007-10-25 15:53 ` Marian Balakowicz
2007-10-23 23:14 ` [PATCH 10/11] [POWERPC] Promess Motion-PRO DTS Marian Balakowicz
2007-10-23 23:14 ` [PATCH 11/11] [POWERPC] Promess Motion-PRO defconfig Marian Balakowicz
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=47274F1A.8030301@semihalf.com \
--to=m8@semihalf$(echo .)com \
--cc=Martin.Krause@tqs$(echo .)de \
--cc=david@gibson$(echo .)dropbear.id.au \
--cc=grant.likely@secretlab$(echo .)ca \
--cc=linuxppc-dev@ozlabs$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox