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From: Ulf Samuelsson <ulf.samuelsson@atmel.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] reloacting uboot
Date: Mon, 07 Sep 2009 00:01:27 +0200	[thread overview]
Message-ID: <4AA43137.6070008@atmel.com> (raw)
In-Reply-To: <20090825203950.BDA4C833DBD2@gemini.denx.de>

Wolfgang Denk skrev:
> Dear E Robertson,
> 
> In message <200908251428.55255.e.robertson.svg@gmail.com> you wrote:
>>> In message <200908251403.20809.e.robertson.svg@gmail.com> you wrote:
>>>> I am using the at91sam9263 device from which the bootstrap code load
>>>> u-boot to the desired ram address. However, I would like to re-relocate
>>>> this at the different address based on memory availability. Can / or
>>>> should this be done?
>>> Yes, it can be done, and it should be done. The fact that we don't do
>>> it so far is due to the fact that the guys who did the original ARM
>>> code found this too complicated (even though they had a working
>>> example in the PowerPC code) and not worth the effort. We're suffering
>>> since from this misconception.
>>>
>>> But there is no reason why you would have to copy the  code  again  -
>>> just copy it to the correct address right from the beginning, like we
>>> do in PowerPC.
>> I don't follow: Yes, but no reason to do so?
> 
> You wrote: "re-relocate". This is bogus. Just relocate it once, to the
> correct address.
> 
>> On the 9263, it's copied once to ram at boot. Are you saying their is no 
>> reason to copy it again? If so, yes, in most cases that would be true but I 
>> would like to move it again after that initial relocation. Since I've already 
>> specified my start address, I wasn't sure about.
> 
> Fix the ARM relocating scheme such that it works like in PowerPC: link
> the image not for a RAM address, but for the address in flash. Then,
> after determining the RAM size, copy & relocate the code once to RAM.
> Only one copy. Not two.
> 
> Best regards,
> 
> Wolfgang Denk
> 

Very few boards based on the SAM9263 store u-boot in parallel flash
and if they are stored in SPI dataflash or in NAND flash it makes
little sense to link the u-boot to the flash address.

Fix at91bootstrap to load where you want it to load.

BR
Ulf Samuelsson

  reply	other threads:[~2009-09-06 22:01 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-25 19:03 [U-Boot] reloacting uboot E Robertson
2009-08-25 19:11 ` Wolfgang Denk
2009-08-25 19:28   ` E Robertson
2009-08-25 20:39     ` Wolfgang Denk
2009-09-06 22:01       ` Ulf Samuelsson [this message]
2009-08-25 19:42   ` E Robertson
2009-08-25 20:43     ` Wolfgang Denk

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