From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulf Samuelsson Date: Mon, 07 Sep 2009 00:01:27 +0200 Subject: [U-Boot] reloacting uboot In-Reply-To: <20090825203950.BDA4C833DBD2@gemini.denx.de> References: <200908251403.20809.e.robertson.svg@gmail.com> <20090825191136.55EAD833DBD2@gemini.denx.de> <200908251428.55255.e.robertson.svg@gmail.com> <20090825203950.BDA4C833DBD2@gemini.denx.de> Message-ID: <4AA43137.6070008@atmel.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.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