From mboxrd@z Thu Jan 1 00:00:00 1970 From: Markus =?iso-8859-1?Q?Klotzb=FCcher?= Date: Wed, 14 Feb 2007 17:21:08 +0100 Subject: [U-Boot-Users] u-boot for Vertex4-based board. In-Reply-To: <406A31B117F2734987636D6CCC93EE3CB05891@ehost011-3.exch011.intermedia.net> (Leonid@a-k-a.net's message of "Wed, 14 Feb 2007 07:24:49 -0800") References: <406A31B117F2734987636D6CCC93EE3CF9D4FB@ehost011-3.exch011.intermedia.net> <87vei52ppc.fsf@denx.de> <406A31B117F2734987636D6CCC93EE3CB05891@ehost011-3.exch011.intermedia.net> Message-ID: <87d54cww0b.fsf@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Dear Leonid, "Leonid" writes: > On Tuesday, February 13, 2007 10:55 PM Markus Klotzb?cher: >> > I'm porting u-boot on Vertex-4 based board (with PPC405 inside); > I'm >> > trying use ml403 u-boot as example. I have first stage boot > loader, >> > taking my u-boot image from serial and loading it to SDRAM, u-boot > is >> > configured to boot from main memory. > >> Are you aware that this setup is strongly discouraged? Have you read >> this: > >>http://www.denx.de/wiki/view/DULG/CanUBootBeConfiguredSuchThatItCanBeStarte> > dInRAM? > > [Leonid] The answer in DULG FAQ chapter you are referring to doesn't > say that such practice is bad, it simply states that u-boot doesn't > support such an option. That could be truth in the time of DULG FAQ > writing but now there are many platforms, naturally using 3-stage > booting. For example, ATMEL ARM boards have small boot program which > fetches u-boot from flash, loads it to RAM and then starts. I would > like to hear why do you think it's so bad, but in any case this way > u-boot is normally used for such boards (at91rm9200-ek for instance). I didn't say it's bad to do this, I just wanted to point out that starting U-Boot from RAM is not the standard way and you might experience difficulties. Having said that, yes, I'm well aware there are boards doing this, to be honest I have done it myself. Sometimes there is no other way. > In my case I probably could change EDK project to put flash on the end > of the memory, but I prefer to load u-boot via XMD debugger or serial > directly to RAM - much more convenient for debugging - since otherwise > I will need to burn flash each time I change something and I cannot > use BDI2000 on this board. Xilinx tools are not that convenient for > frequent flash burning. Well, I guess I would still burn U-Boot to flash if I had the choice. This setup has been tested much better. But as you seem to know what you are doing, it's ok. Best Regards Markus -- DENX Software Engineering GmbH, HRB 165235 Munich, CEO: Wolfgang Denk Office: Kirchenstr. 5, D-82194 Groebenzell, Germany