From: Wolfgang Denk Date: Tue, 07 Oct 2008 16:02:23 +0200 Subject: [U-Boot] how can i change u-boot load address? In-Reply-To: <40a670230810070536w5ab3251cm39b1a4ebd199e14a@mail.gmail.com> References: <19836732.post@talk.nabble.com> <40a670230810061636u3c7c3c1dn26f6860a1b463d8b@mail.gmail.com> <20081007073614.5E35485D90E5@gemini.denx.de> <40a670230810070536w5ab3251cm39b1a4ebd199e14a@mail.gmail.com> Message-ID: <20081007140223.83CD185D90E5@gemini.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 Roman, In message <40a670230810070536w5ab3251cm39b1a4ebd199e14a@mail.gmail.com> you wrote: > > > On ARM it's being done wrong - no real relocation is preformed; > > What do you mean by "real relocation"? As per start.S bootcode is > copied from ROM to RAM. Copied to a fixed address where it is actiually already linked for. See my previous message with a lenghty explanation why this is a poor design when dealing with variable sized memory. > > The problem with the ARM implementation is that the link address is > > fixed, i. e. it cannot be adjusted to varying RAM sizes. > Usually one ports U-Boot on a board with predefined hardware layout, > i.e. flash, SDRAM and peripherals are fixed. If hardware changes, say > SDRAM size, no big deal to make two/three distinct u-boot images -- > after all it ends up by changing TEXT_BASE only, as I understand. This may be your opinion, but it is an isolated one and not shared by *many* board vendors who offer different configurations of boards with smaller and bigger amounts of RAM etc. For these, having only a single binary image of U-Boot for all board configurations is a MAJOR win. Also consider systems which use memory modules. Just try to imagine you have to install a new version of the BIOS on your PC just because you add or remove a memory module. Would you buy such a PC? Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de (null cookie; hope that's ok)