From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Schocher Date: Tue, 02 Nov 2010 07:29:56 +0100 Subject: [U-Boot] [RFC] arm926ejs: fix jump to RAM nand_boot In-Reply-To: <20101101192318.06C231522C0@gemini.denx.de> References: <20101031203243.478E9EA47F@gemini.denx.de> <1288547025-16877-1-git-send-email-albert.aribaud@free.fr> <20101031181244.419EDEA47F@gemini.denx.de> <4CCDB78D.506@ahsoftware.de> <20101031190136.64829EA47F@gemini.denx.de> <4CCDBE71.1010805@free.fr> <20101031192243.7AF531522C0@gemini.denx.de> <4CCDC625.3010209@free.fr> <20101031195941.5AB961522C0@gemini.denx.de> <4CCDD02D.2050304@free.fr> <1288560046-6458-1-git-send-email-albert.aribaud@free.fr> <4CCDED8D.0@ahsoftware.de> <4CCDF5FC.4060704@free.fr> <20101101091515.C8BDD1522C0@gemini.denx.de> <4CCEF2E4.5080003@free.fr> <20101101192318.06C231522C0@gemini.denx.de> Message-ID: <4CCFAFE4.3000600@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 Hello Wolfgang, Wolfgang Denk wrote: > Dear Albert ARIBAUD, > > In message <4CCEF2E4.5080003@free.fr> you wrote: >> Also, I understand why the second RFC change I did was harmful to tx25. >> Contrary to u-boot itself, u-boot-spl is not compiled to be position >> independent; it actually loads at a given address then copies itself, >> without relocating, to its home location. > > It copies _itself_? Not the U-Boot payload? > > Heiko, is this intentional? Do we really first load the whole image, > then copy the U-Boot payload to some other address, then relocate it > to yet another one? - preloader copies first page of nand (nand_spl code) to 0xbb000000 (some cpu internal mem) and jumps to this address - nand_spl does lowlevelinit, relocate itself to TEXT_BASE (nand_spl code) - from there, it copies u-boot code from nand to CONFIG_SYS_NAND_U_BOOT_DST and jumps to CONFIG_SYS_NAND_U_BOOT_START - u-boot run into board_init_f, calculates new relocation address and relocates ... But there is a possibility to prevent one copy, if TEXT_BASE = relocation address = CONFIG_SYS_NAND_U_BOOT_DST In this case nand_spl code copies u-boot from nand to CONFIG_SYS_NAND_U_BOOT_DST. As this is equal to the relocation address, no need to copy code in relocate_code(). But as codesize changes (and with it relocation address) this is not a perfect solution. bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany