From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Roese Date: Tue, 23 Nov 2010 06:51:11 +0100 Subject: [U-Boot] arch/powerpc/cpu/ppc4xx/start.S: comment makes little sense In-Reply-To: <20101121191701.DFCF1678@gemini.denx.de> References: <20101121191701.DFCF1678@gemini.denx.de> Message-ID: <201011230651.11733.sr@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 Hi Wolfgang, On Sunday 21 November 2010 20:17:01 Wolfgang Denk wrote: > I think this comment in arch/powerpc/cpu/ppc4xx/start.S needs a bit of > cleanup: > > 51 /* U-Boot - Startup Code for AMCC 4xx PowerPC based Embedded Boards > 52 * > 53 * > 54 * The processor starts at 0xfffffffc and the code is executed > 55 * from flash/rom. > 56 * in memory, but as long we don't jump around before relocating. > 57 * board_init lies at a quite high address and when the cpu has > 58 * jumped there, everything is ok. > 59 * This works because the cpu gives the FLASH (CS0) the whole > 60 * address space at startup, and board_init lies as a echo of > 61 * the flash somewhere up there in the memorymap. > 62 * > 63 * board_init will change CS0 to be positioned at the correct > 64 * address and (s)dram will be positioned at address 0 > 65 */ > > All this makes pretty little sense to me. Agreed. I'll try to get a better description out soon. Cheers, Stefan -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-0 Fax: (+49)-8142-66989-80 Email: office at denx.de