Re: [U-Boot] Loading and Running u-boot from context RAM
Hi Ronny, On Wednesday 31 March 2010 07:16:33 Ronny D wrote: I am working on PPC440 based customized board having 4MB context ram. what are all changes need to perform to skip relocation of u-boot in DDR and relocated it to context ram and run from the same location. I'm not sure if I understand your question correctly. Are you looking for a way to skip the SDRAM initialisation and relocation from FLASH to SDRAM and directly jump to the U-Boot code already located somewhere in RAM? If yes, then you should take a look at the Sequoia (440EPx) ramboot build target. Here the commit log from the base support patch: ppc4xx: Add Sequoia RAM-booting target This patch adds another build target for the AMCC Sequoia PPC440EPx eval board. This RAM-booting version is targeted for boards without NOR FLASH (NAND booting) which need a possibility to initially program their NAND FLASH. Using a JTAG debugger (e.g. BDI2000/3000) configured to setup the SDRAM, this debugger can load this RAM- booting image to the target address in SDRAM (in this case 0x100) and start it there. Then U-Boot's standard NAND commands can be used to program the NAND FLASH (e.g. nand write ...). Here the commands to load and start this image from the BDI2000: 440EPXreset halt 440EPXload 0x100 /tftpboot/sequoia/u-boot.bin 440EPXgo 0x100 Please note that this image automatically scans for an already initialized SDRAM TLB (detected by EPN=0). This TLB will not be cleared. This TLB doesn't need to be TLB #0, this RAM-booting version will detect it and preserve it. So booting via BDI2000 will work and booting with a complete different TLB init via U-Boot works as well. Hope this helps. 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: off...@denx.de ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] Loading and Running u-boot from context RAM
Dear Ronny D, In message 875745.66478...@web46116.mail.sp1.yahoo.com you wrote: I am working on PPC440 based customized board having 4MB context ram. what are all changes need to perform to skip relocation of u-boot in DDR and relocated it to context ram and run from the same location. first: why would you want to do that? Which advantages do you expect compared to running from DDR? It might be sufficient to change the initialization of addr in board_init_f() in lib_ppc/board.c; instead of basing it on CONFIG_SYS_SDRAM_BASE + get_effective_memsize() set it to the end address of your contaxt RAM (+1). Be careful about the relocation of the exception vectors, though. These probably still need to be relocated to 0. I don't know which other obstacles might be on that way - U-Boot's memory map on Power silently assumes that it has contiguous memory from 0 through the current image address. Also, 4 MB might not be sufficient for example to hold the malloc arena if you want to uncompress bigger bz2 compressed images, and so on. All in all I expect some effort especially for debugging, and little or no benefit. 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: w...@denx.de There is no distinctly American criminal class except Congress. - Mark Twain ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
[U-Boot] Loading and Running u-boot from context RAM
Hello, I am working on PPC440 based customized board having 4MB context ram. what are all changes need to perform to skip relocation of u-boot in DDR and relocated it to context ram and run from the same location. ~Ronny The INTERNET now has a personality. YOURS! See your Yahoo! Homepage. http://in.yahoo.com/___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
