On Sun, Dec 19, 2010 at 10:19 PM, Jason Liu <liu.h.ja...@gmail.com> wrote: > Hi, Stefano, > > 2010/12/17 Stefano Babic <sba...@denx.de>: >> On 12/17/2010 04:05 AM, Jason Liu wrote: >>> There is pretty much different with I.MX51 ROM, we will not use DCD >>> data file to config the >>> DDR script since ROM has the DCD size limitation and use the advance >>> feature of what we >>> called plug-in, the plug-in code must be in the first 2K of MMC card >>> from 0x400 offset, that's >>> why we need put this code section before start.S. The plug-in code >>> will be called by boot ROM >>> to do DDR init first and copy u-boot to DDR and jump to _start to run it. >> >> As I am not understanding what you mean as "plugin", it seems to me you >> need some code able to set-up RAM and copy the u-boot code. This method >> looks like very similar to other SoCs, where a first stage boot loader >> is needed or when we boot from NAND. > > Forget about the case about boot From NAND, we are talking about boot > from SD/MMC card here. > Why I call it here"plug-in", it due to it use the plugin feature of ROM. > > This section of code is for ROM to load and run, thus it should meet > the ROM boot structure requirement. > The plugin feature of ROM can give more flexibility and it can > overcome some shortcomings of DCD(used on mx51). > > By using this plugin we can get around the following issues: > 1. DCD size limitation issue, plugin can be the size of OCRAM free space > region. > 2. Safe environment to re-configure PLL1 (without impacting SDRAM) as > the plugin runs from OCRAM. > >
Jason: No one is arguing about the use the plugin feature. The objection is to how you are getting the plugin bits into the u-boot image. You should use a tool to prepend the plugins to the u-boot.bin file in a similar way to how mkimage is used for i.mx51 and others. Stefano: I know Freescale has a binary to do this but I don't believe the source is available. The binary is included as a package in the i.mx28 BSP as well as some sample plugins. You can find your way to the i.mx28 page by googling "site:freescale.com i.mx28 BSP" and following the top most hit. You have to register to download the BSP. Once you download the BSP you will find a source archive called L2.6.31_10.08.01_SDK_source.tar.gz. The sample plugin package is in the archive in a file called L2.6.31_10.08.01_SDK_source/pkgs/imx-bootlets-src-10.08.01.tar.gz. I guess bootlets are another name for plugins. The binary utility for creating bootlets from elf files is called elftosb-0.4.tar.bz2 in the same archive. The utility appears to be a typical over engineered c++ pile of stuff. One would think that you could accomplish the same thing with objdump, and a patch to mkimage. Chapter 12 of the i.mx28 Technical Reference Manual describes this, I have not seen a doc for i.mx53 yet and am just assuming that it is the same as i.mx28. http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM.pdf br, John _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot