2013/9/14 Albert ARIBAUD <albert.u.b...@aribaud.net>: > Hi Kuo-Jung, > > On Mon, 29 Jul 2013 13:51:51 +0800, Kuo-Jung Su <dant...@gmail.com> > wrote: > >> + * At the time of writting, none of Faraday NAND & SPI controllers >> + * supports XIP (eXecute In Place). So the Faraday A360/A369 SoC has >> + * to implement a 1st level bootstrap code stored in the embedded ROM >> + * inside the SoC. >> + * >> + * After power-on, the ROM code (1st level bootstrap code) would load >> + * the 2nd bootstrap code into SRAM without any SDRAM initialization. >> + * >> + * The 2nd bootstrap code would then initialize SDRAM and load the >> + * generic firmware (u-boot/linux) into SDRAM, and finally make >> + * a long-jump to the firmware. >> + * >> + * Which means the SPL design of U-boot would never fit to A360/A369, >> + * since it's usually not possible to alter a embedded ROM code. > > Sorry, but I don't see why SPL could not run in SRAM as the 2nd > bootloader in your description; SPL certainly does not try to "alter a > embedded ROM". So, please rewrite the paragraph with the correct reason > why SPL cannot be the 2nd bootloader, e.g., is it > > - because the 2nd bootloader is actually in ROM? > - because the SRAM is too small? > - ... > > In any case: >
Got it, thanks. I'll try to study the SPL again, and rewrite the paragraph. >> + * And because both the 1st & 2nd level bootstrap code use the private >> + * Faraday Firmware Image Format, it would be better to drop U-boot >> + * image support to simplify the design. > > "Drop"? Certainly not. "Introduce a new image format where U-Boot is > prepended with a header defined as follow...", yes -- you can even > make a case that, if SPL cannot be the 2nd bootloader, then SPL is > actually "dropped" for this platform. Please rewrite. > Got it, thanks > Also: could the whole description and rationale be moved to some > README.* file either arch/arm/cpu/faraday or in doc/ so that readers > oof the C file can see the start of the actual code without having to > scroll through hundreds of comment lines? > Got it, thanks > Amicalement, > -- > Albert. -- Best wishes, Kuo-Jung Su _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot