Hi Daniel,
This looks like an interesting alternative.
On Thursday 16 June 2011 06:25 PM, Daniel Schwierzeck wrote:
Hi all,
for my MIPS based boards I tested a approach similar to Wolfgang's one in the last weeks. My goal was to create a SPL image, that is able to boot from a SPI flash.
The basic idea is to have a spl directory that is used as remote build directory for all object files needed for the SPL image. It contains only the Makefile and nothing else. This Makefile is a strongly simplified version of the TOPDIR/Makefile, uses TOPDIR/config.mk and creates a u-boot-spl.bin. The SPL build can be enabled by defining CONFIG_UBOOT_SPL in the board config file.
In the last few mails Wolfgang was suggesting re-use of object files themselves, not the source files. In this respect his approach may be different from yours. But I think his objective was to avoid the symbolic link business, which this approach achieves.
If the spl/Makefiles becomes active, an additional variable name CONFIG_UBOOT_SPL_BUILD wiil be exported in the make environment. Additionally -DCONFIG_UBOOT_SPL_BUILD will be added to the CFLAGS (similar to -DCONFIG_PRELOADER). This allows us to reuse almost of the arch, SoC and board code.
So, you are essentially re-using the make infrastructure of normal U-Boot with a different top-level Makefile and the additional flags, right?
With this scheme can you build two different SPLs for a given board, let's say a NAND spl and another MMC spl. I don't know if this is a valid case, but just wondering. I guess you have a unique u-boot- spl.bin much like you have single u-boot.bin, right?
Will you be sending your patches to the list?
best regards, Aneesh