[meta-xilinx] zynqmp: SPL to linux (falcon)

[Jean-Francois Dagenais]

Hi guys,

So I learned a lot more, but have yet to achieve my short-term goal: get to a linux prompt.

Our custom board has an onboard eMMC and an optional module with a regular SD on it. Using the yocto build of u-boot-spl (the elf) and the XSDK with the USB platform cable, I was able to debug (changed -Os to -O0 in u-boot/Makefile). I modified the U-Boot SPL to work with both sdhci correctly based on the selected bootmode (0x3 or 0x5). Patches to u-boot-xlnx to come eventually.

So now I can get through ATF and into the real u-boot, but then, after real u-boot re-programs the tap_delays (through the PMUFW this time), the SD card times out, but eMMC works... sighs.

I didn't quite enjoy my tour of the u-boot code to be honest. It really shows that this codebase has to support a gazillion boards.

With that in mind, I am wondering if anyone could summarize the steps required to go directly from my now functional SPL directly to the linux kernel (a.k.a. falcon), either directly in EL3 (yes, the kernel in EL3), or through ATF if I must or is simpler. I need the quickest, simplest (even if dirty) way. FYI, I already have my own established clones of u-boot-xlnx and linux-xlnx. I have no problems temporarily forking ATF too.

I need to evaluate if I must spend more time in u-boot, or switch to FSBL, or falcon boot our board.

My build is for a single platform, single configuration. It may boot from either eMMC or SD as selected by the "jumpers".

Thanks in advance guys!