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modify mfgtool for ddr cal

Question asked by David Luberger on Sep 13, 2018
Latest reply on Sep 20, 2018 by David Luberger

i'm running the i.mx6ul on a custom board.


1.) I've run the ddr stress test gui to get new calibration values.  the read and write cal values are stable, but the dqs gating keeps changing between two fairly different values, but always the same ones (0x41540150 and 0x4158004e). every time i update the .inc script the result gives me the other dqs value. i'm not sure if it matters or indicates something is wrong, but the read and write cal values are rock solid after the first cal update.


2.) i'm told that i should not be building and loading u-boot, dtb, kernel, and rootfs directly from my linux host using the dd command (e.g., sudo dd if=u-boot.imx of=/dev/sdb bs=1k seek=1 conv=fsync) but that i should always use the mfg tool. i'm also told, however, that i can't use the mfg tool as downloaded from the processor product page because it was pre-built for the eval boards, and has to be modified for a custom board, with it's own u-boot updated for the new ddr cal values.furthermore, i'm told that i really should be using yocto to do all my builds, not just the mfgtool. the problem is that -- and i have to gripe a bit -- the yocto project stuff is incredibly convoluted and confusing to me.  doing direct builds with the make command is fairly straightforward; all i have to do is modify the <my-board>.c file for u-boot, the device tree dts file for the kernel, maybe some other tweaks, run the make my-board-defconfig and make commands for u-boot and kernel and i'm off and running; it's super easy.  but the yocto project stuff is really really hard to follow and understand. all i see are recipes but no c files, no dts files, no rootfs files. and there are no clear instructions that point me to the files i need to modify to customize my builds.  i've looked at the bsp porting guide and it only talks about copying and modifying conf files, it doesn't say anything about how to find and modify the c files and dts files like i do with direct building as above.  how do i customize u-boot? how do i customize my device tree?? i can't figure out how to do any of the stuff i did simply using the make command and modified board files.  i've already looked through the yocto user guide, the linux user guide, all docs, and nothing that tells me step by step how use yocto to do the same stuff i'm doing building the 4 pieces directly.  and to make matters worse, doing the direct builds took minutes, but i did one yocto build for the imx6ul-14x14-evk board and xwayland distro and it literally took all night! i don't have time to build with yocto if it takes hours on end to build.


please help!