why the ddr configure is different with usb and emm/sd boot in imx53?

[rainustc]

I've used MFGTools with usb downloader to set a group of lpddr2 configure parameters which is been hw calibrated by rd and wr delay.But it can't work with emmc/sd boot, I've found out that after the ddr init, when running the ROM function it fails to usb downloader.

I've just checked out the bug, but still couldn't solve it.

I try to calibrate the ddr reg parameter again with emmc or sd boot, still now I only check out the read delay calibration, the write delay is still not work properly.

So, maybe my confuse is very simple, why the ddr reg parameters can't be same in usb boot and emm/sd boot?

[lily_zhang · Accepted solution]

Actually we always used the same DDR script for MFGTool, eMMC/SD boot.

From your description, it's still difficult to judge where is wrong:

- DDR script is still not enough stable to run everything.

- If your DDR script can run for USB downloader, however this DDR script can not make minor bootloader to run, you also need to check other things besides DDR. It may hang before UART initializaiton complete due to other reason.