Sorry for top post and not plain text. connection issue with O365. To JTAG to see whether DRAM is stable. Fire a breakpoint or deadloop in the end of SPL, or beginning of ATF to narrow down which triggers reboot. Yes i.MX8MN has LPDDR version, not upstreamed. Did you try NXP 5.4 Q2 release? 4.19 is a bit old.
THanks, Peng. ________________________________ From: Adam Ford <aford...@gmail.com> Sent: Friday, July 10, 2020 10:56 PM To: U-Boot Mailing List <u-boot@lists.denx.de>; dl-linux-imx <linux-...@nxp.com>; Peng Fan <peng....@nxp.com> Subject: Question Porting U-Boot to iMX8MN with LPDDR4 I have a board already supported in U-Boot based on the i.MX8MM with LPDDR4, and with a simple part change, we have built a Nano version as well with the same LPDDR4. I have mostly copied the imx8mn EVK files to the board support, and migrated the device tree files for my board. I also created a lpddr4 cfg file for the i.MX8MN because it appears to have a different bootloader than the Mini, but I am referencing the LPDDR4 training files used on the 8MM. Unfortunately when I boot, I get a boot-loop with output that looks like this: U-Boot SPL 2020.07-00499-gd9107930af-dirty (Jul 10 2020 - 09:47:31 -0500) spl_init >>SPL: board_init_r() Normal Boot WDT: Started without servicing (60s timeout) Trying to boot from BOOTROM image offset 0x8000, pagesize 0x200, ivt offset 0x0 board_fit_config_name_match: imx8mn-beacon-kit Selecting config 'imx8mn-beacon-kit'outname = uboot@1 board_fit_config_name_match: imx8mn-beacon-kit Selecting config 'imx8mn-beacon-kit'outname = fdt@1 board_fit_config_name_match: imx8mn-beacon-kit Selecting config 'imx8mn-beacon-kit'outname = atf@1 U-Boot SPL 2020.07-00499-gd9107930af-dirty (Jul 10 2020 - 09:47:31 -0500) spl_init ... I was curious to know if any of the NXP people might have any suggestions on what I might try. I have tried building the imx8mn evk and modifying the Kconfig to reference LPDDR4 instead of DDR4, and pointing to the cfg file for lpdd4 on the 8mn. Unfortunately, I don't see any change. I have also tried the NXP repos on Code Aurora going to releases as far back as 4.19_1.10, without success. I see the standard imx8mn_evk appears to use lpddr4, but that board doesn't appear upstream. Does that board exist? thanks, adam
