Jetson Nano with Micron DRAM and PCN211181 Buildroot and custom dtb

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
1

Hello

I’m using Jetpack 32.7.3 kernel with buildroot created rootfs on a custom board with Jetson Nano that has stopped working since the DRAM change.

When running our existing code on the Nano with Micron DRAM U-Boot incorrectly says 2 GiB RAM and the boot fails.

I’ve unpacked the PCN211181 overlay and applied the dtb changes to our device tree as well as copying P3448_A00_lpddr4_204Mhz_P987.cfg to nano_drivers-32.7.3/Linux_for_Tegra/bootloader/t210ref/BCT/

U-Boot now correctly says 4 GiB DRAM however it still fails to boot.

It seems like there is an issue in T-Boot just before C-Boot where I get the following messages

[0001.369] RamCode = 1

[0001.371] get_emc_table_offset: Can’t find emc-table node

[0001.376] LPDDR4 Training: Can’t find emc-table node

Even though when U-Boot runs after CBoot it does correctly say 4 GiB

Do I need to make other changes?

Others must have used PCN211181 with own device tree what changes did you make?

Thanks

3

Is it possible to use the default dtb from the overlay files first to confirm if this is related to the PCN?

1 Like
4

Thanks for your suggestion. Yes indeed that did work. Seems like I had only made changes to /boot/my.dtb as loaded by U-Boot but before then it gets the device tree from the dtb partition and was using tegra210-p3448-0002-p3449-0000-b00.dtb for that.

5

@WayneWWW can you confirm if the new DTBs from PCN211181 should still work with the old DRAM too?

I’ve got a problem now on old boards same build that boots on new Micron DRAM, whilst DRAM training seems to succeed on old DRAM boards the boot fails at starting the Kernel with no further output past
[ 0.014498] console [tty0] enabled
[ 0.018008] bootconsole [uart8250] disabled
When would expect this line next
[ 0.000000] Booting Linux on physical CPU 0x0

6

please check the log of RamCode in UART console as your previous shared info.

RamCode = 1

If the old module shared the same RamCode as the new DRAM, then it will be affected.

8

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