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AM4378: Using 2GB DDR with Linux SDK

Koichiro Tashiro
Mastermind 22945 points
Part Number: AM4378

Hi,

My customer used AM4378 with 1GB DDR and went to production in several years ago.
Now they are trying to modify the existing system and want to increase DDR size to 2GB.
Of course customer changed DDR registers configuration accordingly. 
DDR read/write tests are PASS for all region.

But Linux boot fails while Linux RAMDISK image is relocated to DDR. The system freezes.
Customer checked the issue and found the address range of RAMDISK relocation area and u-boot stack region are overlapped.

Q1) 
The u-boot version customer uses is very old (2014.07).
Is this the one in u-boot git repository "ti-u-boot-2014" branch?

Q2)
Customer also found the root cause of the issue is address calculation done in function "__lmb_alloc_base".
If DDR size is larger than or equal to 2GB, calculated value is overflown and an incorrect address is used.

This issue was fixed in the latest u-boot (2021.10-rc5).
https://source.denx.de/u-boot/u-boot/-/commit/ad3fda521b1557fb0ecc95959e88a79fd0c6b30b

Is this OK to apply the same patch to u-boot(2014.07)?
Are there any other patch required for 2GB DDR?

Thanks and regards,
Koichiro Tashiro

 

  • 0
    TI__Guru**** 168631 points

    Hi Tashiro-san,

    Koichiro Tashiro said:
    The u-boot version customer uses is very old (2014.07).
    Is this the one in u-boot git repository "ti-u-boot-2014" branch?

    I am not sure about the community repo. This forum only supports the software provided in Processor SDK.

    Koichiro Tashiro said:
    This issue was fixed in the latest u-boot (2021.10-rc5).
    https://source.denx.de/u-boot/u-boot/-/commit/ad3fda521b1557fb0ecc95959e88a79fd0c6b30b

    Is this OK to apply the same patch to u-boot(2014.07)?
    Are there any other patch required for 2GB DDR?

    Again, no comments about the community repo.

    (If the issue is solved in newer version, can the customer migrate to 2021,10-rc5 instead of back porting patches?)

  • 0 in reply to Bin Liu
    TI__Mastermind 22945 points

    Hi Bin,

    Thanks for your quick reply.

    Regarding Q1), customer confirmed the u-boot came with below TI SDK.
    ti-processor-sdk-linux-rt-am437x-evm-02.00.01.07

    Could you comment on Q2 as this is TI SDK?

    Thanks and regards,
    Koichiro Tashiro

  • +1 in reply to Koichiro Tashiro
    TI__Guru**** 168631 points

    Hi Tashiro-san,

    If the customer uses TI SDK, the 2014 U-Boot branch name is ti-u-boot-2014.07 on the U-Boot repo on git.ti.com.

    Regarding Q2, 2014 to 2021 are huge jump in terms of U-Boot development, so in general it is not recommended to randomly pick up a patch and backport it. But for experienced developers, if the issue and the patches have been well understood, it is still okay to backport the solution. Regarding this specific commit for this memory issue, sorry we are unable to comment on if it is okay to backport it.