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SPL: am3352 internal SRAM error. Please help.

sviss
Expert 1530 points

Hi forum,

Using UART0/xmodem I (susscessfully) upload the u-boot-spl.bin and see it starting work, on the terminal,

After few printouts it hangs however...

The study shows that global variables (several, including but not limited to, gpmc_cfg from the mem.c module)

are set to zero.

Details apply, running same code on the SK works fine. I wrote few tests, found more details of the case, later I'll

lay them out for you if needed. Currently I'd like to find if somebody experienced this sort of (weird) problem and

if yes where should I look into to solve it?

Once again:

The SPL  /my custom board/ hangs at board_init()/gpmc_init().

Hangs because the SRAM resident global static pointer variable gpmc_cfg is zero (unknown reason).

Same code if run on the TMDSSK3352 works fine.

What could be a reason for the internal memory to be cleared? 

Tests show that it is cleared - side effect of an unknown party - in 100% cases of 10000000 total.

The main question is: how could it be and where to look into? I have several boards, exactly the same behaviour.

Please help! I urgently need it.

Thanks.

  • 0
    Expert 1530 points

    I am new to the Sitara/linux platform (as many of us are, I hope). Much of misunderstanding of the case, from my side, was concerned with too clever PC computer. I mean code optimizer. Half the tests I wrote discovered no errors because the code was just optimized out.

    So, now I know that in 100% cases the SPL writes to static (global) variables, the write operation fail.

    To my understanding, the SPL is supposed to run from the internal SRAM.

    The detailed study showed that it is not quite so: static variables go to addresses above 0x8000 0000 which is the DRAM area.

    Is it a bug or a feature? Is there an option to link all the SPL code to the internal SRAM?

    Could somebody please comment?

    Attached is the screenshot illustration of the static variable addressing (disassembly/CCS5 screenshot)

    Thanks.

  • 0 in reply to sviss
    Intellectual 640 points

    Hi I too have same problem,

    Do any of one sorted this issue? Same code works for Starter kit not on custom hardware

    I am successfully able to  run set_mux_conf_regs ,get_dpll_ddr_params but not able to get inside sdram_init fucntion?


    Thanks is advance,

    Chandra