[U-Boot-Users] Re: Usually dram test executed not on whole sdram
antonio.dibacco at aruba.it
Wed May 10 15:46:46 CEST 2006
Thank you for your help Wolfgang,
I disabled burst mode in ORx register of MPC880 and everything is fine.
The UPM table has to be double checked.
Now I want to look for a dram test that exercise the burst mode. It could be
really useful in debugging these problems.
Thank you very much,
Wolfgang Denk Scrive:
> In message <200605092241.38323.antonio.dibacco at aruba.it> you wrote:
>> Anyone knows why in the u-boot normally the dram test is not executed on the
>> whole DRAM? For example a lot boards that have 16MB specify start_address =
>> 1MB and end_addr = 15MB. If the u-boot is executing in flash the DRAM can be
>> written completely I think!
> The "mtest" can only be run after relocation to RAM, so you have to
> leave out the memory needed ofr exception vectors, U-Boot code,
> malloc arena, stack, etc.
> For the POST tests no such restriction exists.
> But you are on the wrong track. A memory test will NOT detect your
> problem, as it is exercising pleain read / write accesses only, while
> your problem is most probably with burst mode accesses. Please read
> the FAQ!
> Best regards,
> Wolfgang Denk
> Software Engineering: Embedded and Realtime Systems, Embedded Linux
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
> Success in marriage is not so much finding the right person as it is
> being the right person.
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