[U-Boot-Users] Usually dram test executed not on whole sdram

Wolfgang Denk wd at denx.de
Wed May 10 00:07:36 CEST 2006

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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