[U-Boot] CONFIG_MP affects ability to erase upper portions of flash on 8572

[Scott Coulter]

Hi everyone,

I just wanted to share something that I discovered with our 8572-based
board.  The board's 4Mbyte flash is mapped starting at address
0xFFC00000.  When moving to U-boot v2008-10, I discovered that I had
lost the ability to erase the entire flash (in order to update the
U-boot binary).  After the erase operation, the flash device would
contain the erased value, 0xFF, up to the address 0xFFFFF000 with non-FF
data after that point.  After some investigation, it appears that
defining the macro CONFIG_MP was causing the issue.  With CONFIG_MP not
defined, the entire upper portion of flash could be verified as erased.
My guess is that it has something to do with the start page for the
secondary processor.  Ultimately, the solution for me was to move the
flash from 0xFFC00000 to 0xEFC00000 and all was well with CONFIG_MP
defined.

Scott





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  Scott N. Coulter
  Senior Software Engineer
  
  Cyclone Microsystems          
  370 James Street              Phone:  203.786.5536 ext. 118
  New Haven, CT 06513-3051      Email:  scott.coulter at cyclone.com
  U.S.A.                        Web:    http://www.cyclone.com
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