From mboxrd@z Thu Jan  1 00:00:00 1970
From: Detlev Zundel <dzu@denx.de>
Date: Wed, 09 May 2007 18:32:22 +0200
Subject: [U-Boot-Users] CFI driver does not verify writes in buffered mode -
	feature?
Message-ID: <m27iriarft.fsf@sowhat.denx.de>
List-Id: <u-boot.lists.denx.de>
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To: u-boot@lists.denx.de

Hi,

when using the CFI flash driver with CFG_FLASH_USE_BUFFER_WRITE the
"usual" verification whether the write did indeed happen correctly is
not done:

  => erase fc000000 +1
  
  . done
  Erased 1 sectors
  => mw 200000 55555555 100
  => cp.b 200000 fc000000 100
  Copy to Flash... done
  => md fc000000
  fc000000: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000010: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000020: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000030: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000040: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000050: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000060: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000070: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000080: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000090: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000a0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000b0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000c0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000d0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000e0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000f0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  => mw 200000 ffffffff 100
  => cp.b 200000 fc000000 100
  Copy to Flash... done
  => md fc000000
  fc000000: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000010: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000020: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000030: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000040: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000050: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000060: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000070: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000080: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc000090: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000a0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000b0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000c0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000d0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000e0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  fc0000f0: 55555555 55555555 55555555 55555555    UUUUUUUUUUUUUUUU
  

So the write did indeed *not proceed* correctly without the expected
"flash not erased" error message appearing.

The behaviour is not consistent, so either we should do verification
of the write or we should have some kind of warning here.  Does anyone
see an easy way to become consistent here?

Thanks
  Detlev

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