[U-Boot] garbage in early serial output on at91sam9g20 after u-boot v2011.12

[Alexander Dahl]

Hei hei, 

I was updating u-boot for our target hardware in the past few days. We
have a board here very similar in design to the Atmel AT91SAM9G20-EK.
Migrating our patches step by step from v2010.09 to v2011.09 replacing
code based on at91 legacy code took a while but was succesful. Output on
the serial console (debug console of the SoC) was and should be like
this (some output of at91bootstrap before u-boot):

  Start AT91Bootstrap...
  HW_INIT AT91Bootstrap successful...
  NAND-Flash uChipID: 0xADDA
  loaded image into RAM

  U-Boot 2011.06-00027-g21b18a4 (May 08 2012 - 15:03:20)
  
  CPU: AT91SAM9G20
  Crystal frequency:   18.432 MHz
  CPU clock        :  396.288 MHz
  Master clock     :  132.096 MHz
  DRAM:  32 MiB
  NAND:  256 MiB
  In:    serial
  Out:   serial
  Err:   serial
  Net:   macb0
  Hit keys 'is' to stop autoboot (3 seconds).

I know, still v2011.06 but worked. Now with v2011.12 and v2012.04
output of the »greeting line« and CPU info produces garbage, see:

  Start AT91Bootstrap...
  HW_IN­éÅÍɹÁåÙ5!é5)I5éÍÉ5¥essful5)ÿWARNING: Caches not enabled
  NAND:  256 MiB!é5)5 0xADDA
  In:    serial¹ÁÑ¡5RAM
  Out:   serial5!é5))5)
  Err:   serial
  Net:   macb0
  Hit keys 'is' to stop autoboot (3 seconds).

The console works in the end, but in between there's just garbage. I
tried moving the call to at91_seriald_hw_init() from board_init() to
board_early_init_f) but this didn't change the behaviour. I also tried
to find out what was changed in u-boot source since 2011.09 but this is
a lot and just looking over commit messages in git I didn't get a clue.

Has someone had similar problems and maybe a solution? Or is anyone
interested in debugging this and could help me with a start?

Greets
Alex

-- 
»With the first link, the chain is forged. The first speech censured,
the first thought forbidden, the first freedom denied, chains us all
irrevocably.« (Jean-Luc Picard, quoting Judge Aaron Satie)
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