[U-Boot-Users] Re: Low-boot configuration for MPC8272ADS

[Dmytro Bablinyuk]

Thank you again Wolfgang, and thank you very much to everybody who was 
involved in this discussion.

I got everything working.
I would like to summarise output of this discussion - it might be useful 
to somebody else in the future. Please correct me if I am wrong.

_MPC8272ADS_in_low_boot_mode_ (HRCW comming from flash)

(1). Apply patch from Alexandre Bastos (valid for u-boot snapshot from 2 
November 2005, thank you Alex)

http://article.gmane.org/gmane.comp.boot-loaders.u-boot/19108

*MPC8272ADS Flash HRCW 0x0E74B20A

(2). Compile 'make MPC8272ADS_lowboot_config'

(3). Since our HRCW 0x0E74B20A (0x74 => ISB100 => IMMR=0xF000_0000) we 
need to change BDI2000 config file (thank you to Yuli Barcohen)

WM32    0xF0010004      0xFFFFFFC3   ;SYPCR: disable watchdog
WM32    0xF00101A8      0x04700000   ;IMMR : internal space @ 0x04700000

*Note I use default 0x04700000 for IMMR since it came like this.
Wrong HRCW value may cause board to continuously reset.

(4). Move JP9 in position MEMORY, make sure that SW2 Boot Source is ON 
(boot from flash)

(5). In BDI2000 config file change

BOOTADDR    0x00000100  ;boot address used for start-up break

(6). Burn software using BDI (thank you to Wolfgang Denk)

  8272>load 0
  8272>unlock 0xff800000 0x40000 32
  8272>erase 0xFF800000 BLOCK
  8272>prog 0xFF800000 u-boot.bin BIN

Make sure you use load address when loading to memory

i.e. 8272>load 0

If no load address is given or BOOTADDR different from 0x00000100 you 
may see message in BDI console

# PPC: timeout while waiting for freeze

(7). (Haven't tried yet). To program blank flash with 8272 ie. on target 
board without BCSR. (thank you to Jerry Van Baren)
--8<--
For blank flash, you need to pull up the RSTCONF* line (8260UM 5.4.2.1 
"Single MPC8260 with Default Configuration") which will set your HRCW to 
all zeros rather than read it from memory (I'm assuming you are not 
implementing the BCSR).

This will require a different BDI2000 config file because the ISB will 
be set to 0x0000_0000 - if the first line in your special BDI config 
file sets the ISB back to your prefered value (0xF000_0000?), you should 
be able to leave all the rest of your config file the same.

At this point, you should be able to program flash.  After programming 
flash, I go back to normal mode (RSTCONF* pulled low) and _power cycle_ 
the board.  Note that the HRCW is only read on a power cycle, not on a 
software reset.
--8<--