[U-Boot-Users] Booting MPC8272ADS from flash base

[Yuli Barcohen]

>>>>> Alex Zeffertt writes:

    Alex> Hi list, I would like to boot my MPC8272ADS board from the
    Alex> base of flash memory.  By default the BCSR delivers a fixed
    Alex> HRCW which tells the CPU to boot from 0xff700000.

No, it tells CPU to boot from 0xfff00000. There are only two possible
start addresses: 0x100 and 0xfff00100.

    Alex> But there is a jumper on the board which allows you to specify
    Alex> that the CPU should retrieve the HRCW from flash.

    Alex> In an attempt to get it to boot from 0x0 I tried the
    Alex> following:

    Alex> 1. Moved jumper JP9 from "BCSR" to "MEMORY" to tell the CPU to
    Alex>    get its HRCW from flash rather than the BCSR.

Correct. Also make sure it boots from flash and not from EEPROM (SW2
#1).

    Alex> 2. Set TEXT_BASE in config.mk to 0x0

This is wrong. You have to set TEXT_BASE to the address at which you
will burn the U-Boot image to flash. If you're going to burn U-Boot to
the first flash sector, TEXT_BASE must be equal to CFG_FLASH_BASE.

    Alex> 3. define CFG_HRCW_MASTER in MPC8260ADS.h to be the value
    Alex>    normally delivered by the BCSR or'd with (HRCW_CIP |
    Alex>    HRCW_BMS).  This should move the reset vector from
    Alex>    0xfff00100 to 0x100

Correct.

    Alex>    and cause the flash to be mapped from
    Alex>    0x0 to 0x01ffffff.

Initially mapped. It's remapped to CFG_BR0_PRELIM by the U-Boot's
code. This is the reason why TEXT_BASE=0 can't work.

    Alex> Unfortunately this didn't work.

    Alex> Has anybody else managed to get the MPC8272ADS to boot WITHOUT
    Alex> using the BCSR to deliver the HRCW?

-- 
========================================================================
 Yuli Barcohen       | Phone +972-9-765-1788 |  Software Project Leader
 yuli at arabellasw.com | Fax   +972-9-765-7494 | Arabella Software, Israel
========================================================================