[U-Boot-Users] Re garding EEPROM Boot

[U-Boot-Users] Re garding EEPROM Boot

[sivaji]

Hai,
          We have designed MPC8548 based AMC card. We are using u-boot-1.2.0
and it was up. Now we plan to boot the uboot in the EEPROM without using
FLASH. Is it possible to boot the uboot in the EEPROM ?.  We are using
AT24C64C EEPROM(64KB) and it was configured as Extended I2C addressing mode.

Thanks and Regards
Sivaji 


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[U-Boot-Users] Re garding EEPROM Boot

[David Hawkins]

> We have designed MPC8548 based AMC card. We are using u-boot-1.2.0
> and it was up. Now we plan to boot the uboot in the EEPROM without using
> FLASH. Is it possible to boot the uboot in the EEPROM ?.  We are using
> AT24C64C EEPROM(64KB) and it was configured as Extended I2C addressing mode.

Its not quite clear from your comment above;
   * you've designed an 8548-based board
   * you've managed to boot it from Flash
   * now you want to boot from EEPROM

Re-read your data sheet; it is a 64k*bits* EEPROM,
or an 8KB memory. You're not going to fit much code
in that.

If the 8548 is like the 8349, the purpose of the EEPROM
is as a boot-sequencer, i.e., it can be used to program
registers in the processor memory map.

If you don't want to have Flash on the card, and the card is
a peripheral (which an AMC card is), then you can probably
have the processor boot with the core disabled, and use
something like the PCI/PCIe interface to boot the processor.
You'd have to re-read the manual; the 8349 can boot with the
e300 core disabled, have a host copy memory into DDR RAM,
and then enable the core to boot from this data.

Cheers,
Dave

[U-Boot-Users] Re garding EEPROM Boot

[Andy Fleming]

On 12/12/07, sivaji <rameshmrm@gmail.com> wrote:
>
>
> Hai,
>           We have designed MPC8548 based AMC card. We are using
> u-boot-1.2.0
> and it was up. Now we plan to boot the uboot in the EEPROM without using
> FLASH. Is it possible to boot the uboot in the EEPROM ?.  We are using
> AT24C64C EEPROM(64KB) and it was configured as Extended I2C addressing
> mode.



In addition to David's comments about the EEPROM being only 8K, I'm doubtful
that u-boot on the 8548 can fit even in 64k.  The typical build makes it
512k, though I think the actual code size is closer to 150K.  I think 8k
would require some sort of magic.

IIRC, the EEPROM can contain a configuration sequence, and then a data blob
to copy somewhere, which is then executed.  If you want that to be u-boot,
you'll need a bigger EEPROM.  Otherwise, you need to write a boot loader.
Is there a reason you don't want to boot from Flash?  I'm not familiar with
that use case.

Andy
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