[U-Boot] [PATCH 03/25] SPEAr: Place ethaddr write and read within CONFIG_CMD_NET

[Amit Virdi]

Hi Stefan,

Sorry for this delayed response, I'm back to office after almost 2 weeks.

On 3/7/2012 6:51 PM, Stefan Roese wrote:
> On Wednesday 07 March 2012 13:03:52 Amit Virdi wrote:
>> From: Vipin KUMAR<vipin.kumar at st.com>
>>
>> ethaddr can be optionally read from i2c memory. So, chip_config command
>> supports reading/writing hw mac id into i2c memory. Placing this code
>> within CONFIG_CMD_NET as this would only be needed when network interface
>> is configured
>>
>> Signed-off-by: Vipin Kumar<vipin.kumar at st.com>
>> Signed-off-by: Amit Virdi<amit.virdi at st.com>
>
> I'm not really sure, why you have this special ethaddr handling in I2C prom
> here at all. Isn't it enough to have the MAC address (ethaddr) stored in the
> U-Boot environment (NOR, NAND, etc)? Why do you need this additional I2C
> stuff? Could you please explain this?
>

Generally MAC addresses are stored in EEPROMs due to two reasons:
1. Special set of command sequences are required to erase data from an 
EEPROM
2. EEPROMs are cheaper

As a result, board manufacturers provide an EEPROM memory that contains 
MAC address and other vital board parameters. In such case, NAND/NOR 
memories may not have ethaddr stored. On SPEAr, I2C is used to access 
EEPROM. So this patch is required. Please let me know if I understood 
your question correctly and, hence, gave the right answer.

Thanks n Regards
Amit Virdi