[U-Boot] Booting different kernel from U-Boot based on time stamp

[Hemal Patel]

I have made changes in cmd_bootm.c file.
Is it fine?
Does it affect the performance or reliability?
please answer me ASAp.
thank you.

Regards,
Hemal Patel



On Monday 21 January 2013 07:15 PM, Hemal Patel wrote:
> 1.What do you mean by board specific ?
> 2.Which file should I modify?
> 3.From which file this bootm command is called?And where do I find 
> this file in stack?
>
> Regards,
> Hemal Patel
>
>
>
> On Monday 21 January 2013 06:19 PM, Wolfgang Denk wrote:
>> Dear Hemal Patel,
>>
>> In message<assp.0730d63214.50F9164E.7070301 at slscorp.com>  you wrote:
>>> For example:-
>>>
>>> |If kernel-1 is new, U-Boot will boot Kernel-1. and leave kernel-2 
>>> as it is.
>>> If kernel-2 is new, U-Boot will boot kernel-2. and leave kernel-2 as 
>>> it is.
>>> |
>>>
>>> Questions:-
>>>
>>> |Is it possible to do so?
>> This is software,so everything is possible, if you assign sufficient
>> resources to the task ;-)
>>
>>> How can I add such functionality in U-boot?
>> Yes, this is not difficult.
>>
>>> Where to chage the code for the same?
>> The clean way would be to add a (board specific) command to either
>> make accessable (so you can use the itest command on them) or to
>> compare (so that you can use plain "if") the time stamps of two
>> images.
>>
>> Assume your command "is_newer_img" takes the addresses of two legacy
>> image files and returns true (i. e. with a zero return code) if this
>> is the case, then you could just write:
>>
>>     if is_newer_img ${kernel_1_addr} ${kernel_2_addr}
>>     then bootm ${kernel_1_addr}
>>     else bootm ${kernel_2_addr}
>>     fi
>>
>> Alternatively, for a quick&  dirty test or show case, you could of
>> course peek directly at the ih_time entry of the image_header
>> structure.  This would not even need any new code, existing features
>> would be sufficient.
>>
>> Best regards,
>>
>> Wolfgang Denk
>>