[U-Boot] Run a standalone application on a core other than 0

Scott Wood scottwood at freescale.com
Tue Jul 2 23:11:09 CEST 2013


On 07/02/2013 07:02:21 AM, João Fernandes wrote:
> As the subject says, I'm trying to run the "Hello world" standalone
> application example on a core other than 0, on a Freescale QorIQ  
> P4080.
> 
> I tried through the shell and programmatically by exporting  
> cpu_release
> function... nothing. My first thought was that only core 0 has  
> register r2
> with the address of the "global_data" structure, so I tried to set it  
> on
> the other cores, but still nothing. Help on this matter is highly
> appreciated.

If you mean a U-Boot application, this is not supported.  U-Boot  
doesn't run on cores other than 0, except for a small stub for the spin  
table code.

If you have true standalone code, you can release it on other CPUs  
using the "cpu <n> release" command.  That code will not have access to  
any U-Boot functionality.  Its entry state will be as described for  
secondary CPUs in ePAPR.  It will be the same as if an OS were spinning  
up its secondary cores by writing directly to the spin table.

-Scott


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