[U-Boot] Standalone application on secondary cores

[U-Boot] Standalone application on secondary cores

[Francesco Teodoro]

I'm using a SABRE SD board (from Freescale) based on i.MX6 and the u-boot version is the 2014.04 one. What I've been trying to do is to activate the secondary cores so that I would be able to use them. First of all I've imported the commands cpu status/release/reset, then I checked if they were working in this way:
U-boot > cpu 1 status (which gives as result: core1 disabled ...)
U-boot > cpu 1 release 0x12000000 0
U-boot > cpu 1 status (which gives as result: core1 enabled ...)

Next step was to run a standalone application on secondary cores. First I checked the hello_world application, but it seems that the serial debug for secondary cores is not set (but I'm not sure). So I wrote an application to check if I could get changes in memory. This is the simple application (I just modified the hello_world one):

//standalone app
#include <common.h>
#include <exports.h>
volatile int test[5]={1,2,3,4,5};
int hello_world ()
{
   int i;
   for (i=0; i<5; i++) {
      test[i] = -test[i];
   }
   return (0);
}

First I used it on the boot core (core0) with the "go" command and with the "md" command I checked that the results were correct. Then I used the following command to run it on other cores (the application is@address 0x12000000):
U-boot > cpu X release 0x12000000 0
But when I check with the "md" command, I can see that there are no changes in memory. 
What should I do to make it work? Am I missing something to set before running the application on other cores? I'm new to this subject so every suggestion would be appreciated.
Thank you in advance. 		 	   		  

[U-Boot] Standalone application on secondary cores

[James Chargin]

Dear Francesco Teodoro.

On 05/30/2014 01:35 PM, Francesco Teodoro wrote:
> I'm using a SABRE SD board (from Freescale) based on i.MX6 and the u-boot version is the 2014.04 one. What I've been trying to do is to activate the secondary cores so that I would be able to use them. First of all I've imported the commands cpu status/release/reset, then I checked if they were working in this way:
> U-boot > cpu 1 status (which gives as result: core1 disabled ...)
> U-boot > cpu 1 release 0x12000000 0
> U-boot > cpu 1 status (which gives as result: core1 enabled ...)
>
> Next step was to run a standalone application on secondary cores. First I checked the hello_world application, but it seems that the serial debug for secondary cores is not set (but I'm not sure). So I wrote an application to check if I could get changes in memory. This is the simple application (I just modified the hello_world one):
>

Please refer to 
http://www.denx.de/wiki/view/DULG/UBootStandalone#Section_5.12.4.

One of the first things done by the example stand alone application is 
to attempt to call back into U-Boot. This will not work correctly for 
cores other than 0.

Regards,
Jim Chargin