[SOLVED] Angstrom SMP build only brings 1 core online

vidman81 · 08-02-2016, 04:31 PM

I'm running an Arria 10 development board from Rocket Boards - it has two ARM cores. Running Angstrom V2014.12 kernel. Here's the Uname output:

Code:

root@arria10:~# uname -a
Linux arria10 4.6.2 #14 SMP Thu Jul 7 17:21:51 EDT 2016 armv7l GNU/Linux

The build recognizes two cores but core 1 is always offline.

Code:

root@arria10:~# cd /sys/devices/system/cpu
root@arria10:/sys/devices/system/cpu# ls -l
total 0
drwxr-xr-x    5 root     root             0 Jan  1  1970 cpu0
drwxr-xr-x    4 root     root             0 Jan  1  1970 cpu1
drwxr-xr-x    2 root     root             0 Jul 11 20:58 hotplug
-r--r--r--    1 root     root          4096 Jul 11 20:58 isolated
-r--r--r--    1 root     root          4096 Jul 11 20:58 kernel_max
-r--r--r--    1 root     root          4096 Jul 11 20:58 offline
-r--r--r--    1 root     root          4096 Jul 11 20:58 online
-r--r--r--    1 root     root          4096 Jul 11 20:58 possible
drwxr-xr-x    2 root     root             0 Jul 11 20:58 power
-r--r--r--    1 root     root          4096 Jul 11 20:58 present
-rw-r--r--    1 root     root          4096 Jul 11 20:36 uevent

Code:

root@arria10:/sys/devices/system/cpu# cat /sys/devices/system/cpu/online
0
root@arria10:/sys/devices/system/cpu# cat /sys/devices/system/cpu/offline
1

And it won't let me put it online.. even though I'm root.

Code:

root@arria10:/sys/devices/system/cpu# echo 1 > /sys/devices/system/cpu/cpu1/online
-sh: /sys/devices/system/cpu/cpu1/online: Permission denied

root@arria10:/sys/devices/system/cpu# whoami
root

Any ideas would be really helpful. Even if it's just a thread to pull on.

vidman81 · 08-09-2016, 08:09 AM

OK, so it is working now. It looks like an enable method is needed in the DTB to use kernel 4.5.7.

The DTS needed the following:

Code:

enable-method = "altr,socfpga-a10-smp";    /* appended from boardinfo */

Then the DTS hadto be recompiled into a dtb. Since I'm using the Altera tools I could use the Altera embedded command shell:

Code:

dtc -I dts -O dtb -o socfpga_arria10_socdk.dtb socfpga_arria10_socdk.dt

Once compiled, and the new DTB was copied, CPU1 was automatically brought online.