AM2634: How to ensure only one core has permissions to change CMPSS and SDFM comparator configurations

Hi,

1. Incase of multi-core R5F application architecture, we do not have any specific setting for marking a core as "Supervisor" or "Master" core. We do have ways to setup a memory firewall using the TIFS security offering (more granularity) or by using general ARM R5F MPU (Memory Protection Unit) (less granularity). This way you can configure only the R5FSS0-0 core with Read, Write Execute settings for the memory region of CMPSS and SDFM config registers, and for other cores, mark the region as Read-only (or If you want something like FreeRTOS-SMP (which is not directly achievable on R5F cores due to hardware being asymmetric), you can have multiple asks created on all 4 cores and have semaphores in shared memory and post/pend according to your application design, only difference would be that you cannot spawn a new task from other cores like in a true SMP environment.

   I am assuming you are already using TRM: Interprocessor Communication (IPC) to setup the multicore system.

   The best way to then give particular supervisor and user permissions should be through TRM: 3.12 System Memory Protection Unit (MPU)/Firewalls

2. We also have Control Module Lock Mechanism(lock registers that can prevent unauthorized access to critical configuration registers.)

   // On supervisory core during initialization
   void supervisory_core_init_cmpss_sdfm(void)
   {
       // Unlock control module for initial configuration
       SOC_controlModuleUnlockMMR(SOC_DOMAIN_ID_MAIN, CONTROLSS_CTRL_PARTITION0);
       
       // Configure CMPSS instances
       configure_all_cmpss_instances();
       
       // Configure SDFM instances  
       configure_all_sdfm_instances();
       
       // Lock the control module - this prevents other cores from modifying
       SOC_controlModuleLockMMR(SOC_DOMAIN_ID_MAIN, CONTROLSS_CTRL_PARTITION0);
   }

Let me know if any of these resolve your issue!

Regards,
Akshit

Great thanks Akshit! I'll test this out in the coming weeks and return back here if I have any difficulty with setup.