Software can minimize the number of required SMID mask/compare registers per subsystem by assigning the same SMID to all the hosts within a group. When a group of hosts need the same protection precautions, they can have the same SMID. Example situations:
- PLM and boot device
- RPU and LPD DMA channels used in the RPU software environment
The default SMID for each host is listed in the SMID Summary Table section.
Changing owner of boot device can be done by changing SMID value and security, coherency, and virtualization states. The BootROM code can initialize the SMID of a boot device to the PMC SMID to overcome SRST issue.
The programming model of the SMIDs is shown in the following figure. The SMID registers are only reset by a POR reset. The VAL and MASK registers can be locked by a bit in the <hostname>_SMID_LOCK register.