The PMC refers to the PLM firmware running in the PPU processor. The PSM refers to the PSM firmware running in the PSM processor.
System Management IDs
The IPI uses a processor's SMID to match it with an IPI agent. This includes three hardwired agent slots ( PSM , PMC, and PMC_NOBUF) and several software programmed slots. The SMID provides information to the LPD_XPPU protection unit and IPI controller.
The SMIDs are listed in the System Management ID section.
Each agent should have two SMID entries: one for write access and another for read access. Both SMIDs should be programmed to the same value and the read-only bit [SMID_R] in the second MID entry should be set. For example, SMID_00 register (fixed in hardware) is used for permission checking of the write access to the request buffer and agent registers. SMID_01 register (fixed in hardware) is for read accesses to the response buffer and agent registers.
Once the software programs the SMID registers, the hardware internally assigns buffers and register space access permissions. One example is shown in the table in the IPI Agents section.
System Interrupts
In addition to using SMIDs, the processor software must be able to receive and process a system interrupt. The system interrupts for the PMC and PS are level-sensitive and are listed in System Interrupts. Processors in the PL need to have one or more SMIDs assigned to them that are recognized by the protection mechanisms and must have access to the PS-PL system interrupt outputs.
A processor is also a source and a destination agent to itself.
Access Protection
The IPI global area is protected by the LPD XPPU. Each agent can be configured with override capability. This means that the agent with override set can access regions of all the other agents including their message buffer and all registers.
IPI apertures are for the message buffers and registers for each agent. These are similar to the XPPU apertures except IPI protects itself.
Power Domain
The IPI is in the LPD power domain with system interrupt connections to the FPD, PMC, and PL.
System Errors
System errors include the following:
- APB programming interface address decode error
- Interrupt register and message buffer access violations
- Detected in LPD_XPPU and IPI
- SMID incorrect
- Security level violation
- Write violation