Region Checking Operation

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

Document ID
UG1085
Release Date
2022-09-15
Revision
2.3 English

An incoming read or write request on an AXI port is checked against each XMPU region as described in this section.

 

TIP:   When a memory space has overlapping regions, the higher region number has higher priority (for example, region 0 has the lowest priority). An overlapping region is defined as a region where both the MID and address match. An address match with different MIDs is not considered to be an overlapping region. This determines the set of permissions used for the checks described in this section.

For the enabled region, two basic checks are completed first.

Check if the address of the transaction (AXI_ADDR) is within the region.
That is, START_ADDR £ AXI_ADDR £ END_ADDR.

Check whether the master ID of the incoming transaction is allowed. That is, incoming_MID & MID_Mask == MID_Value & MID_Mask.

If these checks are true, then the region configuration is checked with regards to security and read and write permissions.

Note:   Disabled regions do not grant permissions.