14.2 IDAU Region Types

The IDAU region types are defined below:

Table 14-1. IDAU Region Types
IDAU REGION TYPEDESCRIPTION
INVALIDRegions that are not decoded by the BMX.
SEC

Secure region.

Region which cannot be accessed by a Non-secure master.

Non-secure transactions are discarded inside the CPU and a security fault is generated internally to the core.

NONSEC, NONSEC_W

Non-secure region.

Region which is accessible by a non-secure transaction.

When a Secure transaction targets a Non-secure region, transaction type is changed to Non-secure.

(_W means that the region implements a watermark register, refer to Section 2.9).

SECnNONSEC_BRegions of this type can be either secure or non-secure. When a region is configured as secure, SEC region type properties apply. When configured as non-secure, NONSEC region type properties apply.
SECnNONSEC_LThis is a linked IDAU region (denoted by the suffix _L). This region type is very similar to the SECnNONSEC_B type. The only difference is that it does not implement any command to change its state (by trying to issue a command generate a CFGERR). Its secure or non-secure state depends on another IDAU region of either SECnNONSEC_B or EXEMPT type. To change its state, issue a command in the linked IDAU region. The new configuration is applied simultaneously to the linked regions. The status of the linked region is readable through RSTATUSB as for the SECnNONSEC_B and EXEMPT types. When the linked region is configured as secure, SEC region type properties apply. When the linked region is configured as non-secure, NONSEC region type properties apply. The “linked” type variant aims at ensuring coherency between the configuration of multiple interfaces of a same macro instance.
NSC_W

Non-secure callable region. Region which allows Non-secure software to call a Secure function, the first instruction in the called Secure function must be a SG (Secure Gateway).

(_W means that the region implements a watermark register, refer to Section 2.9).

EXEMPT_B

Region exempt from attribution.

The IDAU does not alter the transaction.

(_B means that the region implements a block register, refer to Section 2.9).

CAUTION: _W and _B suffixes do not have the same meaning for IDAU regions and MAIN regions.