14.2 IDAU Region Types
The IDAU region types are defined below:
| IDAU REGION TYPE | DESCRIPTION |
|---|---|
| INVALID | Regions 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_B | Regions 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_L | This 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). |