soc: st: stm32: h7rsxx: Fix MPU region for read-only id flash region

[TD-JBL]

Set correct MPU memory type and size for the uniqe device id, package code and ADC VREF/TS calibration read-only flash region.

(DEVICE_NON_SHAREABLE | REGION_512B | P_RO_U_NA_Msk)) is the same as REGION_IO_ATTR (used for PERIPH region) but RO instead of RW. The size is reduced to 512 bytes, because RM0477 table 28 and chapter 5.3.12 state that this read-only flash area has a size of 512 bytes.

I introduced this region with PR #97364, both configurations work, but it is more correct with this one.

Testing: Network still initializes with this changes (reads uniqe device ID for creating the mac address per default).
Cross-check: Will mem-fault during zephyr init when commenting out this MPU_REGION_ENTRY.

Open question: Create a #define for this type? REGION_IO_ATTR_RO for example

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[djiatsaf-st]

LGTM

[erwango]

Open question: Create a #define for this type? REGION_IO_ATTR_RO for example

I guess we'll need more of those soon, that would be useful.

[JarmouniA]

Open question: Create a #define for this type? REGION_IO_ATTR_RO for example

it's called IO for a reason

[erwango]

Open question: Create a #define for this type? REGION_IO_ATTR_RO for example

Do you plan to do it ?

[TD-JBL]

Open question: Create a #define for this type? REGION_IO_ATTR_RO for example

Do you plan to do it ?

I can, any suggestions for a good name? REGION_DEV_RO_ATTR?

[mathieuchopstm]

Open question: Create a #define for this type? REGION_IO_ATTR_RO for example

I'm not sure if this has a lot of value considering that

(DEVICE_NON_SHAREABLE | REGION_512B | P_RO_U_NA_Msk) is the same as REGION_IO_ATTR but RO instead of RW

(i.e., do we really care about the region being read-only?)