3.2.4. Lockdown Select Register

The lockdown_select Register characteristics are:

Purpose

Controls whether the TZASC permits write accesses to the following registers:

Usage constraints

After aresetn goes HIGH, the TZASC only permits write access to this register, if secure_boot_lock remains LOW. When secure_boot_lock is HIGH for one aclk period, or more then the TZASC ignores writes to this register.

Configurations

Available in all configurations of the TZASC.

Attributes

See the register summary in Table 3.1.

Figure 3.5 shows the lockdown_select Register bit assignments.

Figure 3.5. lockdown_select Register bit assignments


Table 3.5 shows the lockdown_select Register bit assignments.

Table 3.5. lockdown_select Register bit assignments

BitsNameFunction
[31:3]-Reserved, SBZ.
[2]acc_speculation_cntl

Modifies the access type of the speculation_control Register:

0 = no effect. speculation_control Register remains RW.

1 = speculation_control Register is RO.

See Speculation Control Register for more information.

[1]security_inv

Modifies the access type of the security_inversion_en Register:

0 = no effect. security_inversion_en Register remains RW.

1 = security_inversion_en Register is RO.

See Security Inversion Enable Register for more information.

[0]region_register

Modifies the access type of the lockdown_range Register:

0 = no effect. lockdown_range Register remains RW.

1 = lockdown_range Register is RO.

See Lockdown Range Register for more information.


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