3.3.9. Shareable Override Register

The Shareable Override Register characteristics are:

Purpose

Overrides shareability of normal transactions through this interface. The following transaction types are unaffected by any override:

  • FIXED-type bursts.

  • Device transactions.

  • Barrier.

  • DVM message transactions.

Usage constraints

This register is for ACE-Lite slave interfaces only. See the AMBA AXI and ACE Protocol Specification.

Accessible using only Secure accesses, unless you set the Secure Access Register. See Table 3.4.

Configurations

Available in all CCI-400 configurations.

Attributes

Note

Exclusive accesses must not be issued on an interface that is being overridden as shareable. If the CCI-400 is programmed to override transactions as shareable, Exclusive accesses are overridden to normal accesses. An exclusive write then receives an OKAY response to indicate that the slave does not support exclusive accesses.

Figure 3.8 shows the bit assignments.

Figure 3.8. Shareable Override Register bit assignments

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Table 3.11 shows the bit assignments.

Table 3.11. Shareable Override Register bit assignments

Bits

Reset

Access

Function

[31:2]

-

RAZ/WI

Reserved.

[1:0]

0x0

RW

Shareable override for slave interface.

0x0, 0x1

Do not override AxDOMAIN inputs.

0x2

Override AxDOMAIN inputs to 0b00, all transactions are treated as non-shareable:

  • ReadOnce becomes ReadNoSnoop.

  • WriteUnique and WriteLineUnique become WriteNoSnoop.

0x3

Override AxDOMAIN inputs to 0b01, normal transactions are treated as shareable:

  • ReadNoSnoop becomes ReadOnce.

  • WriteNoSnoop becomes WriteUnique.


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