12.2.2 SCU speculative coherent requests

This optimization is available for Cortex®‑R8 processors only, and only if the L2C-310 Cache Controller is present in the design.

When this feature is enabled, coherent linefill requests are sent speculatively to the L2C-310 Cache Controller in parallel with the SCU tag look-up. If the tag look-up misses, the confirmed linefill is sent to the L2C-310 and gets RDATA earlier because the speculative request already initiated the data request. When filtering is enabled, only port 0 can receive speculative linefills.

To support this optimization in the Cortex‑R8 processor:

  1. Program the L2C-310 Cache Controller. See the ARM® CoreLink™ Level 2 Cache Controller L2C-310 Technical Reference Manual.
  2. Set bit[3] of the SCU Control Register.

Note:

You cannot use this feature when bus ECC is implemented and the L2C-310 Cache Controller is connected.
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