3.1.3. Interrupt Distributor arbitration

The interrupt distributor centralizes all interrupt sources before dispatching them to each individual Cortex-A9 processor.

The Interrupt Distributor arbitrates in the following priority order:

  1. Highest priority interrupts. These have the lowest value in the Interrupt Priority Register (ICDIPTR)

  2. For interrupts with the same priority value, the Interrupt Distributor arbitrates on the interrupt ID number. It dispatches the smaller ID number first

  3. For aliased SGI with the same priority value and the same ID number, the Interrupt Distributor arbitrates on the source CPU number. It dispatches the smaller CPU number first.

The Interrupt Controller hardware ensures that an interrupt targeted at several Cortex-A9 processors can only be taken by one Cortex-A9 processor at a time.

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