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Distributor Q-Channels

There is a single Q-Channel for clock gating the GIC-600 Distributor. The Q-Channel interface denies access if the Distributor block is busy processing interrupts.

The Distributor also has a separate Q-Channel that enables power control for each configured ITS. The Q-Channel reads GITS_CTLR.Quiescent to check whether the ITS is fully disabled. If the Quiescent bit is set, the Q-Channel qacceptn_its signal is asserted, and the GIC guarantees that the bus to the relevant ITS is idle in both directions and that the ITS can be powered down.

Note

The qreqn* signals are synchronized internally, and can be driven asynchronously. See A.2 Power control signals.