The AHB-AP has two clock domains that are connected together. HCLK drives both of them:
Drives the DAP bus interface and access control for register read and writes. DAPCLK must be driven by a constant clock. When started, it must not be stopped or altered while the DAP is in use.
AHB clock domain driving AHB interface.
Initializes the state of all registers in the AHB-AP.