Baikal-T1 AXI-APB bridge is used to access the SoC subsystem CSRs.
IO requests are routed to this bus by means of the DW AMBA 3 AXI
Interconnect. In case of any APB protocol collisions, slave device
not responding on timeout an IRQ is raised with an erroneous address
reported to the APB terminator (APB Errors Handler Block). This
driver provides the interrupt handler to detect the erroneous
address, prints an error message about the address fault, updates an
errors counter. The counter and the APB-bus operations timeout can be
accessed via corresponding sysfs nodes.

source code:

drivers/bus/bt1-apb.c