What:		/sys/bus/platform/devices/dfl-port.0/id
Date:		June 2018
KernelVersion:	4.19
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-only. It returns id of this port. One DFL FPGA device
		may have more than one port. Userspace could use this id to
		distinguish different ports under same FPGA device.

What:		/sys/bus/platform/devices/dfl-port.0/afu_id
Date:		June 2018
KernelVersion:	4.19
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-only. User can program different PR bitstreams to FPGA
		Accelerator Function Unit (AFU) for different functions. It
		returns uuid which could be used to identify which PR bitstream
		is programmed in this AFU.

What:		/sys/bus/platform/devices/dfl-port.0/power_state
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-only. It reports the APx (AFU Power) state, different APx
		means different throttling level. When reading this file, it
		returns "0" - Normal / "1" - AP1 / "2" - AP2 / "6" - AP6.

What:		/sys/bus/platform/devices/dfl-port.0/ap1_event
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-write. Read this file for AP1 (AFU Power State 1) event.
		It's used to indicate transient AP1 state. Write 1 to this
		file to clear AP1 event.

What:		/sys/bus/platform/devices/dfl-port.0/ap2_event
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-write. Read this file for AP2 (AFU Power State 2) event.
		It's used to indicate transient AP2 state. Write 1 to this
		file to clear AP2 event.

What:		/sys/bus/platform/devices/dfl-port.0/ltr
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-write. Read or set AFU latency tolerance reporting value.
		Set ltr to 1 if the AFU can tolerate latency >= 40us or set it
		to 0 if it is latency sensitive.