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.

What:		/sys/bus/platform/devices/dfl-port.0/userclk_freqcmd
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Write-only. User writes command to this interface to set
		userclock to AFU.

What:		/sys/bus/platform/devices/dfl-port.0/userclk_freqsts
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-only. Read this file to get the status of issued command
		to userclck_freqcmd.

What:		/sys/bus/platform/devices/dfl-port.0/userclk_freqcntrcmd
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Write-only. User writes command to this interface to set
		userclock counter.

What:		/sys/bus/platform/devices/dfl-port.0/userclk_freqcntrsts
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-only. Read this file to get the status of issued command
		to userclck_freqcntrcmd.

What:		/sys/bus/platform/devices/dfl-port.0/errors/errors
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-Write. Read this file to get errors detected on port and
		Accelerated Function Unit (AFU). Write error code to this file
		to clear errors. Write fails with -EINVAL if input parsing
		fails or input error code doesn't match. Write fails with
		-EBUSY or -ETIMEDOUT if error can't be cleared as hardware
		in low power state (-EBUSY) or not respoding (-ETIMEDOUT).

What:		/sys/bus/platform/devices/dfl-port.0/errors/first_error
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-only. Read this file to get the first error detected by
		hardware.

What:		/sys/bus/platform/devices/dfl-port.0/errors/first_malformed_req
Date:		August 2019
KernelVersion:	5.4
Contact:	Wu Hao <hao.wu@intel.com>
Description:	Read-only. Read this file to get the first malformed request
		captured by hardware.