xref: /linux/Documentation/ABI/testing/sysfs-bus-cxl (revision 86677a4e71070ffa4ee476ea119cd61d254a7af4)

What:		/sys/bus/cxl/flush
Date:		Januarry, 2022
KernelVersion:	v5.18
Contact:	linux-cxl@vger.kernel.org
Description:
		(WO) If userspace manually unbinds a port the kernel schedules
		all descendant memdevs for unbind. Writing '1' to this attribute
		flushes that work.

What:		/sys/bus/cxl/devices/memX/firmware_version
Date:		December, 2020
KernelVersion:	v5.12
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) "FW Revision" string as reported by the Identify
		Memory Device Output Payload in the CXL-2.0
		specification.

What:		/sys/bus/cxl/devices/memX/ram/size
Date:		December, 2020
KernelVersion:	v5.12
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) "Volatile Only Capacity" as bytes. Represents the
		identically named field in the Identify Memory Device Output
		Payload in the CXL-2.0 specification.

What:		/sys/bus/cxl/devices/memX/pmem/size
Date:		December, 2020
KernelVersion:	v5.12
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) "Persistent Only Capacity" as bytes. Represents the
		identically named field in the Identify Memory Device Output
		Payload in the CXL-2.0 specification.

What:		/sys/bus/cxl/devices/memX/serial
Date:		January, 2022
KernelVersion:	v5.18
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) 64-bit serial number per the PCIe Device Serial Number
		capability. Mandatory for CXL devices, see CXL 2.0 8.1.12.2
		Memory Device PCIe Capabilities and Extended Capabilities.

What:		/sys/bus/cxl/devices/memX/numa_node
Date:		January, 2022
KernelVersion:	v5.18
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) If NUMA is enabled and the platform has affinitized the
		host PCI device for this memory device, emit the CPU node
		affinity for this device.

What:		/sys/bus/cxl/devices/*/devtype
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) CXL device objects export the devtype attribute which
		mirrors the same value communicated in the DEVTYPE environment
		variable for uevents for devices on the "cxl" bus.

What:		/sys/bus/cxl/devices/*/modalias
Date:		December, 2021
KernelVersion:	v5.18
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) CXL device objects export the modalias attribute which
		mirrors the same value communicated in the MODALIAS environment
		variable for uevents for devices on the "cxl" bus.

What:		/sys/bus/cxl/devices/portX/uport
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) CXL port objects are enumerated from either a platform
		firmware device (ACPI0017 and ACPI0016) or PCIe switch upstream
		port with CXL component registers. The 'uport' symlink connects
		the CXL portX object to the device that published the CXL port
		capability.

What:		/sys/bus/cxl/devices/portX/dportY
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) CXL port objects are enumerated from either a platform
		firmware device (ACPI0017 and ACPI0016) or PCIe switch upstream
		port with CXL component registers. The 'dportY' symlink
		identifies one or more downstream ports that the upstream port
		may target in its decode of CXL memory resources.  The 'Y'
		integer reflects the hardware port unique-id used in the
		hardware decoder target list.

What:		/sys/bus/cxl/devices/decoderX.Y
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) CXL decoder objects are enumerated from either a platform
		firmware description, or a CXL HDM decoder register set in a
		PCIe device (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder
		Capability Structure). The 'X' in decoderX.Y represents the
		cxl_port container of this decoder, and 'Y' represents the
		instance id of a given decoder resource.

What:		/sys/bus/cxl/devices/decoderX.Y/{start,size}
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) The 'start' and 'size' attributes together convey the
		physical address base and number of bytes mapped in the
		decoder's decode window. For decoders of devtype
		"cxl_decoder_root" the address range is fixed. For decoders of
		devtype "cxl_decoder_switch" the address is bounded by the
		decode range of the cxl_port ancestor of the decoder's cxl_port,
		and dynamically updates based on the active memory regions in
		that address space.

What:		/sys/bus/cxl/devices/decoderX.Y/locked
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) CXL HDM decoders have the capability to lock the
		configuration until the next device reset. For decoders of
		devtype "cxl_decoder_root" there is no standard facility to
		unlock them.  For decoders of devtype "cxl_decoder_switch" a
		secondary bus reset, of the PCIe bridge that provides the bus
		for this decoders uport, unlocks / resets the decoder.

What:		/sys/bus/cxl/devices/decoderX.Y/target_list
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) Display a comma separated list of the current decoder
		target configuration. The list is ordered by the current
		configured interleave order of the decoder's dport instances.
		Each entry in the list is a dport id.

What:		/sys/bus/cxl/devices/decoderX.Y/cap_{pmem,ram,type2,type3}
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) When a CXL decoder is of devtype "cxl_decoder_root", it
		represents a fixed memory window identified by platform
		firmware. A fixed window may only support a subset of memory
		types. The 'cap_*' attributes indicate whether persistent
		memory, volatile memory, accelerator memory, and / or expander
		memory may be mapped behind this decoder's memory window.

What:		/sys/bus/cxl/devices/decoderX.Y/target_type
Date:		June, 2021
KernelVersion:	v5.14
Contact:	linux-cxl@vger.kernel.org
Description:
		(RO) When a CXL decoder is of devtype "cxl_decoder_switch", it
		can optionally decode either accelerator memory (type-2) or
		expander memory (type-3). The 'target_type' attribute indicates
		the current setting which may dynamically change based on what
		memory regions are activated in this decode hierarchy.