Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

4 files changed, 577 insertions, 0 deletions

diff --git a/Documentation/firmware-guide/acpi/dsd/data-node-references.rst b/Documentation/firmware-guide/acpi/dsd/data-node-references.rst
new file mode 100644
index 000000000..8d8b53e96
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/dsd/data-node-references.rst
@@ -0,0 +1,96 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+===================================
+Referencing hierarchical data nodes
+===================================
+
+:Copyright: |copy| 2018, 2021 Intel Corporation
+:Author: Sakari Ailus <sakari.ailus@linux.intel.com>
+
+ACPI in general allows referring to device objects in the tree only.
+Hierarchical data extension nodes may not be referred to directly, hence this
+document defines a scheme to implement such references.
+
+A reference consist of the device object name followed by one or more
+hierarchical data extension [dsd-guide] keys. Specifically, the hierarchical
+data extension node which is referred to by the key shall lie directly under
+the parent object i.e. either the device object or another hierarchical data
+extension node.
+
+The keys in the hierarchical data nodes shall consist of the name of the node,
+"@" character and the number of the node in hexadecimal notation (without pre-
+or postfixes). The same ACPI object shall include the _DSD property extension
+with a property "reg" that shall have the same numerical value as the number of
+the node.
+
+In case a hierarchical data extensions node has no numerical value, then the
+"reg" property shall be omitted from the ACPI object's _DSD properties and the
+"@" character and the number shall be omitted from the hierarchical data
+extension key.
+
+
+Example
+=======
+
+In the ASL snippet below, the "reference" _DSD property contains a
+device object reference to DEV0 and under that device object, a
+hierarchical data extension key "node@1" referring to the NOD1 object
+and lastly, a hierarchical data extension key "anothernode" referring to
+the ANOD object which is also the final target node of the reference.
+::
+
+	Device (DEV0)
+	{
+	    Name (_DSD, Package () {
+		ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+		Package () {
+		    Package () { "node@0", "NOD0" },
+		    Package () { "node@1", "NOD1" },
+		}
+	    })
+	    Name (NOD0, Package() {
+		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () { "reg", 0 },
+		    Package () { "random-property", 3 },
+		}
+	    })
+	    Name (NOD1, Package() {
+		ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+		Package () {
+		    Package () { "reg", 1 },
+		    Package () { "anothernode", "ANOD" },
+		}
+	    })
+	    Name (ANOD, Package() {
+		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () { "random-property", 0 },
+		}
+	    })
+	}
+
+	Device (DEV1)
+	{
+	    Name (_DSD, Package () {
+		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () {
+			"reference", Package () {
+			    ^DEV0, "node@1", "anothernode"
+			}
+		    },
+		}
+	    })
+	}
+
+Please also see a graph example in
+Documentation/firmware-guide/acpi/dsd/graph.rst.
+
+References
+==========
+
+[dsd-guide] DSD Guide.
+    https://github.com/UEFI/DSD-Guide/blob/main/dsd-guide.adoc, referenced
+    2021-11-30.
diff --git a/Documentation/firmware-guide/acpi/dsd/graph.rst b/Documentation/firmware-guide/acpi/dsd/graph.rst
new file mode 100644
index 000000000..b9dbfc73e
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/dsd/graph.rst
@@ -0,0 +1,173 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======
+Graphs
+======
+
+_DSD
+====
+
+_DSD (Device Specific Data) [dsd-guide] is a predefined ACPI device
+configuration object that can be used to convey information on
+hardware features which are not specifically covered by the ACPI
+specification [acpi]. There are two _DSD extensions that are relevant
+for graphs: property [dsd-guide] and hierarchical data extensions. The
+property extension provides generic key-value pairs whereas the
+hierarchical data extension supports nodes with references to other
+nodes, forming a tree. The nodes in the tree may contain properties as
+defined by the property extension. The two extensions together provide
+a tree-like structure with zero or more properties (key-value pairs)
+in each node of the tree.
+
+The data structure may be accessed at runtime by using the device_*
+and fwnode_* functions defined in include/linux/fwnode.h .
+
+Fwnode represents a generic firmware node object. It is independent on
+the firmware type. In ACPI, fwnodes are _DSD hierarchical data
+extensions objects. A device's _DSD object is represented by an
+fwnode.
+
+The data structure may be referenced to elsewhere in the ACPI tables
+by using a hard reference to the device itself and an index to the
+hierarchical data extension array on each depth.
+
+
+Ports and endpoints
+===================
+
+The port and endpoint concepts are very similar to those in Devicetree
+[devicetree, graph-bindings]. A port represents an interface in a device, and
+an endpoint represents a connection to that interface. Also see [data-node-ref]
+for generic data node references.
+
+All port nodes are located under the device's "_DSD" node in the hierarchical
+data extension tree. The data extension related to each port node must begin
+with "port" and must be followed by the "@" character and the number of the
+port as its key. The target object it refers to should be called "PRTX", where
+"X" is the number of the port. An example of such a package would be::
+
+    Package() { "port@4", "PRT4" }
+
+Further on, endpoints are located under the port nodes. The hierarchical
+data extension key of the endpoint nodes must begin with
+"endpoint" and must be followed by the "@" character and the number of the
+endpoint. The object it refers to should be called "EPXY", where "X" is the
+number of the port and "Y" is the number of the endpoint. An example of such a
+package would be::
+
+    Package() { "endpoint@0", "EP40" }
+
+Each port node contains a property extension key "port", the value of which is
+the number of the port. Each endpoint is similarly numbered with a property
+extension key "reg", the value of which is the number of the endpoint. Port
+numbers must be unique within a device and endpoint numbers must be unique
+within a port. If a device object may only has a single port, then the number
+of that port shall be zero. Similarly, if a port may only have a single
+endpoint, the number of that endpoint shall be zero.
+
+The endpoint reference uses property extension with "remote-endpoint" property
+name followed by a reference in the same package. Such references consist of
+the remote device reference, the first package entry of the port data extension
+reference under the device and finally the first package entry of the endpoint
+data extension reference under the port. Individual references thus appear as::
+
+    Package() { device, "port@X", "endpoint@Y" }
+
+In the above example, "X" is the number of the port and "Y" is the number of
+the endpoint.
+
+The references to endpoints must be always done both ways, to the
+remote endpoint and back from the referred remote endpoint node.
+
+A simple example of this is show below::
+
+    Scope (\_SB.PCI0.I2C2)
+    {
+	Device (CAM0)
+	{
+	    Name (_DSD, Package () {
+		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () { "compatible", Package () { "nokia,smia" } },
+		},
+		ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+		Package () {
+		    Package () { "port@0", "PRT0" },
+		}
+	    })
+	    Name (PRT0, Package() {
+		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () { "reg", 0 },
+		},
+		ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+		Package () {
+		    Package () { "endpoint@0", "EP00" },
+		}
+	    })
+	    Name (EP00, Package() {
+		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () { "reg", 0 },
+		    Package () { "remote-endpoint", Package() { \_SB.PCI0.ISP, "port@4", "endpoint@0" } },
+		}
+	    })
+	}
+    }
+
+    Scope (\_SB.PCI0)
+    {
+	Device (ISP)
+	{
+	    Name (_DSD, Package () {
+		ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+		Package () {
+		    Package () { "port@4", "PRT4" },
+		}
+	    })
+
+	    Name (PRT4, Package() {
+		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () { "reg", 4 }, /* CSI-2 port number */
+		},
+		ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+		Package () {
+		    Package () { "endpoint@0", "EP40" },
+		}
+	    })
+
+	    Name (EP40, Package() {
+		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () { "reg", 0 },
+		    Package () { "remote-endpoint", Package () { \_SB.PCI0.I2C2.CAM0, "port@0", "endpoint@0" } },
+		}
+	    })
+	}
+    }
+
+Here, the port 0 of the "CAM0" device is connected to the port 4 of
+the "ISP" device and vice versa.
+
+
+References
+==========
+
+[acpi] Advanced Configuration and Power Interface Specification.
+    https://uefi.org/specifications/ACPI/6.4/, referenced 2021-11-30.
+
+[data-node-ref] Documentation/firmware-guide/acpi/dsd/data-node-references.rst
+
+[devicetree] Devicetree. https://www.devicetree.org, referenced 2016-10-03.
+
+[dsd-guide] DSD Guide.
+    https://github.com/UEFI/DSD-Guide/blob/main/dsd-guide.adoc, referenced
+    2021-11-30.
+
+[dsd-rules] _DSD Device Properties Usage Rules.
+    Documentation/firmware-guide/acpi/DSD-properties-rules.rst
+
+[graph-bindings] Common bindings for device graphs (Devicetree).
+    https://github.com/devicetree-org/dt-schema/blob/main/schemas/graph.yaml,
+    referenced 2021-11-30.
diff --git a/Documentation/firmware-guide/acpi/dsd/leds.rst b/Documentation/firmware-guide/acpi/dsd/leds.rst
new file mode 100644
index 000000000..93db592c9
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/dsd/leds.rst
@@ -0,0 +1,107 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+========================================
+Describing and referring to LEDs in ACPI
+========================================
+
+Individual LEDs are described by hierarchical data extension [5] nodes under the
+device node, the LED driver chip. The "reg" property in the LED specific nodes
+tells the numerical ID of each individual LED output to which the LEDs are
+connected. [leds] The hierarchical data nodes are named "led@X", where X is the
+number of the LED output.
+
+Referring to LEDs in Device tree is documented in [video-interfaces], in
+"flash-leds" property documentation. In short, LEDs are directly referred to by
+using phandles.
+
+While Device tree allows referring to any node in the tree [devicetree], in
+ACPI references are limited to device nodes only [acpi]. For this reason using
+the same mechanism on ACPI is not possible. A mechanism to refer to non-device
+ACPI nodes is documented in [data-node-ref].
+
+ACPI allows (as does DT) using integer arguments after the reference. A
+combination of the LED driver device reference and an integer argument,
+referring to the "reg" property of the relevant LED, is used to identify
+individual LEDs. The value of the "reg" property is a contract between the
+firmware and software, it uniquely identifies the LED driver outputs.
+
+Under the LED driver device, The first hierarchical data extension package list
+entry shall contain the string "led@" followed by the number of the LED,
+followed by the referred object name. That object shall be named "LED" followed
+by the number of the LED.
+
+Example
+=======
+
+An ASL example of a camera sensor device and a LED driver device for two LEDs is
+show below. Objects not relevant for LEDs or the references to them have been
+omitted. ::
+
+	Device (LED)
+	{
+		Name (_DSD, Package () {
+			ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+			Package () {
+				Package () { "led@0", LED0 },
+				Package () { "led@1", LED1 },
+			}
+		})
+		Name (LED0, Package () {
+			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+			Package () {
+				Package () { "reg", 0 },
+				Package () { "flash-max-microamp", 1000000 },
+				Package () { "flash-timeout-us", 200000 },
+				Package () { "led-max-microamp", 100000 },
+				Package () { "label", "white:flash" },
+			}
+		})
+		Name (LED1, Package () {
+			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+			Package () {
+				Package () { "reg", 1 },
+				Package () { "led-max-microamp", 10000 },
+				Package () { "label", "red:indicator" },
+			}
+		})
+	}
+
+	Device (SEN)
+	{
+		Name (_DSD, Package () {
+			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+			Package () {
+				Package () {
+					"flash-leds",
+					Package () { ^LED, "led@0", ^LED, "led@1" },
+				}
+			}
+		})
+	}
+
+where
+::
+
+	LED	LED driver device
+	LED0	First LED
+	LED1	Second LED
+	SEN	Camera sensor device (or another device the LED is related to)
+
+References
+==========
+
+[acpi] Advanced Configuration and Power Interface Specification.
+    https://uefi.org/specifications/ACPI/6.4/, referenced 2021-11-30.
+
+[data-node-ref] Documentation/firmware-guide/acpi/dsd/data-node-references.rst
+
+[devicetree] Devicetree. https://www.devicetree.org, referenced 2019-02-21.
+
+[dsd-guide] DSD Guide.
+    https://github.com/UEFI/DSD-Guide/blob/main/dsd-guide.adoc, referenced
+    2021-11-30.
+
+[leds] Documentation/devicetree/bindings/leds/common.yaml
+
+[video-interfaces] Documentation/devicetree/bindings/media/video-interfaces.yaml
diff --git a/Documentation/firmware-guide/acpi/dsd/phy.rst b/Documentation/firmware-guide/acpi/dsd/phy.rst
new file mode 100644
index 000000000..673ac374f
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/dsd/phy.rst
@@ -0,0 +1,201 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+MDIO bus and PHYs in ACPI
+=========================
+
+The PHYs on an MDIO bus [phy] are probed and registered using
+fwnode_mdiobus_register_phy().
+
+Later, for connecting these PHYs to their respective MACs, the PHYs registered
+on the MDIO bus have to be referenced.
+
+This document introduces two _DSD properties that are to be used
+for connecting PHYs on the MDIO bus [dsd-properties-rules] to the MAC layer.
+
+These properties are defined in accordance with the "Device
+Properties UUID For _DSD" [dsd-guide] document and the
+daffd814-6eba-4d8c-8a91-bc9bbf4aa301 UUID must be used in the Device
+Data Descriptors containing them.
+
+phy-handle
+----------
+For each MAC node, a device property "phy-handle" is used to reference
+the PHY that is registered on an MDIO bus. This is mandatory for
+network interfaces that have PHYs connected to MAC via MDIO bus.
+
+During the MDIO bus driver initialization, PHYs on this bus are probed
+using the _ADR object as shown below and are registered on the MDIO bus.
+
+.. code-block:: none
+
+      Scope(\_SB.MDI0)
+      {
+        Device(PHY1) {
+          Name (_ADR, 0x1)
+        } // end of PHY1
+
+        Device(PHY2) {
+          Name (_ADR, 0x2)
+        } // end of PHY2
+      }
+
+Later, during the MAC driver initialization, the registered PHY devices
+have to be retrieved from the MDIO bus. For this, the MAC driver needs
+references to the previously registered PHYs which are provided
+as device object references (e.g. \_SB.MDI0.PHY1).
+
+phy-mode
+--------
+The "phy-mode" _DSD property is used to describe the connection to
+the PHY. The valid values for "phy-mode" are defined in [ethernet-controller].
+
+managed
+-------
+Optional property, which specifies the PHY management type.
+The valid values for "managed" are defined in [ethernet-controller].
+
+fixed-link
+----------
+The "fixed-link" is described by a data-only subnode of the
+MAC port, which is linked in the _DSD package via
+hierarchical data extension (UUID dbb8e3e6-5886-4ba6-8795-1319f52a966b
+in accordance with [dsd-guide] "_DSD Implementation Guide" document).
+The subnode should comprise a required property ("speed") and
+possibly the optional ones - complete list of parameters and
+their values are specified in [ethernet-controller].
+
+The following ASL example illustrates the usage of these properties.
+
+DSDT entry for MDIO node
+------------------------
+
+The MDIO bus has an SoC component (MDIO controller) and a platform
+component (PHYs on the MDIO bus).
+
+a) Silicon Component
+This node describes the MDIO controller, MDI0
+---------------------------------------------
+
+.. code-block:: none
+
+	Scope(_SB)
+	{
+	  Device(MDI0) {
+	    Name(_HID, "NXP0006")
+	    Name(_CCA, 1)
+	    Name(_UID, 0)
+	    Name(_CRS, ResourceTemplate() {
+	      Memory32Fixed(ReadWrite, MDI0_BASE, MDI_LEN)
+	      Interrupt(ResourceConsumer, Level, ActiveHigh, Shared)
+	       {
+		 MDI0_IT
+	       }
+	    }) // end of _CRS for MDI0
+	  } // end of MDI0
+	}
+
+b) Platform Component
+The PHY1 and PHY2 nodes represent the PHYs connected to MDIO bus MDI0
+---------------------------------------------------------------------
+
+.. code-block:: none
+
+	Scope(\_SB.MDI0)
+	{
+	  Device(PHY1) {
+	    Name (_ADR, 0x1)
+	  } // end of PHY1
+
+	  Device(PHY2) {
+	    Name (_ADR, 0x2)
+	  } // end of PHY2
+	}
+
+DSDT entries representing MAC nodes
+-----------------------------------
+
+Below are the MAC nodes where PHY nodes are referenced.
+phy-mode and phy-handle are used as explained earlier.
+------------------------------------------------------
+
+.. code-block:: none
+
+	Scope(\_SB.MCE0.PR17)
+	{
+	  Name (_DSD, Package () {
+	     ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		 Package () {
+		     Package (2) {"phy-mode", "rgmii-id"},
+		     Package (2) {"phy-handle", \_SB.MDI0.PHY1}
+	      }
+	   })
+	}
+
+	Scope(\_SB.MCE0.PR18)
+	{
+	  Name (_DSD, Package () {
+	    ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package (2) {"phy-mode", "rgmii-id"},
+		    Package (2) {"phy-handle", \_SB.MDI0.PHY2}}
+	    }
+	  })
+	}
+
+MAC node example where "managed" property is specified.
+-------------------------------------------------------
+
+.. code-block:: none
+
+	Scope(\_SB.PP21.ETH0)
+	{
+	  Name (_DSD, Package () {
+	     ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		 Package () {
+		     Package () {"phy-mode", "sgmii"},
+		     Package () {"managed", "in-band-status"}
+		 }
+	   })
+	}
+
+MAC node example with a "fixed-link" subnode.
+---------------------------------------------
+
+.. code-block:: none
+
+	Scope(\_SB.PP21.ETH1)
+	{
+	  Name (_DSD, Package () {
+	    ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		 Package () {
+		     Package () {"phy-mode", "sgmii"},
+		 },
+	    ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+		 Package () {
+		     Package () {"fixed-link", "LNK0"}
+		 }
+	  })
+	  Name (LNK0, Package(){ // Data-only subnode of port
+	    ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		 Package () {
+		     Package () {"speed", 1000},
+		     Package () {"full-duplex", 1}
+		 }
+	  })
+	}
+
+References
+==========
+
+[phy] Documentation/networking/phy.rst
+
+[dsd-properties-rules]
+    Documentation/firmware-guide/acpi/DSD-properties-rules.rst
+
+[ethernet-controller]
+    Documentation/devicetree/bindings/net/ethernet-controller.yaml
+
+[dsd-guide] DSD Guide.
+    https://github.com/UEFI/DSD-Guide/blob/main/dsd-guide.adoc, referenced
+    2021-11-30.