From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- Documentation/hid/hid-sensor.rst | 242 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 242 insertions(+) create mode 100644 Documentation/hid/hid-sensor.rst (limited to 'Documentation/hid/hid-sensor.rst') diff --git a/Documentation/hid/hid-sensor.rst b/Documentation/hid/hid-sensor.rst new file mode 100644 index 000000000..c1c9b8d8d --- /dev/null +++ b/Documentation/hid/hid-sensor.rst @@ -0,0 +1,242 @@ +===================== +HID Sensors Framework +===================== +HID sensor framework provides necessary interfaces to implement sensor drivers, +which are connected to a sensor hub. The sensor hub is a HID device and it provides +a report descriptor conforming to HID 1.12 sensor usage tables. + +Description from the HID 1.12 "HID Sensor Usages" specification: +"Standardization of HID usages for sensors would allow (but not require) sensor +hardware vendors to provide a consistent Plug And Play interface at the USB boundary, +thereby enabling some operating systems to incorporate common device drivers that +could be reused between vendors, alleviating any need for the vendors to provide +the drivers themselves." + +This specification describes many usage IDs, which describe the type of sensor +and also the individual data fields. Each sensor can have variable number of +data fields. The length and order is specified in the report descriptor. For +example a part of report descriptor can look like:: + + INPUT(1)[INPUT] + .. + Field(2) + Physical(0020.0073) + Usage(1) + 0020.045f + Logical Minimum(-32767) + Logical Maximum(32767) + Report Size(8) + Report Count(1) + Report Offset(16) + Flags(Variable Absolute) + .. + .. + +The report is indicating "sensor page (0x20)" contains an accelerometer-3D (0x73). +This accelerometer-3D has some fields. Here for example field 2 is motion intensity +(0x045f) with a logical minimum value of -32767 and logical maximum of 32767. The +order of fields and length of each field is important as the input event raw +data will use this format. + + +Implementation +============== + +This specification defines many different types of sensors with different sets of +data fields. It is difficult to have a common input event to user space applications, +for different sensors. For example an accelerometer can send X,Y and Z data, whereas +an ambient light sensor can send illumination data. +So the implementation has two parts: + +- Core HID driver +- Individual sensor processing part (sensor drivers) + +Core driver +----------- +The core driver (hid-sensor-hub) registers as a HID driver. It parses +report descriptors and identifies all the sensors present. It adds an MFD device +with name HID-SENSOR-xxxx (where xxxx is usage id from the specification). + +For example: + +HID-SENSOR-200073 is registered for an Accelerometer 3D driver. + +So if any driver with this name is inserted, then the probe routine for that +function will be called. So an accelerometer processing driver can register +with this name and will be probed if there is an accelerometer-3D detected. + +The core driver provides a set of APIs which can be used by the processing +drivers to register and get events for that usage id. Also it provides parsing +functions, which get and set each input/feature/output report. + +Individual sensor processing part (sensor drivers) +-------------------------------------------------- + +The processing driver will use an interface provided by the core driver to parse +the report and get the indexes of the fields and also can get events. This driver +can use IIO interface to use the standard ABI defined for a type of sensor. + + +Core driver Interface +===================== + +Callback structure:: + + Each processing driver can use this structure to set some callbacks. + int (*suspend)(..): Callback when HID suspend is received + int (*resume)(..): Callback when HID resume is received + int (*capture_sample)(..): Capture a sample for one of its data fields + int (*send_event)(..): One complete event is received which can have + multiple data fields. + +Registration functions:: + + int sensor_hub_register_callback(struct hid_sensor_hub_device *hsdev, + u32 usage_id, + struct hid_sensor_hub_callbacks *usage_callback): + +Registers callbacks for a usage id. The callback functions are not allowed +to sleep:: + + + int sensor_hub_remove_callback(struct hid_sensor_hub_device *hsdev, + u32 usage_id): + +Removes callbacks for a usage id. + + +Parsing function:: + + int sensor_hub_input_get_attribute_info(struct hid_sensor_hub_device *hsdev, + u8 type, + u32 usage_id, u32 attr_usage_id, + struct hid_sensor_hub_attribute_info *info); + +A processing driver can look for some field of interest and check if it exists +in a report descriptor. If it exists it will store necessary information +so that fields can be set or get individually. +These indexes avoid searching every time and getting field index to get or set. + + +Set Feature report:: + + int sensor_hub_set_feature(struct hid_sensor_hub_device *hsdev, u32 report_id, + u32 field_index, s32 value); + +This interface is used to set a value for a field in feature report. For example +if there is a field report_interval, which is parsed by a call to +sensor_hub_input_get_attribute_info before, then it can directly set that +individual field:: + + + int sensor_hub_get_feature(struct hid_sensor_hub_device *hsdev, u32 report_id, + u32 field_index, s32 *value); + +This interface is used to get a value for a field in input report. For example +if there is a field report_interval, which is parsed by a call to +sensor_hub_input_get_attribute_info before, then it can directly get that +individual field value:: + + + int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev, + u32 usage_id, + u32 attr_usage_id, u32 report_id); + +This is used to get a particular field value through input reports. For example +accelerometer wants to poll X axis value, then it can call this function with +the usage id of X axis. HID sensors can provide events, so this is not necessary +to poll for any field. If there is some new sample, the core driver will call +registered callback function to process the sample. + + +---------- + +HID Custom and generic Sensors +------------------------------ + + +HID Sensor specification defines two special sensor usage types. Since they +don't represent a standard sensor, it is not possible to define using Linux IIO +type interfaces. +The purpose of these sensors is to extend the functionality or provide a +way to obfuscate the data being communicated by a sensor. Without knowing the +mapping between the data and its encapsulated form, it is difficult for +an application/driver to determine what data is being communicated by the sensor. +This allows some differentiating use cases, where vendor can provide applications. +Some common use cases are debug other sensors or to provide some events like +keyboard attached/detached or lid open/close. + +To allow application to utilize these sensors, here they are exported using sysfs +attribute groups, attributes and misc device interface. + +An example of this representation on sysfs:: + + /sys/devices/pci0000:00/INT33C2:00/i2c-0/i2c-INT33D1:00/0018:8086:09FA.0001/HID-SENSOR-2000e1.6.auto$ tree -R + . + │   ├── enable_sensor + │   │   ├── feature-0-200316 + │   │   │   ├── feature-0-200316-maximum + │   │   │   ├── feature-0-200316-minimum + │   │   │   ├── feature-0-200316-name + │   │   │   ├── feature-0-200316-size + │   │   │   ├── feature-0-200316-unit-expo + │   │   │   ├── feature-0-200316-units + │   │   │   ├── feature-0-200316-value + │   │   ├── feature-1-200201 + │   │   │   ├── feature-1-200201-maximum + │   │   │   ├── feature-1-200201-minimum + │   │   │   ├── feature-1-200201-name + │   │   │   ├── feature-1-200201-size + │   │   │   ├── feature-1-200201-unit-expo + │   │   │   ├── feature-1-200201-units + │   │   │   ├── feature-1-200201-value + │   │   ├── input-0-200201 + │   │   │   ├── input-0-200201-maximum + │   │   │   ├── input-0-200201-minimum + │   │   │   ├── input-0-200201-name + │   │   │   ├── input-0-200201-size + │   │   │   ├── input-0-200201-unit-expo + │   │   │   ├── input-0-200201-units + │   │   │   ├── input-0-200201-value + │   │   ├── input-1-200202 + │   │   │   ├── input-1-200202-maximum + │   │   │   ├── input-1-200202-minimum + │   │   │   ├── input-1-200202-name + │   │   │   ├── input-1-200202-size + │   │   │   ├── input-1-200202-unit-expo + │   │   │   ├── input-1-200202-units + │   │   │   ├── input-1-200202-value + +Here there is a custom sensor with four fields: two feature and two inputs. +Each field is represented by a set of attributes. All fields except the "value" +are read only. The value field is a read-write field. + +Example:: + + /sys/bus/platform/devices/HID-SENSOR-2000e1.6.auto/feature-0-200316$ grep -r . * + feature-0-200316-maximum:6 + feature-0-200316-minimum:0 + feature-0-200316-name:property-reporting-state + feature-0-200316-size:1 + feature-0-200316-unit-expo:0 + feature-0-200316-units:25 + feature-0-200316-value:1 + +How to enable such sensor? +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +By default sensor can be power gated. To enable sysfs attribute "enable" can be +used:: + + $ echo 1 > enable_sensor + +Once enabled and powered on, sensor can report value using HID reports. +These reports are pushed using misc device interface in a FIFO order:: + + /dev$ tree | grep HID-SENSOR-2000e1.6.auto + │   │   │   ├── 10:53 -> ../HID-SENSOR-2000e1.6.auto + │   ├── HID-SENSOR-2000e1.6.auto + +Each report can be of variable length preceded by a header. This header +consists of a 32-bit usage id, 64-bit time stamp and 32-bit length field of raw +data. -- cgit v1.2.3