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().
  ...

1 files changed, 221 insertions, 0 deletions

diff --git a/Documentation/i2c/dev-interface.rst b/Documentation/i2c/dev-interface.rst
new file mode 100644
index 000000000..c277a8e12
--- /dev/null
+++ b/Documentation/i2c/dev-interface.rst
@@ -0,0 +1,221 @@
+============================================
+Implementing I2C device drivers in userspace
+============================================
+
+Usually, I2C devices are controlled by a kernel driver. But it is also
+possible to access all devices on an adapter from userspace, through
+the /dev interface. You need to load module i2c-dev for this.
+
+Each registered I2C adapter gets a number, counting from 0. You can
+examine /sys/class/i2c-dev/ to see what number corresponds to which adapter.
+Alternatively, you can run "i2cdetect -l" to obtain a formatted list of all
+I2C adapters present on your system at a given time. i2cdetect is part of
+the i2c-tools package.
+
+I2C device files are character device files with major device number 89
+and a minor device number corresponding to the number assigned as
+explained above. They should be called "i2c-%d" (i2c-0, i2c-1, ...,
+i2c-10, ...). All 256 minor device numbers are reserved for I2C.
+
+
+C example
+=========
+
+So let's say you want to access an I2C adapter from a C program.
+First, you need to include these two headers::
+
+  #include <linux/i2c-dev.h>
+  #include <i2c/smbus.h>
+
+Now, you have to decide which adapter you want to access. You should
+inspect /sys/class/i2c-dev/ or run "i2cdetect -l" to decide this.
+Adapter numbers are assigned somewhat dynamically, so you can not
+assume much about them. They can even change from one boot to the next.
+
+Next thing, open the device file, as follows::
+
+  int file;
+  int adapter_nr = 2; /* probably dynamically determined */
+  char filename[20];
+
+  snprintf(filename, 19, "/dev/i2c-%d", adapter_nr);
+  file = open(filename, O_RDWR);
+  if (file < 0) {
+    /* ERROR HANDLING; you can check errno to see what went wrong */
+    exit(1);
+  }
+
+When you have opened the device, you must specify with what device
+address you want to communicate::
+
+  int addr = 0x40; /* The I2C address */
+
+  if (ioctl(file, I2C_SLAVE, addr) < 0) {
+    /* ERROR HANDLING; you can check errno to see what went wrong */
+    exit(1);
+  }
+
+Well, you are all set up now. You can now use SMBus commands or plain
+I2C to communicate with your device. SMBus commands are preferred if
+the device supports them. Both are illustrated below::
+
+  __u8 reg = 0x10; /* Device register to access */
+  __s32 res;
+  char buf[10];
+
+  /* Using SMBus commands */
+  res = i2c_smbus_read_word_data(file, reg);
+  if (res < 0) {
+    /* ERROR HANDLING: I2C transaction failed */
+  } else {
+    /* res contains the read word */
+  }
+
+  /*
+   * Using I2C Write, equivalent of
+   * i2c_smbus_write_word_data(file, reg, 0x6543)
+   */
+  buf[0] = reg;
+  buf[1] = 0x43;
+  buf[2] = 0x65;
+  if (write(file, buf, 3) != 3) {
+    /* ERROR HANDLING: I2C transaction failed */
+  }
+
+  /* Using I2C Read, equivalent of i2c_smbus_read_byte(file) */
+  if (read(file, buf, 1) != 1) {
+    /* ERROR HANDLING: I2C transaction failed */
+  } else {
+    /* buf[0] contains the read byte */
+  }
+
+Note that only a subset of the I2C and SMBus protocols can be achieved by
+the means of read() and write() calls. In particular, so-called combined
+transactions (mixing read and write messages in the same transaction)
+aren't supported. For this reason, this interface is almost never used by
+user-space programs.
+
+IMPORTANT: because of the use of inline functions, you *have* to use
+'-O' or some variation when you compile your program!
+
+
+Full interface description
+==========================
+
+The following IOCTLs are defined:
+
+``ioctl(file, I2C_SLAVE, long addr)``
+  Change slave address. The address is passed in the 7 lower bits of the
+  argument (except for 10 bit addresses, passed in the 10 lower bits in this
+  case).
+
+``ioctl(file, I2C_TENBIT, long select)``
+  Selects ten bit addresses if select not equals 0, selects normal 7 bit
+  addresses if select equals 0. Default 0.  This request is only valid
+  if the adapter has I2C_FUNC_10BIT_ADDR.
+
+``ioctl(file, I2C_PEC, long select)``
+  Selects SMBus PEC (packet error checking) generation and verification
+  if select not equals 0, disables if select equals 0. Default 0.
+  Used only for SMBus transactions.  This request only has an effect if the
+  the adapter has I2C_FUNC_SMBUS_PEC; it is still safe if not, it just
+  doesn't have any effect.
+
+``ioctl(file, I2C_FUNCS, unsigned long *funcs)``
+  Gets the adapter functionality and puts it in ``*funcs``.
+
+``ioctl(file, I2C_RDWR, struct i2c_rdwr_ioctl_data *msgset)``
+  Do combined read/write transaction without stop in between.
+  Only valid if the adapter has I2C_FUNC_I2C.  The argument is
+  a pointer to a::
+
+    struct i2c_rdwr_ioctl_data {
+      struct i2c_msg *msgs;  /* ptr to array of simple messages */
+      int nmsgs;             /* number of messages to exchange */
+    }
+
+  The msgs[] themselves contain further pointers into data buffers.
+  The function will write or read data to or from that buffers depending
+  on whether the I2C_M_RD flag is set in a particular message or not.
+  The slave address and whether to use ten bit address mode has to be
+  set in each message, overriding the values set with the above ioctl's.
+
+``ioctl(file, I2C_SMBUS, struct i2c_smbus_ioctl_data *args)``
+  If possible, use the provided ``i2c_smbus_*`` methods described below instead
+  of issuing direct ioctls.
+
+You can do plain I2C transactions by using read(2) and write(2) calls.
+You do not need to pass the address byte; instead, set it through
+ioctl I2C_SLAVE before you try to access the device.
+
+You can do SMBus level transactions (see documentation file smbus-protocol.rst
+for details) through the following functions::
+
+  __s32 i2c_smbus_write_quick(int file, __u8 value);
+  __s32 i2c_smbus_read_byte(int file);
+  __s32 i2c_smbus_write_byte(int file, __u8 value);
+  __s32 i2c_smbus_read_byte_data(int file, __u8 command);
+  __s32 i2c_smbus_write_byte_data(int file, __u8 command, __u8 value);
+  __s32 i2c_smbus_read_word_data(int file, __u8 command);
+  __s32 i2c_smbus_write_word_data(int file, __u8 command, __u16 value);
+  __s32 i2c_smbus_process_call(int file, __u8 command, __u16 value);
+  __s32 i2c_smbus_block_process_call(int file, __u8 command, __u8 length,
+                                     __u8 *values);
+  __s32 i2c_smbus_read_block_data(int file, __u8 command, __u8 *values);
+  __s32 i2c_smbus_write_block_data(int file, __u8 command, __u8 length,
+                                   __u8 *values);
+
+All these transactions return -1 on failure; you can read errno to see
+what happened. The 'write' transactions return 0 on success; the
+'read' transactions return the read value, except for read_block, which
+returns the number of values read. The block buffers need not be longer
+than 32 bytes.
+
+The above functions are made available by linking against the libi2c library,
+which is provided by the i2c-tools project.  See:
+https://git.kernel.org/pub/scm/utils/i2c-tools/i2c-tools.git/.
+
+
+Implementation details
+======================
+
+For the interested, here's the code flow which happens inside the kernel
+when you use the /dev interface to I2C:
+
+1) Your program opens /dev/i2c-N and calls ioctl() on it, as described in
+   section "C example" above.
+
+2) These open() and ioctl() calls are handled by the i2c-dev kernel
+   driver: see i2c-dev.c:i2cdev_open() and i2c-dev.c:i2cdev_ioctl(),
+   respectively. You can think of i2c-dev as a generic I2C chip driver
+   that can be programmed from user-space.
+
+3) Some ioctl() calls are for administrative tasks and are handled by
+   i2c-dev directly. Examples include I2C_SLAVE (set the address of the
+   device you want to access) and I2C_PEC (enable or disable SMBus error
+   checking on future transactions.)
+
+4) Other ioctl() calls are converted to in-kernel function calls by
+   i2c-dev. Examples include I2C_FUNCS, which queries the I2C adapter
+   functionality using i2c.h:i2c_get_functionality(), and I2C_SMBUS, which
+   performs an SMBus transaction using i2c-core-smbus.c:i2c_smbus_xfer().
+
+   The i2c-dev driver is responsible for checking all the parameters that
+   come from user-space for validity. After this point, there is no
+   difference between these calls that came from user-space through i2c-dev
+   and calls that would have been performed by kernel I2C chip drivers
+   directly. This means that I2C bus drivers don't need to implement
+   anything special to support access from user-space.
+
+5) These i2c.h functions are wrappers to the actual implementation of
+   your I2C bus driver. Each adapter must declare callback functions
+   implementing these standard calls. i2c.h:i2c_get_functionality() calls
+   i2c_adapter.algo->functionality(), while
+   i2c-core-smbus.c:i2c_smbus_xfer() calls either
+   adapter.algo->smbus_xfer() if it is implemented, or if not,
+   i2c-core-smbus.c:i2c_smbus_xfer_emulated() which in turn calls
+   i2c_adapter.algo->master_xfer().
+
+After your I2C bus driver has processed these requests, execution runs
+up the call chain, with almost no processing done, except by i2c-dev to
+package the returned data, if any, in suitable format for the ioctl.