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/driver-api/vme.rst | 297 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 297 insertions(+) create mode 100644 Documentation/driver-api/vme.rst (limited to 'Documentation/driver-api/vme.rst') diff --git a/Documentation/driver-api/vme.rst b/Documentation/driver-api/vme.rst new file mode 100644 index 000000000..c0b475369 --- /dev/null +++ b/Documentation/driver-api/vme.rst @@ -0,0 +1,297 @@ +VME Device Drivers +================== + +Driver registration +------------------- + +As with other subsystems within the Linux kernel, VME device drivers register +with the VME subsystem, typically called from the devices init routine. This is +achieved via a call to :c:func:`vme_register_driver`. + +A pointer to a structure of type :c:type:`struct vme_driver ` must +be provided to the registration function. Along with the maximum number of +devices your driver is able to support. + +At the minimum, the '.name', '.match' and '.probe' elements of +:c:type:`struct vme_driver ` should be correctly set. The '.name' +element is a pointer to a string holding the device driver's name. + +The '.match' function allows control over which VME devices should be registered +with the driver. The match function should return 1 if a device should be +probed and 0 otherwise. This example match function (from vme_user.c) limits +the number of devices probed to one: + +.. code-block:: c + + #define USER_BUS_MAX 1 + ... + static int vme_user_match(struct vme_dev *vdev) + { + if (vdev->id.num >= USER_BUS_MAX) + return 0; + return 1; + } + +The '.probe' element should contain a pointer to the probe routine. The +probe routine is passed a :c:type:`struct vme_dev ` pointer as an +argument. + +Here, the 'num' field refers to the sequential device ID for this specific +driver. The bridge number (or bus number) can be accessed using +dev->bridge->num. + +A function is also provided to unregister the driver from the VME core called +:c:func:`vme_unregister_driver` and should usually be called from the device +driver's exit routine. + + +Resource management +------------------- + +Once a driver has registered with the VME core the provided match routine will +be called the number of times specified during the registration. If a match +succeeds, a non-zero value should be returned. A zero return value indicates +failure. For all successful matches, the probe routine of the corresponding +driver is called. The probe routine is passed a pointer to the devices +device structure. This pointer should be saved, it will be required for +requesting VME resources. + +The driver can request ownership of one or more master windows +(:c:func:`vme_master_request`), slave windows (:c:func:`vme_slave_request`) +and/or dma channels (:c:func:`vme_dma_request`). Rather than allowing the device +driver to request a specific window or DMA channel (which may be used by a +different driver) the API allows a resource to be assigned based on the required +attributes of the driver in question. For slave windows these attributes are +split into the VME address spaces that need to be accessed in 'aspace' and VME +bus cycle types required in 'cycle'. Master windows add a further set of +attributes in 'width' specifying the required data transfer widths. These +attributes are defined as bitmasks and as such any combination of the +attributes can be requested for a single window, the core will assign a window +that meets the requirements, returning a pointer of type vme_resource that +should be used to identify the allocated resource when it is used. For DMA +controllers, the request function requires the potential direction of any +transfers to be provided in the route attributes. This is typically VME-to-MEM +and/or MEM-to-VME, though some hardware can support VME-to-VME and MEM-to-MEM +transfers as well as test pattern generation. If an unallocated window fitting +the requirements can not be found a NULL pointer will be returned. + +Functions are also provided to free window allocations once they are no longer +required. These functions (:c:func:`vme_master_free`, :c:func:`vme_slave_free` +and :c:func:`vme_dma_free`) should be passed the pointer to the resource +provided during resource allocation. + + +Master windows +-------------- + +Master windows provide access from the local processor[s] out onto the VME bus. +The number of windows available and the available access modes is dependent on +the underlying chipset. A window must be configured before it can be used. + + +Master window configuration +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Once a master window has been assigned :c:func:`vme_master_set` can be used to +configure it and :c:func:`vme_master_get` to retrieve the current settings. The +address spaces, transfer widths and cycle types are the same as described +under resource management, however some of the options are mutually exclusive. +For example, only one address space may be specified. + + +Master window access +~~~~~~~~~~~~~~~~~~~~ + +The function :c:func:`vme_master_read` can be used to read from and +:c:func:`vme_master_write` used to write to configured master windows. + +In addition to simple reads and writes, :c:func:`vme_master_rmw` is provided to +do a read-modify-write transaction. Parts of a VME window can also be mapped +into user space memory using :c:func:`vme_master_mmap`. + + +Slave windows +------------- + +Slave windows provide devices on the VME bus access into mapped portions of the +local memory. The number of windows available and the access modes that can be +used is dependent on the underlying chipset. A window must be configured before +it can be used. + + +Slave window configuration +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Once a slave window has been assigned :c:func:`vme_slave_set` can be used to +configure it and :c:func:`vme_slave_get` to retrieve the current settings. + +The address spaces, transfer widths and cycle types are the same as described +under resource management, however some of the options are mutually exclusive. +For example, only one address space may be specified. + + +Slave window buffer allocation +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Functions are provided to allow the user to allocate +(:c:func:`vme_alloc_consistent`) and free (:c:func:`vme_free_consistent`) +contiguous buffers which will be accessible by the VME bridge. These functions +do not have to be used, other methods can be used to allocate a buffer, though +care must be taken to ensure that they are contiguous and accessible by the VME +bridge. + + +Slave window access +~~~~~~~~~~~~~~~~~~~ + +Slave windows map local memory onto the VME bus, the standard methods for +accessing memory should be used. + + +DMA channels +------------ + +The VME DMA transfer provides the ability to run link-list DMA transfers. The +API introduces the concept of DMA lists. Each DMA list is a link-list which can +be passed to a DMA controller. Multiple lists can be created, extended, +executed, reused and destroyed. + + +List Management +~~~~~~~~~~~~~~~ + +The function :c:func:`vme_new_dma_list` is provided to create and +:c:func:`vme_dma_list_free` to destroy DMA lists. Execution of a list will not +automatically destroy the list, thus enabling a list to be reused for repetitive +tasks. + + +List Population +~~~~~~~~~~~~~~~ + +An item can be added to a list using :c:func:`vme_dma_list_add` (the source and +destination attributes need to be created before calling this function, this is +covered under "Transfer Attributes"). + +.. note:: + + The detailed attributes of the transfers source and destination + are not checked until an entry is added to a DMA list, the request + for a DMA channel purely checks the directions in which the + controller is expected to transfer data. As a result it is + possible for this call to return an error, for example if the + source or destination is in an unsupported VME address space. + +Transfer Attributes +~~~~~~~~~~~~~~~~~~~ + +The attributes for the source and destination are handled separately from adding +an item to a list. This is due to the diverse attributes required for each type +of source and destination. There are functions to create attributes for PCI, VME +and pattern sources and destinations (where appropriate): + + - PCI source or destination: :c:func:`vme_dma_pci_attribute` + - VME source or destination: :c:func:`vme_dma_vme_attribute` + - Pattern source: :c:func:`vme_dma_pattern_attribute` + +The function :c:func:`vme_dma_free_attribute` should be used to free an +attribute. + + +List Execution +~~~~~~~~~~~~~~ + +The function :c:func:`vme_dma_list_exec` queues a list for execution and will +return once the list has been executed. + + +Interrupts +---------- + +The VME API provides functions to attach and detach callbacks to specific VME +level and status ID combinations and for the generation of VME interrupts with +specific VME level and status IDs. + + +Attaching Interrupt Handlers +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The function :c:func:`vme_irq_request` can be used to attach and +:c:func:`vme_irq_free` to free a specific VME level and status ID combination. +Any given combination can only be assigned a single callback function. A void +pointer parameter is provided, the value of which is passed to the callback +function, the use of this pointer is user undefined. The callback parameters are +as follows. Care must be taken in writing a callback function, callback +functions run in interrupt context: + +.. code-block:: c + + void callback(int level, int statid, void *priv); + + +Interrupt Generation +~~~~~~~~~~~~~~~~~~~~ + +The function :c:func:`vme_irq_generate` can be used to generate a VME interrupt +at a given VME level and VME status ID. + + +Location monitors +----------------- + +The VME API provides the following functionality to configure the location +monitor. + + +Location Monitor Management +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The function :c:func:`vme_lm_request` is provided to request the use of a block +of location monitors and :c:func:`vme_lm_free` to free them after they are no +longer required. Each block may provide a number of location monitors, +monitoring adjacent locations. The function :c:func:`vme_lm_count` can be used +to determine how many locations are provided. + + +Location Monitor Configuration +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Once a bank of location monitors has been allocated, the function +:c:func:`vme_lm_set` is provided to configure the location and mode of the +location monitor. The function :c:func:`vme_lm_get` can be used to retrieve +existing settings. + + +Location Monitor Use +~~~~~~~~~~~~~~~~~~~~ + +The function :c:func:`vme_lm_attach` enables a callback to be attached and +:c:func:`vme_lm_detach` allows on to be detached from each location monitor +location. Each location monitor can monitor a number of adjacent locations. The +callback function is declared as follows. + +.. code-block:: c + + void callback(void *data); + + +Slot Detection +-------------- + +The function :c:func:`vme_slot_num` returns the slot ID of the provided bridge. + + +Bus Detection +------------- + +The function :c:func:`vme_bus_num` returns the bus ID of the provided bridge. + + +VME API +------- + +.. kernel-doc:: drivers/staging/vme_user/vme.h + :internal: + +.. kernel-doc:: drivers/staging/vme_user/vme.c + :export: -- cgit v1.2.3