ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/Documentation/infiniband/core_locking.rst b/marvell/linux/Documentation/infiniband/core_locking.rst
new file mode 100644
index 0000000..8f76a8a
--- /dev/null
+++ b/marvell/linux/Documentation/infiniband/core_locking.rst
@@ -0,0 +1,118 @@
+===========================
+InfiniBand Midlayer Locking
+===========================
+
+ This guide is an attempt to make explicit the locking assumptions
+ made by the InfiniBand midlayer. It describes the requirements on
+ both low-level drivers that sit below the midlayer and upper level
+ protocols that use the midlayer.
+
+Sleeping and interrupt context
+==============================
+
+ With the following exceptions, a low-level driver implementation of
+ all of the methods in struct ib_device may sleep. The exceptions
+ are any methods from the list:
+
+ - create_ah
+ - modify_ah
+ - query_ah
+ - destroy_ah
+ - post_send
+ - post_recv
+ - poll_cq
+ - req_notify_cq
+ - map_phys_fmr
+
+ which may not sleep and must be callable from any context.
+
+ The corresponding functions exported to upper level protocol
+ consumers:
+
+ - rdma_create_ah
+ - rdma_modify_ah
+ - rdma_query_ah
+ - rdma_destroy_ah
+ - ib_post_send
+ - ib_post_recv
+ - ib_req_notify_cq
+ - ib_map_phys_fmr
+
+ are therefore safe to call from any context.
+
+ In addition, the function
+
+ - ib_dispatch_event
+
+ used by low-level drivers to dispatch asynchronous events through
+ the midlayer is also safe to call from any context.
+
+Reentrancy
+----------
+
+ All of the methods in struct ib_device exported by a low-level
+ driver must be fully reentrant. The low-level driver is required to
+ perform all synchronization necessary to maintain consistency, even
+ if multiple function calls using the same object are run
+ simultaneously.
+
+ The IB midlayer does not perform any serialization of function calls.
+
+ Because low-level drivers are reentrant, upper level protocol
+ consumers are not required to perform any serialization. However,
+ some serialization may be required to get sensible results. For
+ example, a consumer may safely call ib_poll_cq() on multiple CPUs
+ simultaneously. However, the ordering of the work completion
+ information between different calls of ib_poll_cq() is not defined.
+
+Callbacks
+---------
+
+ A low-level driver must not perform a callback directly from the
+ same callchain as an ib_device method call. For example, it is not
+ allowed for a low-level driver to call a consumer's completion event
+ handler directly from its post_send method. Instead, the low-level
+ driver should defer this callback by, for example, scheduling a
+ tasklet to perform the callback.
+
+ The low-level driver is responsible for ensuring that multiple
+ completion event handlers for the same CQ are not called
+ simultaneously. The driver must guarantee that only one CQ event
+ handler for a given CQ is running at a time. In other words, the
+ following situation is not allowed::
+
+ CPU1 CPU2
+
+ low-level driver ->
+ consumer CQ event callback:
+ /* ... */
+ ib_req_notify_cq(cq, ...);
+ low-level driver ->
+ /* ... */ consumer CQ event callback:
+ /* ... */
+ return from CQ event handler
+
+ The context in which completion event and asynchronous event
+ callbacks run is not defined. Depending on the low-level driver, it
+ may be process context, softirq context, or interrupt context.
+ Upper level protocol consumers may not sleep in a callback.
+
+Hot-plug
+--------
+
+ A low-level driver announces that a device is ready for use by
+ consumers when it calls ib_register_device(), all initialization
+ must be complete before this call. The device must remain usable
+ until the driver's call to ib_unregister_device() has returned.
+
+ A low-level driver must call ib_register_device() and
+ ib_unregister_device() from process context. It must not hold any
+ semaphores that could cause deadlock if a consumer calls back into
+ the driver across these calls.
+
+ An upper level protocol consumer may begin using an IB device as
+ soon as the add method of its struct ib_client is called for that
+ device. A consumer must finish all cleanup and free all resources
+ relating to a device before returning from the remove method.
+
+ A consumer is permitted to sleep in its add and remove methods.
diff --git a/marvell/linux/Documentation/infiniband/index.rst b/marvell/linux/Documentation/infiniband/index.rst
new file mode 100644
index 0000000..9cd7615
--- /dev/null
+++ b/marvell/linux/Documentation/infiniband/index.rst
@@ -0,0 +1,23 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========
+InfiniBand
+==========
+
+.. toctree::
+ :maxdepth: 1
+
+ core_locking
+ ipoib
+ opa_vnic
+ sysfs
+ tag_matching
+ user_mad
+ user_verbs
+
+.. only:: subproject and html
+
+ Indices
+ =======
+
+ * :ref:`genindex`
diff --git a/marvell/linux/Documentation/infiniband/ipoib.rst b/marvell/linux/Documentation/infiniband/ipoib.rst
new file mode 100644
index 0000000..0dd3615
--- /dev/null
+++ b/marvell/linux/Documentation/infiniband/ipoib.rst
@@ -0,0 +1,115 @@
+==================
+IP over InfiniBand
+==================
+
+ The ib_ipoib driver is an implementation of the IP over InfiniBand
+ protocol as specified by RFC 4391 and 4392, issued by the IETF ipoib
+ working group. It is a "native" implementation in the sense of
+ setting the interface type to ARPHRD_INFINIBAND and the hardware
+ address length to 20 (earlier proprietary implementations
+ masqueraded to the kernel as ethernet interfaces).
+
+Partitions and P_Keys
+=====================
+
+ When the IPoIB driver is loaded, it creates one interface for each
+ port using the P_Key at index 0. To create an interface with a
+ different P_Key, write the desired P_Key into the main interface's
+ /sys/class/net/<intf name>/create_child file. For example::
+
+ echo 0x8001 > /sys/class/net/ib0/create_child
+
+ This will create an interface named ib0.8001 with P_Key 0x8001. To
+ remove a subinterface, use the "delete_child" file::
+
+ echo 0x8001 > /sys/class/net/ib0/delete_child
+
+ The P_Key for any interface is given by the "pkey" file, and the
+ main interface for a subinterface is in "parent."
+
+ Child interface create/delete can also be done using IPoIB's
+ rtnl_link_ops, where children created using either way behave the same.
+
+Datagram vs Connected modes
+===========================
+
+ The IPoIB driver supports two modes of operation: datagram and
+ connected. The mode is set and read through an interface's
+ /sys/class/net/<intf name>/mode file.
+
+ In datagram mode, the IB UD (Unreliable Datagram) transport is used
+ and so the interface MTU has is equal to the IB L2 MTU minus the
+ IPoIB encapsulation header (4 bytes). For example, in a typical IB
+ fabric with a 2K MTU, the IPoIB MTU will be 2048 - 4 = 2044 bytes.
+
+ In connected mode, the IB RC (Reliable Connected) transport is used.
+ Connected mode takes advantage of the connected nature of the IB
+ transport and allows an MTU up to the maximal IP packet size of 64K,
+ which reduces the number of IP packets needed for handling large UDP
+ datagrams, TCP segments, etc and increases the performance for large
+ messages.
+
+ In connected mode, the interface's UD QP is still used for multicast
+ and communication with peers that don't support connected mode. In
+ this case, RX emulation of ICMP PMTU packets is used to cause the
+ networking stack to use the smaller UD MTU for these neighbours.
+
+Stateless offloads
+==================
+
+ If the IB HW supports IPoIB stateless offloads, IPoIB advertises
+ TCP/IP checksum and/or Large Send (LSO) offloading capability to the
+ network stack.
+
+ Large Receive (LRO) offloading is also implemented and may be turned
+ on/off using ethtool calls. Currently LRO is supported only for
+ checksum offload capable devices.
+
+ Stateless offloads are supported only in datagram mode.
+
+Interrupt moderation
+====================
+
+ If the underlying IB device supports CQ event moderation, one can
+ use ethtool to set interrupt mitigation parameters and thus reduce
+ the overhead incurred by handling interrupts. The main code path of
+ IPoIB doesn't use events for TX completion signaling so only RX
+ moderation is supported.
+
+Debugging Information
+=====================
+
+ By compiling the IPoIB driver with CONFIG_INFINIBAND_IPOIB_DEBUG set
+ to 'y', tracing messages are compiled into the driver. They are
+ turned on by setting the module parameters debug_level and
+ mcast_debug_level to 1. These parameters can be controlled at
+ runtime through files in /sys/module/ib_ipoib/.
+
+ CONFIG_INFINIBAND_IPOIB_DEBUG also enables files in the debugfs
+ virtual filesystem. By mounting this filesystem, for example with::
+
+ mount -t debugfs none /sys/kernel/debug
+
+ it is possible to get statistics about multicast groups from the
+ files /sys/kernel/debug/ipoib/ib0_mcg and so on.
+
+ The performance impact of this option is negligible, so it
+ is safe to enable this option with debug_level set to 0 for normal
+ operation.
+
+ CONFIG_INFINIBAND_IPOIB_DEBUG_DATA enables even more debug output in
+ the data path when data_debug_level is set to 1. However, even with
+ the output disabled, enabling this configuration option will affect
+ performance, because it adds tests to the fast path.
+
+References
+==========
+
+ Transmission of IP over InfiniBand (IPoIB) (RFC 4391)
+ http://ietf.org/rfc/rfc4391.txt
+
+ IP over InfiniBand (IPoIB) Architecture (RFC 4392)
+ http://ietf.org/rfc/rfc4392.txt
+
+ IP over InfiniBand: Connected Mode (RFC 4755)
+ http://ietf.org/rfc/rfc4755.txt
diff --git a/marvell/linux/Documentation/infiniband/opa_vnic.rst b/marvell/linux/Documentation/infiniband/opa_vnic.rst
new file mode 100644
index 0000000..2f888d9
--- /dev/null
+++ b/marvell/linux/Documentation/infiniband/opa_vnic.rst
@@ -0,0 +1,159 @@
+=================================================================
+Intel Omni-Path (OPA) Virtual Network Interface Controller (VNIC)
+=================================================================
+
+Intel Omni-Path (OPA) Virtual Network Interface Controller (VNIC) feature
+supports Ethernet functionality over Omni-Path fabric by encapsulating
+the Ethernet packets between HFI nodes.
+
+Architecture
+=============
+The patterns of exchanges of Omni-Path encapsulated Ethernet packets
+involves one or more virtual Ethernet switches overlaid on the Omni-Path
+fabric topology. A subset of HFI nodes on the Omni-Path fabric are
+permitted to exchange encapsulated Ethernet packets across a particular
+virtual Ethernet switch. The virtual Ethernet switches are logical
+abstractions achieved by configuring the HFI nodes on the fabric for
+header generation and processing. In the simplest configuration all HFI
+nodes across the fabric exchange encapsulated Ethernet packets over a
+single virtual Ethernet switch. A virtual Ethernet switch, is effectively
+an independent Ethernet network. The configuration is performed by an
+Ethernet Manager (EM) which is part of the trusted Fabric Manager (FM)
+application. HFI nodes can have multiple VNICs each connected to a
+different virtual Ethernet switch. The below diagram presents a case
+of two virtual Ethernet switches with two HFI nodes::
+
+ +-------------------+
+ | Subnet/ |
+ | Ethernet |
+ | Manager |
+ +-------------------+
+ / /
+ / /
+ / /
+ / /
+ +-----------------------------+ +------------------------------+
+ | Virtual Ethernet Switch | | Virtual Ethernet Switch |
+ | +---------+ +---------+ | | +---------+ +---------+ |
+ | | VPORT | | VPORT | | | | VPORT | | VPORT | |
+ +--+---------+----+---------+-+ +-+---------+----+---------+---+
+ | \ / |
+ | \ / |
+ | \/ |
+ | / \ |
+ | / \ |
+ +-----------+------------+ +-----------+------------+
+ | VNIC | VNIC | | VNIC | VNIC |
+ +-----------+------------+ +-----------+------------+
+ | HFI | | HFI |
+ +------------------------+ +------------------------+
+
+
+The Omni-Path encapsulated Ethernet packet format is as described below.
+
+==================== ================================
+Bits Field
+==================== ================================
+Quad Word 0:
+0-19 SLID (lower 20 bits)
+20-30 Length (in Quad Words)
+31 BECN bit
+32-51 DLID (lower 20 bits)
+52-56 SC (Service Class)
+57-59 RC (Routing Control)
+60 FECN bit
+61-62 L2 (=10, 16B format)
+63 LT (=1, Link Transfer Head Flit)
+
+Quad Word 1:
+0-7 L4 type (=0x78 ETHERNET)
+8-11 SLID[23:20]
+12-15 DLID[23:20]
+16-31 PKEY
+32-47 Entropy
+48-63 Reserved
+
+Quad Word 2:
+0-15 Reserved
+16-31 L4 header
+32-63 Ethernet Packet
+
+Quad Words 3 to N-1:
+0-63 Ethernet packet (pad extended)
+
+Quad Word N (last):
+0-23 Ethernet packet (pad extended)
+24-55 ICRC
+56-61 Tail
+62-63 LT (=01, Link Transfer Tail Flit)
+==================== ================================
+
+Ethernet packet is padded on the transmit side to ensure that the VNIC OPA
+packet is quad word aligned. The 'Tail' field contains the number of bytes
+padded. On the receive side the 'Tail' field is read and the padding is
+removed (along with ICRC, Tail and OPA header) before passing packet up
+the network stack.
+
+The L4 header field contains the virtual Ethernet switch id the VNIC port
+belongs to. On the receive side, this field is used to de-multiplex the
+received VNIC packets to different VNIC ports.
+
+Driver Design
+==============
+Intel OPA VNIC software design is presented in the below diagram.
+OPA VNIC functionality has a HW dependent component and a HW
+independent component.
+
+The support has been added for IB device to allocate and free the RDMA
+netdev devices. The RDMA netdev supports interfacing with the network
+stack thus creating standard network interfaces. OPA_VNIC is an RDMA
+netdev device type.
+
+The HW dependent VNIC functionality is part of the HFI1 driver. It
+implements the verbs to allocate and free the OPA_VNIC RDMA netdev.
+It involves HW resource allocation/management for VNIC functionality.
+It interfaces with the network stack and implements the required
+net_device_ops functions. It expects Omni-Path encapsulated Ethernet
+packets in the transmit path and provides HW access to them. It strips
+the Omni-Path header from the received packets before passing them up
+the network stack. It also implements the RDMA netdev control operations.
+
+The OPA VNIC module implements the HW independent VNIC functionality.
+It consists of two parts. The VNIC Ethernet Management Agent (VEMA)
+registers itself with IB core as an IB client and interfaces with the
+IB MAD stack. It exchanges the management information with the Ethernet
+Manager (EM) and the VNIC netdev. The VNIC netdev part allocates and frees
+the OPA_VNIC RDMA netdev devices. It overrides the net_device_ops functions
+set by HW dependent VNIC driver where required to accommodate any control
+operation. It also handles the encapsulation of Ethernet packets with an
+Omni-Path header in the transmit path. For each VNIC interface, the
+information required for encapsulation is configured by the EM via VEMA MAD
+interface. It also passes any control information to the HW dependent driver
+by invoking the RDMA netdev control operations::
+
+ +-------------------+ +----------------------+
+ | | | Linux |
+ | IB MAD | | Network |
+ | | | Stack |
+ +-------------------+ +----------------------+
+ | | |
+ | | |
+ +----------------------------+ |
+ | | |
+ | OPA VNIC Module | |
+ | (OPA VNIC RDMA Netdev | |
+ | & EMA functions) | |
+ | | |
+ +----------------------------+ |
+ | |
+ | |
+ +------------------+ |
+ | IB core | |
+ +------------------+ |
+ | |
+ | |
+ +--------------------------------------------+
+ | |
+ | HFI1 Driver with VNIC support |
+ | |
+ +--------------------------------------------+
diff --git a/marvell/linux/Documentation/infiniband/sysfs.rst b/marvell/linux/Documentation/infiniband/sysfs.rst
new file mode 100644
index 0000000..f0abd6f
--- /dev/null
+++ b/marvell/linux/Documentation/infiniband/sysfs.rst
@@ -0,0 +1,6 @@
+===========
+Sysfs files
+===========
+
+The sysfs interface has moved to
+Documentation/ABI/stable/sysfs-class-infiniband.
diff --git a/marvell/linux/Documentation/infiniband/tag_matching.rst b/marvell/linux/Documentation/infiniband/tag_matching.rst
new file mode 100644
index 0000000..ef56ea5
--- /dev/null
+++ b/marvell/linux/Documentation/infiniband/tag_matching.rst
@@ -0,0 +1,69 @@
+==================
+Tag matching logic
+==================
+
+The MPI standard defines a set of rules, known as tag-matching, for matching
+source send operations to destination receives. The following parameters must
+match the following source and destination parameters:
+
+* Communicator
+* User tag - wild card may be specified by the receiver
+* Source rank – wild car may be specified by the receiver
+* Destination rank – wild
+
+The ordering rules require that when more than one pair of send and receive
+message envelopes may match, the pair that includes the earliest posted-send
+and the earliest posted-receive is the pair that must be used to satisfy the
+matching operation. However, this doesn’t imply that tags are consumed in
+the order they are created, e.g., a later generated tag may be consumed, if
+earlier tags can’t be used to satisfy the matching rules.
+
+When a message is sent from the sender to the receiver, the communication
+library may attempt to process the operation either after or before the
+corresponding matching receive is posted. If a matching receive is posted,
+this is an expected message, otherwise it is called an unexpected message.
+Implementations frequently use different matching schemes for these two
+different matching instances.
+
+To keep MPI library memory footprint down, MPI implementations typically use
+two different protocols for this purpose:
+
+1. The Eager protocol- the complete message is sent when the send is
+processed by the sender. A completion send is received in the send_cq
+notifying that the buffer can be reused.
+
+2. The Rendezvous Protocol - the sender sends the tag-matching header,
+and perhaps a portion of data when first notifying the receiver. When the
+corresponding buffer is posted, the responder will use the information from
+the header to initiate an RDMA READ operation directly to the matching buffer.
+A fin message needs to be received in order for the buffer to be reused.
+
+Tag matching implementation
+===========================
+
+There are two types of matching objects used, the posted receive list and the
+unexpected message list. The application posts receive buffers through calls
+to the MPI receive routines in the posted receive list and posts send messages
+using the MPI send routines. The head of the posted receive list may be
+maintained by the hardware, with the software expected to shadow this list.
+
+When send is initiated and arrives at the receive side, if there is no
+pre-posted receive for this arriving message, it is passed to the software and
+placed in the unexpected message list. Otherwise the match is processed,
+including rendezvous processing, if appropriate, delivering the data to the
+specified receive buffer. This allows overlapping receive-side MPI tag
+matching with computation.
+
+When a receive-message is posted, the communication library will first check
+the software unexpected message list for a matching receive. If a match is
+found, data is delivered to the user buffer, using a software controlled
+protocol. The UCX implementation uses either an eager or rendezvous protocol,
+depending on data size. If no match is found, the entire pre-posted receive
+list is maintained by the hardware, and there is space to add one more
+pre-posted receive to this list, this receive is passed to the hardware.
+Software is expected to shadow this list, to help with processing MPI cancel
+operations. In addition, because hardware and software are not expected to be
+tightly synchronized with respect to the tag-matching operation, this shadow
+list is used to detect the case that a pre-posted receive is passed to the
+hardware, as the matching unexpected message is being passed from the hardware
+to the software.
diff --git a/marvell/linux/Documentation/infiniband/user_mad.rst b/marvell/linux/Documentation/infiniband/user_mad.rst
new file mode 100644
index 0000000..d88abfc
--- /dev/null
+++ b/marvell/linux/Documentation/infiniband/user_mad.rst
@@ -0,0 +1,166 @@
+====================
+Userspace MAD access
+====================
+
+Device files
+============
+
+ Each port of each InfiniBand device has a "umad" device and an
+ "issm" device attached. For example, a two-port HCA will have two
+ umad devices and two issm devices, while a switch will have one
+ device of each type (for switch port 0).
+
+Creating MAD agents
+===================
+
+ A MAD agent can be created by filling in a struct ib_user_mad_reg_req
+ and then calling the IB_USER_MAD_REGISTER_AGENT ioctl on a file
+ descriptor for the appropriate device file. If the registration
+ request succeeds, a 32-bit id will be returned in the structure.
+ For example::
+
+ struct ib_user_mad_reg_req req = { /* ... */ };
+ ret = ioctl(fd, IB_USER_MAD_REGISTER_AGENT, (char *) &req);
+ if (!ret)
+ my_agent = req.id;
+ else
+ perror("agent register");
+
+ Agents can be unregistered with the IB_USER_MAD_UNREGISTER_AGENT
+ ioctl. Also, all agents registered through a file descriptor will
+ be unregistered when the descriptor is closed.
+
+ 2014
+ a new registration ioctl is now provided which allows additional
+ fields to be provided during registration.
+ Users of this registration call are implicitly setting the use of
+ pkey_index (see below).
+
+Receiving MADs
+==============
+
+ MADs are received using read(). The receive side now supports
+ RMPP. The buffer passed to read() must be at least one
+ struct ib_user_mad + 256 bytes. For example:
+
+ If the buffer passed is not large enough to hold the received
+ MAD (RMPP), the errno is set to ENOSPC and the length of the
+ buffer needed is set in mad.length.
+
+ Example for normal MAD (non RMPP) reads::
+
+ struct ib_user_mad *mad;
+ mad = malloc(sizeof *mad + 256);
+ ret = read(fd, mad, sizeof *mad + 256);
+ if (ret != sizeof mad + 256) {
+ perror("read");
+ free(mad);
+ }
+
+ Example for RMPP reads::
+
+ struct ib_user_mad *mad;
+ mad = malloc(sizeof *mad + 256);
+ ret = read(fd, mad, sizeof *mad + 256);
+ if (ret == -ENOSPC)) {
+ length = mad.length;
+ free(mad);
+ mad = malloc(sizeof *mad + length);
+ ret = read(fd, mad, sizeof *mad + length);
+ }
+ if (ret < 0) {
+ perror("read");
+ free(mad);
+ }
+
+ In addition to the actual MAD contents, the other struct ib_user_mad
+ fields will be filled in with information on the received MAD. For
+ example, the remote LID will be in mad.lid.
+
+ If a send times out, a receive will be generated with mad.status set
+ to ETIMEDOUT. Otherwise when a MAD has been successfully received,
+ mad.status will be 0.
+
+ poll()/select() may be used to wait until a MAD can be read.
+
+Sending MADs
+============
+
+ MADs are sent using write(). The agent ID for sending should be
+ filled into the id field of the MAD, the destination LID should be
+ filled into the lid field, and so on. The send side does support
+ RMPP so arbitrary length MAD can be sent. For example::
+
+ struct ib_user_mad *mad;
+
+ mad = malloc(sizeof *mad + mad_length);
+
+ /* fill in mad->data */
+
+ mad->hdr.id = my_agent; /* req.id from agent registration */
+ mad->hdr.lid = my_dest; /* in network byte order... */
+ /* etc. */
+
+ ret = write(fd, &mad, sizeof *mad + mad_length);
+ if (ret != sizeof *mad + mad_length)
+ perror("write");
+
+Transaction IDs
+===============
+
+ Users of the umad devices can use the lower 32 bits of the
+ transaction ID field (that is, the least significant half of the
+ field in network byte order) in MADs being sent to match
+ request/response pairs. The upper 32 bits are reserved for use by
+ the kernel and will be overwritten before a MAD is sent.
+
+P_Key Index Handling
+====================
+
+ The old ib_umad interface did not allow setting the P_Key index for
+ MADs that are sent and did not provide a way for obtaining the P_Key
+ index of received MADs. A new layout for struct ib_user_mad_hdr
+ with a pkey_index member has been defined; however, to preserve binary
+ compatibility with older applications, this new layout will not be used
+ unless one of IB_USER_MAD_ENABLE_PKEY or IB_USER_MAD_REGISTER_AGENT2 ioctl's
+ are called before a file descriptor is used for anything else.
+
+ In September 2008, the IB_USER_MAD_ABI_VERSION will be incremented
+ to 6, the new layout of struct ib_user_mad_hdr will be used by
+ default, and the IB_USER_MAD_ENABLE_PKEY ioctl will be removed.
+
+Setting IsSM Capability Bit
+===========================
+
+ To set the IsSM capability bit for a port, simply open the
+ corresponding issm device file. If the IsSM bit is already set,
+ then the open call will block until the bit is cleared (or return
+ immediately with errno set to EAGAIN if the O_NONBLOCK flag is
+ passed to open()). The IsSM bit will be cleared when the issm file
+ is closed. No read, write or other operations can be performed on
+ the issm file.
+
+/dev files
+==========
+
+ To create the appropriate character device files automatically with
+ udev, a rule like::
+
+ KERNEL=="umad*", NAME="infiniband/%k"
+ KERNEL=="issm*", NAME="infiniband/%k"
+
+ can be used. This will create device nodes named::
+
+ /dev/infiniband/umad0
+ /dev/infiniband/issm0
+
+ for the first port, and so on. The InfiniBand device and port
+ associated with these devices can be determined from the files::
+
+ /sys/class/infiniband_mad/umad0/ibdev
+ /sys/class/infiniband_mad/umad0/port
+
+ and::
+
+ /sys/class/infiniband_mad/issm0/ibdev
+ /sys/class/infiniband_mad/issm0/port
diff --git a/marvell/linux/Documentation/infiniband/user_verbs.rst b/marvell/linux/Documentation/infiniband/user_verbs.rst
new file mode 100644
index 0000000..8ddc4b1
--- /dev/null
+++ b/marvell/linux/Documentation/infiniband/user_verbs.rst
@@ -0,0 +1,75 @@
+======================
+Userspace verbs access
+======================
+
+ The ib_uverbs module, built by enabling CONFIG_INFINIBAND_USER_VERBS,
+ enables direct userspace access to IB hardware via "verbs," as
+ described in chapter 11 of the InfiniBand Architecture Specification.
+
+ To use the verbs, the libibverbs library, available from
+ https://github.com/linux-rdma/rdma-core, is required. libibverbs contains a
+ device-independent API for using the ib_uverbs interface.
+ libibverbs also requires appropriate device-dependent kernel and
+ userspace driver for your InfiniBand hardware. For example, to use
+ a Mellanox HCA, you will need the ib_mthca kernel module and the
+ libmthca userspace driver be installed.
+
+User-kernel communication
+=========================
+
+ Userspace communicates with the kernel for slow path, resource
+ management operations via the /dev/infiniband/uverbsN character
+ devices. Fast path operations are typically performed by writing
+ directly to hardware registers mmap()ed into userspace, with no
+ system call or context switch into the kernel.
+
+ Commands are sent to the kernel via write()s on these device files.
+ The ABI is defined in drivers/infiniband/include/ib_user_verbs.h.
+ The structs for commands that require a response from the kernel
+ contain a 64-bit field used to pass a pointer to an output buffer.
+ Status is returned to userspace as the return value of the write()
+ system call.
+
+Resource management
+===================
+
+ Since creation and destruction of all IB resources is done by
+ commands passed through a file descriptor, the kernel can keep track
+ of which resources are attached to a given userspace context. The
+ ib_uverbs module maintains idr tables that are used to translate
+ between kernel pointers and opaque userspace handles, so that kernel
+ pointers are never exposed to userspace and userspace cannot trick
+ the kernel into following a bogus pointer.
+
+ This also allows the kernel to clean up when a process exits and
+ prevent one process from touching another process's resources.
+
+Memory pinning
+==============
+
+ Direct userspace I/O requires that memory regions that are potential
+ I/O targets be kept resident at the same physical address. The
+ ib_uverbs module manages pinning and unpinning memory regions via
+ get_user_pages() and put_page() calls. It also accounts for the
+ amount of memory pinned in the process's pinned_vm, and checks that
+ unprivileged processes do not exceed their RLIMIT_MEMLOCK limit.
+
+ Pages that are pinned multiple times are counted each time they are
+ pinned, so the value of pinned_vm may be an overestimate of the
+ number of pages pinned by a process.
+
+/dev files
+==========
+
+ To create the appropriate character device files automatically with
+ udev, a rule like::
+
+ KERNEL=="uverbs*", NAME="infiniband/%k"
+
+ can be used. This will create device nodes named::
+
+ /dev/infiniband/uverbs0
+
+ and so on. Since the InfiniBand userspace verbs should be safe for
+ use by non-privileged processes, it may be useful to add an
+ appropriate MODE or GROUP to the udev rule.