docs: rapidio: add it to the driver API

This is actually a subsystem description, with contains both
kAPI and uAPI.

While it should ideally be slplit, let's place it at driver-api,
as most things are related to kAPI and driver-specific info.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

6 files changed, 739 insertions, 0 deletions

diff --git a/Documentation/driver-api/rapidio/index.rst b/Documentation/driver-api/rapidio/index.rst
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+===========================
+The Linux RapidIO Subsystem
+===========================
+
+.. toctree::
+   :maxdepth: 1
+
+   rapidio
+   sysfs
+
+   tsi721
+   mport_cdev
+   rio_cm
diff --git a/Documentation/driver-api/rapidio/mport_cdev.rst b/Documentation/driver-api/rapidio/mport_cdev.rst
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+==================================================================
+RapidIO subsystem mport character device driver (rio_mport_cdev.c)
+==================================================================
+
+1. Overview
+===========
+
+This device driver is the result of collaboration within the RapidIO.org
+Software Task Group (STG) between Texas Instruments, Freescale,
+Prodrive Technologies, Nokia Networks, BAE and IDT.  Additional input was
+received from other members of RapidIO.org. The objective was to create a
+character mode driver interface which exposes the capabilities of RapidIO
+devices directly to applications, in a manner that allows the numerous and
+varied RapidIO implementations to interoperate.
+
+This driver (MPORT_CDEV) provides access to basic RapidIO subsystem operations
+for user-space applications. Most of RapidIO operations are supported through
+'ioctl' system calls.
+
+When loaded this device driver creates filesystem nodes named rio_mportX in /dev
+directory for each registered RapidIO mport device. 'X' in the node name matches
+to unique port ID assigned to each local mport device.
+
+Using available set of ioctl commands user-space applications can perform
+following RapidIO bus and subsystem operations:
+
+- Reads and writes from/to configuration registers of mport devices
+  (RIO_MPORT_MAINT_READ_LOCAL/RIO_MPORT_MAINT_WRITE_LOCAL)
+- Reads and writes from/to configuration registers of remote RapidIO devices.
+  This operations are defined as RapidIO Maintenance reads/writes in RIO spec.
+  (RIO_MPORT_MAINT_READ_REMOTE/RIO_MPORT_MAINT_WRITE_REMOTE)
+- Set RapidIO Destination ID for mport devices (RIO_MPORT_MAINT_HDID_SET)
+- Set RapidIO Component Tag for mport devices (RIO_MPORT_MAINT_COMPTAG_SET)
+- Query logical index of mport devices (RIO_MPORT_MAINT_PORT_IDX_GET)
+- Query capabilities and RapidIO link configuration of mport devices
+  (RIO_MPORT_GET_PROPERTIES)
+- Enable/Disable reporting of RapidIO doorbell events to user-space applications
+  (RIO_ENABLE_DOORBELL_RANGE/RIO_DISABLE_DOORBELL_RANGE)
+- Enable/Disable reporting of RIO port-write events to user-space applications
+  (RIO_ENABLE_PORTWRITE_RANGE/RIO_DISABLE_PORTWRITE_RANGE)
+- Query/Control type of events reported through this driver: doorbells,
+  port-writes or both (RIO_SET_EVENT_MASK/RIO_GET_EVENT_MASK)
+- Configure/Map mport's outbound requests window(s) for specific size,
+  RapidIO destination ID, hopcount and request type
+  (RIO_MAP_OUTBOUND/RIO_UNMAP_OUTBOUND)
+- Configure/Map mport's inbound requests window(s) for specific size,
+  RapidIO base address and local memory base address
+  (RIO_MAP_INBOUND/RIO_UNMAP_INBOUND)
+- Allocate/Free contiguous DMA coherent memory buffer for DMA data transfers
+  to/from remote RapidIO devices (RIO_ALLOC_DMA/RIO_FREE_DMA)
+- Initiate DMA data transfers to/from remote RapidIO devices (RIO_TRANSFER).
+  Supports blocking, asynchronous and posted (a.k.a 'fire-and-forget') data
+  transfer modes.
+- Check/Wait for completion of asynchronous DMA data transfer
+  (RIO_WAIT_FOR_ASYNC)
+- Manage device objects supported by RapidIO subsystem (RIO_DEV_ADD/RIO_DEV_DEL).
+  This allows implementation of various RapidIO fabric enumeration algorithms
+  as user-space applications while using remaining functionality provided by
+  kernel RapidIO subsystem.
+
+2. Hardware Compatibility
+=========================
+
+This device driver uses standard interfaces defined by kernel RapidIO subsystem
+and therefore it can be used with any mport device driver registered by RapidIO
+subsystem with limitations set by available mport implementation.
+
+At this moment the most common limitation is availability of RapidIO-specific
+DMA engine framework for specific mport device. Users should verify available
+functionality of their platform when planning to use this driver:
+
+- IDT Tsi721 PCIe-to-RapidIO bridge device and its mport device driver are fully
+  compatible with this driver.
+- Freescale SoCs 'fsl_rio' mport driver does not have implementation for RapidIO
+  specific DMA engine support and therefore DMA data transfers mport_cdev driver
+  are not available.
+
+3. Module parameters
+====================
+
+- 'dma_timeout'
+      - DMA transfer completion timeout (in msec, default value 3000).
+        This parameter set a maximum completion wait time for SYNC mode DMA
+        transfer requests and for RIO_WAIT_FOR_ASYNC ioctl requests.
+
+- 'dbg_level'
+      - This parameter allows to control amount of debug information
+        generated by this device driver. This parameter is formed by set of
+        bit masks that correspond to the specific functional blocks.
+        For mask definitions see 'drivers/rapidio/devices/rio_mport_cdev.c'
+        This parameter can be changed dynamically.
+        Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level.
+
+4. Known problems
+=================
+
+  None.
+
+5. User-space Applications and API
+==================================
+
+API library and applications that use this device driver are available from
+RapidIO.org.
+
+6. TODO List
+============
+
+- Add support for sending/receiving "raw" RapidIO messaging packets.
+- Add memory mapped DMA data transfers as an option when RapidIO-specific DMA
+  is not available.
diff --git a/Documentation/driver-api/rapidio/rapidio.rst b/Documentation/driver-api/rapidio/rapidio.rst
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+============
+Introduction
+============
+
+The RapidIO standard is a packet-based fabric interconnect standard designed for
+use in embedded systems. Development of the RapidIO standard is directed by the
+RapidIO Trade Association (RTA). The current version of the RapidIO specification
+is publicly available for download from the RTA web-site [1].
+
+This document describes the basics of the Linux RapidIO subsystem and provides
+information on its major components.
+
+1 Overview
+==========
+
+Because the RapidIO subsystem follows the Linux device model it is integrated
+into the kernel similarly to other buses by defining RapidIO-specific device and
+bus types and registering them within the device model.
+
+The Linux RapidIO subsystem is architecture independent and therefore defines
+architecture-specific interfaces that provide support for common RapidIO
+subsystem operations.
+
+2. Core Components
+==================
+
+A typical RapidIO network is a combination of endpoints and switches.
+Each of these components is represented in the subsystem by an associated data
+structure. The core logical components of the RapidIO subsystem are defined
+in include/linux/rio.h file.
+
+2.1 Master Port
+---------------
+
+A master port (or mport) is a RapidIO interface controller that is local to the
+processor executing the Linux code. A master port generates and receives RapidIO
+packets (transactions). In the RapidIO subsystem each master port is represented
+by a rio_mport data structure. This structure contains master port specific
+resources such as mailboxes and doorbells. The rio_mport also includes a unique
+host device ID that is valid when a master port is configured as an enumerating
+host.
+
+RapidIO master ports are serviced by subsystem specific mport device drivers
+that provide functionality defined for this subsystem. To provide a hardware
+independent interface for RapidIO subsystem operations, rio_mport structure
+includes rio_ops data structure which contains pointers to hardware specific
+implementations of RapidIO functions.
+
+2.2 Device
+----------
+
+A RapidIO device is any endpoint (other than mport) or switch in the network.
+All devices are presented in the RapidIO subsystem by corresponding rio_dev data
+structure. Devices form one global device list and per-network device lists
+(depending on number of available mports and networks).
+
+2.3 Switch
+----------
+
+A RapidIO switch is a special class of device that routes packets between its
+ports towards their final destination. The packet destination port within a
+switch is defined by an internal routing table. A switch is presented in the
+RapidIO subsystem by rio_dev data structure expanded by additional rio_switch
+data structure, which contains switch specific information such as copy of the
+routing table and pointers to switch specific functions.
+
+The RapidIO subsystem defines the format and initialization method for subsystem
+specific switch drivers that are designed to provide hardware-specific
+implementation of common switch management routines.
+
+2.4 Network
+-----------
+
+A RapidIO network is a combination of interconnected endpoint and switch devices.
+Each RapidIO network known to the system is represented by corresponding rio_net
+data structure. This structure includes lists of all devices and local master
+ports that form the same network. It also contains a pointer to the default
+master port that is used to communicate with devices within the network.
+
+2.5 Device Drivers
+------------------
+
+RapidIO device-specific drivers follow Linux Kernel Driver Model and are
+intended to support specific RapidIO devices attached to the RapidIO network.
+
+2.6 Subsystem Interfaces
+------------------------
+
+RapidIO interconnect specification defines features that may be used to provide
+one or more common service layers for all participating RapidIO devices. These
+common services may act separately from device-specific drivers or be used by
+device-specific drivers. Example of such service provider is the RIONET driver
+which implements Ethernet-over-RapidIO interface. Because only one driver can be
+registered for a device, all common RapidIO services have to be registered as
+subsystem interfaces. This allows to have multiple common services attached to
+the same device without blocking attachment of a device-specific driver.
+
+3. Subsystem Initialization
+===========================
+
+In order to initialize the RapidIO subsystem, a platform must initialize and
+register at least one master port within the RapidIO network. To register mport
+within the subsystem controller driver's initialization code calls function
+rio_register_mport() for each available master port.
+
+After all active master ports are registered with a RapidIO subsystem,
+an enumeration and/or discovery routine may be called automatically or
+by user-space command.
+
+RapidIO subsystem can be configured to be built as a statically linked or
+modular component of the kernel (see details below).
+
+4. Enumeration and Discovery
+============================
+
+4.1 Overview
+------------
+
+RapidIO subsystem configuration options allow users to build enumeration and
+discovery methods as statically linked components or loadable modules.
+An enumeration/discovery method implementation and available input parameters
+define how any given method can be attached to available RapidIO mports:
+simply to all available mports OR individually to the specified mport device.
+
+Depending on selected enumeration/discovery build configuration, there are
+several methods to initiate an enumeration and/or discovery process:
+
+  (a) Statically linked enumeration and discovery process can be started
+  automatically during kernel initialization time using corresponding module
+  parameters. This was the original method used since introduction of RapidIO
+  subsystem. Now this method relies on enumerator module parameter which is
+  'rio-scan.scan' for existing basic enumeration/discovery method.
+  When automatic start of enumeration/discovery is used a user has to ensure
+  that all discovering endpoints are started before the enumerating endpoint
+  and are waiting for enumeration to be completed.
+  Configuration option CONFIG_RAPIDIO_DISC_TIMEOUT defines time that discovering
+  endpoint waits for enumeration to be completed. If the specified timeout
+  expires the discovery process is terminated without obtaining RapidIO network
+  information. NOTE: a timed out discovery process may be restarted later using
+  a user-space command as it is described below (if the given endpoint was
+  enumerated successfully).
+
+  (b) Statically linked enumeration and discovery process can be started by
+  a command from user space. This initiation method provides more flexibility
+  for a system startup compared to the option (a) above. After all participating
+  endpoints have been successfully booted, an enumeration process shall be
+  started first by issuing a user-space command, after an enumeration is
+  completed a discovery process can be started on all remaining endpoints.
+
+  (c) Modular enumeration and discovery process can be started by a command from
+  user space. After an enumeration/discovery module is loaded, a network scan
+  process can be started by issuing a user-space command.
+  Similar to the option (b) above, an enumerator has to be started first.
+
+  (d) Modular enumeration and discovery process can be started by a module
+  initialization routine. In this case an enumerating module shall be loaded
+  first.
+
+When a network scan process is started it calls an enumeration or discovery
+routine depending on the configured role of a master port: host or agent.
+
+Enumeration is performed by a master port if it is configured as a host port by
+assigning a host destination ID greater than or equal to zero. The host
+destination ID can be assigned to a master port using various methods depending
+on RapidIO subsystem build configuration:
+
+  (a) For a statically linked RapidIO subsystem core use command line parameter
+  "rapidio.hdid=" with a list of destination ID assignments in order of mport
+  device registration. For example, in a system with two RapidIO controllers
+  the command line parameter "rapidio.hdid=-1,7" will result in assignment of
+  the host destination ID=7 to the second RapidIO controller, while the first
+  one will be assigned destination ID=-1.
+
+  (b) If the RapidIO subsystem core is built as a loadable module, in addition
+  to the method shown above, the host destination ID(s) can be specified using
+  traditional methods of passing module parameter "hdid=" during its loading:
+
+  - from command line: "modprobe rapidio hdid=-1,7", or
+  - from modprobe configuration file using configuration command "options",
+    like in this example: "options rapidio hdid=-1,7". An example of modprobe
+    configuration file is provided in the section below.
+
+NOTES:
+  (i) if "hdid=" parameter is omitted all available mport will be assigned
+  destination ID = -1;
+
+  (ii) the "hdid=" parameter in systems with multiple mports can have
+  destination ID assignments omitted from the end of list (default = -1).
+
+If the host device ID for a specific master port is set to -1, the discovery
+process will be performed for it.
+
+The enumeration and discovery routines use RapidIO maintenance transactions
+to access the configuration space of devices.
+
+NOTE: If RapidIO switch-specific device drivers are built as loadable modules
+they must be loaded before enumeration/discovery process starts.
+This requirement is cased by the fact that enumeration/discovery methods invoke
+vendor-specific callbacks on early stages.
+
+4.2 Automatic Start of Enumeration and Discovery
+------------------------------------------------
+
+Automatic enumeration/discovery start method is applicable only to built-in
+enumeration/discovery RapidIO configuration selection. To enable automatic
+enumeration/discovery start by existing basic enumerator method set use boot
+command line parameter "rio-scan.scan=1".
+
+This configuration requires synchronized start of all RapidIO endpoints that
+form a network which will be enumerated/discovered. Discovering endpoints have
+to be started before an enumeration starts to ensure that all RapidIO
+controllers have been initialized and are ready to be discovered. Configuration
+parameter CONFIG_RAPIDIO_DISC_TIMEOUT defines time (in seconds) which
+a discovering endpoint will wait for enumeration to be completed.
+
+When automatic enumeration/discovery start is selected, basic method's
+initialization routine calls rio_init_mports() to perform enumeration or
+discovery for all known mport devices.
+
+Depending on RapidIO network size and configuration this automatic
+enumeration/discovery start method may be difficult to use due to the
+requirement for synchronized start of all endpoints.
+
+4.3 User-space Start of Enumeration and Discovery
+-------------------------------------------------
+
+User-space start of enumeration and discovery can be used with built-in and
+modular build configurations. For user-space controlled start RapidIO subsystem
+creates the sysfs write-only attribute file '/sys/bus/rapidio/scan'. To initiate
+an enumeration or discovery process on specific mport device, a user needs to
+write mport_ID (not RapidIO destination ID) into that file. The mport_ID is a
+sequential number (0 ... RIO_MAX_MPORTS) assigned during mport device
+registration. For example for machine with single RapidIO controller, mport_ID
+for that controller always will be 0.
+
+To initiate RapidIO enumeration/discovery on all available mports a user may
+write '-1' (or RIO_MPORT_ANY) into the scan attribute file.
+
+4.4 Basic Enumeration Method
+----------------------------
+
+This is an original enumeration/discovery method which is available since
+first release of RapidIO subsystem code. The enumeration process is
+implemented according to the enumeration algorithm outlined in the RapidIO
+Interconnect Specification: Annex I [1].
+
+This method can be configured as statically linked or loadable module.
+The method's single parameter "scan" allows to trigger the enumeration/discovery
+process from module initialization routine.
+
+This enumeration/discovery method can be started only once and does not support
+unloading if it is built as a module.
+
+The enumeration process traverses the network using a recursive depth-first
+algorithm. When a new device is found, the enumerator takes ownership of that
+device by writing into the Host Device ID Lock CSR. It does this to ensure that
+the enumerator has exclusive right to enumerate the device. If device ownership
+is successfully acquired, the enumerator allocates a new rio_dev structure and
+initializes it according to device capabilities.
+
+If the device is an endpoint, a unique device ID is assigned to it and its value
+is written into the device's Base Device ID CSR.
+
+If the device is a switch, the enumerator allocates an additional rio_switch
+structure to store switch specific information. Then the switch's vendor ID and
+device ID are queried against a table of known RapidIO switches. Each switch
+table entry contains a pointer to a switch-specific initialization routine that
+initializes pointers to the rest of switch specific operations, and performs
+hardware initialization if necessary. A RapidIO switch does not have a unique
+device ID; it relies on hopcount and routing for device ID of an attached
+endpoint if access to its configuration registers is required. If a switch (or
+chain of switches) does not have any endpoint (except enumerator) attached to
+it, a fake device ID will be assigned to configure a route to that switch.
+In the case of a chain of switches without endpoint, one fake device ID is used
+to configure a route through the entire chain and switches are differentiated by
+their hopcount value.
+
+For both endpoints and switches the enumerator writes a unique component tag
+into device's Component Tag CSR. That unique value is used by the error
+management notification mechanism to identify a device that is reporting an
+error management event.
+
+Enumeration beyond a switch is completed by iterating over each active egress
+port of that switch. For each active link, a route to a default device ID
+(0xFF for 8-bit systems and 0xFFFF for 16-bit systems) is temporarily written
+into the routing table. The algorithm recurs by calling itself with hopcount + 1
+and the default device ID in order to access the device on the active port.
+
+After the host has completed enumeration of the entire network it releases
+devices by clearing device ID locks (calls rio_clear_locks()). For each endpoint
+in the system, it sets the Discovered bit in the Port General Control CSR
+to indicate that enumeration is completed and agents are allowed to execute
+passive discovery of the network.
+
+The discovery process is performed by agents and is similar to the enumeration
+process that is described above. However, the discovery process is performed
+without changes to the existing routing because agents only gather information
+about RapidIO network structure and are building an internal map of discovered
+devices. This way each Linux-based component of the RapidIO subsystem has
+a complete view of the network. The discovery process can be performed
+simultaneously by several agents. After initializing its RapidIO master port
+each agent waits for enumeration completion by the host for the configured wait
+time period. If this wait time period expires before enumeration is completed,
+an agent skips RapidIO discovery and continues with remaining kernel
+initialization.
+
+4.5 Adding New Enumeration/Discovery Method
+-------------------------------------------
+
+RapidIO subsystem code organization allows addition of new enumeration/discovery
+methods as new configuration options without significant impact to the core
+RapidIO code.
+
+A new enumeration/discovery method has to be attached to one or more mport
+devices before an enumeration/discovery process can be started. Normally,
+method's module initialization routine calls rio_register_scan() to attach
+an enumerator to a specified mport device (or devices). The basic enumerator
+implementation demonstrates this process.
+
+4.6 Using Loadable RapidIO Switch Drivers
+-----------------------------------------
+
+In the case when RapidIO switch drivers are built as loadable modules a user
+must ensure that they are loaded before the enumeration/discovery starts.
+This process can be automated by specifying pre- or post- dependencies in the
+RapidIO-specific modprobe configuration file as shown in the example below.
+
+File /etc/modprobe.d/rapidio.conf::
+
+  # Configure RapidIO subsystem modules
+
+  # Set enumerator host destination ID (overrides kernel command line option)
+  options rapidio hdid=-1,2
+
+  # Load RapidIO switch drivers immediately after rapidio core module was loaded
+  softdep rapidio post: idt_gen2 idtcps tsi57x
+
+  # OR :
+
+  # Load RapidIO switch drivers just before rio-scan enumerator module is loaded
+  softdep rio-scan pre: idt_gen2 idtcps tsi57x
+
+  --------------------------
+
+NOTE:
+  In the example above, one of "softdep" commands must be removed or
+  commented out to keep required module loading sequence.
+
+5. References
+=============
+
+[1] RapidIO Trade Association. RapidIO Interconnect Specifications.
+    http://www.rapidio.org.
+
+[2] Rapidio TA. Technology Comparisons.
+    http://www.rapidio.org/education/technology_comparisons/
+
+[3] RapidIO support for Linux.
+    http://lwn.net/Articles/139118/
+
+[4] Matt Porter. RapidIO for Linux. Ottawa Linux Symposium, 2005
+    http://www.kernel.org/doc/ols/2005/ols2005v2-pages-43-56.pdf
diff --git a/Documentation/driver-api/rapidio/rio_cm.rst b/Documentation/driver-api/rapidio/rio_cm.rst
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+==========================================================================
+RapidIO subsystem Channelized Messaging character device driver (rio_cm.c)
+==========================================================================
+
+
+1. Overview
+===========
+
+This device driver is the result of collaboration within the RapidIO.org
+Software Task Group (STG) between Texas Instruments, Prodrive Technologies,
+Nokia Networks, BAE and IDT.  Additional input was received from other members
+of RapidIO.org.
+
+The objective was to create a character mode driver interface which exposes
+messaging capabilities of RapidIO endpoint devices (mports) directly
+to applications, in a manner that allows the numerous and varied RapidIO
+implementations to interoperate.
+
+This driver (RIO_CM) provides to user-space applications shared access to
+RapidIO mailbox messaging resources.
+
+RapidIO specification (Part 2) defines that endpoint devices may have up to four
+messaging mailboxes in case of multi-packet message (up to 4KB) and
+up to 64 mailboxes if single-packet messages (up to 256 B) are used. In addition
+to protocol definition limitations, a particular hardware implementation can
+have reduced number of messaging mailboxes.  RapidIO aware applications must
+therefore share the messaging resources of a RapidIO endpoint.
+
+Main purpose of this device driver is to provide RapidIO mailbox messaging
+capability to large number of user-space processes by introducing socket-like
+operations using a single messaging mailbox.  This allows applications to
+use the limited RapidIO messaging hardware resources efficiently.
+
+Most of device driver's operations are supported through 'ioctl' system calls.
+
+When loaded this device driver creates a single file system node named rio_cm
+in /dev directory common for all registered RapidIO mport devices.
+
+Following ioctl commands are available to user-space applications:
+
+- RIO_CM_MPORT_GET_LIST:
+    Returns to caller list of local mport devices that
+    support messaging operations (number of entries up to RIO_MAX_MPORTS).
+    Each list entry is combination of mport's index in the system and RapidIO
+    destination ID assigned to the port.
+- RIO_CM_EP_GET_LIST_SIZE:
+    Returns number of messaging capable remote endpoints
+    in a RapidIO network associated with the specified mport device.
+- RIO_CM_EP_GET_LIST:
+    Returns list of RapidIO destination IDs for messaging
+    capable remote endpoints (peers) available in a RapidIO network associated
+    with the specified mport device.
+- RIO_CM_CHAN_CREATE:
+    Creates RapidIO message exchange channel data structure
+    with channel ID assigned automatically or as requested by a caller.
+- RIO_CM_CHAN_BIND:
+    Binds the specified channel data structure to the specified
+    mport device.
+- RIO_CM_CHAN_LISTEN:
+    Enables listening for connection requests on the specified
+    channel.
+- RIO_CM_CHAN_ACCEPT:
+    Accepts a connection request from peer on the specified
+    channel. If wait timeout for this request is specified by a caller it is
+    a blocking call. If timeout set to 0 this is non-blocking call - ioctl
+    handler checks for a pending connection request and if one is not available
+    exits with -EGAIN error status immediately.
+- RIO_CM_CHAN_CONNECT:
+    Sends a connection request to a remote peer/channel.
+- RIO_CM_CHAN_SEND:
+    Sends a data message through the specified channel.
+    The handler for this request assumes that message buffer specified by
+    a caller includes the reserved space for a packet header required by
+    this driver.
+- RIO_CM_CHAN_RECEIVE:
+    Receives a data message through a connected channel.
+    If the channel does not have an incoming message ready to return this ioctl
+    handler will wait for new message until timeout specified by a caller
+    expires. If timeout value is set to 0, ioctl handler uses a default value
+    defined by MAX_SCHEDULE_TIMEOUT.
+- RIO_CM_CHAN_CLOSE:
+    Closes a specified channel and frees associated buffers.
+    If the specified channel is in the CONNECTED state, sends close notification
+    to the remote peer.
+
+The ioctl command codes and corresponding data structures intended for use by
+user-space applications are defined in 'include/uapi/linux/rio_cm_cdev.h'.
+
+2. Hardware Compatibility
+=========================
+
+This device driver uses standard interfaces defined by kernel RapidIO subsystem
+and therefore it can be used with any mport device driver registered by RapidIO
+subsystem with limitations set by available mport HW implementation of messaging
+mailboxes.
+
+3. Module parameters
+====================
+
+- 'dbg_level'
+      - This parameter allows to control amount of debug information
+        generated by this device driver. This parameter is formed by set of
+        bit masks that correspond to the specific functional block.
+        For mask definitions see 'drivers/rapidio/devices/rio_cm.c'
+        This parameter can be changed dynamically.
+        Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level.
+
+- 'cmbox'
+      - Number of RapidIO mailbox to use (default value is 1).
+        This parameter allows to set messaging mailbox number that will be used
+        within entire RapidIO network. It can be used when default mailbox is
+        used by other device drivers or is not supported by some nodes in the
+        RapidIO network.
+
+- 'chstart'
+      - Start channel number for dynamic assignment. Default value - 256.
+        Allows to exclude channel numbers below this parameter from dynamic
+        allocation to avoid conflicts with software components that use
+        reserved predefined channel numbers.
+
+4. Known problems
+=================
+
+  None.
+
+5. User-space Applications and API Library
+==========================================
+
+Messaging API library and applications that use this device driver are available
+from RapidIO.org.
+
+6. TODO List
+============
+
+- Add support for system notification messages (reserved channel 0).
diff --git a/Documentation/driver-api/rapidio/sysfs.rst b/Documentation/driver-api/rapidio/sysfs.rst
new file mode 100644
index 000000000000..540f72683496
--- /dev/null
+++ b/Documentation/driver-api/rapidio/sysfs.rst
@@ -0,0 +1,7 @@
+=============
+Sysfs entries
+=============
+
+The RapidIO sysfs files have moved to:
+Documentation/ABI/testing/sysfs-bus-rapidio and
+Documentation/ABI/testing/sysfs-class-rapidio
diff --git a/Documentation/driver-api/rapidio/tsi721.rst b/Documentation/driver-api/rapidio/tsi721.rst
new file mode 100644
index 000000000000..42aea438cd20
--- /dev/null
+++ b/Documentation/driver-api/rapidio/tsi721.rst
@@ -0,0 +1,112 @@
+=========================================================================
+RapidIO subsystem mport driver for IDT Tsi721 PCI Express-to-SRIO bridge.
+=========================================================================
+
+1. Overview
+===========
+
+This driver implements all currently defined RapidIO mport callback functions.
+It supports maintenance read and write operations, inbound and outbound RapidIO
+doorbells, inbound maintenance port-writes and RapidIO messaging.
+
+To generate SRIO maintenance transactions this driver uses one of Tsi721 DMA
+channels. This mechanism provides access to larger range of hop counts and
+destination IDs without need for changes in outbound window translation.
+
+RapidIO messaging support uses dedicated messaging channels for each mailbox.
+For inbound messages this driver uses destination ID matching to forward messages
+into the corresponding message queue. Messaging callbacks are implemented to be
+fully compatible with RIONET driver (Ethernet over RapidIO messaging services).
+
+1. Module parameters:
+
+- 'dbg_level'
+      - This parameter allows to control amount of debug information
+        generated by this device driver. This parameter is formed by set of
+        This parameter can be changed bit masks that correspond to the specific
+        functional block.
+        For mask definitions see 'drivers/rapidio/devices/tsi721.h'
+        This parameter can be changed dynamically.
+        Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level.
+
+- 'dma_desc_per_channel'
+      - This parameter defines number of hardware buffer
+        descriptors allocated for each registered Tsi721 DMA channel.
+        Its default value is 128.
+
+- 'dma_txqueue_sz'
+      - DMA transactions queue size. Defines number of pending
+        transaction requests that can be accepted by each DMA channel.
+        Default value is 16.
+
+- 'dma_sel'
+      - DMA channel selection mask. Bitmask that defines which hardware
+        DMA channels (0 ... 6) will be registered with DmaEngine core.
+        If bit is set to 1, the corresponding DMA channel will be registered.
+        DMA channels not selected by this mask will not be used by this device
+        driver. Default value is 0x7f (use all channels).
+
+- 'pcie_mrrs'
+      - override value for PCIe Maximum Read Request Size (MRRS).
+        This parameter gives an ability to override MRRS value set during PCIe
+        configuration process. Tsi721 supports read request sizes up to 4096B.
+        Value for this parameter must be set as defined by PCIe specification:
+        0 = 128B, 1 = 256B, 2 = 512B, 3 = 1024B, 4 = 2048B and 5 = 4096B.
+        Default value is '-1' (= keep platform setting).
+
+- 'mbox_sel'
+      - RIO messaging MBOX selection mask. This is a bitmask that defines
+        messaging MBOXes are managed by this device driver. Mask bits 0 - 3
+        correspond to MBOX0 - MBOX3. MBOX is under driver's control if the
+        corresponding bit is set to '1'. Default value is 0x0f (= all).
+
+2. Known problems
+=================
+
+  None.
+
+3. DMA Engine Support
+=====================
+
+Tsi721 mport driver supports DMA data transfers between local system memory and
+remote RapidIO devices. This functionality is implemented according to SLAVE
+mode API defined by common Linux kernel DMA Engine framework.
+
+Depending on system requirements RapidIO DMA operations can be included/excluded
+by setting CONFIG_RAPIDIO_DMA_ENGINE option. Tsi721 miniport driver uses seven
+out of eight available BDMA channels to support DMA data transfers.
+One BDMA channel is reserved for generation of maintenance read/write requests.
+
+If Tsi721 mport driver have been built with RAPIDIO_DMA_ENGINE support included,
+this driver will accept DMA-specific module parameter:
+
+  "dma_desc_per_channel"
+			 - defines number of hardware buffer descriptors used by
+                           each BDMA channel of Tsi721 (by default - 128).
+
+4. Version History
+
+  =====   ====================================================================
+  1.1.0   DMA operations re-worked to support data scatter/gather lists larger
+          than hardware buffer descriptors ring.
+  1.0.0   Initial driver release.
+  =====   ====================================================================
+
+5.  License
+===========
+
+  Copyright(c) 2011 Integrated Device Technology, Inc. All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by the Free
+  Software Foundation; either version 2 of the License, or (at your option)
+  any later version.
+
+  This program is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+  more details.
+
+  You should have received a copy of the GNU General Public License along with
+  this program; if not, write to the Free Software Foundation, Inc.,
+  59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.