1 ============================================== 1 ==========================================================================
2 RapidIO subsystem Channelized Messaging charac 2 RapidIO subsystem Channelized Messaging character device driver (rio_cm.c)
3 ============================================== 3 ==========================================================================
4 4
5 5
6 1. Overview 6 1. Overview
7 =========== 7 ===========
8 8
9 This device driver is the result of collaborat 9 This device driver is the result of collaboration within the RapidIO.org
10 Software Task Group (STG) between Texas Instru 10 Software Task Group (STG) between Texas Instruments, Prodrive Technologies,
11 Nokia Networks, BAE and IDT. Additional input 11 Nokia Networks, BAE and IDT. Additional input was received from other members
12 of RapidIO.org. 12 of RapidIO.org.
13 13
14 The objective was to create a character mode d 14 The objective was to create a character mode driver interface which exposes
15 messaging capabilities of RapidIO endpoint dev 15 messaging capabilities of RapidIO endpoint devices (mports) directly
16 to applications, in a manner that allows the n 16 to applications, in a manner that allows the numerous and varied RapidIO
17 implementations to interoperate. 17 implementations to interoperate.
18 18
19 This driver (RIO_CM) provides to user-space ap 19 This driver (RIO_CM) provides to user-space applications shared access to
20 RapidIO mailbox messaging resources. 20 RapidIO mailbox messaging resources.
21 21
22 RapidIO specification (Part 2) defines that en 22 RapidIO specification (Part 2) defines that endpoint devices may have up to four
23 messaging mailboxes in case of multi-packet me 23 messaging mailboxes in case of multi-packet message (up to 4KB) and
24 up to 64 mailboxes if single-packet messages ( 24 up to 64 mailboxes if single-packet messages (up to 256 B) are used. In addition
25 to protocol definition limitations, a particul 25 to protocol definition limitations, a particular hardware implementation can
26 have reduced number of messaging mailboxes. R 26 have reduced number of messaging mailboxes. RapidIO aware applications must
27 therefore share the messaging resources of a R 27 therefore share the messaging resources of a RapidIO endpoint.
28 28
29 Main purpose of this device driver is to provi 29 Main purpose of this device driver is to provide RapidIO mailbox messaging
30 capability to large number of user-space proce 30 capability to large number of user-space processes by introducing socket-like
31 operations using a single messaging mailbox. 31 operations using a single messaging mailbox. This allows applications to
32 use the limited RapidIO messaging hardware res 32 use the limited RapidIO messaging hardware resources efficiently.
33 33
34 Most of device driver's operations are support 34 Most of device driver's operations are supported through 'ioctl' system calls.
35 35
36 When loaded this device driver creates a singl 36 When loaded this device driver creates a single file system node named rio_cm
37 in /dev directory common for all registered Ra 37 in /dev directory common for all registered RapidIO mport devices.
38 38
39 Following ioctl commands are available to user 39 Following ioctl commands are available to user-space applications:
40 40
41 - RIO_CM_MPORT_GET_LIST: 41 - RIO_CM_MPORT_GET_LIST:
42 Returns to caller list of local mport devi 42 Returns to caller list of local mport devices that
43 support messaging operations (number of en 43 support messaging operations (number of entries up to RIO_MAX_MPORTS).
44 Each list entry is combination of mport's 44 Each list entry is combination of mport's index in the system and RapidIO
45 destination ID assigned to the port. 45 destination ID assigned to the port.
46 - RIO_CM_EP_GET_LIST_SIZE: 46 - RIO_CM_EP_GET_LIST_SIZE:
47 Returns number of messaging capable remote 47 Returns number of messaging capable remote endpoints
48 in a RapidIO network associated with the s 48 in a RapidIO network associated with the specified mport device.
49 - RIO_CM_EP_GET_LIST: 49 - RIO_CM_EP_GET_LIST:
50 Returns list of RapidIO destination IDs fo 50 Returns list of RapidIO destination IDs for messaging
51 capable remote endpoints (peers) available 51 capable remote endpoints (peers) available in a RapidIO network associated
52 with the specified mport device. 52 with the specified mport device.
53 - RIO_CM_CHAN_CREATE: 53 - RIO_CM_CHAN_CREATE:
54 Creates RapidIO message exchange channel d 54 Creates RapidIO message exchange channel data structure
55 with channel ID assigned automatically or 55 with channel ID assigned automatically or as requested by a caller.
56 - RIO_CM_CHAN_BIND: 56 - RIO_CM_CHAN_BIND:
57 Binds the specified channel data structure 57 Binds the specified channel data structure to the specified
58 mport device. 58 mport device.
59 - RIO_CM_CHAN_LISTEN: 59 - RIO_CM_CHAN_LISTEN:
60 Enables listening for connection requests 60 Enables listening for connection requests on the specified
61 channel. 61 channel.
62 - RIO_CM_CHAN_ACCEPT: 62 - RIO_CM_CHAN_ACCEPT:
63 Accepts a connection request from peer on 63 Accepts a connection request from peer on the specified
64 channel. If wait timeout for this request 64 channel. If wait timeout for this request is specified by a caller it is
65 a blocking call. If timeout set to 0 this 65 a blocking call. If timeout set to 0 this is non-blocking call - ioctl
66 handler checks for a pending connection re 66 handler checks for a pending connection request and if one is not available
67 exits with -EGAIN error status immediately 67 exits with -EGAIN error status immediately.
68 - RIO_CM_CHAN_CONNECT: 68 - RIO_CM_CHAN_CONNECT:
69 Sends a connection request to a remote pee 69 Sends a connection request to a remote peer/channel.
70 - RIO_CM_CHAN_SEND: 70 - RIO_CM_CHAN_SEND:
71 Sends a data message through the specified 71 Sends a data message through the specified channel.
72 The handler for this request assumes that 72 The handler for this request assumes that message buffer specified by
73 a caller includes the reserved space for a 73 a caller includes the reserved space for a packet header required by
74 this driver. 74 this driver.
75 - RIO_CM_CHAN_RECEIVE: 75 - RIO_CM_CHAN_RECEIVE:
76 Receives a data message through a connecte 76 Receives a data message through a connected channel.
77 If the channel does not have an incoming m 77 If the channel does not have an incoming message ready to return this ioctl
78 handler will wait for new message until ti 78 handler will wait for new message until timeout specified by a caller
79 expires. If timeout value is set to 0, ioc 79 expires. If timeout value is set to 0, ioctl handler uses a default value
80 defined by MAX_SCHEDULE_TIMEOUT. 80 defined by MAX_SCHEDULE_TIMEOUT.
81 - RIO_CM_CHAN_CLOSE: 81 - RIO_CM_CHAN_CLOSE:
82 Closes a specified channel and frees assoc 82 Closes a specified channel and frees associated buffers.
83 If the specified channel is in the CONNECT 83 If the specified channel is in the CONNECTED state, sends close notification
84 to the remote peer. 84 to the remote peer.
85 85
86 The ioctl command codes and corresponding data 86 The ioctl command codes and corresponding data structures intended for use by
87 user-space applications are defined in 'includ 87 user-space applications are defined in 'include/uapi/linux/rio_cm_cdev.h'.
88 88
89 2. Hardware Compatibility 89 2. Hardware Compatibility
90 ========================= 90 =========================
91 91
92 This device driver uses standard interfaces de 92 This device driver uses standard interfaces defined by kernel RapidIO subsystem
93 and therefore it can be used with any mport de 93 and therefore it can be used with any mport device driver registered by RapidIO
94 subsystem with limitations set by available mp 94 subsystem with limitations set by available mport HW implementation of messaging
95 mailboxes. 95 mailboxes.
96 96
97 3. Module parameters 97 3. Module parameters
98 ==================== 98 ====================
99 99
100 - 'dbg_level' 100 - 'dbg_level'
101 - This parameter allows to control amoun 101 - This parameter allows to control amount of debug information
102 generated by this device driver. This 102 generated by this device driver. This parameter is formed by set of
103 bit masks that correspond to the speci 103 bit masks that correspond to the specific functional block.
104 For mask definitions see 'drivers/rapi 104 For mask definitions see 'drivers/rapidio/devices/rio_cm.c'
105 This parameter can be changed dynamica 105 This parameter can be changed dynamically.
106 Use CONFIG_RAPIDIO_DEBUG=y to enable d 106 Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level.
107 107
108 - 'cmbox' 108 - 'cmbox'
109 - Number of RapidIO mailbox to use (defa 109 - Number of RapidIO mailbox to use (default value is 1).
110 This parameter allows to set messaging 110 This parameter allows to set messaging mailbox number that will be used
111 within entire RapidIO network. It can 111 within entire RapidIO network. It can be used when default mailbox is
112 used by other device drivers or is not 112 used by other device drivers or is not supported by some nodes in the
113 RapidIO network. 113 RapidIO network.
114 114
115 - 'chstart' 115 - 'chstart'
116 - Start channel number for dynamic assig 116 - Start channel number for dynamic assignment. Default value - 256.
117 Allows to exclude channel numbers belo 117 Allows to exclude channel numbers below this parameter from dynamic
118 allocation to avoid conflicts with sof 118 allocation to avoid conflicts with software components that use
119 reserved predefined channel numbers. 119 reserved predefined channel numbers.
120 120
121 4. Known problems 121 4. Known problems
122 ================= 122 =================
123 123
124 None. 124 None.
125 125
126 5. User-space Applications and API Library 126 5. User-space Applications and API Library
127 ========================================== 127 ==========================================
128 128
129 Messaging API library and applications that us 129 Messaging API library and applications that use this device driver are available
130 from RapidIO.org. 130 from RapidIO.org.
131 131
132 6. TODO List 132 6. TODO List
133 ============ 133 ============
134 134
135 - Add support for system notification messages 135 - Add support for system notification messages (reserved channel 0).
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