1RapidIO subsystem mport character device driver (rio_mport_cdev.c)
2==================================================================
3
4Version History:
5----------------
6  1.0.0 - Initial driver release.
7
8==================================================================
9
10I. Overview
11
12This device driver is the result of collaboration within the RapidIO.org
13Software Task Group (STG) between Texas Instruments, Freescale,
14Prodrive Technologies, Nokia Networks, BAE and IDT.  Additional input was
15received from other members of RapidIO.org. The objective was to create a
16character mode driver interface which exposes the capabilities of RapidIO
17devices directly to applications, in a manner that allows the numerous and
18varied RapidIO implementations to interoperate.
19
20This driver (MPORT_CDEV) provides access to basic RapidIO subsystem operations
21for user-space applications. Most of RapidIO operations are supported through
22'ioctl' system calls.
23
24When loaded this device driver creates filesystem nodes named rio_mportX in /dev
25directory for each registered RapidIO mport device. 'X' in the node name matches
26to unique port ID assigned to each local mport device.
27
28Using available set of ioctl commands user-space applications can perform
29following RapidIO bus and subsystem operations:
30
31- Reads and writes from/to configuration registers of mport devices
32    (RIO_MPORT_MAINT_READ_LOCAL/RIO_MPORT_MAINT_WRITE_LOCAL)
33- Reads and writes from/to configuration registers of remote RapidIO devices.
34  This operations are defined as RapidIO Maintenance reads/writes in RIO spec.
35    (RIO_MPORT_MAINT_READ_REMOTE/RIO_MPORT_MAINT_WRITE_REMOTE)
36- Set RapidIO Destination ID for mport devices (RIO_MPORT_MAINT_HDID_SET)
37- Set RapidIO Component Tag for mport devices (RIO_MPORT_MAINT_COMPTAG_SET)
38- Query logical index of mport devices (RIO_MPORT_MAINT_PORT_IDX_GET)
39- Query capabilities and RapidIO link configuration of mport devices
40    (RIO_MPORT_GET_PROPERTIES)
41- Enable/Disable reporting of RapidIO doorbell events to user-space applications
42    (RIO_ENABLE_DOORBELL_RANGE/RIO_DISABLE_DOORBELL_RANGE)
43- Enable/Disable reporting of RIO port-write events to user-space applications
44    (RIO_ENABLE_PORTWRITE_RANGE/RIO_DISABLE_PORTWRITE_RANGE)
45- Query/Control type of events reported through this driver: doorbells,
46  port-writes or both (RIO_SET_EVENT_MASK/RIO_GET_EVENT_MASK)
47- Configure/Map mport's outbound requests window(s) for specific size,
48  RapidIO destination ID, hopcount and request type
49    (RIO_MAP_OUTBOUND/RIO_UNMAP_OUTBOUND)
50- Configure/Map mport's inbound requests window(s) for specific size,
51  RapidIO base address and local memory base address
52    (RIO_MAP_INBOUND/RIO_UNMAP_INBOUND)
53- Allocate/Free contiguous DMA coherent memory buffer for DMA data transfers
54  to/from remote RapidIO devices (RIO_ALLOC_DMA/RIO_FREE_DMA)
55- Initiate DMA data transfers to/from remote RapidIO devices (RIO_TRANSFER).
56  Supports blocking, asynchronous and posted (a.k.a 'fire-and-forget') data
57  transfer modes.
58- Check/Wait for completion of asynchronous DMA data transfer
59    (RIO_WAIT_FOR_ASYNC)
60- Manage device objects supported by RapidIO subsystem (RIO_DEV_ADD/RIO_DEV_DEL).
61  This allows implementation of various RapidIO fabric enumeration algorithms
62  as user-space applications while using remaining functionality provided by
63  kernel RapidIO subsystem.
64
65II. Hardware Compatibility
66
67This device driver uses standard interfaces defined by kernel RapidIO subsystem
68and therefore it can be used with any mport device driver registered by RapidIO
69subsystem with limitations set by available mport implementation.
70
71At this moment the most common limitation is availability of RapidIO-specific
72DMA engine framework for specific mport device. Users should verify available
73functionality of their platform when planning to use this driver:
74
75- IDT Tsi721 PCIe-to-RapidIO bridge device and its mport device driver are fully
76  compatible with this driver.
77- Freescale SoCs 'fsl_rio' mport driver does not have implementation for RapidIO
78  specific DMA engine support and therefore DMA data transfers mport_cdev driver
79  are not available.
80
81III. Module parameters
82
83- 'dma_timeout' - DMA transfer completion timeout (in msec, default value 3000).
84        This parameter set a maximum completion wait time for SYNC mode DMA
85        transfer requests and for RIO_WAIT_FOR_ASYNC ioctl requests.
86
87- 'dbg_level' - This parameter allows to control amount of debug information
88        generated by this device driver. This parameter is formed by set of
89        bit masks that correspond to the specific functional blocks.
90        For mask definitions see 'drivers/rapidio/devices/rio_mport_cdev.c'
91        This parameter can be changed dynamically.
92        Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level.
93
94IV. Known problems
95
96  None.
97
98V. User-space Applications and API
99
100API library and applications that use this device driver are available from
101RapidIO.org.
102
103VI. TODO List
104
105- Add support for sending/receiving "raw" RapidIO messaging packets.
106- Add memory mapped DMA data transfers as an option when RapidIO-specific DMA
107  is not available.
108