1=========================================================================
2RapidIO subsystem mport driver for IDT Tsi721 PCI Express-to-SRIO bridge.
3=========================================================================
4
51. Overview
6===========
7
8This driver implements all currently defined RapidIO mport callback functions.
9It supports maintenance read and write operations, inbound and outbound RapidIO
10doorbells, inbound maintenance port-writes and RapidIO messaging.
11
12To generate SRIO maintenance transactions this driver uses one of Tsi721 DMA
13channels. This mechanism provides access to larger range of hop counts and
14destination IDs without need for changes in outbound window translation.
15
16RapidIO messaging support uses dedicated messaging channels for each mailbox.
17For inbound messages this driver uses destination ID matching to forward messages
18into the corresponding message queue. Messaging callbacks are implemented to be
19fully compatible with RIONET driver (Ethernet over RapidIO messaging services).
20
211. Module parameters:
22
23- 'dbg_level'
24      - This parameter allows to control amount of debug information
25        generated by this device driver. This parameter is formed by set of
26        This parameter can be changed bit masks that correspond to the specific
27        functional block.
28        For mask definitions see 'drivers/rapidio/devices/tsi721.h'
29        This parameter can be changed dynamically.
30        Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level.
31
32- 'dma_desc_per_channel'
33      - This parameter defines number of hardware buffer
34        descriptors allocated for each registered Tsi721 DMA channel.
35        Its default value is 128.
36
37- 'dma_txqueue_sz'
38      - DMA transactions queue size. Defines number of pending
39        transaction requests that can be accepted by each DMA channel.
40        Default value is 16.
41
42- 'dma_sel'
43      - DMA channel selection mask. Bitmask that defines which hardware
44        DMA channels (0 ... 6) will be registered with DmaEngine core.
45        If bit is set to 1, the corresponding DMA channel will be registered.
46        DMA channels not selected by this mask will not be used by this device
47        driver. Default value is 0x7f (use all channels).
48
49- 'pcie_mrrs'
50      - override value for PCIe Maximum Read Request Size (MRRS).
51        This parameter gives an ability to override MRRS value set during PCIe
52        configuration process. Tsi721 supports read request sizes up to 4096B.
53        Value for this parameter must be set as defined by PCIe specification:
54        0 = 128B, 1 = 256B, 2 = 512B, 3 = 1024B, 4 = 2048B and 5 = 4096B.
55        Default value is '-1' (= keep platform setting).
56
57- 'mbox_sel'
58      - RIO messaging MBOX selection mask. This is a bitmask that defines
59        messaging MBOXes are managed by this device driver. Mask bits 0 - 3
60        correspond to MBOX0 - MBOX3. MBOX is under driver's control if the
61        corresponding bit is set to '1'. Default value is 0x0f (= all).
62
632. Known problems
64=================
65
66  None.
67
683. DMA Engine Support
69=====================
70
71Tsi721 mport driver supports DMA data transfers between local system memory and
72remote RapidIO devices. This functionality is implemented according to SLAVE
73mode API defined by common Linux kernel DMA Engine framework.
74
75Depending on system requirements RapidIO DMA operations can be included/excluded
76by setting CONFIG_RAPIDIO_DMA_ENGINE option. Tsi721 miniport driver uses seven
77out of eight available BDMA channels to support DMA data transfers.
78One BDMA channel is reserved for generation of maintenance read/write requests.
79
80If Tsi721 mport driver have been built with RAPIDIO_DMA_ENGINE support included,
81this driver will accept DMA-specific module parameter:
82
83  "dma_desc_per_channel"
84			 - defines number of hardware buffer descriptors used by
85                           each BDMA channel of Tsi721 (by default - 128).
86
874. Version History
88
89  =====   ====================================================================
90  1.1.0   DMA operations re-worked to support data scatter/gather lists larger
91          than hardware buffer descriptors ring.
92  1.0.0   Initial driver release.
93  =====   ====================================================================
94
955.  License
96===========
97
98  Copyright(c) 2011 Integrated Device Technology, Inc. All rights reserved.
99
100  This program is free software; you can redistribute it and/or modify it
101  under the terms of the GNU General Public License as published by the Free
102  Software Foundation; either version 2 of the License, or (at your option)
103  any later version.
104
105  This program is distributed in the hope that it will be useful, but WITHOUT
106  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
107  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
108  more details.
109
110  You should have received a copy of the GNU General Public License along with
111  this program; if not, write to the Free Software Foundation, Inc.,
112  59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
113