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48618fb4 AB |
1 | RapidIO subsystem mport driver for IDT Tsi721 PCI Express-to-SRIO bridge. |
2 | ========================================================================= | |
3 | ||
4 | I. Overview | |
5 | ||
6 | This driver implements all currently defined RapidIO mport callback functions. | |
7 | It supports maintenance read and write operations, inbound and outbound RapidIO | |
8 | doorbells, inbound maintenance port-writes and RapidIO messaging. | |
9 | ||
10 | To generate SRIO maintenance transactions this driver uses one of Tsi721 DMA | |
11 | channels. This mechanism provides access to larger range of hop counts and | |
12 | destination IDs without need for changes in outbound window translation. | |
13 | ||
14 | RapidIO messaging support uses dedicated messaging channels for each mailbox. | |
15 | For inbound messages this driver uses destination ID matching to forward messages | |
16 | into the corresponding message queue. Messaging callbacks are implemented to be | |
17 | fully compatible with RIONET driver (Ethernet over RapidIO messaging services). | |
18 | ||
72d8a0d2 AB |
19 | 1. Module parameters: |
20 | - 'dbg_level' - This parameter allows to control amount of debug information | |
21 | generated by this device driver. This parameter is formed by set of | |
22 | This parameter can be changed bit masks that correspond to the specific | |
23 | functional block. | |
24 | For mask definitions see 'drivers/rapidio/devices/tsi721.h' | |
25 | This parameter can be changed dynamically. | |
26 | Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level. | |
27 | ||
4498c31a AB |
28 | - 'dma_desc_per_channel' - This parameter defines number of hardware buffer |
29 | descriptors allocated for each registered Tsi721 DMA channel. | |
30 | Its default value is 128. | |
31 | ||
32 | - 'dma_txqueue_sz' - DMA transactions queue size. Defines number of pending | |
33 | transaction requests that can be accepted by each DMA channel. | |
34 | Default value is 16. | |
35 | ||
36 | - 'dma_sel' - DMA channel selection mask. Bitmask that defines which hardware | |
37 | DMA channels (0 ... 6) will be registered with DmaEngine core. | |
38 | If bit is set to 1, the corresponding DMA channel will be registered. | |
39 | DMA channels not selected by this mask will not be used by this device | |
40 | driver. Default value is 0x7f (use all channels). | |
41 | ||
cb782cdd AB |
42 | - 'pcie_mrrs' - override value for PCIe Maximum Read Request Size (MRRS). |
43 | This parameter gives an ability to override MRRS value set during PCIe | |
44 | configuration process. Tsi721 supports read request sizes up to 4096B. | |
45 | Value for this parameter must be set as defined by PCIe specification: | |
46 | 0 = 128B, 1 = 256B, 2 = 512B, 3 = 1024B, 4 = 2048B and 5 = 4096B. | |
47 | Default value is '-1' (= keep platform setting). | |
48 | ||
e519685d AB |
49 | - 'mbox_sel' - RIO messaging MBOX selection mask. This is a bitmask that defines |
50 | messaging MBOXes are managed by this device driver. Mask bits 0 - 3 | |
51 | correspond to MBOX0 - MBOX3. MBOX is under driver's control if the | |
52 | corresponding bit is set to '1'. Default value is 0x0f (= all). | |
53 | ||
48618fb4 AB |
54 | II. Known problems |
55 | ||
56 | None. | |
57 | ||
50835e97 | 58 | III. DMA Engine Support |
48618fb4 | 59 | |
50835e97 AB |
60 | Tsi721 mport driver supports DMA data transfers between local system memory and |
61 | remote RapidIO devices. This functionality is implemented according to SLAVE | |
62 | mode API defined by common Linux kernel DMA Engine framework. | |
63 | ||
64 | Depending on system requirements RapidIO DMA operations can be included/excluded | |
65 | by setting CONFIG_RAPIDIO_DMA_ENGINE option. Tsi721 miniport driver uses seven | |
66 | out of eight available BDMA channels to support DMA data transfers. | |
67 | One BDMA channel is reserved for generation of maintenance read/write requests. | |
68 | ||
69 | If Tsi721 mport driver have been built with RAPIDIO_DMA_ENGINE support included, | |
70 | this driver will accept DMA-specific module parameter: | |
71 | "dma_desc_per_channel" - defines number of hardware buffer descriptors used by | |
72 | each BDMA channel of Tsi721 (by default - 128). | |
48618fb4 AB |
73 | |
74 | IV. Version History | |
75 | ||
50835e97 AB |
76 | 1.1.0 - DMA operations re-worked to support data scatter/gather lists larger |
77 | than hardware buffer descriptors ring. | |
48618fb4 AB |
78 | 1.0.0 - Initial driver release. |
79 | ||
80 | V. License | |
81 | ----------------------------------------------- | |
82 | ||
83 | Copyright(c) 2011 Integrated Device Technology, Inc. All rights reserved. | |
84 | ||
85 | This program is free software; you can redistribute it and/or modify it | |
86 | under the terms of the GNU General Public License as published by the Free | |
87 | Software Foundation; either version 2 of the License, or (at your option) | |
88 | any later version. | |
89 | ||
90 | This program is distributed in the hope that it will be useful, but WITHOUT | |
91 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
92 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
93 | more details. | |
94 | ||
95 | You should have received a copy of the GNU General Public License along with | |
96 | this program; if not, write to the Free Software Foundation, Inc., | |
97 | 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |