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Documentation / rapidio / tsi721.txt

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Based on kernel version 4.13.3. Page generated on 2017-09-23 13:55 EST.

1	RapidIO subsystem mport driver for IDT Tsi721 PCI Express-to-SRIO bridge.
2	=========================================================================
4	I. Overview
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.
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.
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).
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.
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.
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.
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).
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).
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).
54	II. Known problems
56	  None.
58	III. DMA Engine Support
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.
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.
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).
74	IV. Version History
76	  1.1.0 - DMA operations re-worked to support data scatter/gather lists larger
77	          than hardware buffer descriptors ring.
78	  1.0.0 - Initial driver release.
80	V.  License
81	-----------------------------------------------
83	  Copyright(c) 2011 Integrated Device Technology, Inc. All rights reserved.
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.
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.
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.
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