0001 =========================================================================
0002 RapidIO subsystem mport driver for IDT Tsi721 PCI Express-to-SRIO bridge.
0003 =========================================================================
0004
0005 1. Overview
0006 ===========
0007
0008 This driver implements all currently defined RapidIO mport callback functions.
0009 It supports maintenance read and write operations, inbound and outbound RapidIO
0010 doorbells, inbound maintenance port-writes and RapidIO messaging.
0011
0012 To generate SRIO maintenance transactions this driver uses one of Tsi721 DMA
0013 channels. This mechanism provides access to larger range of hop counts and
0014 destination IDs without need for changes in outbound window translation.
0015
0016 RapidIO messaging support uses dedicated messaging channels for each mailbox.
0017 For inbound messages this driver uses destination ID matching to forward messages
0018 into the corresponding message queue. Messaging callbacks are implemented to be
0019 fully compatible with RIONET driver (Ethernet over RapidIO messaging services).
0020
0021 1. Module parameters:
0022
0023 - 'dbg_level'
0024 - This parameter allows to control amount of debug information
0025 generated by this device driver. This parameter is formed by set of
0026 This parameter can be changed bit masks that correspond to the specific
0027 functional block.
0028 For mask definitions see 'drivers/rapidio/devices/tsi721.h'
0029 This parameter can be changed dynamically.
0030 Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level.
0031
0032 - 'dma_desc_per_channel'
0033 - This parameter defines number of hardware buffer
0034 descriptors allocated for each registered Tsi721 DMA channel.
0035 Its default value is 128.
0036
0037 - 'dma_txqueue_sz'
0038 - DMA transactions queue size. Defines number of pending
0039 transaction requests that can be accepted by each DMA channel.
0040 Default value is 16.
0041
0042 - 'dma_sel'
0043 - DMA channel selection mask. Bitmask that defines which hardware
0044 DMA channels (0 ... 6) will be registered with DmaEngine core.
0045 If bit is set to 1, the corresponding DMA channel will be registered.
0046 DMA channels not selected by this mask will not be used by this device
0047 driver. Default value is 0x7f (use all channels).
0048
0049 - 'pcie_mrrs'
0050 - override value for PCIe Maximum Read Request Size (MRRS).
0051 This parameter gives an ability to override MRRS value set during PCIe
0052 configuration process. Tsi721 supports read request sizes up to 4096B.
0053 Value for this parameter must be set as defined by PCIe specification:
0054 0 = 128B, 1 = 256B, 2 = 512B, 3 = 1024B, 4 = 2048B and 5 = 4096B.
0055 Default value is '-1' (= keep platform setting).
0056
0057 - 'mbox_sel'
0058 - RIO messaging MBOX selection mask. This is a bitmask that defines
0059 messaging MBOXes are managed by this device driver. Mask bits 0 - 3
0060 correspond to MBOX0 - MBOX3. MBOX is under driver's control if the
0061 corresponding bit is set to '1'. Default value is 0x0f (= all).
0062
0063 2. Known problems
0064 =================
0065
0066 None.
0067
0068 3. DMA Engine Support
0069 =====================
0070
0071 Tsi721 mport driver supports DMA data transfers between local system memory and
0072 remote RapidIO devices. This functionality is implemented according to SLAVE
0073 mode API defined by common Linux kernel DMA Engine framework.
0074
0075 Depending on system requirements RapidIO DMA operations can be included/excluded
0076 by setting CONFIG_RAPIDIO_DMA_ENGINE option. Tsi721 miniport driver uses seven
0077 out of eight available BDMA channels to support DMA data transfers.
0078 One BDMA channel is reserved for generation of maintenance read/write requests.
0079
0080 If Tsi721 mport driver have been built with RAPIDIO_DMA_ENGINE support included,
0081 this driver will accept DMA-specific module parameter:
0082
0083 "dma_desc_per_channel"
0084 - defines number of hardware buffer descriptors used by
0085 each BDMA channel of Tsi721 (by default - 128).
0086
0087 4. Version History
0088
0089 ===== ====================================================================
0090 1.1.0 DMA operations re-worked to support data scatter/gather lists larger
0091 than hardware buffer descriptors ring.
0092 1.0.0 Initial driver release.
0093 ===== ====================================================================
0094
0095 5. License
0096 ===========
0097
0098 Copyright(c) 2011 Integrated Device Technology, Inc. All rights reserved.
0099
0100 This program is free software; you can redistribute it and/or modify it
0101 under the terms of the GNU General Public License as published by the Free
0102 Software Foundation; either version 2 of the License, or (at your option)
0103 any later version.
0104
0105 This program is distributed in the hope that it will be useful, but WITHOUT
0106 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
0107 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
0108 more details.
0109
0110 You should have received a copy of the GNU General Public License along with
0111 this program; if not, write to the Free Software Foundation, Inc.,
0112 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
