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- =========================================================================
- RapidIO subsystem mport driver for IDT Tsi721 PCI Express-to-SRIO bridge.
- =========================================================================
- 1. Overview
- ===========
- This driver implements all currently defined RapidIO mport callback functions.
- It supports maintenance read and write operations, inbound and outbound RapidIO
- doorbells, inbound maintenance port-writes and RapidIO messaging.
- To generate SRIO maintenance transactions this driver uses one of Tsi721 DMA
- channels. This mechanism provides access to larger range of hop counts and
- destination IDs without need for changes in outbound window translation.
- RapidIO messaging support uses dedicated messaging channels for each mailbox.
- For inbound messages this driver uses destination ID matching to forward messages
- into the corresponding message queue. Messaging callbacks are implemented to be
- fully compatible with RIONET driver (Ethernet over RapidIO messaging services).
- 1. Module parameters:
- - 'dbg_level'
- - This parameter allows to control amount of debug information
- generated by this device driver. This parameter is formed by set of
- This parameter can be changed bit masks that correspond to the specific
- functional block.
- For mask definitions see 'drivers/rapidio/devices/tsi721.h'
- This parameter can be changed dynamically.
- Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level.
- - 'dma_desc_per_channel'
- - This parameter defines number of hardware buffer
- descriptors allocated for each registered Tsi721 DMA channel.
- Its default value is 128.
- - 'dma_txqueue_sz'
- - DMA transactions queue size. Defines number of pending
- transaction requests that can be accepted by each DMA channel.
- Default value is 16.
- - 'dma_sel'
- - DMA channel selection mask. Bitmask that defines which hardware
- DMA channels (0 ... 6) will be registered with DmaEngine core.
- If bit is set to 1, the corresponding DMA channel will be registered.
- DMA channels not selected by this mask will not be used by this device
- driver. Default value is 0x7f (use all channels).
- - 'pcie_mrrs'
- - override value for PCIe Maximum Read Request Size (MRRS).
- This parameter gives an ability to override MRRS value set during PCIe
- configuration process. Tsi721 supports read request sizes up to 4096B.
- Value for this parameter must be set as defined by PCIe specification:
- 0 = 128B, 1 = 256B, 2 = 512B, 3 = 1024B, 4 = 2048B and 5 = 4096B.
- Default value is '-1' (= keep platform setting).
- - 'mbox_sel'
- - RIO messaging MBOX selection mask. This is a bitmask that defines
- messaging MBOXes are managed by this device driver. Mask bits 0 - 3
- correspond to MBOX0 - MBOX3. MBOX is under driver's control if the
- corresponding bit is set to '1'. Default value is 0x0f (= all).
- 2. Known problems
- =================
- None.
- 3. DMA Engine Support
- =====================
- Tsi721 mport driver supports DMA data transfers between local system memory and
- remote RapidIO devices. This functionality is implemented according to SLAVE
- mode API defined by common Linux kernel DMA Engine framework.
- Depending on system requirements RapidIO DMA operations can be included/excluded
- by setting CONFIG_RAPIDIO_DMA_ENGINE option. Tsi721 miniport driver uses seven
- out of eight available BDMA channels to support DMA data transfers.
- One BDMA channel is reserved for generation of maintenance read/write requests.
- If Tsi721 mport driver have been built with RAPIDIO_DMA_ENGINE support included,
- this driver will accept DMA-specific module parameter:
- "dma_desc_per_channel"
- - defines number of hardware buffer descriptors used by
- each BDMA channel of Tsi721 (by default - 128).
- 4. Version History
- ===== ====================================================================
- 1.1.0 DMA operations re-worked to support data scatter/gather lists larger
- than hardware buffer descriptors ring.
- 1.0.0 Initial driver release.
- ===== ====================================================================
- 5. License
- ===========
- Copyright(c) 2011 Integrated Device Technology, Inc. All rights reserved.
- This program is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the Free
- Software Foundation; either version 2 of the License, or (at your option)
- any later version.
- This program is distributed in the hope that it will be useful, but WITHOUT
- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- more details.
- You should have received a copy of the GNU General Public License along with
- this program; if not, write to the Free Software Foundation, Inc.,
- 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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