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