mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-28 15:13:55 +08:00
d2bdd48a65
This is actually a subsystem description, with contains both kAPI and uAPI. While it should ideally be slplit, let's place it at driver-api, as most things are related to kAPI and driver-specific info. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
113 lines
4.9 KiB
ReStructuredText
113 lines
4.9 KiB
ReStructuredText
=========================================================================
|
|
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.
|