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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-16 12:21:41 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-16 12:21:41 -0700 |
commit | c309b6f24222246c18a8b65d3950e6e755440865 (patch) | |
tree | 11893170f5c246bb0dee8066e85878af04162ab0 /Documentation/driver-api/rapidio/tsi721.rst | |
parent | 3e859477a1db52a0435d06a55fdb54f62d69c292 (diff) | |
parent | 168869492e7009b6861b615f1d030c99bc805e83 (diff) | |
download | linux-c309b6f24222246c18a8b65d3950e6e755440865.tar.gz linux-c309b6f24222246c18a8b65d3950e6e755440865.tar.bz2 linux-c309b6f24222246c18a8b65d3950e6e755440865.zip |
Merge tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull rst conversion of docs from Mauro Carvalho Chehab:
"As agreed with Jon, I'm sending this big series directly to you, c/c
him, as this series required a special care, in order to avoid
conflicts with other trees"
* tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (77 commits)
docs: kbuild: fix build with pdf and fix some minor issues
docs: block: fix pdf output
docs: arm: fix a breakage with pdf output
docs: don't use nested tables
docs: gpio: add sysfs interface to the admin-guide
docs: locking: add it to the main index
docs: add some directories to the main documentation index
docs: add SPDX tags to new index files
docs: add a memory-devices subdir to driver-api
docs: phy: place documentation under driver-api
docs: serial: move it to the driver-api
docs: driver-api: add remaining converted dirs to it
docs: driver-api: add xilinx driver API documentation
docs: driver-api: add a series of orphaned documents
docs: admin-guide: add a series of orphaned documents
docs: cgroup-v1: add it to the admin-guide book
docs: aoe: add it to the driver-api book
docs: add some documentation dirs to the driver-api book
docs: driver-model: move it to the driver-api book
docs: lp855x-driver.rst: add it to the driver-api book
...
Diffstat (limited to 'Documentation/driver-api/rapidio/tsi721.rst')
-rw-r--r-- | Documentation/driver-api/rapidio/tsi721.rst | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/Documentation/driver-api/rapidio/tsi721.rst b/Documentation/driver-api/rapidio/tsi721.rst new file mode 100644 index 000000000000..42aea438cd20 --- /dev/null +++ b/Documentation/driver-api/rapidio/tsi721.rst @@ -0,0 +1,112 @@ +========================================================================= +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. |