600003a364
Steen Hegelund says:
====================
Adding Frame DMA functionality to Sparx5
v2:
Removed an unused variable (proc_ctrl) from sparx5_fdma_start.
This add frame DMA functionality to the Sparx5 platform.
Until now the Sparx5 SwitchDev driver has been using register based
injection and extraction when sending frames to/from the host CPU.
With this series the Frame DMA functionality now added.
The Frame DMA is only used if the Frame DMA interrupt is configured in the
device tree; otherwise the existing register based injection and extraction
is used.
The Sparx5 has two ports that can be used for sending and receiving frames,
but there are 8 channels that can be configured: 6 for injection and 2 for
extraction.
The additional channels can be used for more advanced scenarios e.g. where
virtual cores are used, but currently the driver only uses port 0 and
channel 0 and 6 respectively.
DCB (data control block) structures are passed to the Frame DMA with
suitable information about frame start/end etc, as well as pointers to DB
(data blocks) buffers.
The Frame DMA engine can use interrupts to signal back when the frames have
been injected or extracted.
There is a limitation on the DB alignment also for injection: Block must
start on 16byte boundaries, and this is why the driver currently copies the
data to into separate buffers.
The Sparx5 switch core needs a IFH (Internal Frame Header) to pass
information from the port to the switch core, and this header is added
before injection and stripped after extraction.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.