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Synopsys DesignWare XPCS IP-core is a Physical Coding Sublayer (PCS) layer providing an interface between the Media Access Control (MAC) and Physical Medium Attachment Sublayer (PMA) through a Media independent interface. From software point of view it exposes IEEE std. Clause 45 CSR space and can be accessible either by MDIO or MCI/APB3 bus interfaces. In the former case the PCS device is supposed to be defined under the respective MDIO bus DT-node. In the later case the DW xPCS will be just a normal IO memory-mapped device. Besides of that DW XPCS DT-nodes can have an interrupt signal and clock source properties specified. The former one indicates the Clause 73/37 auto-negotiation events like: negotiation page received, AN is completed or incompatible link partner. The clock DT-properties can describe up to three clock sources: peripheral bus clock source, internal reference clock and the externally connected reference clock. Finally the DW XPCS IP-core can be optionally synthesized with a vendor-specific interface connected to the Synopsys PMA (also called DesignWare Consumer/Enterprise PHY). Alas that isn't auto-detectable in a portable way. So if the DW XPCS device has the respective PMA attached then it should be reflected in the DT-node compatible string so the driver would be aware of the PMA-specific device capabilities (mainly connected with CSRs available for the fine-tunings). Signed-off-by: Serge Semin <fancer.lancer@gmail.com> 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 reStructuredText 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.