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Michael Sit Wei Hong says: ==================== Enable 2.5Gbps speed for stmmac Intel mGbE supports 2.5Gbps link speed by overclocking the clock rate by 2.5 times to support 2.5Gbps link speed. In this mode, the serdes/PHY operates at a serial baud rate of 3.125 Gbps and the PCS data path and GMII interface of the MAC operate at 312.5 MHz instead of 125 MHz. This is configured in the BIOS during boot up. The kernel driver is not able access to modify the clock rate for 1Gbps/2.5G mode on the fly. The way to determine the current 1G/2.5G mode is by reading a dedicated adhoc register through mdio bus. Changes: v5 -> v6 patch 1/3 - Check if mdio_bus_data is populated to prevent NULL pointer dereferencing when accesing mdio_bus_data member v4 -> v5 patch 1/3 - Rebase to latest code changes after Vladimir's code is merged and fix build warnings v3 -> v4 patch 1/3 - Rebase to latest code and Initialize 'found' to 0 to avoid build warning patch 2/3 - Fix indentation issue from v3 v2 -> v3 patch 1/3 -New patch added to restructure the code. enabling reading the dedicated adhoc register to determine link speed mode. patch 2/3 -Restructure for 2.5G speed to use 2500BaseX configuration as the PHY interface. patch 3/3 -Restructure to read serdes registers to set max_speed and configure to use 2500BaseX in 2.5G speeds. v1 -> v2 patch 1/2 -Remove MAC supported link speed masking patch 2/2 -Add supported link speed masking in the PCS iperf3 and ping for 2.5Gbps and regression test on 10M/100M/1000Mbps is done to prevent regresson issues. ==================== 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.