This patch introduces the function 'ksz8_phy_port_link_up' to the Microchip KSZ8xxx driver. This function is responsible for setting up flow control and duplex settings for the ports that are integrated with PHYs. The KSZ8795 switch supports asymmetric pause control, which can't be fully utilized since a single bit controls both RX and TX pause. Despite this, the flow control can be adjusted based on the auto-negotiation process, taking into account the capabilities of both link partners. On the other hand, the KSZ8873's PORT_FORCE_FLOW_CTRL bit can be set by the hardware bootstrap, which ignores the auto-negotiation result. Therefore, even in auto-negotiation mode, we need to ensure that this bit is correctly set. When auto-negotiation isn't in use, we enforce symmetric pause control for the KSZ8795 switch. Please note, forcing flow control disable on a port while still advertising pause support isn't possible. While this scenario might not be practical or desired, it's important to be aware of this limitation when working with the KSZ8873 and similar devices. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Reviewed-by: Simon Horman <simon.horman@corigine.com> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://lore.kernel.org/r/20231127145101.3039399-3-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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.
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