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Vladimir Oltean
7bf4a5b071
The MAC Merge IRQ of all ports is shared with the PTP TX timestamp IRQ of all ports, which means that currently, when a PTP TX timestamp is generated, felix_irq_handler() also polls for the MAC Merge layer status of all ports, looking for changes. This makes the kernel do more work, and under certain circumstances may make ptp4l require a tx_timestamp_timeout argument higher than before. Changes to the MAC Merge layer status are only to be expected under certain conditions - its TX direction needs to be enabled - so we can check early if that is the case, and omit register access otherwise. Make ocelot_mm_update_port_status() skip register access if mm->tx_enabled is unset, and also call it once more, outside IRQ context, from ocelot_port_set_mm(), when mm->tx_enabled transitions from true to false, because an IRQ is also expected in that case. Also, a port may have its MAC Merge layer enabled but it may not have generated the interrupt. In that case, there's no point in writing to DEV_MM_STATUS to acknowledge that IRQ. We can reduce the number of register writes per port with MM enabled by keeping an "ack" variable which writes the "write-one-to-clear" bits. Those are 3 in number: PRMPT_ACTIVE_STICKY, UNEXP_RX_PFRM_STICKY and UNEXP_TX_PFRM_STICKY. The other fields in DEV_MM_STATUS are read-only and it doesn't matter what is written to them, so writing zero is just fine. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> 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.