9fcf024dd6
The PTP egress timestamp N must be captured from register PTPEGR_TS[n], where n = 2 * PORT + TSREG. There are 10 PTPEGR_TS registers, 2 per port. We are only using TSREG=0. As opposed to the management slots, which are 4 in number (SJA1105_NUM_PORTS, minus the CPU port). Any management frame (which includes PTP frames) can be sent to any non-CPU port through any management slot. When the CPU port is not the last port (#4), there will be a mismatch between the slot and the port number. Luckily, the only mainline occurrence with this switch (arch/arm/boot/dts/ls1021a-tsn.dts) does have the CPU port as #4, so the issue did not manifest itself thus far. Fixes: 47ed985e97f5 ("net: dsa: sja1105: Add logic for TX timestamping") Signed-off-by: Vladimir Oltean <olteanv@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 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.