abc33494dd
Not all fec MDIO bus drivers support C45 mode transactions. The older fec
hardware block in many ColdFire SoCs does not appear to support them, at
least according to most of the different ColdFire SoC reference manuals.
The bits used to generate C45 access on the iMX parts, in the OP field
of the MMFR register, are documented as generating non-compliant MII
frames (it is not documented as to exactly how they are non-compliant).
Commit 8d03ad1ab0b0 ("net: fec: Separate C22 and C45 transactions")
means the fec driver will always register c45 MDIO read and write
methods. During probe these will always be accessed now generating
non-compliant MII accesses on ColdFire based devices.
Add a quirk define, FEC_QUIRK_HAS_MDIO_C45, that can be used to
distinguish silicon that supports MDIO C45 framing or not. Add this to
all the existing iMX quirks, so they will be behave as they do now (*).
(*) it seems that some iMX parts may not support C45 transactions either.
The iMX25 and iMX50 Reference Manuals contain similar wording to
the ColdFire Reference Manuals on this.
Fixes: 8d03ad1ab0b0 ("net: fec: Separate C22 and C45 transactions")
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20230404052207.3064861-1-gerg@linux-m68k.org
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
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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.