Xu Yang d4ef3c9c79 usb: ehci: add workaround for chipidea PORTSC.PEC bug
[ Upstream commit dda4b60ed70bd670eefda081f70c0cb20bbeb1fa ]

Some NXP processor using chipidea IP has a bug when frame babble is
detected.

As per 4.15.1.1.1 Serial Bus Babble:
  A babble condition also exists if IN transaction is in progress at
High-speed SOF2 point. This is called frame babble. The host controller
must disable the port to which the frame babble is detected.

The USB controller has disabled the port (PE cleared) and has asserted
USBERRINT when frame babble is detected, but PEC is not asserted.
Therefore, the SW isn't aware that port has been disabled. Then the
SW keeps sending packets to this port, but all of the transfers will
fail.

This workaround will firstly assert PCD by SW when USBERRINT is detected
and then judge whether port change has really occurred or not by polling
roothub status. Because the PEC doesn't get asserted in our case, this
patch will also assert it by SW when specific conditions are satisfied.

Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/20230809024432.535160-1-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-23 11:09:59 +02:00
2021-10-18 20:22:03 -10:00
2023-09-19 12:23:04 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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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.
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