2406fa2adf
[ Upstream commit 3a0a88fcbaf9e027ecca3fe8775be9700b4d6460 ] This patch updates the workaround for a problem similar to erratum DS80000789E 6 of the mcp2518fd, the other variants of the chip family (mcp2517fd and mcp251863) are probably also affected. Erratum DS80000789E 6 says "reading of the FIFOCI bits in the FIFOSTA register for an RX FIFO may be corrupted". However observation shows that this problem is not limited to RX FIFOs but also effects the TEF FIFO. In the bad case, the driver reads a too large head index. As the FIFO is implemented as a ring buffer, this results in re-handling old CAN transmit complete events. Every transmit complete event contains with a sequence number that equals to the sequence number of the corresponding TX request. This way old TX complete events can be detected. If the original driver detects a non matching sequence number, it prints an info message and tries again later. As wrong sequence numbers can be explained by the erratum DS80000789E 6, demote the info message to debug level, streamline the code and update the comments. Keep the behavior: If an old CAN TX complete event is detected, abort the iteration and mark the number of valid CAN TX complete events as processed in the chip by incrementing the FIFO's tail index. Cc: Stefan Althöfer <Stefan.Althoefer@janztec.com> Cc: Thomas Kopp <thomas.kopp@microchip.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Sasha Levin <sashal@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 reStructuredText 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.