b8e0ddd36c
This is a preparatory patch to work around 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. When handling the TEF interrupt, the driver reads the FIFO header index from the TEF FIFO STA register of the chip. In the bad case, the driver reads a too large head index. In the original code, the driver always trusted the read value, which caused old CAN transmit complete events that were already processed to be re-processed. Instead of reading and trusting the head index, read the head index and calculate the number of CAN frames that were supposedly received - replace mcp251xfd_tef_ring_update() with mcp251xfd_get_tef_len(). The mcp251xfd_handle_tefif() function reads the CAN transmit complete events from the chip, iterates over them and pushes them into the network stack. The original driver already contains code to detect old CAN transmit complete events, that will be updated in the next patch. Cc: Stefan Althöfer <Stefan.Althoefer@janztec.com> Cc: Thomas Kopp <thomas.kopp@microchip.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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.