e63aef9c91
Current behavior is that spi-mem operations do not increment statistics,
neither per-controller nor per-device, if ->exec_op() is used. For
operations that do NOT use ->exec_op(), stats are increased as the
usual spi_sync() is called.
The newly implemented spi_mem_add_op_stats() function is strongly
inspired by spi_statistics_add_transfer_stats(); locking logic and
l2len computation comes from there.
Statistics that are being filled: bytes{,_rx,_tx}, messages, transfers,
errors, timedout, transfer_bytes_histo_*.
Note about messages & transfers counters: in the fallback to spi_sync()
case, there are from 1 to 4 transfers per message. We only register one
big transfer in the ->exec_op() case as that is closer to reality.
This patch is NOT touching:
- spi_async, spi_sync, spi_sync_immediate: those counters describe
precise function calls, incrementing them would be lying. I believe
comparing the messages counter to spi_async+spi_sync is a good way
to detect ->exec_op() calls, but I might be missing edge cases
knowledge.
- transfers_split_maxsize: splitting cannot happen if ->exec_op() is
provided.
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://msgid.link/r/20240216-spi-mem-stats-v2-1-9256dfe4887d@bootlin.com
Signed-off-by: Mark Brown <broonie@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 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.