Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next...

Merge branch '100GbE' of git://git./linux/kernel/git/tnguy/next-queue

Tony Nguyen says:

====================
add v2 FW logging for ice driver

Paul Stillwell says:

Firmware (FW) log support was added to the ice driver, but that version is
no longer supported. There is a newer version of FW logging (v2) that
adds more control knobs to get the exact data out of the FW
for debugging.

The interface for FW logging is debugfs. This was chosen based on
discussions here:
https://lore.kernel.org/netdev/20230214180712.53fc8ba2@kernel.org/ and
https://lore.kernel.org/netdev/20231012164033.1069fb4b@kernel.org/

We talked about using devlink in a variety of ways, but none of those
options made any sense for the way the FW reports data. We briefly talked
about using ethtool, but that seemed to go by the wayside. Ultimately it
seems like using debugfs is the way to go so re-implement the code to use
that.

FW logging is across all the PFs on the device so restrict the commands to
only PF0.

If the device supports FW logging then a directory named 'fwlog' will be
created under '/sys/kernel/debug/ice/<pci_dev>'. A variety of files will be
created to manage the behavior of logging. The following files will be
created:
- modules/<module>
- nr_messages
- enable
- log_size
- data

where
modules/<module> is used to read/write the log level for a specific module

nr_messages is used to determine how many events should be in each message
sent to the driver

enable is used to start/stop FW logging. This is a boolean value so only 1
or 0 are permissible values

log_size is used to configure the amount of memory the driver uses for log
data

data is used to read/clear the log data

Generally there is a lot of data and dumping that data to syslog will
result in a loss of data. This causes problems when decoding the data and
the user doesn't know that data is missing until later. Instead of dumping
the FW log output to syslog use debugfs. This ensures that all the data the
driver has gets retrieved correctly.

The FW log data is binary data that the FW team decodes to determine what
happened in firmware. The binary blob is sent to Intel for decoding.
---
v6:
- use seq_printf() for outputting module info when reading from 'module' file
- replace code that created argc and argv for handling command line input
- removed checks in all the _read() and _write() functions to see if FW logging
  is supported because the files will not exist if it is not supported
- removed warnings on allocation failures on debugfs file creation failures
- removed a newline between memory allocation and checking if the memory was
  allocated
- fixed cases where we could just return the value from a function call
  instead of saving the value in a variable
- moved the check for PFO in ice_fwlog_init() to an earlier patch
- reworked all of argument scanning in the _write() functions in ice_debugfs.c
  to remove adding characters past the end of the buffer

v5: https://lore.kernel.org/netdev/20231205211251.2122874-1-anthony.l.nguyen@intel.com/
- changed the log level configuration from a single file for all modules to a
  file per module.
- changed 'nr_buffs' to 'log_size' because users understand memory sizes
  better than a number of buffers
- changed 'resolution' to 'nr_messages' to better reflect what it represents
- updated documentation to reflect these changes
- updated documentation to indicate that FW logging must be disabled to
  clear the data. also clarified that any value written to the 'data' file will
  clear the data

v4: https://lore.kernel.org/netdev/20231005170110.3221306-1-anthony.l.nguyen@intel.com/
- removed CONFIG_DEBUG_FS wrapper around code because the debugfs calls handle
  this case already
- moved ice_debugfs_exit() call to remove unreachable code issue
- minor changes to documentation based on feedback

v3: https://lore.kernel.org/netdev/20230815165750.2789609-1-anthony.l.nguyen@intel.com/
- Adjust error path cleanup in ice_module_init() for unreachable code.

v2: https://lore.kernel.org/netdev/20230810170109.1963832-1-anthony.l.nguyen@intel.com/
- Rewrote code to use debugfs instead of devlink

v1: https://lore.kernel.org/netdev/20230209190702.3638688-1-anthony.l.nguyen@intel.com/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>