ice: configure FW logging

Users want the ability to debug FW issues by retrieving the
FW logs from the E8xx devices. Use debugfs to allow the user to
configure the log level and number of messages for FW logging.

If FW logging is supported on the E8xx then the file 'fwlog' will be
created under the PCI device ID for the ice driver. If the file does not
exist then either the E8xx doesn't support FW logging or debugfs is not
enabled on the system.

One thing users want to do is control which events are reported. The
user can read and write the 'fwlog/modules/<module name>' to get/set
the log levels. Each module in the FW that supports logging ht as a file
under 'fwlog/modules' that supports reading (to see what the current log
level is) and writing (to change the log level).

The format to set the log levels for a module are:

  # echo <log level> > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/<module>

The supported log levels are:

      *	none
      *	error
      *	warning
      *	normal
      *	verbose

Each level includes the messages from the previous/lower level

The modules that are supported are:

      *	general
      *	ctrl
      *	link
      *	link_topo
      *	dnl
      *	i2c
      *	sdp
      *	mdio
      *	adminq
      *	hdma
      *	lldp
      *	dcbx
      *	dcb
      *	xlr
      *	nvm
      *	auth
      *	vpd
      *	iosf
      *	parser
      *	sw
      *	scheduler
      *	txq
      *	rsvd
      *	post
      *	watchdog
      *	task_dispatch
      *	mng
      *	synce
      *	health
      *	tsdrv
      *	pfreg
      *	mdlver
      *	all

The module 'all' is a special module which allows the user to read or
write to all of the modules.

The following example command would set the DCB module to the 'normal'
log level:

  # echo normal > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/dcb

If the user wants to set the DCB, Link, and the AdminQ modules to
'verbose' then the commands are:

  # echo verbose > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/dcb
  # echo verbose > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/link
  # echo verbose > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/adminq

If the user wants to set all modules to the 'warning' level then the
command is:

  # echo warning > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/all

If the user wants to disable logging for a module then they can set the
level to 'none'. An example setting the 'watchdog' module is:

  # echo none > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/watchdog

If the user wants to see what the log level is for a specific module
then the command is:

  # cat /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/dcb

This will return the log level for the DCB module. If the user wants to
see the log level for all the modules then the command is:

  # cat /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules/all

Writing to the module file will update the configuration, but NOT enable the
configuration (that is a separate command).

In addition to configuring the modules, the user can also configure the
number of log messages (nr_messages) to include in a single Admin Receive
Queue (ARQ) event.The range is 1-128 (1 means push every log message, 128
means push only when the max AQ command buffer is full). The suggested
value is 10.

To see/change the resolution the user can read/write the
'fwlog/nr_messages' file. An example changing the value to 50 is

  # echo 50 > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/nr_messages

To see the current value of 'nr_messages' then the command is:

  # cat /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/nr_messages

Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>