[PATCH net-next v2 5/5] ice: add documentation for FW logging

[Tony Nguyen <anthony.l.nguyen@intel.com>]

From: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>

Add documentation for FW logging in
Documentation/networking/device-drivers/ethernet/intel/ice.rst

Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
 .../device_drivers/ethernet/intel/ice.rst     | 117 ++++++++++++++++++
 1 file changed, 117 insertions(+)

diff --git a/Documentation/networking/device_drivers/ethernet/intel/ice.rst b/Documentation/networking/device_drivers/ethernet/intel/ice.rst
index e4d065c55ea8..3ddef911faaa 100644
--- a/Documentation/networking/device_drivers/ethernet/intel/ice.rst
+++ b/Documentation/networking/device_drivers/ethernet/intel/ice.rst
@@ -895,6 +895,123 @@ driver writes raw bytes by the GNSS object to the receiver through i2c. Please
 refer to the hardware GNSS module documentation for configuration details.
 
 
+Firmware (FW) logging
+---------------------
+The driver supports FW logging via the debugfs interface on PF 0 only. In order
+for FW logging to work, the NVM must support it. The 'fwlog' file will only get
+created in the ice debugfs directory if the NVM supports FW logging.
+
+Module configuration
+~~~~~~~~~~~~~~~~~~~~
+To see the status of FW logging then read the 'fwlog/modules' file like this::
+
+  # cat /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules
+
+To configure FW logging then write to the 'fwlog/modules' file like this::
+
+  # echo <fwlog_event> <fwlog_level> > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules
+
+where
+
+* fwlog_level is a name as described below. Each level includes the
+  messages from the previous/lower level
+
+      * NONE
+      *	ERROR
+      *	WARNING
+      *	NORMAL
+      *	VERBOSE
+
+* fwlog_event is a name that represents the module to receive events for. The
+  module names 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 name ALL is special and specifies setting all of the modules to the
+specified fwlog_level.
+
+Example usage to configure the modules::
+
+  # echo LINK VERBOSE > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/modules
+
+Enabling FW log
+~~~~~~~~~~~~~~~
+Once the desired modules are configured the user will enable the logging. To do
+this the user can write a 1 (enable) or 0 (disable) to 'fwlog/enable'. An
+example is::
+
+  # echo 1 > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/enable
+
+Retrieving FW log data
+~~~~~~~~~~~~~~~~~~~~~~
+The FW log data can be retrieved by reading from 'fwlog/data'. The user can
+write to 'fwlog/data' to clear the data. The data can only be cleared when FW
+logging is disabled. The FW log data is a binary file that is sent to Intel and
+used to help debug user issues.
+
+An example to read the data is::
+
+  # cat /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/data > fwlog.bin
+
+An example to clear the data is::
+
+  # echo 0 > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/data
+
+Changing how often the log events are sent to the driver
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver receives FW log data from the Admin Receive Queue (ARQ). The
+frequency that the FW sends the ARQ events can be configured by writing to
+'fwlog/resolution'. 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. The user can see what the value is configured to by reading
+'fwlog/resolution'. An example to set the value is::
+
+  # echo 50 > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/resolution
+
+Configuring the number of buffers used to store FW log data
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver stores FW log data in a ring within the driver. The default size of
+the ring is 256 4K buffers. Some use cases may require more or less data so
+the user can change the number of buffers that are allocated for FW log data.
+To change the number of buffers write to 'fwlog/nr_buffs'. The value must be a
+power of two and between the values 64-512. FW logging must be disabled to
+change the value. An example of changing the value is::
+
+  # echo 128 > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/nr_buffs
+
+
 Performance Optimization
 ========================
 Driver defaults are meant to fit a wide variety of workloads, but if further
-- 
2.38.1