iwlwifi: add continuous uCode event log capability

In order to help uCode debugging, adding the capability to provide
continuous uCode event logging function.

uCode events is located in round-robin event queue and filled by uCode,
by enable continuous event logging, driver check the write pointer
and log the newly added events in iwl_bg_ucode_trace() timer function.

There is still possibility of missing events if event queue being
wrapped before next event dump; but with this capability, we can have
much better understanding of the uCode behavior during runtime; it can
help to debug the uCode related issues.

Methods to enable/disable the continuous event log:
step 1: enable ucode trace timer
     "echo 1 >
/sys/kernel/debug/ieee80211/phyX/iwlagn/debug/ucode_tracing"
step 2: start ftrace
     sudo ./trace-cmd record -e iwlwifi_ucode:* sleep 1d
step 3: stop ftrace
     sudo ./trace-cmd report trace.dat
step 4: disable ucode trace timer
     "echo 0 >
/sys/kernel/debug/ieee80211/phyX/iwlagn/debug/ucode_tracing"

use "ucode_tracing" debugfs file to display number of event
queue wrapped when driver attempt the continuous event logging. If event
queue being wrapped more than once when driver has opportunity to log
the event; it indicated there are events missing in the event log trace.

This continuous event log function only available for 4965 and newer
NICs.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 2673e9a4db92..b3a29c7cdbc0 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -984,6 +984,32 @@ struct iwl_switch_rxon {
 	__le16 channel;
 };
 
+/*
+ * schedule the timer to wake up every UCODE_TRACE_PERIOD milliseconds
+ * to perform continuous uCode event logging operation if enabled
+ */
+#define UCODE_TRACE_PERIOD (100)
+
+/*
+ * iwl_event_log: current uCode event log position
+ *
+ * @ucode_trace: enable/disable ucode continuous trace timer
+ * @num_wraps: how many times the event buffer wraps
+ * @next_entry:  the entry just before the next one that uCode would fill
+ * @non_wraps_count: counter for no wrap detected when dump ucode events
+ * @wraps_once_count: counter for wrap once detected when dump ucode events
+ * @wraps_more_count: counter for wrap more than once detected
+ *		      when dump ucode events
+ */
+struct iwl_event_log {
+	bool ucode_trace;
+	u32 num_wraps;
+	u32 next_entry;
+	int non_wraps_count;
+	int wraps_once_count;
+	int wraps_more_count;
+};
+
 struct iwl_priv {
 
 	/* ieee device used by generic ieee processing code */
@@ -1261,6 +1287,7 @@ struct iwl_priv {
 	u32 disable_tx_power_cal;
 	struct work_struct run_time_calib_work;
 	struct timer_list statistics_periodic;
+	struct timer_list ucode_trace;
 	bool hw_ready;
 	/*For 3945*/
 #define IWL_DEFAULT_TX_POWER 0x0F
@@ -1268,6 +1295,8 @@ struct iwl_priv {
 	struct iwl3945_notif_statistics statistics_39;
 
 	u32 sta_supp_rates;
+
+	struct iwl_event_log event_log;
 }; /*iwl_priv */
 
 static inline void iwl_txq_ctx_activate(struct iwl_priv *priv, int txq_id)