iwlwifi: new debugging feature for dumping data traffic

The traffic buffer will only beallocated and used if either bit 23
(IWL_DX_TX) or bit 24 (IWL_DL_RX) of "debug" is set;
example: "debug=0x800000" - log tx data traffic
         "debug=0x1000000" - log rx data traffic
         "debug=0x1800000" - log both tx and rx traffic

The traffic log will store the beginning portion (64 bytes)  of the
latest 256 of tx and rx packets in the round-robbin buffer for
debugging,
user can examine the log through debugfs file.

How to display the current logged tx/rx traffic and txfifo and rxfifo
read/write point:
"cat traffic_log" in /sys/kernel/debug/ieee80211/phy0/iwlagn/debug
directory

By echo "0" to traffic_log file will empty the traffic log buffer and
reset both tx and rx taffic log index to 0.

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>
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 624656a..899b75f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -877,6 +877,8 @@
 #define	EEPROM_SEM_TIMEOUT 10		/* milliseconds */
 #define EEPROM_SEM_RETRY_LIMIT 1000	/* number of attempts (not time) */
 
+#define IWL_TRAFFIC_ENTRIES	(256)
+#define IWL_TRAFFIC_ENTRY_SIZE  (64)
 
 enum {
 	MEASUREMENT_READY = (1 << 0),
@@ -1182,6 +1184,10 @@
 	bool disable_ht40;
 #ifdef CONFIG_IWLWIFI_DEBUGFS
 	/* debugfs */
+	u16 tx_traffic_idx;
+	u16 rx_traffic_idx;
+	u8 *tx_traffic;
+	u8 *rx_traffic;
 	struct iwl_debugfs *dbgfs;
 #endif /* CONFIG_IWLWIFI_DEBUGFS */
 #endif /* CONFIG_IWLWIFI_DEBUG */