iwlwifi: Tune radio to prevent unexpected behavior

We have seen the throughput dropped due to external noisy environment
and the radio is out of tune.  There are lot of plcp errors indicating
this condition. Eventually the station can get de-authenticated by the
Access Point.  By resetting and tuning the radio, the plcp errors are
reduced or eliminated and the throughput starts to rise.

To prevent unexpected behavior such as drop in throughput or deauthentication,
- The change provides the driver feature to monitor and tune the radio base on
the statistics notification from the uCode.
- It also allows the setting of the plcp error rate threshold via
the plcp_delta under debugfs interface.

Signed-off-by: Trieu 'Andrew' Nguyen <trieux.t.nguyen@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 86d38ae2ec7..a1f3ecb69ed 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1026,6 +1026,15 @@ struct iwl_event_log {
 #define IWL_HOST_INT_CALIB_TIMEOUT_DEF  (0x10)
 #define IWL_HOST_INT_CALIB_TIMEOUT_MIN  (0x0)
 
+/*
+ * This is the threshold value of plcp error rate per 100mSecs.  It is
+ * used to set and check for the validity of plcp_delta.
+ */
+#define IWL_MAX_PLCP_ERR_THRESHOLD_MIN  (0)
+#define IWL_MAX_PLCP_ERR_THRESHOLD_DEF  (50)
+#define IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF     (100)
+#define IWL_MAX_PLCP_ERR_THRESHOLD_MAX  (255)
+
 struct iwl_priv {
 
         /* ieee device used by generic ieee processing code */
@@ -1055,6 +1064,9 @@ struct iwl_priv {
         u32 ucode_beacon_time;
         int missed_beacon_threshold;
 
+        /* storing the jiffies when the plcp error rate is received */
+        unsigned long plcp_jiffies;
+
         /* we allocate array of iwl4965_channel_info for NIC's valid channels.
          *    Access via channel # using indirect index array */
         struct iwl_channel_info *channel_info;  /* channel info array */