iwl3945: add plcp error checking

Add plcp error checking for 3945. After threshold of plcp
is reached , it resets the radio

Signed-off-by: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

3 files changed, 69 insertions, 3 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-3945.c b/drivers/net/wireless/iwlwifi/iwl-3945.c
index a4d842a05836..05d808b28777 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945.c
@@ -390,6 +390,67 @@ static void iwl3945_accumulative_statistics(struct iwl_priv *priv,
 }
 #endif
 
+/**
+ * iwl3945_good_plcp_health - checks for plcp error.
+ *
+ * When the plcp error is exceeding the thresholds, reset the radio
+ * to improve the throughput.
+ */
+static bool iwl3945_good_plcp_health(struct iwl_priv *priv,
+                                struct iwl_rx_packet *pkt)
+{
+        bool rc = true;
+        struct iwl3945_notif_statistics current_stat;
+        int combined_plcp_delta;
+        unsigned int plcp_msec;
+        unsigned long plcp_received_jiffies;
+
+        memcpy(&current_stat, pkt->u.raw, sizeof(struct
+                        iwl3945_notif_statistics));
+        /*
+         * check for plcp_err and trigger radio reset if it exceeds
+         * the plcp error threshold plcp_delta.
+         */
+        plcp_received_jiffies = jiffies;
+        plcp_msec = jiffies_to_msecs((long) plcp_received_jiffies -
+                                        (long) priv->plcp_jiffies);
+        priv->plcp_jiffies = plcp_received_jiffies;
+        /*
+         * check to make sure plcp_msec is not 0 to prevent division
+         * by zero.
+         */
+        if (plcp_msec) {
+                combined_plcp_delta =
+                        (le32_to_cpu(current_stat.rx.ofdm.plcp_err) -
+                        le32_to_cpu(priv->_3945.statistics.rx.ofdm.plcp_err));
+
+                if ((combined_plcp_delta > 0) &&
+                        ((combined_plcp_delta * 100) / plcp_msec) >
+                        priv->cfg->plcp_delta_threshold) {
+                        /*
+                         * if plcp_err exceed the threshold, the following
+                         * data is printed in csv format:
+                         *    Text: plcp_err exceeded %d,
+                         *    Received ofdm.plcp_err,
+                         *    Current ofdm.plcp_err,
+                         *    combined_plcp_delta,
+                         *    plcp_msec
+                         */
+                        IWL_DEBUG_RADIO(priv, "plcp_err exceeded %u, "
+                                "%u, %d, %u mSecs\n",
+                                priv->cfg->plcp_delta_threshold,
+                                le32_to_cpu(current_stat.rx.ofdm.plcp_err),
+                                combined_plcp_delta, plcp_msec);
+                        /*
+                         * Reset the RF radio due to the high plcp
+                         * error rate
+                         */
+                        rc = false;
+                }
+        }
+        return rc;
+}
+
 void iwl3945_hw_rx_statistics(struct iwl_priv *priv,
                 struct iwl_rx_mem_buffer *rxb)
 {
@@ -401,6 +462,7 @@ void iwl3945_hw_rx_statistics(struct iwl_priv *priv,
 #ifdef CONFIG_IWLWIFI_DEBUG
         iwl3945_accumulative_statistics(priv, (__le32 *)&pkt->u.raw);
 #endif
+        iwl_recover_from_statistics(priv, pkt);
 
         memcpy(&priv->_3945.statistics, pkt->u.raw, sizeof(priv->_3945.statistics));
 }
@@ -2792,6 +2854,7 @@ static struct iwl_lib_ops iwl3945_lib = {
         .config_ap = iwl3945_config_ap,
         .manage_ibss_station = iwl3945_manage_ibss_station,
         .add_bcast_station = iwl3945_add_bcast_station,
+        .check_plcp_health = iwl3945_good_plcp_health,
 
         .debugfs_ops = {
                 .rx_stats_read = iwl3945_ucode_rx_stats_read,
@@ -2832,7 +2895,7 @@ static struct iwl_cfg iwl3945_bg_cfg = {
         .ht_greenfield_support = false,
         .led_compensation = 64,
         .broken_powersave = true,
-        .plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+        .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
         .monitor_recover_period = IWL_MONITORING_PERIOD,
         .max_event_log_size = 512,
         .tx_power_by_driver = true,
@@ -2853,7 +2916,7 @@ static struct iwl_cfg iwl3945_abg_cfg = {
         .ht_greenfield_support = false,
         .led_compensation = 64,
         .broken_powersave = true,
-        .plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+        .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
         .monitor_recover_period = IWL_MONITORING_PERIOD,
         .max_event_log_size = 512,
         .tx_power_by_driver = true,
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index 2f664a3f0484..7a3f94926c25 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -441,6 +441,8 @@ bool iwl_good_plcp_health(struct iwl_priv *priv,
                                  struct iwl_rx_packet *pkt);
 bool iwl_good_ack_health(struct iwl_priv *priv,
                                  struct iwl_rx_packet *pkt);
+void iwl_recover_from_statistics(struct iwl_priv *priv,
+                                struct iwl_rx_packet *pkt);
 void iwl_rx_statistics(struct iwl_priv *priv,
                               struct iwl_rx_mem_buffer *rxb);
 void iwl_reply_statistics(struct iwl_priv *priv,
diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c
index d661fce000c2..c7c8d8a43eb3 100644
--- a/drivers/net/wireless/iwlwifi/iwl-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-rx.c
@@ -397,7 +397,7 @@ bool iwl_good_plcp_health(struct iwl_priv *priv,
 }
 EXPORT_SYMBOL(iwl_good_plcp_health);
 
-static void iwl_recover_from_statistics(struct iwl_priv *priv,
+void iwl_recover_from_statistics(struct iwl_priv *priv,
                                 struct iwl_rx_packet *pkt)
 {
         if (test_bit(STATUS_EXIT_PENDING, &priv->status))
@@ -428,6 +428,7 @@ static void iwl_recover_from_statistics(struct iwl_priv *priv,
                 }
         }
 }
+EXPORT_SYMBOL(iwl_recover_from_statistics);
 
 void iwl_rx_statistics(struct iwl_priv *priv,
                               struct iwl_rx_mem_buffer *rxb)