iwlwifi: add debugfs to control stuck queue timer

In current implementation, stuck queue timer is fixed to 1 second. Add
debugfs file to modify the timer to enhance the flexibility:

Set the monitor_period as following:
   0: disable stuck queue force reset function
   1 - 60000: monitor period (1 - 60 second)

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

3 files changed, 39 insertions, 6 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index 13d2dcea85d1..34cba38f1d0c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -2697,12 +2697,14 @@ void iwl_bg_monitor_recover(unsigned long data)
                                 return;
                 }
         }
-        /*
-         * Reschedule the timer to occur in
-         * priv->cfg->monitor_recover_period
-         */
-        mod_timer(&priv->monitor_recover,
-                jiffies + msecs_to_jiffies(priv->cfg->monitor_recover_period));
+        if (priv->cfg->monitor_recover_period) {
+                /*
+                 * Reschedule the timer to occur in
+                 * priv->cfg->monitor_recover_period
+                 */
+                mod_timer(&priv->monitor_recover, jiffies + msecs_to_jiffies(
+                          priv->cfg->monitor_recover_period));
+        }
 }
 EXPORT_SYMBOL(iwl_bg_monitor_recover);
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-debugfs.c b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
index d3acdae72381..aae9eb552350 100644
--- a/drivers/net/wireless/iwlwifi/iwl-debugfs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
@@ -1527,6 +1527,34 @@ static ssize_t iwl_dbgfs_ucode_bt_stats_read(struct file *file,
                         user_buf, count, ppos);
 }
 
+static ssize_t iwl_dbgfs_monitor_period_write(struct file *file,
+                                        const char __user *user_buf,
+                                        size_t count, loff_t *ppos) {
+
+        struct iwl_priv *priv = file->private_data;
+        char buf[8];
+        int buf_size;
+        int period;
+
+        memset(buf, 0, sizeof(buf));
+        buf_size = min(count, sizeof(buf) -  1);
+        if (copy_from_user(buf, user_buf, buf_size))
+                return -EFAULT;
+        if (sscanf(buf, "%d", &period) != 1)
+                return -EINVAL;
+        if (period < 0 || period > IWL_MAX_MONITORING_PERIOD)
+                priv->cfg->monitor_recover_period = IWL_DEF_MONITORING_PERIOD;
+        else
+                priv->cfg->monitor_recover_period = period;
+
+        if (priv->cfg->monitor_recover_period)
+                mod_timer(&priv->monitor_recover, jiffies + msecs_to_jiffies(
+                          priv->cfg->monitor_recover_period));
+        else
+                del_timer_sync(&priv->monitor_recover);
+        return count;
+}
+
 DEBUGFS_READ_FILE_OPS(rx_statistics);
 DEBUGFS_READ_FILE_OPS(tx_statistics);
 DEBUGFS_READ_WRITE_FILE_OPS(traffic_log);
@@ -1550,6 +1578,7 @@ DEBUGFS_READ_FILE_OPS(rxon_flags);
 DEBUGFS_READ_FILE_OPS(rxon_filter_flags);
 DEBUGFS_WRITE_FILE_OPS(txfifo_flush);
 DEBUGFS_READ_FILE_OPS(ucode_bt_stats);
+DEBUGFS_WRITE_FILE_OPS(monitor_period);
 
 /*
  * Create the debugfs files and directories
@@ -1621,6 +1650,7 @@ int iwl_dbgfs_register(struct iwl_priv *priv, const char *name)
                 DEBUGFS_ADD_FILE(ucode_bt_stats, dir_debug, S_IRUSR);
         DEBUGFS_ADD_FILE(rxon_flags, dir_debug, S_IWUSR);
         DEBUGFS_ADD_FILE(rxon_filter_flags, dir_debug, S_IWUSR);
+        DEBUGFS_ADD_FILE(monitor_period, dir_debug, S_IWUSR);
         if (priv->cfg->sensitivity_calib_by_driver)
                 DEBUGFS_ADD_BOOL(disable_sensitivity, dir_rf,
                                  &priv->disable_sens_cal);
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 7a96d9dd1732..bb92a7f01988 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1064,6 +1064,7 @@ struct iwl_event_log {
 #define IWL_DEF_MONITORING_PERIOD       (1000)
 #define IWL_LONG_MONITORING_PERIOD      (5000)
 #define IWL_ONE_HUNDRED_MSECS   (100)
+#define IWL_MAX_MONITORING_PERIOD       (60000)
 
 /* BT Antenna Coupling Threshold (dB) */
 #define IWL_BT_ANTENNA_COUPLING_THRESHOLD       (35)