iwlwifi: mvm: add a scan timeout for regular scans

If something goes wrong with the firmware and we never get a scan
complete notification, we stay stuck forever.  In order to avoid this
situation, add a timeout and trigger an NMI if it expires before
receiving the notification., so we can clean things up.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

3 files changed, 28 insertions, 0 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h b/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
index cd5f16e9cab4..2d685e02d488 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
@@ -710,6 +710,7 @@ struct iwl_mvm {
         struct iwl_mcast_filter_cmd *mcast_filter_cmd;
         enum iwl_mvm_scan_type scan_type;
         enum iwl_mvm_sched_scan_pass_all_states sched_scan_pass_all;
+        struct timer_list scan_timer;
 
         /* max number of simultaneous scans the FW supports */
         unsigned int max_scans;
@@ -1314,6 +1315,7 @@ int iwl_mvm_scan_size(struct iwl_mvm *mvm);
 int iwl_mvm_scan_stop(struct iwl_mvm *mvm, int type, bool notify);
 int iwl_mvm_max_scan_ie_len(struct iwl_mvm *mvm);
 void iwl_mvm_report_scan_aborted(struct iwl_mvm *mvm);
+void iwl_mvm_scan_timeout(unsigned long data);
 
 /* Scheduled scan */
 void iwl_mvm_rx_lmac_scan_complete_notif(struct iwl_mvm *mvm,
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
index cb0092609595..656541c5360a 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
@@ -728,6 +728,9 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 
         iwl_mvm_tof_init(mvm);
 
+        setup_timer(&mvm->scan_timer, iwl_mvm_scan_timeout,
+                    (unsigned long)mvm);
+
         return op_mode;
 
  out_unregister:
@@ -783,6 +786,8 @@ static void iwl_op_mode_mvm_stop(struct iwl_op_mode *op_mode)
 
         iwl_mvm_tof_clean(mvm);
 
+        del_timer_sync(&mvm->scan_timer);
+
         mutex_destroy(&mvm->mutex);
         mutex_destroy(&mvm->d0i3_suspend_mutex);
 
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
index 25b007cf7db7..c1d1be9c5d01 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
@@ -70,6 +70,7 @@
 
 #include "mvm.h"
 #include "fw-api-scan.h"
+#include "iwl-io.h"
 
 #define IWL_DENSE_EBS_SCAN_RATIO 5
 #define IWL_SPARSE_EBS_SCAN_RATIO 1
@@ -398,6 +399,10 @@ void iwl_mvm_rx_lmac_scan_complete_notif(struct iwl_mvm *mvm,
                 ieee80211_scan_completed(mvm->hw,
                                 scan_notif->status == IWL_SCAN_OFFLOAD_ABORTED);
                 iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
+                del_timer(&mvm->scan_timer);
+        } else {
+                IWL_ERR(mvm,
+                        "got scan complete notification but no scan is running\n");
         }
 
         mvm->last_ebs_successful =
@@ -1217,6 +1222,18 @@ static int iwl_mvm_check_running_scans(struct iwl_mvm *mvm, int type)
         return -EIO;
 }
 
+#define SCAN_TIMEOUT (16 * HZ)
+
+void iwl_mvm_scan_timeout(unsigned long data)
+{
+        struct iwl_mvm *mvm = (struct iwl_mvm *)data;
+
+        IWL_ERR(mvm, "regular scan timed out\n");
+
+        del_timer(&mvm->scan_timer);
+        iwl_force_nmi(mvm->trans);
+}
+
 int iwl_mvm_reg_scan_start(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
                            struct cfg80211_scan_request *req,
                            struct ieee80211_scan_ies *ies)
@@ -1296,6 +1313,8 @@ int iwl_mvm_reg_scan_start(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
         mvm->scan_status |= IWL_MVM_SCAN_REGULAR;
         iwl_mvm_ref(mvm, IWL_MVM_REF_SCAN);
 
+        mod_timer(&mvm->scan_timer, jiffies + SCAN_TIMEOUT);
+
         return 0;
 }
 
@@ -1413,6 +1432,7 @@ void iwl_mvm_rx_umac_scan_complete_notif(struct iwl_mvm *mvm,
         if (mvm->scan_uid_status[uid] == IWL_MVM_SCAN_REGULAR) {
                 ieee80211_scan_completed(mvm->hw, aborted);
                 iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
+                del_timer(&mvm->scan_timer);
         } else if (mvm->scan_uid_status[uid] == IWL_MVM_SCAN_SCHED) {
                 ieee80211_sched_scan_stopped(mvm->hw);
                 mvm->sched_scan_pass_all = SCHED_SCAN_PASS_ALL_DISABLED;
@@ -1608,6 +1628,7 @@ out:
                  * to release the scan reference here.
                  */
                 iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
+                del_timer(&mvm->scan_timer);
                 if (notify)
                         ieee80211_scan_completed(mvm->hw, true);
         } else if (notify) {