mei: use hbm idle state to prevent spurious resets

When reset is caused by hbm protocol mismatch or timeout
we might end up in an endless reset loop and hbm protocol
will never sync

Cc: <stable@vger.kernel.org>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 15 insertions, 10 deletions

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index bbb61bec863b..206dbe99bedd 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -537,7 +537,6 @@ EXPORT_SYMBOL_GPL(mei_irq_write_handler);
  *
  * @work: pointer to the work_struct structure
  *
- * NOTE: This function is called by timer interrupt work
  */
 void mei_timer(struct work_struct *work)
 {
@@ -552,18 +551,24 @@ void mei_timer(struct work_struct *work)
 
 
         mutex_lock(&dev->device_lock);
-        if (dev->dev_state != MEI_DEV_ENABLED) {
-                if (dev->dev_state == MEI_DEV_INIT_CLIENTS) {
-                        if (dev->init_clients_timer) {
-                                if (--dev->init_clients_timer == 0) {
-                                        dev_err(&dev->pdev->dev, "reset: init clients timeout hbm_state = %d.\n",
-                                                dev->hbm_state);
-                                        mei_reset(dev, 1);
-                                }
+
+        /* Catch interrupt stalls during HBM init handshake */
+        if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
+            dev->hbm_state != MEI_HBM_IDLE) {
+
+                if (dev->init_clients_timer) {
+                        if (--dev->init_clients_timer == 0) {
+                                dev_err(&dev->pdev->dev, "timer: init clients timeout hbm_state = %d.\n",
+                                        dev->hbm_state);
+                                mei_reset(dev, 1);
+                                goto out;
                         }
                 }
-                goto out;
         }
+
+        if (dev->dev_state != MEI_DEV_ENABLED)
+                goto out;
+
         /*** connect/disconnect timeouts ***/
         list_for_each_entry_safe(cl_pos, cl_next, &dev->file_list, link) {
                 if (cl_pos->timer_count) {