4 files changed, 43 insertions, 14 deletions

diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index 8109b9a98cc3..836f92db7983 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -126,6 +126,17 @@ static bool is_treat_specially_client(struct mei_cl *cl,
         return false;
 }
 
+/**
+ * mei_hbm_idle - set hbm to idle state
+ *
+ * @dev: the device structure
+ */
+void mei_hbm_idle(struct mei_device *dev)
+{
+        dev->init_clients_timer = 0;
+        dev->hbm_state = MEI_HBM_IDLE;
+}
+
 int mei_hbm_start_wait(struct mei_device *dev)
 {
         int ret;
@@ -583,6 +594,14 @@ int mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr)
         mei_read_slots(dev, dev->rd_msg_buf, hdr->length);
         mei_msg = (struct mei_bus_message *)dev->rd_msg_buf;
 
+        /* ignore spurious message and prevent reset nesting
+         * hbm is put to idle during system reset
+         */
+        if (dev->hbm_state == MEI_HBM_IDLE) {
+                dev_dbg(&dev->pdev->dev, "hbm: state is idle ignore spurious messages\n");
+                return 0;
+        }
+
         switch (mei_msg->hbm_cmd) {
         case HOST_START_RES_CMD:
                 dev_dbg(&dev->pdev->dev, "hbm: start: response message received.\n");
diff --git a/drivers/misc/mei/hbm.h b/drivers/misc/mei/hbm.h
index f2540fff7080..5f92188a5cd7 100644
--- a/drivers/misc/mei/hbm.h
+++ b/drivers/misc/mei/hbm.h
@@ -49,6 +49,7 @@ static inline void mei_hbm_hdr(struct mei_msg_hdr *hdr, size_t length)
         hdr->reserved = 0;
 }
 
+void mei_hbm_idle(struct mei_device *dev);
 int mei_hbm_start_req(struct mei_device *dev);
 int mei_hbm_start_wait(struct mei_device *dev);
 int mei_hbm_cl_flow_control_req(struct mei_device *dev, struct mei_cl *cl);
diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index 87c077bae5d8..c47fa273879e 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -129,14 +129,19 @@ void mei_reset(struct mei_device *dev, int interrupts_enabled)
                 dev_warn(&dev->pdev->dev, "unexpected reset: dev_state = %s\n",
                          mei_dev_state_str(dev->dev_state));
 
+        /* we're already in reset, cancel the init timer
+         * if the reset was called due the hbm protocol error
+         * we need to call it before hw start
+         * so the hbm watchdog won't kick in
+         */
+        mei_hbm_idle(dev);
+
         ret = mei_hw_reset(dev, interrupts_enabled);
         if (ret) {
                 dev_err(&dev->pdev->dev, "hw reset failed disabling the device\n");
                 interrupts_enabled = false;
-                dev->dev_state = MEI_DEV_DISABLED;
         }
 
-        dev->hbm_state = MEI_HBM_IDLE;
 
         if (dev->dev_state != MEI_DEV_INITIALIZING &&
             dev->dev_state != MEI_DEV_POWER_UP) {
@@ -160,8 +165,6 @@ void mei_reset(struct mei_device *dev, int interrupts_enabled)
                 memset(&dev->wr_ext_msg, 0, sizeof(dev->wr_ext_msg));
         }
 
-        /* we're already in reset, cancel the init timer */
-        dev->init_clients_timer = 0;
 
         dev->me_clients_num = 0;
         dev->rd_msg_hdr = 0;
@@ -169,6 +172,7 @@ void mei_reset(struct mei_device *dev, int interrupts_enabled)
 
         if (!interrupts_enabled) {
                 dev_dbg(&dev->pdev->dev, "intr not enabled end of reset\n");
+                dev->dev_state = MEI_DEV_DISABLED;
                 return;
         }
 
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) {