mei: use hbm idle state to prevent spurious resets

commit 66ae460b13c31a176b41550259683c841a62af3e upstream.

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

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>

diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index 0a0448326e9d583f951932b220d90186c59f92b7..98f95614b5b1f2c7b0f0275a7e34de5fae970435 100644 (file)
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -128,6 +128,17 @@ 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;
@@ -577,6 +588,14 @@ void 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:
                version_res = (struct hbm_host_version_response *)mei_msg;

diff --git a/drivers/misc/mei/hbm.h b/drivers/misc/mei/hbm.h
index 4ae2e56e404f8d9a99808c24df94d69e6c21ca3b..210757701207ed85d84427b100c33fe7800661ee 100644 (file)
--- 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 6197018e2f16a24296619442fe6c8744c7c55b88..3fd43b0e69d160e3b800059a3aa08e6784c7f417 100644 (file)
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -139,14 +139,19 @@ void mei_reset(struct mei_device *dev, int interrupts_enabled)
                        dev->dev_state != MEI_DEV_POWER_DOWN &&
                        dev->dev_state != MEI_DEV_POWER_UP);
 
+       /* 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) {
@@ -175,8 +180,6 @@ 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;
@@ -188,6 +191,7 @@ 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 4b59cb742dee9bac451b4cbf5d268083c8534ea7..1b922e971d3eb347121dfe3b70865bb28c898380 100644 (file)
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -536,7 +536,6 @@ 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)
 {
@@ -551,18 +550,24 @@ 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) {