mei: disconnect on connection request timeout

For the FW with  HBM version >= 2.0 we don't need to reset the whole
device in case of a particular client failing to connect, it is enough
to send disconnect a request to bring the device to the stable state.

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

6 files changed, 95 insertions, 29 deletions

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 9dacea7a9a60..40285e02b612 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -836,44 +836,24 @@ int mei_cl_irq_disconnect(struct mei_cl *cl, struct mei_cl_cb *cb,
         return ret;
 }
 
-
-
 /**
- * mei_cl_disconnect - disconnect host client from the me one
+ * __mei_cl_disconnect - disconnect host client from the me one
+ *     internal function runtime pm has to be already acquired
  *
  * @cl: host client
  *
- * Locking: called under "dev->device_lock" lock
- *
  * Return: 0 on success, <0 on failure.
  */
-int mei_cl_disconnect(struct mei_cl *cl)
+static int __mei_cl_disconnect(struct mei_cl *cl)
 {
         struct mei_device *dev;
         struct mei_cl_cb *cb;
         int rets;
 
-        if (WARN_ON(!cl || !cl->dev))
-                return -ENODEV;
-
         dev = cl->dev;
 
-        cl_dbg(dev, cl, "disconnecting");
-
-        if (!mei_cl_is_connected(cl))
-                return 0;
-
-        if (mei_cl_is_fixed_address(cl)) {
-                mei_cl_set_disconnected(cl);
-                return 0;
-        }
-
-        rets = pm_runtime_get(dev->dev);
-        if (rets < 0 && rets != -EINPROGRESS) {
-                pm_runtime_put_noidle(dev->dev);
-                cl_err(dev, cl, "rpm: get failed %d\n", rets);
-                return rets;
-        }
+        if (WARN_ON(!pm_runtime_active(dev->dev)))
+                return -EFAULT;
 
         cl->state = MEI_FILE_DISCONNECTING;
 
@@ -910,11 +890,52 @@ out:
         if (!rets)
                 cl_dbg(dev, cl, "successfully disconnected from FW client.\n");
 
+        mei_io_cb_free(cb);
+        return rets;
+}
+
+/**
+ * mei_cl_disconnect - disconnect host client from the me one
+ *
+ * @cl: host client
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * Return: 0 on success, <0 on failure.
+ */
+int mei_cl_disconnect(struct mei_cl *cl)
+{
+        struct mei_device *dev;
+        int rets;
+
+        if (WARN_ON(!cl || !cl->dev))
+                return -ENODEV;
+
+        dev = cl->dev;
+
+        cl_dbg(dev, cl, "disconnecting");
+
+        if (!mei_cl_is_connected(cl))
+                return 0;
+
+        if (mei_cl_is_fixed_address(cl)) {
+                mei_cl_set_disconnected(cl);
+                return 0;
+        }
+
+        rets = pm_runtime_get(dev->dev);
+        if (rets < 0 && rets != -EINPROGRESS) {
+                pm_runtime_put_noidle(dev->dev);
+                cl_err(dev, cl, "rpm: get failed %d\n", rets);
+                return rets;
+        }
+
+        rets = __mei_cl_disconnect(cl);
+
         cl_dbg(dev, cl, "rpm: autosuspend\n");
         pm_runtime_mark_last_busy(dev->dev);
         pm_runtime_put_autosuspend(dev->dev);
 
-        mei_io_cb_free(cb);
         return rets;
 }
 
@@ -1059,11 +1080,23 @@ int mei_cl_connect(struct mei_cl *cl, struct mei_me_client *me_cl,
         mutex_unlock(&dev->device_lock);
         wait_event_timeout(cl->wait,
                         (cl->state == MEI_FILE_CONNECTED ||
+                         cl->state == MEI_FILE_DISCONNECT_REQUIRED ||
                          cl->state == MEI_FILE_DISCONNECT_REPLY),
                         mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
         mutex_lock(&dev->device_lock);
 
         if (!mei_cl_is_connected(cl)) {
+                if (cl->state == MEI_FILE_DISCONNECT_REQUIRED) {
+                        mei_io_list_flush(&dev->ctrl_rd_list, cl);
+                        mei_io_list_flush(&dev->ctrl_wr_list, cl);
+                         /* ignore disconnect return valuue;
+                          * in case of failure reset will be invoked
+                          */
+                        __mei_cl_disconnect(cl);
+                        rets = -EFAULT;
+                        goto out;
+                }
+
                 /* timeout or something went really wrong */
                 if (!cl->status)
                         cl->status = -EFAULT;
diff --git a/drivers/misc/mei/debugfs.c b/drivers/misc/mei/debugfs.c
index a65a1e6f386f..e39cfe6bc5bc 100644
--- a/drivers/misc/mei/debugfs.c
+++ b/drivers/misc/mei/debugfs.c
@@ -156,6 +156,8 @@ static ssize_t mei_dbgfs_read_devstate(struct file *fp, char __user *ubuf,
                                  dev->hbm_f_pg_supported);
                 pos += scnprintf(buf + pos, bufsz - pos, "\tDC: %01d\n",
                                  dev->hbm_f_dc_supported);
+                pos += scnprintf(buf + pos, bufsz - pos, "\tDOT: %01d\n",
+                                 dev->hbm_f_dot_supported);
         }
 
         pos += scnprintf(buf + pos, bufsz - pos, "pg:  %s, %s\n",
diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index d4dba639db37..07a8ea8362a3 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -774,6 +774,10 @@ static void mei_hbm_config_features(struct mei_device *dev)
 
         if (dev->version.major_version >= HBM_MAJOR_VERSION_DC)
                 dev->hbm_f_dc_supported = 1;
+
+        /* disconnect on connect timeout instead of link reset */
+        if (dev->version.major_version >= HBM_MAJOR_VERSION_DOT)
+                dev->hbm_f_dot_supported = 1;
 }
 
 /**
diff --git a/drivers/misc/mei/hw.h b/drivers/misc/mei/hw.h
index 815f40a604b9..e961be392fae 100644
--- a/drivers/misc/mei/hw.h
+++ b/drivers/misc/mei/hw.h
@@ -52,6 +52,12 @@
 #define HBM_MINOR_VERSION_DC               0
 #define HBM_MAJOR_VERSION_DC               2
 
+/*
+ * MEI version with disconnect on connection timeout support
+ */
+#define HBM_MINOR_VERSION_DOT              0
+#define HBM_MAJOR_VERSION_DOT              2
+
 /* Host bus message command opcode */
 #define MEI_HBM_CMD_OP_MSK                  0x7f
 /* Host bus message command RESPONSE */
diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 3f3405269c39..89d8e1304077 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -424,6 +424,24 @@ int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list)
 EXPORT_SYMBOL_GPL(mei_irq_write_handler);
 
 
+/**
+ * mei_connect_timeout  - connect/disconnect timeouts
+ *
+ * @cl: host client
+ */
+static void mei_connect_timeout(struct mei_cl *cl)
+{
+        struct mei_device *dev = cl->dev;
+
+        if (cl->state == MEI_FILE_CONNECTING) {
+                if (dev->hbm_f_dot_supported) {
+                        cl->state = MEI_FILE_DISCONNECT_REQUIRED;
+                        wake_up(&cl->wait);
+                        return;
+                }
+        }
+        mei_reset(dev);
+}
 
 /**
  * mei_timer - timer function.
@@ -464,7 +482,7 @@ void mei_timer(struct work_struct *work)
                 if (cl->timer_count) {
                         if (--cl->timer_count == 0) {
                                 dev_err(dev->dev, "timer: connect/disconnect timeout.\n");
-                                mei_reset(dev);
+                                mei_connect_timeout(cl);
                                 goto out;
                         }
                 }
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 33823f4a1cf2..8bd46cd95b7a 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -89,6 +89,7 @@ enum file_state {
         MEI_FILE_CONNECTED,
         MEI_FILE_DISCONNECTING,
         MEI_FILE_DISCONNECT_REPLY,
+        MEI_FILE_DISCONNECT_REQUIRED,
         MEI_FILE_DISCONNECTED,
 };
 
@@ -407,8 +408,9 @@ const char *mei_pg_state_str(enum mei_pg_state state);
  * @wr_msg      : the buffer for hbm control messages
  *
  * @version     : HBM protocol version in use
- * @hbm_f_pg_supported : hbm feature pgi protocol
- * @hbm_f_dc_supported : hbm feature dynamic clients
+ * @hbm_f_pg_supported  : hbm feature pgi protocol
+ * @hbm_f_dc_supported  : hbm feature dynamic clients
+ * @hbm_f_dot_supported : hbm feature disconnect on timeout
  *
  * @me_clients_rwsem: rw lock over me_clients list
  * @me_clients  : list of FW clients
@@ -503,6 +505,7 @@ struct mei_device {
         struct hbm_version version;
         unsigned int hbm_f_pg_supported:1;
         unsigned int hbm_f_dc_supported:1;
+        unsigned int hbm_f_dot_supported:1;
 
         struct rw_semaphore me_clients_rwsem;
         struct list_head me_clients;