mei: support HBM versioning

Driver can work properly if device support driver HBM version
or driver can downgrade its supported HBM version level

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

3 files changed, 34 insertions, 8 deletions

diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index 6916045166eb..565027b1bc73 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -536,6 +536,20 @@ static void mei_hbm_fw_disconnect_req(struct mei_device *dev,
 
 
 /**
+ * mei_hbm_version_is_supported - checks whether the driver can
+ *     support the hbm version of the device
+ *
+ * @dev: the device structure
+ * returns true if driver can support hbm version of the device
+ */
+bool mei_hbm_version_is_supported(struct mei_device *dev)
+{
+        return  (dev->version.major_version < HBM_MAJOR_VERSION) ||
+                (dev->version.major_version == HBM_MAJOR_VERSION &&
+                 dev->version.minor_version <= HBM_MINOR_VERSION);
+}
+
+/**
  * mei_hbm_dispatch - bottom half read routine after ISR to
  * handle the read bus message cmd processing.
  *
@@ -562,9 +576,24 @@ void mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr)
         switch (mei_msg->hbm_cmd) {
         case HOST_START_RES_CMD:
                 version_res = (struct hbm_host_version_response *)mei_msg;
-                if (!version_res->host_version_supported) {
-                        dev->version = version_res->me_max_version;
-                        dev_dbg(&dev->pdev->dev, "version mismatch.\n");
+
+                dev_dbg(&dev->pdev->dev, "HBM VERSION: DRIVER=%02d:%02d DEVICE=%02d:%02d\n",
+                                HBM_MAJOR_VERSION, HBM_MINOR_VERSION,
+                                version_res->me_max_version.major_version,
+                                version_res->me_max_version.minor_version);
+
+                if (version_res->host_version_supported) {
+                        dev->version.major_version = HBM_MAJOR_VERSION;
+                        dev->version.minor_version = HBM_MINOR_VERSION;
+                } else {
+                        dev->version.major_version =
+                                version_res->me_max_version.major_version;
+                        dev->version.minor_version =
+                                version_res->me_max_version.minor_version;
+                }
+
+                if (!mei_hbm_version_is_supported(dev)) {
+                        dev_warn(&dev->pdev->dev, "hbm version mismatch: stopping the driver.\n");
 
                         dev->hbm_state = MEI_HBM_STOP;
                         mei_hbm_stop_req_prepare(dev, &dev->wr_msg.hdr,
@@ -575,8 +604,6 @@ void mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr)
                         return;
                 }
 
-                dev->version.major_version = HBM_MAJOR_VERSION;
-                dev->version.minor_version = HBM_MINOR_VERSION;
                 if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
                     dev->hbm_state == MEI_HBM_START) {
                         dev->init_clients_timer = 0;
diff --git a/drivers/misc/mei/hbm.h b/drivers/misc/mei/hbm.h
index e80dc24ef3e2..4ae2e56e404f 100644
--- a/drivers/misc/mei/hbm.h
+++ b/drivers/misc/mei/hbm.h
@@ -54,7 +54,7 @@ int mei_hbm_start_wait(struct mei_device *dev);
 int mei_hbm_cl_flow_control_req(struct mei_device *dev, struct mei_cl *cl);
 int mei_hbm_cl_disconnect_req(struct mei_device *dev, struct mei_cl *cl);
 int mei_hbm_cl_connect_req(struct mei_device *dev, struct mei_cl *cl);
-
+bool mei_hbm_version_is_supported(struct mei_device *dev);
 
 #endif /* _MEI_HBM_H_ */
 
diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index f580d30bb784..79e9e1c30562 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -106,8 +106,7 @@ int mei_start(struct mei_device *dev)
                 goto err;
         }
 
-        if (dev->version.major_version != HBM_MAJOR_VERSION ||
-            dev->version.minor_version != HBM_MINOR_VERSION) {
+        if (!mei_hbm_version_is_supported(dev)) {
                 dev_dbg(&dev->pdev->dev, "MEI start failed.\n");
                 goto err;
         }