mei: add vtag support bit in client properties

Vtag support is on a client basis, meaning not every client
supports it. The vtag capability is communicated via the client properties
structure during client enumeration process.
Export the propertiy via sysfs.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20200818115147.2567012-4-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-mei

@@ -41,6 +41,13 @@ Contact:	Tomas Winkler <tomas.winkler@intel.com>
 Description:	Stores mei client fixed address, if any
 		Format: %d
 
+What:		/sys/bus/mei/devices/.../vtag
+Date:		Nov 2020
+KernelVersion:	5.9
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:	Stores mei client vtag support status
+		Format: %d
+
 What:		/sys/bus/mei/devices/.../max_len
 Date:		Nov 2019
 KernelVersion:	5.5

drivers/misc/mei/bus.c

@@ -810,6 +810,16 @@ static ssize_t fixed_show(struct device *dev, struct device_attribute *a,
 }
 static DEVICE_ATTR_RO(fixed);
 
+static ssize_t vtag_show(struct device *dev, struct device_attribute *a,
+			 char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	bool vt = mei_me_cl_vt(cldev->me_cl);
+
+	return sprintf(buf, "%d", vt);
+}
+static DEVICE_ATTR_RO(vtag);
+
 static ssize_t max_len_show(struct device *dev, struct device_attribute *a,
 			    char *buf)
 {
@@ -827,6 +837,7 @@ static struct attribute *mei_cldev_attrs[] = {
 	&dev_attr_modalias.attr,
 	&dev_attr_max_conn.attr,
 	&dev_attr_fixed.attr,
+	&dev_attr_vtag.attr,
 	&dev_attr_max_len.attr,
 	NULL,
 };

drivers/misc/mei/client.h

@@ -93,6 +93,18 @@ static inline u8 mei_me_cl_fixed(const struct mei_me_client *me_cl)
 	return me_cl->props.fixed_address;
 }
 
+/**
+ * mei_me_cl_vt - return me client vtag supported status
+ *
+ * @me_cl: me client
+ *
+ * Return: true if me client supports vt tagging
+ */
+static inline bool mei_me_cl_vt(const struct mei_me_client *me_cl)
+{
+	return me_cl->props.vt_supported == 1;
+}
+
 /**
  * mei_me_cl_max_len - return me client max msg length
  *

drivers/misc/mei/debugfs.c

@@ -27,7 +27,7 @@ static int mei_dbgfs_meclients_show(struct seq_file *m, void *unused)
 
 	down_read(&dev->me_clients_rwsem);
 
-	seq_puts(m, "  |id|fix|         UUID                       |con|msg len|sb|refc|\n");
+	seq_puts(m, "  |id|fix|         UUID                       |con|msg len|sb|refc|vt|\n");
 
 	/*  if the driver is not enabled the list won't be consistent */
 	if (dev->dev_state != MEI_DEV_ENABLED)
@@ -37,14 +37,15 @@ static int mei_dbgfs_meclients_show(struct seq_file *m, void *unused)
 		if (!mei_me_cl_get(me_cl))
 			continue;
 
-		seq_printf(m, "%2d|%2d|%3d|%pUl|%3d|%7d|%2d|%4d|\n",
+		seq_printf(m, "%2d|%2d|%3d|%pUl|%3d|%7d|%2d|%4d|%2d|\n",
 			   i++, me_cl->client_id,
 			   me_cl->props.fixed_address,
 			   &me_cl->props.protocol_name,
 			   me_cl->props.max_number_of_connections,
 			   me_cl->props.max_msg_length,
 			   me_cl->props.single_recv_buf,
-			   kref_read(&me_cl->refcnt));
+			   kref_read(&me_cl->refcnt),
+			   me_cl->props.vt_supported);
 		mei_me_cl_put(me_cl);
 	}
 

drivers/misc/mei/hw.h

@@ -314,13 +314,26 @@ struct hbm_host_enum_response {
 	u8 valid_addresses[32];
 } __packed;
 
+/**
+ * struct mei_client_properties - mei client properties
+ *
+ * @protocol_name: guid of the client
+ * @protocol_version: client protocol version
+ * @max_number_of_connections: number of possible connections.
+ * @fixed_address: fixed me address (0 if the client is dynamic)
+ * @single_recv_buf: 1 if all connections share a single receive buffer.
+ * @vt_supported: the client support vtag
+ * @reserved: reserved
+ * @max_msg_length: MTU of the client
+ */
 struct mei_client_properties {
 	uuid_le protocol_name;
 	u8 protocol_version;
 	u8 max_number_of_connections;
 	u8 fixed_address;
 	u8 single_recv_buf:1;
-	u8 reserved:7;
+	u8 vt_supported:1;
+	u8 reserved:6;
 	u32 max_msg_length;
 } __packed;