greybus: greybus_protocols: add missing version-request definition

Add the missing version-request definition that was falsely claimed to
be empty.

Update the generic version-request helper and SVC version-request
handler to use the request definition rather than rely on the response
happening to have the same layout, something which also improves
readability.

Remove a misplaced "Control Protocol" header while at it.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/greybus_protocols.h

@@ -103,9 +103,11 @@ struct gb_operation_msg_hdr {
 #define GB_REQUEST_TYPE_INVALID			0x00
 #define GB_REQUEST_TYPE_PROTOCOL_VERSION	0x01
 
-/* Control Protocol */
+struct gb_protocol_version_request {
+	__u8	major;
+	__u8	minor;
+} __packed;
 
-/* version request has no payload */
 struct gb_protocol_version_response {
 	__u8	major;
 	__u8	minor;
@@ -748,7 +750,10 @@ struct gb_spi_transfer_response {
 #define GB_SVC_TYPE_ROUTE_CREATE	0x0b
 #define GB_SVC_TYPE_ROUTE_DESTROY	0x0c
 
-/* SVC version request/response have same payload as gb_protocol_version_response */
+/*
+ * SVC version request/response has the same payload as
+ * gb_protocol_version_request/response.
+ */
 
 /* SVC protocol hello request */
 struct gb_svc_hello_request {

drivers/staging/greybus/protocol.c

@@ -165,30 +165,31 @@ struct gb_protocol *gb_protocol_get(u8 id, u8 major, u8 minor)
 
 int gb_protocol_get_version(struct gb_connection *connection)
 {
-	struct gb_protocol_version_response version;
+	struct gb_protocol_version_request request;
+	struct gb_protocol_version_response response;
 	int retval;
 
-	version.major = connection->protocol->major;
-	version.minor = connection->protocol->minor;
+	request.major = connection->protocol->major;
+	request.minor = connection->protocol->minor;
 
 	retval = gb_operation_sync(connection, GB_REQUEST_TYPE_PROTOCOL_VERSION,
-				   &version, sizeof(version), &version,
-				   sizeof(version));
+				   &request, sizeof(request), &response,
+				   sizeof(response));
 	if (retval)
 		return retval;
 
-	if (version.major > connection->protocol->major) {
+	if (response.major > connection->protocol->major) {
 		dev_err(&connection->dev,
 			"unsupported major version (%hhu > %hhu)\n",
-			version.major, connection->protocol->major);
+			response.major, connection->protocol->major);
 		return -ENOTSUPP;
 	}
 
-	connection->module_major = version.major;
-	connection->module_minor = version.minor;
+	connection->module_major = response.major;
+	connection->module_minor = response.minor;
 
 	dev_dbg(&connection->dev, "version_major = %u version_minor = %u\n",
-		version.major, version.minor);
+		response.major, response.minor);
 
 	return 0;
 }

drivers/staging/greybus/svc.c

@@ -256,30 +256,31 @@ static void gb_svc_route_destroy(struct gb_svc *svc, u8 intf1_id, u8 intf2_id)
 static int gb_svc_version_request(struct gb_operation *op)
 {
 	struct gb_connection *connection = op->connection;
-	struct gb_protocol_version_response *version;
+	struct gb_protocol_version_request *request;
+	struct gb_protocol_version_response *response;
 	struct device *dev = &connection->dev;
 
-	version = op->request->payload;
+	request = op->request->payload;
 
-	if (version->major > GB_SVC_VERSION_MAJOR) {
+	if (request->major > GB_SVC_VERSION_MAJOR) {
 		dev_err(&connection->dev,
 			"unsupported major version (%hhu > %hhu)\n",
-			version->major, GB_SVC_VERSION_MAJOR);
+			request->major, GB_SVC_VERSION_MAJOR);
 		return -ENOTSUPP;
 	}
 
-	connection->module_major = version->major;
-	connection->module_minor = version->minor;
+	connection->module_major = request->major;
+	connection->module_minor = request->minor;
 
-	if (!gb_operation_response_alloc(op, sizeof(*version), GFP_KERNEL)) {
+	if (!gb_operation_response_alloc(op, sizeof(*response), GFP_KERNEL)) {
 		dev_err(dev, "%s: error allocating response\n",
 				__func__);
 		return -ENOMEM;
 	}
 
-	version = op->response->payload;
-	version->major = connection->module_major;
-	version->minor = connection->module_minor;
+	response = op->response->payload;
+	response->major = connection->module_major;
+	response->minor = connection->module_minor;
 
 	return 0;
 }