greybus: Add control protocol support

Add control protocol driver that is responsible for handling operations
on control CPort. The AP also needs to support incoming requests on its
control port. Features not implemented yet are marked as TODO for now.

NOTE: This also fixes cport-bundle-id to 0 and cport-id to 2 for control
protocol.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/Makefile

@@ -8,6 +8,7 @@ greybus-y :=	core.o		\
 		bundle.o	\
 		connection.o	\
 		protocol.o	\
+		control.o	\
 		operation.o
 
 gb-phy-y :=	gpbridge.o	\

drivers/staging/greybus/control.c

+/*
+ * Greybus CPort control protocol.
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include "greybus.h"
+
+/* Define get_version() routine */
+define_get_version(gb_control, CONTROL);
+
+/* Get Manifest's size from the interface */
+int gb_control_get_manifest_size_operation(struct gb_interface *intf)
+{
+	struct gb_control_get_manifest_size_response response;
+	struct gb_connection *connection = intf->control->connection;
+	int ret;
+
+	ret = gb_operation_sync(connection, GB_CONTROL_TYPE_GET_MANIFEST_SIZE,
+				NULL, 0, &response, sizeof(response));
+	if (ret) {
+		dev_err(&connection->dev,
+			"%s: Manifest size get operation failed (%d)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return le16_to_cpu(response.size);
+}
+
+/* Reads Manifest from the interface */
+int gb_control_get_manifest_operation(struct gb_interface *intf, void *manifest,
+				      size_t size)
+{
+	struct gb_connection *connection = intf->control->connection;
+
+	return gb_operation_sync(connection, GB_CONTROL_TYPE_GET_MANIFEST,
+				NULL, 0, manifest, size);
+}
+
+int gb_control_connected_operation(struct gb_control *control, u16 cport_id)
+{
+	struct gb_control_connected_request request;
+
+	request.cport_id = cpu_to_le16(cport_id);
+	return gb_operation_sync(control->connection, GB_CONTROL_TYPE_CONNECTED,
+				 &request, sizeof(request), NULL, 0);
+}
+
+int gb_control_disconnected_operation(struct gb_control *control, u16 cport_id)
+{
+	struct gb_control_disconnected_request request;
+
+	request.cport_id = cpu_to_le16(cport_id);
+	return gb_operation_sync(control->connection,
+				 GB_CONTROL_TYPE_DISCONNECTED, &request,
+				 sizeof(request), NULL, 0);
+}
+
+static int gb_control_request_recv(u8 type, struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_protocol_version_response *version;
+
+	switch (type) {
+	case GB_CONTROL_TYPE_PROBE_AP:
+		// TODO
+		// Send authenticated block of data, confirming this module is
+		// an AP.
+		break;
+	case GB_CONTROL_TYPE_PROTOCOL_VERSION:
+		if (!gb_operation_response_alloc(op, sizeof(*version))) {
+			dev_err(&connection->dev,
+				"%s: error allocating response\n", __func__);
+			return -ENOMEM;
+		}
+
+		version = op->response->payload;
+		version->major = GB_CONTROL_VERSION_MAJOR;
+		version->minor = GB_CONTROL_VERSION_MINOR;
+		break;
+	case GB_CONTROL_TYPE_CONNECTED:
+	case GB_CONTROL_TYPE_DISCONNECTED:
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+
+	return 0;
+}
+
+static int gb_control_connection_init(struct gb_connection *connection)
+{
+	struct gb_control *control;
+	int ret;
+
+	control = kzalloc(sizeof(*control), GFP_KERNEL);
+	if (!control)
+		return -ENOMEM;
+
+	control->connection = connection;
+	connection->private = control;
+
+	ret = get_version(control);
+	if (ret)
+		kfree(control);
+
+	/* Set interface's control connection */
+	connection->bundle->intf->control = control;
+
+	return ret;
+}
+
+static void gb_control_connection_exit(struct gb_connection *connection)
+{
+	struct gb_control *control = connection->private;
+
+	if (WARN_ON(connection->bundle->intf->control != control))
+		return;
+
+	connection->bundle->intf->control = NULL;
+	kfree(control);
+}
+
+static struct gb_protocol control_protocol = {
+	.name			= "control",
+	.id			= GREYBUS_PROTOCOL_CONTROL,
+	.major			= 0,
+	.minor			= 1,
+	.connection_init	= gb_control_connection_init,
+	.connection_exit	= gb_control_connection_exit,
+	.request_recv		= gb_control_request_recv,
+};
+
+int gb_control_protocol_init(void)
+{
+	return gb_protocol_register(&control_protocol);
+}
+
+void gb_control_protocol_exit(void)
+{
+	gb_protocol_deregister(&control_protocol);
+}

drivers/staging/greybus/control.h

+/*
+ * Greybus CPort control protocol
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __CONTROL_H
+#define __CONTROL_H
+
+struct gb_control {
+	struct gb_connection	*connection;
+	u8			version_major;
+	u8			version_minor;
+};
+
+int gb_control_connected_operation(struct gb_control *control, u16 cport_id);
+int gb_control_disconnected_operation(struct gb_control *control, u16 cport_id);
+int gb_control_get_manifest_size_operation(struct gb_interface *intf);
+int gb_control_get_manifest_operation(struct gb_interface *intf, void *manifest,
+				      size_t size);
+
+int gb_control_protocol_init(void);
+void gb_control_protocol_exit(void);
+#endif /* __CONTROL_H */

drivers/staging/greybus/core.c

@@ -274,8 +274,16 @@ static int __init gb_init(void)
 		goto error_endo;
 	}
 
+	retval = gb_control_protocol_init();
+	if (retval) {
+		pr_err("gb_control_protocol_init failed\n");
+		goto error_control;
+	}
+
 	return 0;	/* Success */
 
+error_control:
+	gb_endo_exit();
 error_endo:
 	gb_operation_exit();
 error_operation:
@@ -291,6 +299,7 @@ module_init(gb_init);
 
 static void __exit gb_exit(void)
 {
+	gb_control_protocol_exit();
 	gb_endo_exit();
 	gb_operation_exit();
 	gb_ap_exit();

drivers/staging/greybus/greybus.h

@@ -28,6 +28,7 @@
 #include "endo.h"
 #include "svc.h"
 #include "module.h"
+#include "control.h"
 #include "interface.h"
 #include "bundle.h"
 #include "connection.h"

drivers/staging/greybus/greybus_protocols.h

@@ -52,6 +52,45 @@
 #ifndef __GREYBUS_PROTOCOLS_H
 #define __GREYBUS_PROTOCOLS_H
 
+/* Control Protocol */
+
+/* Bundle-id and cport-id for control cport */
+#define GB_CONTROL_BUNDLE_ID			0
+#define GB_CONTROL_CPORT_ID			2
+
+/* Version of the Greybus control protocol we support */
+#define GB_CONTROL_VERSION_MAJOR		0x00
+#define GB_CONTROL_VERSION_MINOR		0x01
+
+/* Greybus control request types */
+#define GB_CONTROL_TYPE_INVALID			0x00
+#define GB_CONTROL_TYPE_PROTOCOL_VERSION	0x01
+#define GB_CONTROL_TYPE_PROBE_AP		0x02
+#define GB_CONTROL_TYPE_GET_MANIFEST_SIZE	0x03
+#define GB_CONTROL_TYPE_GET_MANIFEST		0x04
+#define GB_CONTROL_TYPE_CONNECTED		0x05
+#define GB_CONTROL_TYPE_DISCONNECTED		0x06
+
+/* Control protocol manifest get size request has no payload*/
+struct gb_control_get_manifest_size_response {
+	__le16			size;
+};
+
+/* Control protocol manifest get request has no payload */
+struct gb_control_get_manifest_response {
+	__u8			data[0];
+};
+
+/* Control protocol [dis]connected request */
+struct gb_control_connected_request {
+	__le16			cport_id;
+};
+
+struct gb_control_disconnected_request {
+	__le16			cport_id;
+};
+/* Control protocol [dis]connected response has no payload */
+
 /* I2C */
 
 /* Version of the Greybus i2c protocol we support */

drivers/staging/greybus/interface.h

@@ -13,6 +13,7 @@
 /* Greybus "public" definitions" */
 struct gb_interface {
 	struct device dev;
+	struct gb_control *control;
 
 	struct list_head bundles;
 	struct list_head links;	/* greybus_host_device->interfaces */