greybus: svc: Implement DME peer get/set attributes helpers

These are required to get/set DME attributes of the modules. This is
implemented based on the greybus specifications.
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/greybus_protocols.h

@@ -742,6 +742,8 @@ struct gb_spi_transfer_response {
 #define GB_SVC_TYPE_INTF_RESET		0x06
 #define GB_SVC_TYPE_CONN_CREATE		0x07
 #define GB_SVC_TYPE_CONN_DESTROY	0x08
+#define GB_SVC_TYPE_DME_PEER_GET	0x09
+#define GB_SVC_TYPE_DME_PEER_SET	0x0a
 #define GB_SVC_TYPE_ROUTE_CREATE	0x0b
 #define GB_SVC_TYPE_ROUTE_DESTROY	0x0c
 
@@ -799,6 +801,28 @@ struct gb_svc_conn_destroy_request {
 } __packed;
 /* connection destroy response has no payload */
 
+struct gb_svc_dme_peer_get_request {
+	__u8	intf_id;
+	__u16	attr;
+	__u16	selector;
+} __packed;
+
+struct gb_svc_dme_peer_get_response {
+	__u16	result_code;
+	__u32	attr_value;
+} __packed;
+
+struct gb_svc_dme_peer_set_request {
+	__u8	intf_id;
+	__u16	attr;
+	__u16	selector;
+	__u32	value;
+} __packed;
+
+struct gb_svc_dme_peer_set_response {
+	__u16	result_code;
+} __packed;
+
 struct gb_svc_route_create_request {
 	__u8	intf1_id;
 	__u8	dev1_id;

drivers/staging/greybus/svc.c

@@ -104,6 +104,78 @@ int gb_svc_intf_reset(struct gb_svc *svc, u8 intf_id)
 }
 EXPORT_SYMBOL_GPL(gb_svc_intf_reset);
 
+int gb_svc_dme_peer_get(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
+			u32 *value)
+{
+	struct gb_svc_dme_peer_get_request request;
+	struct gb_svc_dme_peer_get_response response;
+	u16 result;
+	int ret;
+
+	request.intf_id = intf_id;
+	request.attr = cpu_to_le16(attr);
+	request.selector = cpu_to_le16(selector);
+
+	ret = gb_operation_sync(svc->connection, GB_SVC_TYPE_DME_PEER_GET,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&svc->connection->dev,
+			"failed to get DME attribute (%hhu %hx %hu) %d\n",
+			intf_id, attr, selector, ret);
+		return ret;
+	}
+
+	result = le16_to_cpu(response.result_code);
+	if (result) {
+		dev_err(&svc->connection->dev,
+			"Unipro error %hu while getting DME attribute (%hhu %hx %hu)\n",
+			result, intf_id, attr, selector);
+		return -EINVAL;
+	}
+
+	if (value)
+		*value = le32_to_cpu(response.attr_value);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_svc_dme_peer_get);
+
+int gb_svc_dme_peer_set(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
+			u32 value)
+{
+	struct gb_svc_dme_peer_set_request request;
+	struct gb_svc_dme_peer_set_response response;
+	u16 result;
+	int ret;
+
+	request.intf_id = intf_id;
+	request.attr = cpu_to_le16(attr);
+	request.selector = cpu_to_le16(selector);
+	request.value = cpu_to_le32(value);
+
+	ret = gb_operation_sync(svc->connection, GB_SVC_TYPE_DME_PEER_SET,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&svc->connection->dev,
+			"failed to set DME attribute (%hhu %hx %hu %u) %d\n",
+			intf_id, attr, selector, value, ret);
+		return ret;
+	}
+
+	result = le16_to_cpu(response.result_code);
+	if (result) {
+		dev_err(&svc->connection->dev,
+			"Unipro error %hu while setting DME attribute (%hhu %hx %hu %u)\n",
+			result, intf_id, attr, selector, value);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_svc_dme_peer_set);
+
 int gb_svc_connection_create(struct gb_svc *svc,
 				u8 intf1_id, u16 cport1_id,
 				u8 intf2_id, u16 cport2_id)

drivers/staging/greybus/svc.h

@@ -17,6 +17,10 @@ int gb_svc_connection_create(struct gb_svc *svc, u8 intf1_id, u16 cport1_id,
 						u8 intf2_id, u16 cport2_id);
 void gb_svc_connection_destroy(struct gb_svc *svc, u8 intf1_id, u16 cport1_id,
 			       u8 intf2_id, u16 cport2_id);
+int gb_svc_dme_peer_get(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
+			u32 *value);
+int gb_svc_dme_peer_set(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
+			u32 value);
 
 int gb_svc_protocol_init(void);
 void gb_svc_protocol_exit(void);