ethercat: add stub for new ethercat node interface

include/villas/nodes/ethercat.h

@@ -0,0 +1,84 @@
+/** Node type: ethercat
+ *
+ * @file
+ * @author Niklas Eiling <niklas.eiling@eonerc.rwth-aachen.de>
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2018, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLASnode
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *********************************************************************************/
+
+/**
+ * @addtogroup ethercats WebSockets node type
+ * @ingroup node
+ * @{
+ */
+
+#pragma once
+
+#include <villas/node.h>
+#include <villas/pool.h>
+#include <villas/queue_signalled.h>
+#include <villas/common.h>
+#include <villas/io.h>
+#include <villas/config.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define DEFAULT_ETHERCAT_QUEUE_LENGTH	(DEFAULT_QUEUE_LENGTH * 64)
+#define DEFAULT_ETHERCAT_SAMPLE_LENGTH	DEFAULT_SAMPLE_LENGTH
+
+/* Forward declaration */
+struct lws;
+
+/** Internal data per ethercat node */
+struct ethercat {
+	struct pool pool;
+	struct queue_signalled queue;		/**< For samples which are received from WebSockets */
+};
+
+/* Internal datastructures */
+
+
+/** @see node_type::type_start */
+int ethercat_type_start(struct super_node *sn);
+
+/** @see node_type::type_stop */
+int ethercat_type_stop();
+
+/** @see node_type::open */
+int ethercat_start(struct node *n);
+
+/** @see node_type::close */
+int ethercat_stop(struct node *n);
+
+/** @see node_type::close */
+int ethercat_destroy(struct node *n);
+
+/** @see node_type::read */
+int ethercat_read(struct node *n, struct sample *smps[], unsigned cnt, unsigned *release);
+
+/** @see node_type::write */
+int ethercat_write(struct node *n, struct sample *smps[], unsigned cnt, unsigned *release);
+
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif

lib/nodes/CMakeLists.txt

@@ -161,6 +161,9 @@ if(WITH_NODE_EXAMPLE)
 #    list(APPEND LIBRARIES PkgConfig::EXAMPLELIB)
 endif()
 
+# Enable ethercat support
+# TODO
+
 add_library(nodes STATIC ${NODE_SRC})
 target_include_directories(nodes PUBLIC ${INCLUDE_DIRS})
 target_link_libraries(nodes INTERFACE ${LIBRARIES} PUBLIC villas-common)

lib/nodes/ethercat.c

@@ -0,0 +1,191 @@
+/** Node type: Ethercat
+ *
+ * @author Niklas Eiling <niklas.eiling@eonerc.rwth-aachen.de>
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2018, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLASnode
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *********************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <signal.h>
+
+#include <villas/super_node.h>
+#include <villas/timing.h>
+#include <villas/utils.h>
+#include <villas/buffer.h>
+#include <villas/plugin.h>
+#include <villas/nodes/ethercat.h>
+#include <villas/format_type.h>
+#include <villas/formats/msg_format.h>
+
+/* Private static storage */
+
+/* Forward declarations */
+static struct plugin p;
+
+
+int ethercat_type_start(struct super_node *sn)
+{
+    /* TODO: type start ethercat */
+
+	return 0;
+}
+
+int ethercat_start(struct node *n)
+{
+	int ret;
+	struct ethercat *w = (struct ethercat *) n->_vd;
+
+	ret = pool_init(&w->pool, DEFAULT_ETHERCAT_QUEUE_LENGTH, SAMPLE_LENGTH(DEFAULT_ETHERCAT_SAMPLE_LENGTH), &memory_hugepage);
+	if (ret)
+		return ret;
+
+	ret = queue_signalled_init(&w->queue, DEFAULT_ETHERCAT_QUEUE_LENGTH, &memory_hugepage, 0);
+	if (ret)
+		return ret;
+
+    /* TODO: start ethercat connection */
+
+	return 0;
+}
+
+int ethercat_stop(struct node *n)
+{
+	int ret;
+	struct ethercat *w = (struct ethercat *) n->_vd;
+
+    /* TODO: stop ethercat connection */
+
+	ret = queue_signalled_destroy(&w->queue);
+	if (ret)
+		return ret;
+
+	ret = pool_destroy(&w->pool);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+int ethercat_destroy(struct node *n)
+{
+	struct websocket *w = (struct websocket *) n->_vd;
+	int ret;
+
+    /* TODO: destroy ethercat connection */
+
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+int ethercat_read(struct node *n, struct sample *smps[], unsigned cnt, unsigned *release)
+{
+	int avail;
+
+	struct ethercat *w = (struct ethercat *) n->_vd;
+	struct sample *cpys[cnt];
+
+	avail = queue_signalled_pull_many(&w->queue, (void **) cpys, cnt);
+	if (avail < 0)
+		return avail;
+
+	sample_copy_many(smps, cpys, avail);
+	sample_decref_many(cpys, avail);
+
+	return avail;
+}
+
+int ethercat_write(struct node *n, struct sample *smps[], unsigned cnt, unsigned *release)
+{
+	int avail;
+
+	struct ethercat *w = (struct ethercat *) n->_vd;
+	struct sample *cpys[cnt];
+
+	/* Make copies of all samples */
+	avail = sample_alloc_many(&w->pool, cpys, cnt);
+	if (avail < cnt)
+		warn("Pool underrun for node %s: avail=%u", node_name(n), avail);
+
+	sample_copy_many(cpys, smps, avail);
+
+    /* TODO: write samples to ethercat driver */
+
+	sample_decref_many(cpys, avail);
+
+	return cnt;
+}
+
+int ethercat_parse(struct node *n, json_t *cfg)
+{
+	struct ethercat *w = (struct ethercat *) n->_vd;
+	int ret;
+
+	size_t i;
+	json_t *json_dests = NULL;
+	json_t *json_dest;
+	json_error_t err;
+
+    /* TODO: parse json */
+
+	return 0;
+}
+
+char * ethercat_print(struct node *n)
+{
+	struct ethercat *w = (struct ethercat *) n->_vd;
+
+	char *buf = NULL;
+    /* TODO: maybe use asprintf to build string? */
+
+	return buf;
+}
+
+int ethercat_fd(struct node *n)
+{
+	struct ethercat *w = (struct ethercat *) n->_vd;
+
+	return queue_signalled_fd(&w->queue);
+}
+
+static struct plugin p = {
+	.name		= "ethercat",
+	.description	= "Send and receive samples of an ethercat connection",
+	.type		= PLUGIN_TYPE_NODE,
+	.node		= {
+		.vectorize	= 0, /* unlimited */
+		.size		= sizeof(struct ethercat),
+		.type.start	= ethercat_type_start,
+		.start		= ethercat_start,
+		.stop		= ethercat_stop,
+		.destroy	= ethercat_destroy,
+		.read		= ethercat_read,
+		.write		= ethercat_write,
+		.print		= ethercat_print,
+		.parse		= ethercat_parse,
+		.fd		    = ethercat_fd
+	}
+};
+
+REGISTER_PLUGIN(&p)
+LIST_INIT_STATIC(&p.node.instances)