--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/master/coe_emerg_ring.c	Tue Nov 06 14:23:44 2012 +0100
@@ -0,0 +1,170 @@
+/******************************************************************************
+ *
+ *  $Id$
+ *
+ *  Copyright (C) 2012  Florian Pose, Ingenieurgemeinschaft IgH
+ *
+ *  This file is part of the IgH EtherCAT Master.
+ *
+ *  The IgH EtherCAT Master is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License version 2, as
+ *  published by the Free Software Foundation.
+ *
+ *  The IgH EtherCAT Master 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 the IgH EtherCAT Master; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *  ---
+ *
+ *  The license mentioned above concerns the source code only. Using the
+ *  EtherCAT technology and brand is only permitted in compliance with the
+ *  industrial property and similar rights of Beckhoff Automation GmbH.
+ *
+ *  vim: expandtab
+ *
+ *****************************************************************************/
+
+/**
+   \file
+   EtherCAT CoE emergency ring buffer methods.
+*/
+
+/*****************************************************************************/
+
+#include <linux/slab.h>
+
+#include "coe_emerg_ring.h"
+
+/*****************************************************************************/
+
+/** Emergency ring buffer constructor.
+ */
+void ec_coe_emerg_ring_init(
+        ec_coe_emerg_ring_t *ring, /**< Emergency ring. */
+        ec_slave_config_t *sc /**< Slave configuration. */
+        )
+{
+    ring->sc = sc;
+    ring->msgs = NULL;
+    ring->size = 0;
+    ring->read_index = 0;
+    ring->write_index = 0;
+    ring->overruns = 0;
+}
+
+/*****************************************************************************/
+
+/** Emergency ring buffer destructor.
+ */
+void ec_coe_emerg_ring_clear(
+        ec_coe_emerg_ring_t *ring /**< Emergency ring. */
+        )
+{
+    if (ring->msgs) {
+        kfree(ring->msgs);
+    }
+}
+
+/*****************************************************************************/
+
+/** Set the ring size.
+ */
+int ec_coe_emerg_ring_size(
+        ec_coe_emerg_ring_t *ring, /**< Emergency ring. */
+        size_t size /**< Maximum number of messages in the ring. */
+        )
+{
+    ring->size = 0;
+
+    if (size < 0) {
+        size = 0;
+    }
+
+    ring->read_index = ring->write_index = 0;
+
+    if (ring->msgs) {
+        kfree(ring->msgs);
+    }
+    ring->msgs = NULL;
+
+    if (size == 0) {
+        return 0;
+    }
+
+    ring->msgs = kmalloc(sizeof(ec_coe_emerg_msg_t) * (size + 1), GFP_KERNEL);
+    if (!ring->msgs) {
+        return -ENOMEM;
+    }
+
+    ring->size = size;
+    return 0;
+}
+
+/*****************************************************************************/
+
+/** Add a new emergency message.
+ */
+void ec_coe_emerg_ring_push(
+        ec_coe_emerg_ring_t *ring, /**< Emergency ring. */
+        const u8 *msg /**< Emergency message. */
+        )
+{
+    if (!ring->size ||
+            (ring->write_index + 1) % (ring->size + 1) == ring->read_index) {
+        ring->overruns++;
+        return;
+    }
+
+    memcpy(ring->msgs[ring->write_index].data, msg,
+            EC_COE_EMERGENCY_MSG_SIZE);
+    ring->write_index = (ring->write_index + 1) % (ring->size + 1);
+}
+
+/*****************************************************************************/
+
+/** Remove an emergency message from the ring.
+ */
+int ec_coe_emerg_ring_pop(
+        ec_coe_emerg_ring_t *ring, /**< Emergency ring. */
+        u8 *msg /**< Memory to store the emergency message. */
+        )
+{
+    if (ring->read_index == ring->write_index) {
+        return -ENOENT;
+    }
+
+    memcpy(msg, ring->msgs[ring->read_index].data, EC_COE_EMERGENCY_MSG_SIZE);
+    ring->read_index = (ring->read_index + 1) % (ring->size + 1);
+    return 0;
+}
+
+/*****************************************************************************/
+
+/** Clear the ring.
+ */
+int ec_coe_emerg_ring_clear_ring(
+        ec_coe_emerg_ring_t *ring /**< Emergency ring. */
+        )
+{
+    ring->read_index = ring->write_index;
+    ring->overruns = 0;
+    return 0;
+}
+
+/*****************************************************************************/
+
+/** Read the number of overruns.
+ */
+int ec_coe_emerg_ring_overruns(
+        ec_coe_emerg_ring_t *ring /**< Emergency ring. */
+        )
+{
+    return ring->overruns;
+}
+
+/*****************************************************************************/