Move ACRN Device Model code in a devicemodel/ folder

This is part of the short series of commits that will lead
to a unified repository for the ACRN hypervisor, device model
and the associated documentation.

Signed-off-by: Geoffroy Van Cutsem <geoffroy.vancutsem@intel.com>

devicemodel/tools/acrntrace/sbuf.c

@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2018 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *   * Neither the name of Intel Corporation nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <asm/errno.h>
+#include <string.h>
+#include <stdbool.h>
+#include "sbuf.h"
+
+static inline bool sbuf_is_empty(shared_buf_t *sbuf)
+{
+	return (sbuf->head == sbuf->tail);
+}
+
+static inline uint32_t sbuf_next_ptr(uint32_t pos,
+		uint32_t span, uint32_t scope)
+{
+	pos += span;
+	pos = (pos >= scope) ? (pos - scope) : pos;
+	return pos;
+}
+
+int sbuf_get(shared_buf_t *sbuf, uint8_t *data)
+{
+	const void *from;
+
+	if ((sbuf == NULL) || (data == NULL))
+		return -EINVAL;
+
+	if (sbuf_is_empty(sbuf)) {
+		/* no data available */
+		return 0;
+	}
+
+	from = (void *)sbuf + SBUF_HEAD_SIZE + sbuf->head;
+
+	memcpy(data, from, sbuf->ele_size);
+
+	sbuf->head = sbuf_next_ptr(sbuf->head, sbuf->ele_size, sbuf->size);
+
+	return sbuf->ele_size;
+}
+
+int sbuf_clear_buffered(shared_buf_t *sbuf)
+{
+	if (sbuf == NULL)
+		return -EINVAL;
+
+	sbuf->head = sbuf->tail;
+
+	return 0;
+}