[dpdk-dev] [PATCH 10/38] bus/dpaa: add routines for managing a RB tree

[Shreyansh Jain <shreyansh.jain@nxp.com>]

QMAN frames are managed over a RB tree data structure.
This patch introduces necessary routines for implementing a RB tree.

Signed-off-by: Geoff Thorpe <geoff.thorpe@nxp.com>
Signed-off-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
---
 drivers/bus/dpaa/include/dpaa_rbtree.h | 143 +++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100644 drivers/bus/dpaa/include/dpaa_rbtree.h

diff --git a/drivers/bus/dpaa/include/dpaa_rbtree.h b/drivers/bus/dpaa/include/dpaa_rbtree.h
new file mode 100644
index 0000000..fff2110
--- /dev/null
+++ b/drivers/bus/dpaa/include/dpaa_rbtree.h
@@ -0,0 +1,143 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright 2017 NXP. 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 NXP 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.
+ */
+
+#ifndef __DPAA_RBTREE_H
+#define __DPAA_RBTREE_H
+
+#include <rte_common.h>
+/************/
+/* RB-trees */
+/************/
+
+/* Linux has a good RB-tree implementation, that we can't use (GPL). It also has
+ * a flat/hooked-in interface that virtually requires license-contamination in
+ * order to write a caller-compatible implementation. Instead, I've created an
+ * RB-tree encapsulation on top of linux's primitives (it does some of the work
+ * the client logic would normally do), and this gives us something we can
+ * reimplement on LWE. Unfortunately there's no good+free RB-tree
+ * implementations out there that are license-compatible and "flat" (ie. no
+ * dynamic allocation). I did find a malloc-based one that I could convert, but
+ * that will be a task for later on. For now, LWE's RB-tree is implemented using
+ * an ordered linked-list.
+ *
+ * Note, the only linux-esque type is "struct rb_node", because it's used
+ * statically in the exported header, so it can't be opaque. Our version doesn't
+ * include a "rb_parent_color" field because we're doing linked-list instead of
+ * a true rb-tree.
+ */
+
+struct rb_node {
+	struct rb_node *prev, *next;
+};
+
+struct dpa_rbtree {
+	struct rb_node *head, *tail;
+};
+
+#define DPAA_RBTREE { NULL, NULL }
+static inline void dpa_rbtree_init(struct dpa_rbtree *tree)
+{
+	tree->head = tree->tail = NULL;
+}
+
+#define QMAN_NODE2OBJ(ptr, type, node_field) \
+	(type *)((char *)ptr - offsetof(type, node_field))
+
+#define IMPLEMENT_DPAA_RBTREE(name, type, node_field, val_field) \
+static inline int name##_push(struct dpa_rbtree *tree, type *obj) \
+{ \
+	struct rb_node *node = tree->head; \
+	if (!node) { \
+		tree->head = tree->tail = &obj->node_field; \
+		obj->node_field.prev = obj->node_field.next = NULL; \
+		return 0; \
+	} \
+	while (node) { \
+		type *item = QMAN_NODE2OBJ(node, type, node_field); \
+		if (obj->val_field == item->val_field) \
+			return -EBUSY; \
+		if (obj->val_field < item->val_field) { \
+			if (tree->head == node) \
+				tree->head = &obj->node_field; \
+			else \
+				node->prev->next = &obj->node_field; \
+			obj->node_field.prev = node->prev; \
+			obj->node_field.next = node; \
+			node->prev = &obj->node_field; \
+			return 0; \
+		} \
+		node = node->next; \
+	} \
+	obj->node_field.prev = tree->tail; \
+	obj->node_field.next = NULL; \
+	tree->tail->next = &obj->node_field; \
+	tree->tail = &obj->node_field; \
+	return 0; \
+} \
+static inline void name##_del(struct dpa_rbtree *tree, type *obj) \
+{ \
+	if (tree->head == &obj->node_field) { \
+		if (tree->tail == &obj->node_field) \
+			/* Only item in the list */ \
+			tree->head = tree->tail = NULL; \
+		else { \
+			/* Is the head, next != NULL */ \
+			tree->head = tree->head->next; \
+			tree->head->prev = NULL; \
+		} \
+	} else { \
+		if (tree->tail == &obj->node_field) { \
+			/* Is the tail, prev != NULL */ \
+			tree->tail = tree->tail->prev; \
+			tree->tail->next = NULL; \
+		} else { \
+			/* Is neither the head nor the tail */ \
+			obj->node_field.prev->next = obj->node_field.next; \
+			obj->node_field.next->prev = obj->node_field.prev; \
+		} \
+	} \
+} \
+static inline type *name##_find(struct dpa_rbtree *tree, u32 val) \
+{ \
+	struct rb_node *node = tree->head; \
+	while (node) { \
+		type *item = QMAN_NODE2OBJ(node, type, node_field); \
+		if (val == item->val_field) \
+			return item; \
+		if (val < item->val_field) \
+			return NULL; \
+		node = node->next; \
+	} \
+	return NULL; \
+}
+
+#endif /* __DPAA_RBTREE_H */
-- 
2.7.4